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1 | <!-- |
2 | ||
3 | lxc: linux Container library | |
4 | ||
5 | (C) Copyright IBM Corp. 2007, 2008 | |
6 | ||
7 | Authors: | |
8 | Daniel Lezcano <daniel.lezcano at free.fr> | |
9 | ||
10 | This library is free software; you can redistribute it and/or | |
11 | modify it under the terms of the GNU Lesser General Public | |
12 | License as published by the Free Software Foundation; either | |
13 | version 2.1 of the License, or (at your option) any later version. | |
14 | ||
15 | This library is distributed in the hope that it will be useful, | |
16 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
18 | Lesser General Public License for more details. | |
19 | ||
20 | You should have received a copy of the GNU Lesser General Public | |
21 | License along with this library; if not, write to the Free Software | |
22 | Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
23 | ||
24 | --> | |
25 | ||
26 | <!DOCTYPE refentry PUBLIC @docdtd@ [ | |
27 | ||
28 | <!ENTITY seealso SYSTEM "@builddir@/see_also.sgml"> | |
29 | ]> | |
30 | ||
31 | <refentry> | |
32 | ||
33 | <docinfo><date>@LXC_GENERATE_DATE@</date></docinfo> | |
34 | ||
35 | <refmeta> | |
36 | <refentrytitle>lxc.container.conf</refentrytitle> | |
37 | <manvolnum>5</manvolnum> | |
38 | </refmeta> | |
39 | ||
40 | <refnamediv> | |
41 | <refname>lxc.container.conf</refname> | |
42 | ||
43 | <refpurpose> | |
44 | LXC container configuration file | |
45 | </refpurpose> | |
46 | </refnamediv> | |
47 | ||
48 | <refsect1> | |
49 | <title>Description</title> | |
50 | ||
51 | <para> | |
b9986e43 CB |
52 | LXC is the well-known and heavily tested low-level Linux container |
53 | runtime. It is in active development since 2008 and has proven itself in | |
54 | critical production environments world-wide. Some of its core contributors | |
55 | are the same people that helped to implement various well-known | |
56 | containerization features inside the Linux kernel. | |
55fc19a1 SG |
57 | </para> |
58 | ||
59 | <para> | |
b9986e43 CB |
60 | LXC's main focus is system containers. That is, containers which offer an |
61 | environment as close as possible as the one you'd get from a VM but | |
62 | without the overhead that comes with running a separate kernel and | |
63 | simulating all the hardware. | |
55fc19a1 SG |
64 | </para> |
65 | ||
66 | <para> | |
b9986e43 CB |
67 | This is achieved through a combination of kernel security features such as |
68 | namespaces, mandatory access control and control groups. | |
69 | </para> | |
70 | ||
71 | <para> | |
72 | LXC has supports unprivileged containers. Unprivileged containers are | |
73 | containers that are run without any privilege. This requires support for | |
74 | user namespaces in the kernel that the container is run on. LXC was the | |
75 | first runtime to support unprivileged containers after user namespaces | |
76 | were merged into the mainline kernel. | |
77 | </para> | |
78 | ||
79 | <para> | |
80 | In essence, user namespaces isolate given sets of UIDs and GIDs. This is | |
81 | achieved by establishing a mapping between a range of UIDs and GIDs on the | |
82 | host to a different (unprivileged) range of UIDs and GIDs in the | |
83 | container. The kernel will translate this mapping in such a way that | |
84 | inside the container all UIDs and GIDs appear as you would expect from the | |
85 | host whereas on the host these UIDs and GIDs are in fact unprivileged. For | |
86 | example, a process running as UID and GID 0 inside the container might | |
87 | appear as UID and GID 100000 on the host. The implementation and working | |
88 | details can be gathered from the corresponding user namespace man page. | |
89 | UID and GID mappings can be defined with the <option>lxc.id_map</option> | |
90 | key. | |
91 | </para> | |
92 | ||
93 | <para> | |
94 | Linux containers are defined with a simple configuration file. Each | |
95 | option in the configuration file has the form <command>key = | |
96 | value</command> fitting in one line. The "#" character means the line is a | |
97 | comment. List options, like capabilities and cgroups options, can be used | |
98 | with no value to clear any previously defined values of that option. | |
99 | </para> | |
100 | ||
101 | <para> | |
102 | LXC namespaces configuration keys by using single dots. This means complex | |
7fa3f2e9 | 103 | configuration keys such as <option>lxc.net.0</option> expose various |
104 | subkeys such as <option>lxc.net.0.type</option>, | |
105 | <option>lxc.net.0.link</option>, <option>lxc.net.0.ipv6</option>, and | |
b9986e43 | 106 | others for even more fine-grained configuration. |
55fc19a1 SG |
107 | </para> |
108 | ||
109 | <refsect2> | |
110 | <title>Configuration</title> | |
111 | <para> | |
b9986e43 CB |
112 | In order to ease administration of multiple related containers, it is |
113 | possible to have a container configuration file cause another file to be | |
114 | loaded. For instance, network configuration can be defined in one common | |
115 | file which is included by multiple containers. Then, if the containers | |
116 | are moved to another host, only one file may need to be updated. | |
55fc19a1 SG |
117 | </para> |
118 | ||
119 | <variablelist> | |
c464fd7e SG |
120 | <varlistentry> |
121 | <term> | |
122 | <option>lxc.include</option> | |
123 | </term> | |
124 | <listitem> | |
125 | <para> | |
126 | Specify the file to be included. The included file must be | |
127 | in the same valid lxc configuration file format. | |
128 | </para> | |
129 | </listitem> | |
130 | </varlistentry> | |
55fc19a1 SG |
131 | </variablelist> |
132 | </refsect2> | |
133 | ||
134 | <refsect2> | |
135 | <title>Architecture</title> | |
136 | <para> | |
b9986e43 CB |
137 | Allows one to set the architecture for the container. For example, set a |
138 | 32bits architecture for a container running 32bits binaries on a 64bits | |
139 | host. This fixes the container scripts which rely on the architecture to | |
140 | do some work like downloading the packages. | |
55fc19a1 SG |
141 | </para> |
142 | ||
143 | <variablelist> | |
c464fd7e SG |
144 | <varlistentry> |
145 | <term> | |
146 | <option>lxc.arch</option> | |
147 | </term> | |
148 | <listitem> | |
149 | <para> | |
150 | Specify the architecture for the container. | |
151 | </para> | |
152 | <para> | |
b9986e43 | 153 | Some valid options are |
c464fd7e SG |
154 | <option>x86</option>, |
155 | <option>i686</option>, | |
156 | <option>x86_64</option>, | |
157 | <option>amd64</option> | |
158 | </para> | |
159 | </listitem> | |
160 | </varlistentry> | |
55fc19a1 SG |
161 | </variablelist> |
162 | ||
163 | </refsect2> | |
164 | ||
165 | <refsect2> | |
166 | <title>Hostname</title> | |
167 | <para> | |
b9986e43 CB |
168 | The utsname section defines the hostname to be set for the container. |
169 | That means the container can set its own hostname without changing the | |
170 | one from the system. That makes the hostname private for the container. | |
55fc19a1 SG |
171 | </para> |
172 | <variablelist> | |
c464fd7e SG |
173 | <varlistentry> |
174 | <term> | |
175 | <option>lxc.utsname</option> | |
176 | </term> | |
177 | <listitem> | |
178 | <para> | |
179 | specify the hostname for the container | |
180 | </para> | |
181 | </listitem> | |
182 | </varlistentry> | |
55fc19a1 SG |
183 | </variablelist> |
184 | </refsect2> | |
185 | ||
186 | <refsect2> | |
187 | <title>Halt signal</title> | |
188 | <para> | |
b9986e43 CB |
189 | Allows one to specify signal name or number sent to the container's |
190 | init process to cleanly shutdown the container. Different init systems | |
191 | could use different signals to perform clean shutdown sequence. This | |
192 | option allows the signal to be specified in kill(1) fashion, e.g. | |
193 | SIGPWR, SIGRTMIN+14, SIGRTMAX-10 or plain number. The default signal is | |
194 | SIGPWR. | |
55fc19a1 SG |
195 | </para> |
196 | <variablelist> | |
936762f3 BP |
197 | <varlistentry> |
198 | <term> | |
199 | <option>lxc.haltsignal</option> | |
200 | </term> | |
201 | <listitem> | |
202 | <para> | |
203 | specify the signal used to halt the container | |
204 | </para> | |
205 | </listitem> | |
206 | </varlistentry> | |
207 | </variablelist> | |
208 | </refsect2> | |
209 | ||
210 | <refsect2> | |
211 | <title>Reboot signal</title> | |
212 | <para> | |
b9986e43 CB |
213 | Allows one to specify signal name or number to reboot the container. |
214 | This option allows signal to be specified in kill(1) fashion, e.g. | |
215 | SIGTERM, SIGRTMIN+14, SIGRTMAX-10 or plain number. The default signal | |
216 | is SIGINT. | |
936762f3 BP |
217 | </para> |
218 | <variablelist> | |
219 | <varlistentry> | |
220 | <term> | |
221 | <option>lxc.rebootsignal</option> | |
222 | </term> | |
223 | <listitem> | |
224 | <para> | |
225 | specify the signal used to reboot the container | |
226 | </para> | |
227 | </listitem> | |
228 | </varlistentry> | |
55fc19a1 SG |
229 | </variablelist> |
230 | </refsect2> | |
231 | ||
232 | <refsect2> | |
233 | <title>Stop signal</title> | |
234 | <para> | |
b9986e43 CB |
235 | Allows one to specify signal name or number to forcibly shutdown the |
236 | container. This option allows signal to be specified in kill(1) fashion, | |
237 | e.g. SIGKILL, SIGRTMIN+14, SIGRTMAX-10 or plain number. The default | |
238 | signal is SIGKILL. | |
936762f3 BP |
239 | </para> |
240 | <variablelist> | |
241 | <varlistentry> | |
242 | <term> | |
243 | <option>lxc.stopsignal</option> | |
244 | </term> | |
245 | <listitem> | |
246 | <para> | |
247 | specify the signal used to stop the container | |
248 | </para> | |
249 | </listitem> | |
250 | </varlistentry> | |
55fc19a1 SG |
251 | </variablelist> |
252 | </refsect2> | |
253 | ||
67c660d0 SG |
254 | <refsect2> |
255 | <title>Init command</title> | |
256 | <para> | |
257 | Sets the command to use as the init system for the containers. | |
258 | ||
259 | This option is ignored when using lxc-execute. | |
260 | ||
261 | Defaults to: /sbin/init | |
262 | </para> | |
263 | <variablelist> | |
936762f3 BP |
264 | <varlistentry> |
265 | <term> | |
266 | <option>lxc.init_cmd</option> | |
267 | </term> | |
268 | <listitem> | |
269 | <para> | |
270 | Absolute path from container rootfs to the binary to use as init. | |
271 | </para> | |
272 | </listitem> | |
273 | </varlistentry> | |
67c660d0 SG |
274 | </variablelist> |
275 | </refsect2> | |
276 | ||
dbca9237 PT |
277 | <refsect2> |
278 | <title>Init ID</title> | |
279 | <para> | |
b9986e43 CB |
280 | Sets the UID/GID to use for the init system, and subsequent commands. |
281 | Note that using a non-root uid when booting a system container will | |
282 | likely not work due to missing privileges. Setting the UID/GID is mostly | |
283 | useful when running application container. | |
dbca9237 PT |
284 | |
285 | Defaults to: UID(0), GID(0) | |
286 | </para> | |
287 | <variablelist> | |
288 | <varlistentry> | |
289 | <term> | |
290 | <option>lxc.init_uid</option> | |
291 | </term> | |
292 | <listitem> | |
293 | <para> | |
b9986e43 | 294 | UID to use for init. |
dbca9237 PT |
295 | </para> |
296 | </listitem> | |
297 | </varlistentry> | |
298 | <varlistentry> | |
299 | <term> | |
300 | <option>lxc.init_gid</option> | |
301 | </term> | |
302 | <listitem> | |
303 | <para> | |
b9986e43 | 304 | GID to use for init. |
dbca9237 PT |
305 | </para> |
306 | </listitem> | |
307 | </varlistentry> | |
308 | </variablelist> | |
309 | </refsect2> | |
310 | ||
4e6eb26b CB |
311 | <refsect2> |
312 | <title>Ephemeral</title> | |
313 | <para> | |
314 | Allows one to specify whether a container will be destroyed on shutdown. | |
315 | </para> | |
316 | <variablelist> | |
317 | <varlistentry> | |
318 | <term> | |
319 | <option>lxc.ephemeral</option> | |
320 | </term> | |
321 | <listitem> | |
322 | <para> | |
323 | The only allowed values are 0 and 1. Set this to 1 to destroy a | |
324 | container on shutdown. | |
325 | </para> | |
326 | </listitem> | |
327 | </varlistentry> | |
328 | </variablelist> | |
329 | </refsect2> | |
330 | ||
55fc19a1 SG |
331 | <refsect2> |
332 | <title>Network</title> | |
333 | <para> | |
c464fd7e SG |
334 | The network section defines how the network is virtualized in |
335 | the container. The network virtualization acts at layer | |
336 | two. In order to use the network virtualization, parameters | |
337 | must be specified to define the network interfaces of the | |
338 | container. Several virtual interfaces can be assigned and used | |
339 | in a container even if the system has only one physical | |
340 | network interface. | |
55fc19a1 SG |
341 | </para> |
342 | <variablelist> | |
020104c3 MH |
343 | <varlistentry> |
344 | <term> | |
7fa3f2e9 | 345 | <option>lxc.net</option> |
020104c3 MH |
346 | </term> |
347 | <listitem> | |
348 | <para> | |
349 | may be used without a value to clear all previous network options. | |
350 | </para> | |
351 | </listitem> | |
352 | </varlistentry> | |
c464fd7e SG |
353 | <varlistentry> |
354 | <term> | |
7fa3f2e9 | 355 | <option>lxc.net.[i].type</option> |
c464fd7e SG |
356 | </term> |
357 | <listitem> | |
358 | <para> | |
359 | specify what kind of network virtualization to be used | |
b9986e43 CB |
360 | for the container. |
361 | Multiple networks can be specified by using an additional index | |
362 | <option>i</option> | |
7fa3f2e9 | 363 | after all <option>lxc.net.*</option> keys. For example, |
364 | <option>lxc.net.0.type = veth</option> and | |
365 | <option>lxc.net.1.type = veth</option> specify two different | |
b9986e43 CB |
366 | networks of the same type. All keys sharing the same index |
367 | <option>i</option> will be treated as belonging to the same | |
7fa3f2e9 | 368 | network. For example, <option>lxc.net.0.link = br0</option> |
369 | will belong to <option>lxc.net.0.type</option>. | |
b9986e43 | 370 | Currently, the different virtualization types can be: |
c464fd7e SG |
371 | </para> |
372 | ||
373 | <para> | |
374 | <option>none:</option> will cause the container to share | |
375 | the host's network namespace. This means the host | |
376 | network devices are usable in the container. It also | |
377 | means that if both the container and host have upstart as | |
378 | init, 'halt' in a container (for instance) will shut down the | |
379 | host. | |
380 | </para> | |
381 | ||
382 | <para> | |
383 | <option>empty:</option> will create only the loopback | |
384 | interface. | |
385 | </para> | |
386 | ||
387 | <para> | |
38005c54 MA |
388 | <option>veth:</option> a virtual ethernet pair |
389 | device is created with one side assigned to the container | |
390 | and the other side attached to a bridge specified by | |
7fa3f2e9 | 391 | the <option>lxc.net.[i].link</option> option. |
38005c54 MA |
392 | If the bridge is not specified, then the veth pair device |
393 | will be created but not attached to any bridge. | |
394 | Otherwise, the bridge has to be created on the system | |
395 | before starting the container. | |
396 | <command>lxc</command> won't handle any | |
397 | configuration outside of the container. | |
398 | By default, <command>lxc</command> chooses a name for the | |
c464fd7e | 399 | network device belonging to the outside of the |
38005c54 MA |
400 | container, but if you wish to handle |
401 | this name yourselves, you can tell <command>lxc</command> | |
c464fd7e | 402 | to set a specific name with |
7fa3f2e9 | 403 | the <option>lxc.net.[i].veth.pair</option> option (except for |
c464fd7e SG |
404 | unprivileged containers where this option is ignored for security |
405 | reasons). | |
406 | </para> | |
407 | ||
408 | <para> | |
409 | <option>vlan:</option> a vlan interface is linked with | |
410 | the interface specified by | |
7fa3f2e9 | 411 | the <option>lxc.net.[i].link</option> and assigned to |
c464fd7e | 412 | the container. The vlan identifier is specified with the |
7fa3f2e9 | 413 | option <option>lxc.net.[i].vlan.id</option>. |
c464fd7e SG |
414 | </para> |
415 | ||
416 | <para> | |
417 | <option>macvlan:</option> a macvlan interface is linked | |
418 | with the interface specified by | |
7fa3f2e9 | 419 | the <option>lxc.net.[i].link</option> and assigned to |
c464fd7e | 420 | the container. |
7fa3f2e9 | 421 | <option>lxc.net.[i].macvlan.mode</option> specifies the |
c464fd7e SG |
422 | mode the macvlan will use to communicate between |
423 | different macvlan on the same upper device. The accepted | |
c15ea607 EL |
424 | modes are <option>private</option>, <option>vepa</option>, |
425 | <option>bridge</option> and <option>passthru</option>. | |
426 | In <option>private</option> mode, the device never | |
427 | communicates with any other device on the same upper_dev (default). | |
428 | In <option>vepa</option> mode, the new Virtual Ethernet Port | |
c464fd7e SG |
429 | Aggregator (VEPA) mode, it assumes that the adjacent |
430 | bridge returns all frames where both source and | |
431 | destination are local to the macvlan port, i.e. the | |
432 | bridge is set up as a reflective relay. Broadcast | |
433 | frames coming in from the upper_dev get flooded to all | |
434 | macvlan interfaces in VEPA mode, local frames are not | |
c15ea607 | 435 | delivered locally. In <option>bridge</option> mode, it |
c464fd7e SG |
436 | provides the behavior of a simple bridge between |
437 | different macvlan interfaces on the same port. Frames | |
438 | from one interface to another one get delivered directly | |
439 | and are not sent out externally. Broadcast frames get | |
440 | flooded to all other bridge ports and to the external | |
441 | interface, but when they come back from a reflective | |
442 | relay, we don't deliver them again. Since we know all | |
443 | the MAC addresses, the macvlan bridge mode does not | |
c15ea607 EL |
444 | require learning or STP like the bridge module does. In |
445 | <option>passthru</option> mode, all frames received by | |
446 | the physical interface are forwarded to the macvlan | |
447 | interface. Only one macvlan interface in <option>passthru</option> | |
448 | mode is possible for one physical interface. | |
c464fd7e SG |
449 | </para> |
450 | ||
451 | <para> | |
452 | <option>phys:</option> an already existing interface | |
7fa3f2e9 | 453 | specified by the <option>lxc.net.[i].link</option> is |
c464fd7e SG |
454 | assigned to the container. |
455 | </para> | |
456 | </listitem> | |
457 | </varlistentry> | |
458 | ||
459 | <varlistentry> | |
460 | <term> | |
7fa3f2e9 | 461 | <option>lxc.net.[i].flags</option> |
c464fd7e SG |
462 | </term> |
463 | <listitem> | |
464 | <para> | |
b9986e43 | 465 | Specify an action to do for the network. |
c464fd7e SG |
466 | </para> |
467 | ||
468 | <para><option>up:</option> activates the interface. | |
469 | </para> | |
470 | </listitem> | |
471 | </varlistentry> | |
472 | ||
473 | <varlistentry> | |
474 | <term> | |
7fa3f2e9 | 475 | <option>lxc.net.[i].link</option> |
c464fd7e SG |
476 | </term> |
477 | <listitem> | |
478 | <para> | |
b9986e43 CB |
479 | Specify the interface to be used for real network traffic. |
480 | </para> | |
c464fd7e SG |
481 | </listitem> |
482 | </varlistentry> | |
483 | ||
484 | <varlistentry> | |
485 | <term> | |
7fa3f2e9 | 486 | <option>lxc.net.[i].mtu</option> |
c464fd7e SG |
487 | </term> |
488 | <listitem> | |
489 | <para> | |
b9986e43 | 490 | Specify the maximum transfer unit for this interface. |
c464fd7e SG |
491 | </para> |
492 | </listitem> | |
493 | </varlistentry> | |
494 | ||
495 | <varlistentry> | |
496 | <term> | |
7fa3f2e9 | 497 | <option>lxc.net.[i].name</option> |
c464fd7e SG |
498 | </term> |
499 | <listitem> | |
500 | <para> | |
b9986e43 CB |
501 | The interface name is dynamically allocated, but if another name |
502 | is needed because the configuration files being used by the | |
503 | container use a generic name, eg. eth0, this option will rename | |
504 | the interface in the container. | |
c464fd7e SG |
505 | </para> |
506 | </listitem> | |
507 | </varlistentry> | |
508 | ||
509 | <varlistentry> | |
510 | <term> | |
7fa3f2e9 | 511 | <option>lxc.net.[i].hwaddr</option> |
c464fd7e SG |
512 | </term> |
513 | <listitem> | |
514 | <para> | |
b9986e43 CB |
515 | The interface mac address is dynamically allocated by default to |
516 | the virtual interface, but in some cases, this is needed to | |
517 | resolve a mac address conflict or to always have the same | |
518 | link-local ipv6 address. Any "x" in address will be replaced by | |
519 | random value, this allows setting hwaddr templates. | |
c464fd7e SG |
520 | </para> |
521 | </listitem> | |
522 | </varlistentry> | |
523 | ||
524 | <varlistentry> | |
525 | <term> | |
7fa3f2e9 | 526 | <option>lxc.net.[i].ipv4</option> |
c464fd7e SG |
527 | </term> |
528 | <listitem> | |
529 | <para> | |
b9986e43 CB |
530 | Specify the ipv4 address to assign to the virtualized interface. |
531 | Several lines specify several ipv4 addresses. The address is in | |
532 | format x.y.z.t/m, eg. 192.168.1.123/24. | |
c464fd7e SG |
533 | </para> |
534 | </listitem> | |
535 | </varlistentry> | |
536 | ||
537 | <varlistentry> | |
538 | <term> | |
7fa3f2e9 | 539 | <option>lxc.net.[i].ipv4.gateway</option> |
c464fd7e SG |
540 | </term> |
541 | <listitem> | |
542 | <para> | |
b9986e43 CB |
543 | Specify the ipv4 address to use as the gateway inside the |
544 | container. The address is in format x.y.z.t, eg. 192.168.1.123. | |
c464fd7e SG |
545 | |
546 | Can also have the special value <option>auto</option>, | |
547 | which means to take the primary address from the bridge | |
548 | interface (as specified by the | |
7fa3f2e9 | 549 | <option>lxc.net.[i].link</option> option) and use that as |
c464fd7e SG |
550 | the gateway. <option>auto</option> is only available when |
551 | using the <option>veth</option> and | |
552 | <option>macvlan</option> network types. | |
553 | </para> | |
554 | </listitem> | |
555 | </varlistentry> | |
556 | ||
557 | ||
558 | <varlistentry> | |
559 | <term> | |
7fa3f2e9 | 560 | <option>lxc.net.[i].ipv6</option> |
c464fd7e SG |
561 | </term> |
562 | <listitem> | |
563 | <para> | |
b9986e43 CB |
564 | Specify the ipv6 address to assign to the virtualized |
565 | interface. Several lines specify several ipv6 addresses. The | |
566 | address is in format x::y/m, eg. | |
567 | 2003:db8:1:0:214:1234:fe0b:3596/64 | |
c464fd7e SG |
568 | </para> |
569 | </listitem> | |
570 | </varlistentry> | |
571 | ||
572 | <varlistentry> | |
573 | <term> | |
7fa3f2e9 | 574 | <option>lxc.net.[i].ipv6.gateway</option> |
c464fd7e SG |
575 | </term> |
576 | <listitem> | |
577 | <para> | |
b9986e43 CB |
578 | Specify the ipv6 address to use as the gateway inside the |
579 | container. The address is in format x::y, eg. 2003:db8:1:0::1 | |
c464fd7e SG |
580 | |
581 | Can also have the special value <option>auto</option>, | |
582 | which means to take the primary address from the bridge | |
583 | interface (as specified by the | |
7fa3f2e9 | 584 | <option>lxc.net.[i].link</option> option) and use that as |
c464fd7e SG |
585 | the gateway. <option>auto</option> is only available when |
586 | using the <option>veth</option> and | |
587 | <option>macvlan</option> network types. | |
588 | </para> | |
589 | </listitem> | |
590 | </varlistentry> | |
591 | ||
592 | <varlistentry> | |
593 | <term> | |
7fa3f2e9 | 594 | <option>lxc.net.[i].script.up</option> |
c464fd7e SG |
595 | </term> |
596 | <listitem> | |
597 | <para> | |
b9986e43 | 598 | Add a configuration option to specify a script to be |
c464fd7e SG |
599 | executed after creating and configuring the network used |
600 | from the host side. The following arguments are passed | |
601 | to the script: container name and config section name | |
602 | (net) Additional arguments depend on the config section | |
603 | employing a script hook; the following are used by the | |
604 | network system: execution context (up), network type | |
605 | (empty/veth/macvlan/phys), Depending on the network | |
606 | type, other arguments may be passed: | |
607 | veth/macvlan/phys. And finally (host-sided) device name. | |
608 | </para> | |
609 | <para> | |
610 | Standard output from the script is logged at debug level. | |
611 | Standard error is not logged, but can be captured by the | |
612 | hook redirecting its standard error to standard output. | |
613 | </para> | |
614 | </listitem> | |
615 | </varlistentry> | |
616 | ||
617 | <varlistentry> | |
618 | <term> | |
7fa3f2e9 | 619 | <option>lxc.net.[i].script.down</option> |
c464fd7e SG |
620 | </term> |
621 | <listitem> | |
622 | <para> | |
b9986e43 | 623 | Add a configuration option to specify a script to be |
c464fd7e SG |
624 | executed before destroying the network used from the |
625 | host side. The following arguments are passed to the | |
626 | script: container name and config section name (net) | |
627 | Additional arguments depend on the config section | |
628 | employing a script hook; the following are used by the | |
629 | network system: execution context (down), network type | |
630 | (empty/veth/macvlan/phys), Depending on the network | |
631 | type, other arguments may be passed: | |
632 | veth/macvlan/phys. And finally (host-sided) device name. | |
633 | </para> | |
634 | <para> | |
635 | Standard output from the script is logged at debug level. | |
636 | Standard error is not logged, but can be captured by the | |
637 | hook redirecting its standard error to standard output. | |
638 | </para> | |
639 | </listitem> | |
640 | </varlistentry> | |
55fc19a1 SG |
641 | </variablelist> |
642 | </refsect2> | |
643 | ||
644 | <refsect2> | |
645 | <title>New pseudo tty instance (devpts)</title> | |
646 | <para> | |
c464fd7e SG |
647 | For stricter isolation the container can have its own private |
648 | instance of the pseudo tty. | |
55fc19a1 SG |
649 | </para> |
650 | <variablelist> | |
c464fd7e SG |
651 | <varlistentry> |
652 | <term> | |
653 | <option>lxc.pts</option> | |
654 | </term> | |
655 | <listitem> | |
656 | <para> | |
657 | If set, the container will have a new pseudo tty | |
658 | instance, making this private to it. The value specifies | |
55fc19a1 SG |
659 | the maximum number of pseudo ttys allowed for a pts |
660 | instance (this limitation is not implemented yet). | |
c464fd7e SG |
661 | </para> |
662 | </listitem> | |
663 | </varlistentry> | |
55fc19a1 SG |
664 | </variablelist> |
665 | </refsect2> | |
666 | ||
667 | <refsect2> | |
668 | <title>Container system console</title> | |
669 | <para> | |
c464fd7e SG |
670 | If the container is configured with a root filesystem and the |
671 | inittab file is setup to use the console, you may want to specify | |
672 | where the output of this console goes. | |
55fc19a1 SG |
673 | </para> |
674 | <variablelist> | |
c464fd7e SG |
675 | <varlistentry> |
676 | <term> | |
677 | <option>lxc.console.logfile</option> | |
678 | </term> | |
679 | <listitem> | |
680 | <para> | |
681 | Specify a path to a file where the console output will | |
682 | be written. | |
683 | </para> | |
684 | </listitem> | |
685 | </varlistentry> | |
686 | <varlistentry> | |
687 | <term> | |
688 | <option>lxc.console</option> | |
689 | </term> | |
690 | <listitem> | |
691 | <para> | |
692 | Specify a path to a device to which the console will be | |
6e3bb289 CB |
693 | attached. The keyword 'none' will simply disable the |
694 | console. Note, when specifying 'none' and creating a device node | |
695 | for the console in the container at /dev/console or bind-mounting | |
696 | the hosts's /dev/console into the container at /dev/console the | |
697 | container will have direct access to the hosts's /dev/console. | |
698 | This is dangerous when the container has write access to the | |
699 | device and should thus be used with caution. | |
c464fd7e SG |
700 | </para> |
701 | </listitem> | |
702 | </varlistentry> | |
55fc19a1 SG |
703 | </variablelist> |
704 | </refsect2> | |
705 | ||
706 | <refsect2> | |
707 | <title>Console through the ttys</title> | |
708 | <para> | |
c464fd7e SG |
709 | This option is useful if the container is configured with a root |
710 | filesystem and the inittab file is setup to launch a getty on the | |
711 | ttys. The option specifies the number of ttys to be available for | |
712 | the container. The number of gettys in the inittab file of the | |
713 | container should not be greater than the number of ttys specified | |
714 | in this option, otherwise the excess getty sessions will die and | |
715 | respawn indefinitely giving annoying messages on the console or in | |
716 | <filename>/var/log/messages</filename>. | |
55fc19a1 SG |
717 | </para> |
718 | <variablelist> | |
c464fd7e SG |
719 | <varlistentry> |
720 | <term> | |
721 | <option>lxc.tty</option> | |
722 | </term> | |
723 | <listitem> | |
724 | <para> | |
725 | Specify the number of tty to make available to the | |
726 | container. | |
727 | </para> | |
728 | </listitem> | |
729 | </varlistentry> | |
55fc19a1 SG |
730 | </variablelist> |
731 | </refsect2> | |
732 | ||
733 | <refsect2> | |
734 | <title>Console devices location</title> | |
735 | <para> | |
736 | LXC consoles are provided through Unix98 PTYs created on the | |
c464fd7e SG |
737 | host and bind-mounted over the expected devices in the container. |
738 | By default, they are bind-mounted over <filename>/dev/console</filename> | |
739 | and <filename>/dev/ttyN</filename>. This can prevent package upgrades | |
740 | in the guest. Therefore you can specify a directory location (under | |
741 | <filename>/dev</filename> under which LXC will create the files and | |
742 | bind-mount over them. These will then be symbolically linked to | |
743 | <filename>/dev/console</filename> and <filename>/dev/ttyN</filename>. | |
744 | A package upgrade can then succeed as it is able to remove and replace | |
745 | the symbolic links. | |
55fc19a1 SG |
746 | </para> |
747 | <variablelist> | |
c464fd7e SG |
748 | <varlistentry> |
749 | <term> | |
750 | <option>lxc.devttydir</option> | |
751 | </term> | |
752 | <listitem> | |
753 | <para> | |
754 | Specify a directory under <filename>/dev</filename> | |
6e3bb289 CB |
755 | under which to create the container console devices. Note that LXC |
756 | will move any bind-mounts or device nodes for /dev/console into | |
757 | this directory. | |
c464fd7e SG |
758 | </para> |
759 | </listitem> | |
760 | </varlistentry> | |
55fc19a1 SG |
761 | </variablelist> |
762 | </refsect2> | |
763 | ||
764 | <refsect2> | |
765 | <title>/dev directory</title> | |
766 | <para> | |
c464fd7e SG |
767 | By default, lxc creates a few symbolic links (fd,stdin,stdout,stderr) |
768 | in the container's <filename>/dev</filename> directory but does not | |
769 | automatically create device node entries. This allows the container's | |
770 | <filename>/dev</filename> to be set up as needed in the container | |
771 | rootfs. If lxc.autodev is set to 1, then after mounting the container's | |
772 | rootfs LXC will mount a fresh tmpfs under <filename>/dev</filename> | |
c35d2909 | 773 | (limited to 500k) and fill in a minimal set of initial devices. |
55fc19a1 SG |
774 | This is generally required when starting a container containing |
775 | a "systemd" based "init" but may be optional at other times. Additional | |
776 | devices in the containers /dev directory may be created through the | |
777 | use of the <option>lxc.hook.autodev</option> hook. | |
778 | </para> | |
779 | <variablelist> | |
c464fd7e SG |
780 | <varlistentry> |
781 | <term> | |
782 | <option>lxc.autodev</option> | |
783 | </term> | |
784 | <listitem> | |
785 | <para> | |
124fa0a8 | 786 | Set this to 0 to stop LXC from mounting and populating a minimal |
c464fd7e SG |
787 | <filename>/dev</filename> when starting the container. |
788 | </para> | |
789 | </listitem> | |
790 | </varlistentry> | |
55fc19a1 | 791 | </variablelist> |
55fc19a1 SG |
792 | </refsect2> |
793 | ||
794 | <refsect2> | |
795 | <title>Mount points</title> | |
796 | <para> | |
c464fd7e SG |
797 | The mount points section specifies the different places to be |
798 | mounted. These mount points will be private to the container | |
799 | and won't be visible by the processes running outside of the | |
800 | container. This is useful to mount /etc, /var or /home for | |
801 | examples. | |
55fc19a1 | 802 | </para> |
592fd47a SH |
803 | <para> |
804 | NOTE - LXC will generally ensure that mount targets and relative | |
805 | bind-mount sources are properly confined under the container | |
806 | root, to avoid attacks involving over-mounting host directories | |
807 | and files. (Symbolic links in absolute mount sources are ignored) | |
808 | However, if the container configuration first mounts a directory which | |
809 | is under the control of the container user, such as /home/joe, into | |
810 | the container at some <filename>path</filename>, and then mounts | |
811 | under <filename>path</filename>, then a TOCTTOU attack would be | |
812 | possible where the container user modifies a symbolic link under | |
813 | his home directory at just the right time. | |
814 | </para> | |
55fc19a1 | 815 | <variablelist> |
c464fd7e SG |
816 | <varlistentry> |
817 | <term> | |
818 | <option>lxc.mount</option> | |
819 | </term> | |
820 | <listitem> | |
821 | <para> | |
822 | specify a file location in | |
823 | the <filename>fstab</filename> format, containing the | |
824 | mount information. The mount target location can and in | |
825 | most cases should be a relative path, which will become | |
826 | relative to the mounted container root. For instance, | |
827 | </para> | |
b9986e43 CB |
828 | <programlisting> |
829 | proc proc proc nodev,noexec,nosuid 0 0 | |
830 | </programlisting> | |
c464fd7e SG |
831 | <para> |
832 | Will mount a proc filesystem under the container's /proc, | |
833 | regardless of where the root filesystem comes from. This | |
834 | is resilient to block device backed filesystems as well as | |
835 | container cloning. | |
836 | </para> | |
837 | <para> | |
838 | Note that when mounting a filesystem from an | |
839 | image file or block device the third field (fs_vfstype) | |
840 | cannot be auto as with | |
55fc19a1 | 841 | <citerefentry> |
c464fd7e | 842 | <refentrytitle>mount</refentrytitle> |
55fc19a1 SG |
843 | <manvolnum>8</manvolnum> |
844 | </citerefentry> | |
845 | but must be explicitly specified. | |
c464fd7e SG |
846 | </para> |
847 | </listitem> | |
848 | </varlistentry> | |
849 | ||
850 | <varlistentry> | |
851 | <term> | |
852 | <option>lxc.mount.entry</option> | |
853 | </term> | |
854 | <listitem> | |
855 | <para> | |
856 | specify a mount point corresponding to a line in the | |
857 | fstab format. | |
f5b67b36 NC |
858 | |
859 | Moreover lxc add two options to mount. | |
860 | <option>optional</option> don't fail if mount does not work. | |
861 | <option>create=dir</option> or <option>create=file</option> | |
862 | to create dir (or file) when the point will be mounted. | |
c464fd7e SG |
863 | </para> |
864 | </listitem> | |
865 | </varlistentry> | |
866 | ||
867 | <varlistentry> | |
868 | <term> | |
869 | <option>lxc.mount.auto</option> | |
870 | </term> | |
871 | <listitem> | |
872 | <para> | |
873 | specify which standard kernel file systems should be | |
874 | automatically mounted. This may dramatically simplify | |
875 | the configuration. The file systems are: | |
876 | </para> | |
877 | <itemizedlist> | |
878 | <listitem> | |
879 | <para> | |
880 | <option>proc:mixed</option> (or <option>proc</option>): | |
881 | mount <filename>/proc</filename> as read-write, but | |
882 | remount <filename>/proc/sys</filename> and | |
883 | <filename>/proc/sysrq-trigger</filename> read-only | |
884 | for security / container isolation purposes. | |
885 | </para> | |
886 | </listitem> | |
887 | <listitem> | |
888 | <para> | |
889 | <option>proc:rw</option>: mount | |
890 | <filename>/proc</filename> as read-write | |
891 | </para> | |
892 | </listitem> | |
893 | <listitem> | |
894 | <para> | |
f24a52d5 SG |
895 | <option>sys:mixed</option> (or <option>sys</option>): |
896 | mount <filename>/sys</filename> as read-only but with | |
897 | /sys/devices/virtual/net writable. | |
898 | </para> | |
899 | </listitem> | |
900 | <listitem> | |
901 | <para> | |
902 | <option>sys:ro</option>: | |
c464fd7e SG |
903 | mount <filename>/sys</filename> as read-only |
904 | for security / container isolation purposes. | |
905 | </para> | |
906 | </listitem> | |
907 | <listitem> | |
908 | <para> | |
909 | <option>sys:rw</option>: mount | |
910 | <filename>/sys</filename> as read-write | |
911 | </para> | |
912 | </listitem> | |
913 | <listitem> | |
914 | <para> | |
915 | <option>cgroup:mixed</option>: | |
916 | mount a tmpfs to <filename>/sys/fs/cgroup</filename>, | |
917 | create directories for all hierarchies to which | |
918 | the container is added, create subdirectories | |
919 | there with the name of the cgroup, and bind-mount | |
920 | the container's own cgroup into that directory. | |
921 | The container will be able to write to its own | |
922 | cgroup directory, but not the parents, since they | |
4608594e | 923 | will be remounted read-only. |
c464fd7e SG |
924 | </para> |
925 | </listitem> | |
926 | <listitem> | |
927 | <para> | |
928 | <option>cgroup:ro</option>: similar to | |
929 | <option>cgroup:mixed</option>, but everything will | |
930 | be mounted read-only. | |
931 | </para> | |
932 | </listitem> | |
933 | <listitem> | |
934 | <para> | |
935 | <option>cgroup:rw</option>: similar to | |
936 | <option>cgroup:mixed</option>, but everything will | |
937 | be mounted read-write. Note that the paths leading | |
938 | up to the container's own cgroup will be writable, | |
939 | but will not be a cgroup filesystem but just part | |
940 | of the tmpfs of <filename>/sys/fs/cgroup</filename> | |
941 | </para> | |
942 | </listitem> | |
943 | <listitem> | |
944 | <para> | |
945 | <option>cgroup</option> (without specifier): | |
946 | defaults to <option>cgroup:rw</option> if the | |
947 | container retains the CAP_SYS_ADMIN capability, | |
948 | <option>cgroup:mixed</option> otherwise. | |
949 | </para> | |
950 | </listitem> | |
951 | <listitem> | |
952 | <para> | |
953 | <option>cgroup-full:mixed</option>: | |
954 | mount a tmpfs to <filename>/sys/fs/cgroup</filename>, | |
955 | create directories for all hierarchies to which | |
956 | the container is added, bind-mount the hierarchies | |
957 | from the host to the container and make everything | |
958 | read-only except the container's own cgroup. Note | |
959 | that compared to <option>cgroup</option>, where | |
960 | all paths leading up to the container's own cgroup | |
961 | are just simple directories in the underlying | |
962 | tmpfs, here | |
963 | <filename>/sys/fs/cgroup/$hierarchy</filename> | |
964 | will contain the host's full cgroup hierarchy, | |
965 | albeit read-only outside the container's own cgroup. | |
966 | This may leak quite a bit of information into the | |
967 | container. | |
968 | </para> | |
969 | </listitem> | |
970 | <listitem> | |
971 | <para> | |
972 | <option>cgroup-full:ro</option>: similar to | |
973 | <option>cgroup-full:mixed</option>, but everything | |
974 | will be mounted read-only. | |
975 | </para> | |
976 | </listitem> | |
977 | <listitem> | |
978 | <para> | |
979 | <option>cgroup-full:rw</option>: similar to | |
980 | <option>cgroup-full:mixed</option>, but everything | |
981 | will be mounted read-write. Note that in this case, | |
982 | the container may escape its own cgroup. (Note also | |
983 | that if the container has CAP_SYS_ADMIN support | |
984 | and can mount the cgroup filesystem itself, it may | |
985 | do so anyway.) | |
986 | </para> | |
987 | </listitem> | |
988 | <listitem> | |
989 | <para> | |
990 | <option>cgroup-full</option> (without specifier): | |
991 | defaults to <option>cgroup-full:rw</option> if the | |
992 | container retains the CAP_SYS_ADMIN capability, | |
993 | <option>cgroup-full:mixed</option> otherwise. | |
994 | </para> | |
995 | </listitem> | |
996 | </itemizedlist> | |
4608594e SH |
997 | <para> |
998 | If cgroup namespaces are enabled, then any <option>cgroup</option> | |
999 | auto-mounting request will be ignored, since the container can | |
1000 | mount the filesystems itself, and automounting can confuse the | |
1001 | container init. | |
1002 | </para> | |
c464fd7e SG |
1003 | <para> |
1004 | Note that if automatic mounting of the cgroup filesystem | |
1005 | is enabled, the tmpfs under | |
1006 | <filename>/sys/fs/cgroup</filename> will always be | |
1007 | mounted read-write (but for the <option>:mixed</option> | |
1008 | and <option>:ro</option> cases, the individual | |
1009 | hierarchies, | |
1010 | <filename>/sys/fs/cgroup/$hierarchy</filename>, will be | |
1011 | read-only). This is in order to work around a quirk in | |
1012 | Ubuntu's | |
b46f0553 | 1013 | <citerefentry> |
c464fd7e | 1014 | <refentrytitle>mountall</refentrytitle> |
b46f0553 CS |
1015 | <manvolnum>8</manvolnum> |
1016 | </citerefentry> | |
c464fd7e SG |
1017 | command that will cause containers to wait for user |
1018 | input at boot if | |
1019 | <filename>/sys/fs/cgroup</filename> is mounted read-only | |
1020 | and the container can't remount it read-write due to a | |
1021 | lack of CAP_SYS_ADMIN. | |
1022 | </para> | |
1023 | <para> | |
1024 | Examples: | |
1025 | </para> | |
1026 | <programlisting> | |
1027 | lxc.mount.auto = proc sys cgroup | |
1028 | lxc.mount.auto = proc:rw sys:rw cgroup-full:rw | |
1029 | </programlisting> | |
1030 | </listitem> | |
1031 | </varlistentry> | |
55fc19a1 SG |
1032 | |
1033 | </variablelist> | |
1034 | </refsect2> | |
1035 | ||
1036 | <refsect2> | |
1037 | <title>Root file system</title> | |
1038 | <para> | |
c464fd7e SG |
1039 | The root file system of the container can be different than that |
1040 | of the host system. | |
55fc19a1 SG |
1041 | </para> |
1042 | <variablelist> | |
c464fd7e SG |
1043 | <varlistentry> |
1044 | <term> | |
1045 | <option>lxc.rootfs</option> | |
1046 | </term> | |
1047 | <listitem> | |
1048 | <para> | |
1049 | specify the root file system for the container. It can | |
1050 | be an image file, a directory or a block device. If not | |
1051 | specified, the container shares its root file system | |
1052 | with the host. | |
1053 | </para> | |
1054 | <para> | |
f1c26f2c SH |
1055 | For directory or simple block-device backed containers, |
1056 | a pathname can be used. If the rootfs is backed by a nbd | |
1057 | device, then <filename>nbd:file:1</filename> specifies that | |
1058 | <filename>file</filename> should be attached to a nbd device, | |
1059 | and partition 1 should be mounted as the rootfs. | |
1060 | <filename>nbd:file</filename> specifies that the nbd device | |
1061 | itself should be mounted. <filename>overlayfs:/lower:/upper</filename> | |
1062 | specifies that the rootfs should be an overlay with <filename>/upper</filename> | |
1063 | being mounted read-write over a read-only mount of <filename>/lower</filename>. | |
1064 | <filename>aufs:/lower:/upper</filename> does the same using aufs in place | |
280d2379 CB |
1065 | of overlayfs. For both <filename>overlayfs</filename> and |
1066 | <filename>aufs</filename> multiple <filename>/lower</filename> | |
1067 | directories can be specified. <filename>loop:/file</filename> tells lxc to attach | |
f1c26f2c | 1068 | <filename>/file</filename> to a loop device and mount the loop device. |
c464fd7e SG |
1069 | </para> |
1070 | </listitem> | |
1071 | </varlistentry> | |
1072 | ||
1073 | <varlistentry> | |
1074 | <term> | |
1075 | <option>lxc.rootfs.mount</option> | |
1076 | </term> | |
1077 | <listitem> | |
1078 | <para> | |
1079 | where to recursively bind <option>lxc.rootfs</option> | |
1080 | before pivoting. This is to ensure success of the | |
1081 | <citerefentry> | |
1082 | <refentrytitle><command>pivot_root</command></refentrytitle> | |
1083 | <manvolnum>8</manvolnum> | |
1084 | </citerefentry> | |
1085 | syscall. Any directory suffices, the default should | |
1086 | generally work. | |
1087 | </para> | |
1088 | </listitem> | |
1089 | </varlistentry> | |
1090 | ||
1091 | <varlistentry> | |
1092 | <term> | |
1093 | <option>lxc.rootfs.options</option> | |
1094 | </term> | |
1095 | <listitem> | |
1096 | <para> | |
1097 | extra mount options to use when mounting the rootfs. | |
1098 | </para> | |
1099 | </listitem> | |
1100 | </varlistentry> | |
a17b1e65 | 1101 | |
f9039861 SH |
1102 | <varlistentry> |
1103 | <term> | |
1104 | <option>lxc.rootfs.backend</option> | |
1105 | </term> | |
1106 | <listitem> | |
1107 | <para> | |
1108 | specify the rootfs backend type to use, for instance 'dir' or | |
1109 | 'zfs'. While this can be guessed by lxc at container startup, | |
1110 | doing so takes time. Specifying it here avoids extra | |
1111 | processing. | |
1112 | </para> | |
1113 | </listitem> | |
1114 | </varlistentry> | |
1115 | ||
55fc19a1 SG |
1116 | </variablelist> |
1117 | </refsect2> | |
1118 | ||
1119 | <refsect2> | |
1120 | <title>Control group</title> | |
1121 | <para> | |
c464fd7e SG |
1122 | The control group section contains the configuration for the |
1123 | different subsystem. <command>lxc</command> does not check the | |
1124 | correctness of the subsystem name. This has the disadvantage | |
1125 | of not detecting configuration errors until the container is | |
1126 | started, but has the advantage of permitting any future | |
1127 | subsystem. | |
55fc19a1 SG |
1128 | </para> |
1129 | <variablelist> | |
c464fd7e SG |
1130 | <varlistentry> |
1131 | <term> | |
1132 | <option>lxc.cgroup.[subsystem name]</option> | |
1133 | </term> | |
1134 | <listitem> | |
1135 | <para> | |
1136 | specify the control group value to be set. The | |
1137 | subsystem name is the literal name of the control group | |
1138 | subsystem. The permitted names and the syntax of their | |
1139 | values is not dictated by LXC, instead it depends on the | |
1140 | features of the Linux kernel running at the time the | |
1141 | container is started, | |
1142 | eg. <option>lxc.cgroup.cpuset.cpus</option> | |
1143 | </para> | |
1144 | </listitem> | |
1145 | </varlistentry> | |
55fc19a1 SG |
1146 | </variablelist> |
1147 | </refsect2> | |
1148 | ||
1149 | <refsect2> | |
1150 | <title>Capabilities</title> | |
1151 | <para> | |
c464fd7e SG |
1152 | The capabilities can be dropped in the container if this one |
1153 | is run as root. | |
55fc19a1 SG |
1154 | </para> |
1155 | <variablelist> | |
c464fd7e SG |
1156 | <varlistentry> |
1157 | <term> | |
1158 | <option>lxc.cap.drop</option> | |
1159 | </term> | |
1160 | <listitem> | |
1161 | <para> | |
1162 | Specify the capability to be dropped in the container. A | |
1163 | single line defining several capabilities with a space | |
1164 | separation is allowed. The format is the lower case of | |
1165 | the capability definition without the "CAP_" prefix, | |
1166 | eg. CAP_SYS_MODULE should be specified as | |
1167 | sys_module. See | |
1168 | <citerefentry> | |
1169 | <refentrytitle><command>capabilities</command></refentrytitle> | |
1170 | <manvolnum>7</manvolnum> | |
7eff30fd MH |
1171 | </citerefentry>. |
1172 | If used with no value, lxc will clear any drop capabilities | |
1173 | specified up to this point. | |
c464fd7e SG |
1174 | </para> |
1175 | </listitem> | |
1176 | </varlistentry> | |
1177 | <varlistentry> | |
1178 | <term> | |
1179 | <option>lxc.cap.keep</option> | |
1180 | </term> | |
1181 | <listitem> | |
1182 | <para> | |
1183 | Specify the capability to be kept in the container. All other | |
1184 | capabilities will be dropped. When a special value of "none" is | |
1185 | encountered, lxc will clear any keep capabilities specified up | |
1186 | to this point. A value of "none" alone can be used to drop all | |
1187 | capabilities. | |
1188 | </para> | |
1189 | </listitem> | |
1190 | </varlistentry> | |
55fc19a1 SG |
1191 | </variablelist> |
1192 | </refsect2> | |
1193 | ||
93f9e90d WB |
1194 | <refsect2> |
1195 | <title>Resource limits</title> | |
1196 | <para> | |
1197 | The soft and hard resource limits for the container can be changed. | |
1198 | Unprivileged containers can only lower them. Resources which are not | |
1199 | explicitly specified will be inherited. | |
1200 | </para> | |
1201 | <variablelist> | |
1202 | <varlistentry> | |
1203 | <term> | |
1204 | <option>lxc.limit.[limit name]</option> | |
1205 | </term> | |
1206 | <listitem> | |
1207 | <para> | |
1208 | Specify the resource limit to be set. A limit is specified as two | |
1209 | colon separated values which are either numeric or the word | |
1210 | 'unlimited'. A single value can be used as a shortcut to set both | |
1211 | soft and hard limit to the same value. The permitted names the | |
1212 | "RLIMIT_" resource names in lowercase without the "RLIMIT_" | |
1213 | prefix, eg. RLIMIT_NOFILE should be specified as "nofile". See | |
1214 | <citerefentry> | |
1215 | <refentrytitle><command>setrlimit</command></refentrytitle> | |
1216 | <manvolnum>2</manvolnum> | |
1217 | </citerefentry>. | |
1218 | If used with no value, lxc will clear the resource limit | |
1219 | specified up to this point. A resource with no explicitly | |
1220 | configured limitation will be inherited from the process starting | |
1221 | up the container. | |
1222 | </para> | |
1223 | </listitem> | |
1224 | </varlistentry> | |
1225 | </variablelist> | |
1226 | </refsect2> | |
1227 | ||
55fc19a1 SG |
1228 | <refsect2> |
1229 | <title>Apparmor profile</title> | |
1230 | <para> | |
c464fd7e SG |
1231 | If lxc was compiled and installed with apparmor support, and the host |
1232 | system has apparmor enabled, then the apparmor profile under which the | |
1233 | container should be run can be specified in the container | |
7a126ae1 SH |
1234 | configuration. The default is <command>lxc-container-default-cgns</command> |
1235 | if the host kernel is cgroup namespace aware, or | |
1236 | <command>lxc-container-default</command> othewise. | |
55fc19a1 SG |
1237 | </para> |
1238 | <variablelist> | |
c464fd7e SG |
1239 | <varlistentry> |
1240 | <term> | |
1241 | <option>lxc.aa_profile</option> | |
1242 | </term> | |
1243 | <listitem> | |
1244 | <para> | |
1245 | Specify the apparmor profile under which the container should | |
1246 | be run. To specify that the container should be unconfined, | |
1247 | use | |
1248 | </para> | |
1249 | <programlisting>lxc.aa_profile = unconfined</programlisting> | |
7a126ae1 SH |
1250 | <para> |
1251 | If the apparmor profile should remain unchanged (i.e. if you | |
1252 | are nesting containers and are already confined), then use | |
1253 | </para> | |
1254 | <programlisting>lxc.aa_profile = unchanged</programlisting> | |
c464fd7e SG |
1255 | </listitem> |
1256 | </varlistentry> | |
1257 | <varlistentry> | |
1258 | <term> | |
1259 | <option>lxc.aa_allow_incomplete</option> | |
1260 | </term> | |
1261 | <listitem> | |
1262 | <para> | |
1263 | Apparmor profiles are pathname based. Therefore many file | |
1264 | restrictions require mount restrictions to be effective against | |
1265 | a determined attacker. However, these mount restrictions are not | |
1266 | yet implemented in the upstream kernel. Without the mount | |
1267 | restrictions, the apparmor profiles still protect against accidental | |
1268 | damager. | |
1269 | </para> | |
1270 | <para> | |
1271 | If this flag is 0 (default), then the container will not be | |
1272 | started if the kernel lacks the apparmor mount features, so that a | |
1273 | regression after a kernel upgrade will be detected. To start the | |
1274 | container under partial apparmor protection, set this flag to 1. | |
1275 | </para> | |
1276 | </listitem> | |
1277 | </varlistentry> | |
55fc19a1 SG |
1278 | </variablelist> |
1279 | </refsect2> | |
1280 | ||
1281 | <refsect2> | |
1282 | <title>SELinux context</title> | |
1283 | <para> | |
c464fd7e SG |
1284 | If lxc was compiled and installed with SELinux support, and the host |
1285 | system has SELinux enabled, then the SELinux context under which the | |
1286 | container should be run can be specified in the container | |
1287 | configuration. The default is <command>unconfined_t</command>, | |
1288 | which means that lxc will not attempt to change contexts. | |
1289 | See @DATADIR@/lxc/selinux/lxc.te for an example policy and more | |
1290 | information. | |
55fc19a1 SG |
1291 | </para> |
1292 | <variablelist> | |
c464fd7e SG |
1293 | <varlistentry> |
1294 | <term> | |
1295 | <option>lxc.se_context</option> | |
1296 | </term> | |
1297 | <listitem> | |
1298 | <para> | |
1299 | Specify the SELinux context under which the container should | |
1300 | be run or <command>unconfined_t</command>. For example | |
1301 | </para> | |
1302 | <programlisting>lxc.se_context = system_u:system_r:lxc_t:s0:c22</programlisting> | |
1303 | </listitem> | |
1304 | </varlistentry> | |
55fc19a1 SG |
1305 | </variablelist> |
1306 | </refsect2> | |
1307 | ||
1308 | <refsect2> | |
1309 | <title>Seccomp configuration</title> | |
1310 | <para> | |
1311 | A container can be started with a reduced set of available | |
c464fd7e SG |
1312 | system calls by loading a seccomp profile at startup. The |
1313 | seccomp configuration file must begin with a version number | |
1314 | on the first line, a policy type on the second line, followed | |
1315 | by the configuration. | |
55fc19a1 | 1316 | </para> |
a7c27357 SH |
1317 | <para> |
1318 | Versions 1 and 2 are currently supported. In version 1, the | |
c464fd7e SG |
1319 | policy is a simple whitelist. The second line therefore must |
1320 | read "whitelist", with the rest of the file containing one (numeric) | |
1321 | sycall number per line. Each syscall number is whitelisted, | |
1322 | while every unlisted number is blacklisted for use in the container | |
a7c27357 SH |
1323 | </para> |
1324 | ||
1325 | <para> | |
1326 | In version 2, the policy may be blacklist or whitelist, | |
1327 | supports per-rule and per-policy default actions, and supports | |
1328 | per-architecture system call resolution from textual names. | |
1329 | </para> | |
1330 | <para> | |
1331 | An example blacklist policy, in which all system calls are | |
1332 | allowed except for mknod, which will simply do nothing and | |
1333 | return 0 (success), looks like: | |
1334 | </para> | |
b9986e43 CB |
1335 | |
1336 | <programlisting> | |
1337 | 2 | |
1338 | blacklist | |
1339 | mknod errno 0 | |
1340 | </programlisting> | |
1341 | ||
55fc19a1 | 1342 | <variablelist> |
c464fd7e SG |
1343 | <varlistentry> |
1344 | <term> | |
1345 | <option>lxc.seccomp</option> | |
1346 | </term> | |
1347 | <listitem> | |
1348 | <para> | |
1349 | Specify a file containing the seccomp configuration to | |
1350 | load before the container starts. | |
1351 | </para> | |
1352 | </listitem> | |
1353 | </varlistentry> | |
55fc19a1 SG |
1354 | </variablelist> |
1355 | </refsect2> | |
1356 | ||
222ddc91 CB |
1357 | <refsect2> |
1358 | <title>PR_SET_NO_NEW_PRIVS</title> | |
1359 | <para> | |
1360 | With PR_SET_NO_NEW_PRIVS active execve() promises not to grant | |
1361 | privileges to do anything that could not have been done without | |
1362 | the execve() call (for example, rendering the set-user-ID and | |
1363 | set-group-ID mode bits, and file capabilities non-functional). | |
1364 | Once set, this bit cannot be unset. The setting of this bit is | |
1365 | inherited by children created by fork() and clone(), and preserved | |
1366 | across execve(). | |
1367 | Note that PR_SET_NO_NEW_PRIVS is applied after the container has | |
1368 | changed into its intended AppArmor profile or SElinux context. | |
1369 | </para> | |
1370 | <variablelist> | |
1371 | <varlistentry> | |
1372 | <term> | |
1373 | <option>lxc.no_new_privs</option> | |
1374 | </term> | |
1375 | <listitem> | |
1376 | <para> | |
1377 | Specify whether the PR_SET_NO_NEW_PRIVS flag should be set for the | |
1378 | container. Set to 1 to activate. | |
1379 | </para> | |
1380 | </listitem> | |
1381 | </varlistentry> | |
1382 | </variablelist> | |
1383 | </refsect2> | |
1384 | ||
55fc19a1 SG |
1385 | <refsect2> |
1386 | <title>UID mappings</title> | |
1387 | <para> | |
1388 | A container can be started in a private user namespace with | |
c464fd7e SG |
1389 | user and group id mappings. For instance, you can map userid |
1390 | 0 in the container to userid 200000 on the host. The root | |
1391 | user in the container will be privileged in the container, | |
1392 | but unprivileged on the host. Normally a system container | |
1393 | will want a range of ids, so you would map, for instance, | |
1394 | user and group ids 0 through 20,000 in the container to the | |
1395 | ids 200,000 through 220,000. | |
55fc19a1 SG |
1396 | </para> |
1397 | <variablelist> | |
c464fd7e SG |
1398 | <varlistentry> |
1399 | <term> | |
1400 | <option>lxc.id_map</option> | |
1401 | </term> | |
1402 | <listitem> | |
1403 | <para> | |
1404 | Four values must be provided. First a character, either | |
1405 | 'u', or 'g', to specify whether user or group ids are | |
1406 | being mapped. Next is the first userid as seen in the | |
1407 | user namespace of the container. Next is the userid as | |
1408 | seen on the host. Finally, a range indicating the number | |
1409 | of consecutive ids to map. | |
1410 | </para> | |
1411 | </listitem> | |
1412 | </varlistentry> | |
55fc19a1 SG |
1413 | </variablelist> |
1414 | </refsect2> | |
1415 | ||
1416 | <refsect2> | |
1417 | <title>Container hooks</title> | |
1418 | <para> | |
1419 | Container hooks are programs or scripts which can be executed | |
c464fd7e | 1420 | at various times in a container's lifetime. |
55fc19a1 SG |
1421 | </para> |
1422 | <para> | |
1423 | When a container hook is executed, information is passed both | |
c464fd7e SG |
1424 | as command line arguments and through environment variables. |
1425 | The arguments are: | |
1426 | <itemizedlist> | |
1427 | <listitem><para> Container name. </para></listitem> | |
1428 | <listitem><para> Section (always 'lxc'). </para></listitem> | |
1429 | <listitem><para> The hook type (i.e. 'clone' or 'pre-mount'). </para></listitem> | |
0a2b5ab1 | 1430 | <listitem><para> Additional arguments. In the |
c464fd7e | 1431 | case of the clone hook, any extra arguments passed to |
0a2b5ab1 WB |
1432 | lxc-clone will appear as further arguments to the hook. |
1433 | In the case of the stop hook, paths to filedescriptors | |
1434 | for each of the container's namespaces along with their types | |
1435 | are passed. </para></listitem> | |
c464fd7e SG |
1436 | </itemizedlist> |
1437 | The following environment variables are set: | |
1438 | <itemizedlist> | |
1439 | <listitem><para> LXC_NAME: is the container's name. </para></listitem> | |
1440 | <listitem><para> LXC_ROOTFS_MOUNT: the path to the mounted root filesystem. </para></listitem> | |
1441 | <listitem><para> LXC_CONFIG_FILE: the path to the container configuration file. </para></listitem> | |
1442 | <listitem><para> LXC_SRC_NAME: in the case of the clone hook, this is the original container's name. </para></listitem> | |
1443 | <listitem><para> LXC_ROOTFS_PATH: this is the lxc.rootfs entry for the container. Note this is likely not where the mounted rootfs is to be found, use LXC_ROOTFS_MOUNT for that. </para></listitem> | |
1444 | </itemizedlist> | |
55fc19a1 SG |
1445 | </para> |
1446 | <para> | |
1447 | Standard output from the hooks is logged at debug level. | |
1448 | Standard error is not logged, but can be captured by the | |
1449 | hook redirecting its standard error to standard output. | |
1450 | </para> | |
1451 | <variablelist> | |
c464fd7e SG |
1452 | <varlistentry> |
1453 | <term> | |
1454 | <option>lxc.hook.pre-start</option> | |
1455 | </term> | |
1456 | <listitem> | |
1457 | <para> | |
1458 | A hook to be run in the host's namespace before the | |
1459 | container ttys, consoles, or mounts are up. | |
1460 | </para> | |
1461 | </listitem> | |
1462 | </varlistentry> | |
55fc19a1 SG |
1463 | </variablelist> |
1464 | <variablelist> | |
c464fd7e SG |
1465 | <varlistentry> |
1466 | <term> | |
1467 | <option>lxc.hook.pre-mount</option> | |
1468 | </term> | |
1469 | <listitem> | |
1470 | <para> | |
1471 | A hook to be run in the container's fs namespace but before | |
1472 | the rootfs has been set up. This allows for manipulation | |
1473 | of the rootfs, i.e. to mount an encrypted filesystem. Mounts | |
1474 | done in this hook will not be reflected on the host (apart from | |
1475 | mounts propagation), so they will be automatically cleaned up | |
1476 | when the container shuts down. | |
1477 | </para> | |
1478 | </listitem> | |
1479 | </varlistentry> | |
55fc19a1 SG |
1480 | </variablelist> |
1481 | <variablelist> | |
c464fd7e SG |
1482 | <varlistentry> |
1483 | <term> | |
1484 | <option>lxc.hook.mount</option> | |
1485 | </term> | |
1486 | <listitem> | |
1487 | <para> | |
1488 | A hook to be run in the container's namespace after | |
1489 | mounting has been done, but before the pivot_root. | |
1490 | </para> | |
1491 | </listitem> | |
1492 | </varlistentry> | |
55fc19a1 SG |
1493 | </variablelist> |
1494 | <variablelist> | |
c464fd7e SG |
1495 | <varlistentry> |
1496 | <term> | |
1497 | <option>lxc.hook.autodev</option> | |
1498 | </term> | |
1499 | <listitem> | |
1500 | <para> | |
1501 | A hook to be run in the container's namespace after | |
1502 | mounting has been done and after any mount hooks have | |
1503 | run, but before the pivot_root, if | |
1504 | <option>lxc.autodev</option> == 1. | |
1505 | The purpose of this hook is to assist in populating the | |
1506 | /dev directory of the container when using the autodev | |
1507 | option for systemd based containers. The container's /dev | |
1508 | directory is relative to the | |
1509 | ${<option>LXC_ROOTFS_MOUNT</option>} environment | |
1510 | variable available when the hook is run. | |
1511 | </para> | |
1512 | </listitem> | |
1513 | </varlistentry> | |
55fc19a1 SG |
1514 | </variablelist> |
1515 | <variablelist> | |
c464fd7e SG |
1516 | <varlistentry> |
1517 | <term> | |
1518 | <option>lxc.hook.start</option> | |
1519 | </term> | |
1520 | <listitem> | |
1521 | <para> | |
1522 | A hook to be run in the container's namespace immediately | |
1523 | before executing the container's init. This requires the | |
1524 | program to be available in the container. | |
1525 | </para> | |
1526 | </listitem> | |
1527 | </varlistentry> | |
55fc19a1 | 1528 | </variablelist> |
0a2b5ab1 WB |
1529 | <variablelist> |
1530 | <varlistentry> | |
1531 | <term> | |
1532 | <option>lxc.hook.stop</option> | |
1533 | </term> | |
1534 | <listitem> | |
1535 | <para> | |
1536 | A hook to be run in the host's namespace with references | |
1537 | to the container's namespaces after the container has been shut | |
1538 | down. For each namespace an extra argument is passed to the hook | |
1539 | containing the namespace's type and a filename that can be used to | |
1540 | obtain a file descriptor to the corresponding namespace, separated | |
1541 | by a colon. The type is the name as it would appear in the | |
1542 | <filename>/proc/PID/ns</filename> directory. | |
1543 | For instance for the mount namespace the argument usually looks | |
1544 | like <filename>mnt:/proc/PID/fd/12</filename>. | |
1545 | </para> | |
1546 | </listitem> | |
1547 | </varlistentry> | |
1548 | </variablelist> | |
55fc19a1 | 1549 | <variablelist> |
c464fd7e SG |
1550 | <varlistentry> |
1551 | <term> | |
1552 | <option>lxc.hook.post-stop</option> | |
1553 | </term> | |
1554 | <listitem> | |
1555 | <para> | |
1556 | A hook to be run in the host's namespace after the | |
1557 | container has been shut down. | |
1558 | </para> | |
1559 | </listitem> | |
1560 | </varlistentry> | |
55fc19a1 SG |
1561 | </variablelist> |
1562 | <variablelist> | |
c464fd7e SG |
1563 | <varlistentry> |
1564 | <term> | |
1565 | <option>lxc.hook.clone</option> | |
1566 | </term> | |
1567 | <listitem> | |
1568 | <para> | |
1569 | A hook to be run when the container is cloned to a new one. | |
1570 | See <citerefentry><refentrytitle><command>lxc-clone</command></refentrytitle> | |
1571 | <manvolnum>1</manvolnum></citerefentry> for more information. | |
1572 | </para> | |
1573 | </listitem> | |
1574 | </varlistentry> | |
55fc19a1 | 1575 | </variablelist> |
37cf711b SY |
1576 | <variablelist> |
1577 | <varlistentry> | |
1578 | <term> | |
1579 | <option>lxc.hook.destroy</option> | |
1580 | </term> | |
1581 | <listitem> | |
1582 | <para> | |
1583 | A hook to be run when the container is destroyed. | |
1584 | </para> | |
1585 | </listitem> | |
1586 | </varlistentry> | |
1587 | </variablelist> | |
55fc19a1 SG |
1588 | </refsect2> |
1589 | ||
1590 | <refsect2> | |
1591 | <title>Container hooks Environment Variables</title> | |
1592 | <para> | |
1593 | A number of environment variables are made available to the startup | |
1594 | hooks to provide configuration information and assist in the | |
1595 | functioning of the hooks. Not all variables are valid in all | |
1596 | contexts. In particular, all paths are relative to the host system | |
1597 | and, as such, not valid during the <option>lxc.hook.start</option> hook. | |
1598 | </para> | |
1599 | <variablelist> | |
c464fd7e SG |
1600 | <varlistentry> |
1601 | <term> | |
1602 | <option>LXC_NAME</option> | |
1603 | </term> | |
1604 | <listitem> | |
1605 | <para> | |
1606 | The LXC name of the container. Useful for logging messages | |
1607 | in common log environments. [<option>-n</option>] | |
1608 | </para> | |
1609 | </listitem> | |
1610 | </varlistentry> | |
55fc19a1 SG |
1611 | </variablelist> |
1612 | <variablelist> | |
c464fd7e SG |
1613 | <varlistentry> |
1614 | <term> | |
1615 | <option>LXC_CONFIG_FILE</option> | |
1616 | </term> | |
1617 | <listitem> | |
1618 | <para> | |
1619 | Host relative path to the container configuration file. This | |
1620 | gives the container to reference the original, top level, | |
1621 | configuration file for the container in order to locate any | |
1622 | additional configuration information not otherwise made | |
1623 | available. [<option>-f</option>] | |
1624 | </para> | |
1625 | </listitem> | |
1626 | </varlistentry> | |
55fc19a1 SG |
1627 | </variablelist> |
1628 | <variablelist> | |
c464fd7e SG |
1629 | <varlistentry> |
1630 | <term> | |
1631 | <option>LXC_CONSOLE</option> | |
1632 | </term> | |
1633 | <listitem> | |
1634 | <para> | |
1635 | The path to the console output of the container if not NULL. | |
1636 | [<option>-c</option>] [<option>lxc.console</option>] | |
1637 | </para> | |
1638 | </listitem> | |
1639 | </varlistentry> | |
55fc19a1 SG |
1640 | </variablelist> |
1641 | <variablelist> | |
c464fd7e SG |
1642 | <varlistentry> |
1643 | <term> | |
1644 | <option>LXC_CONSOLE_LOGPATH</option> | |
1645 | </term> | |
1646 | <listitem> | |
1647 | <para> | |
1648 | The path to the console log output of the container if not NULL. | |
1649 | [<option>-L</option>] | |
1650 | </para> | |
1651 | </listitem> | |
1652 | </varlistentry> | |
55fc19a1 SG |
1653 | </variablelist> |
1654 | <variablelist> | |
c464fd7e SG |
1655 | <varlistentry> |
1656 | <term> | |
1657 | <option>LXC_ROOTFS_MOUNT</option> | |
1658 | </term> | |
1659 | <listitem> | |
1660 | <para> | |
1661 | The mount location to which the container is initially bound. | |
1662 | This will be the host relative path to the container rootfs | |
1663 | for the container instance being started and is where changes | |
1664 | should be made for that instance. | |
1665 | [<option>lxc.rootfs.mount</option>] | |
1666 | </para> | |
1667 | </listitem> | |
1668 | </varlistentry> | |
55fc19a1 SG |
1669 | </variablelist> |
1670 | <variablelist> | |
c464fd7e SG |
1671 | <varlistentry> |
1672 | <term> | |
1673 | <option>LXC_ROOTFS_PATH</option> | |
1674 | </term> | |
1675 | <listitem> | |
1676 | <para> | |
1677 | The host relative path to the container root which has been | |
1678 | mounted to the rootfs.mount location. | |
1679 | [<option>lxc.rootfs</option>] | |
1680 | </para> | |
1681 | </listitem> | |
1682 | </varlistentry> | |
55fc19a1 | 1683 | </variablelist> |
07945418 KY |
1684 | <variablelist> |
1685 | <varlistentry> | |
1686 | <term> | |
1687 | <option>LXC_SRC_NAME</option> | |
1688 | </term> | |
1689 | <listitem> | |
1690 | <para> | |
1691 | Only for the clone hook. Is set to the original container name. | |
1692 | </para> | |
1693 | </listitem> | |
1694 | </varlistentry> | |
1695 | </variablelist> | |
c154af98 SG |
1696 | <variablelist> |
1697 | <varlistentry> | |
1698 | <term> | |
1699 | <option>LXC_TARGET</option> | |
1700 | </term> | |
1701 | <listitem> | |
1702 | <para> | |
1703 | Only for the stop hook. Is set to "stop" for a container | |
1704 | shutdown or "reboot" for a container reboot. | |
1705 | </para> | |
1706 | </listitem> | |
1707 | </varlistentry> | |
c4cafa08 SH |
1708 | </variablelist> |
1709 | <variablelist> | |
1710 | <varlistentry> | |
1711 | <term> | |
1712 | <option>LXC_CGNS_AWARE</option> | |
1713 | </term> | |
1714 | <listitem> | |
1715 | <para> | |
1716 | If unset, then this version of lxc is not aware of cgroup | |
1717 | namespaces. If set, it will be set to 1, and lxc is aware | |
1718 | of cgroup namespaces. Note this does not guarantee that | |
1719 | cgroup namespaces are enabled in the kernel. This is used | |
1720 | by the lxcfs mount hook. | |
1721 | </para> | |
1722 | </listitem> | |
1723 | </varlistentry> | |
c154af98 | 1724 | </variablelist> |
55fc19a1 SG |
1725 | </refsect2> |
1726 | <refsect2> | |
1727 | <title>Logging</title> | |
1728 | <para> | |
1729 | Logging can be configured on a per-container basis. By default, | |
1730 | depending upon how the lxc package was compiled, container startup | |
1731 | is logged only at the ERROR level, and logged to a file named after | |
1732 | the container (with '.log' appended) either under the container path, | |
1733 | or under @LOGPATH@. | |
1734 | </para> | |
1735 | <para> | |
1736 | Both the default log level and the log file can be specified in the | |
1737 | container configuration file, overriding the default behavior. Note | |
1738 | that the configuration file entries can in turn be overridden by the | |
1739 | command line options to <command>lxc-start</command>. | |
1740 | </para> | |
1741 | <variablelist> | |
c464fd7e SG |
1742 | <varlistentry> |
1743 | <term> | |
1744 | <option>lxc.loglevel</option> | |
1745 | </term> | |
1746 | <listitem> | |
1747 | <para> | |
1748 | The level at which to log. The log level is an integer in | |
1749 | the range of 0..8 inclusive, where a lower number means more | |
1750 | verbose debugging. In particular 0 = trace, 1 = debug, 2 = | |
1751 | info, 3 = notice, 4 = warn, 5 = error, 6 = critical, 7 = | |
1752 | alert, and 8 = fatal. If unspecified, the level defaults | |
1753 | to 5 (error), so that only errors and above are logged. | |
1754 | </para> | |
1755 | <para> | |
1756 | Note that when a script (such as either a hook script or a | |
1757 | network interface up or down script) is called, the script's | |
1758 | standard output is logged at level 1, debug. | |
1759 | </para> | |
1760 | </listitem> | |
1761 | </varlistentry> | |
1762 | <varlistentry> | |
1763 | <term> | |
1764 | <option>lxc.logfile</option> | |
1765 | </term> | |
1766 | <listitem> | |
1767 | <para> | |
1768 | The file to which logging info should be written. | |
1769 | </para> | |
1770 | </listitem> | |
1771 | </varlistentry> | |
204dfdf2 BD |
1772 | <varlistentry> |
1773 | <term> | |
1774 | <option>lxc.syslog</option> | |
1775 | </term> | |
1776 | <listitem> | |
1777 | <para> | |
1778 | Send logging info to syslog. It respects the log level defined in | |
1779 | <command>lxc.loglevel</command>. The argument should be the syslog | |
1780 | facility to use, valid ones are: daemon, local0, local1, local2, | |
917420dd | 1781 | local3, local4, local5, local5, local6, local7. |
204dfdf2 BD |
1782 | </para> |
1783 | </listitem> | |
1784 | </varlistentry> | |
55fc19a1 SG |
1785 | </variablelist> |
1786 | </refsect2> | |
1787 | ||
1788 | <refsect2> | |
1789 | <title>Autostart</title> | |
1790 | <para> | |
1791 | The autostart options support marking which containers should be | |
1792 | auto-started and in what order. These options may be used by LXC tools | |
1793 | directly or by external tooling provided by the distributions. | |
1794 | </para> | |
1795 | ||
1796 | <variablelist> | |
1797 | <varlistentry> | |
1798 | <term> | |
1799 | <option>lxc.start.auto</option> | |
1800 | </term> | |
1801 | <listitem> | |
1802 | <para> | |
1803 | Whether the container should be auto-started. | |
1804 | Valid values are 0 (off) and 1 (on). | |
1805 | </para> | |
1806 | </listitem> | |
1807 | </varlistentry> | |
1808 | <varlistentry> | |
1809 | <term> | |
1810 | <option>lxc.start.delay</option> | |
1811 | </term> | |
1812 | <listitem> | |
1813 | <para> | |
1814 | How long to wait (in seconds) after the container is | |
1815 | started before starting the next one. | |
1816 | </para> | |
1817 | </listitem> | |
1818 | </varlistentry> | |
1819 | <varlistentry> | |
1820 | <term> | |
1821 | <option>lxc.start.order</option> | |
1822 | </term> | |
1823 | <listitem> | |
1824 | <para> | |
1825 | An integer used to sort the containers when auto-starting | |
1826 | a series of containers at once. | |
1827 | </para> | |
1828 | </listitem> | |
1829 | </varlistentry> | |
a8dfe4e0 WB |
1830 | <varlistentry> |
1831 | <term> | |
1832 | <option>lxc.monitor.unshare</option> | |
1833 | </term> | |
1834 | <listitem> | |
1835 | <para> | |
1836 | If not zero the mount namespace will be unshared from the host | |
1837 | before initializing the container (before running any pre-start | |
6039eaa2 WB |
1838 | hooks). This requires the CAP_SYS_ADMIN capability at startup. |
1839 | Default is 0. | |
a8dfe4e0 WB |
1840 | </para> |
1841 | </listitem> | |
1842 | </varlistentry> | |
55fc19a1 SG |
1843 | <varlistentry> |
1844 | <term> | |
1845 | <option>lxc.group</option> | |
1846 | </term> | |
1847 | <listitem> | |
1848 | <para> | |
1849 | A multi-value key (can be used multiple times) to put the | |
1850 | container in a container group. Those groups can then be | |
1851 | used (amongst other things) to start a series of related | |
1852 | containers. | |
1853 | </para> | |
1854 | </listitem> | |
1855 | </varlistentry> | |
1856 | </variablelist> | |
1857 | </refsect2> | |
015f0dd7 MW |
1858 | |
1859 | <refsect2> | |
1860 | <title>Autostart and System Boot</title> | |
1861 | <para> | |
1862 | Each container can be part of any number of groups or no group at all. | |
1863 | Two groups are special. One is the NULL group, i.e. the container does | |
1864 | not belong to any group. The other group is the "onboot" group. | |
1865 | </para> | |
1866 | ||
1867 | <para> | |
1868 | When the system boots with the LXC service enabled, it will first | |
1869 | attempt to boot any containers with lxc.start.auto == 1 that is a member | |
1870 | of the "onboot" group. The startup will be in order of lxc.start.order. | |
1871 | If an lxc.start.delay has been specified, that delay will be honored | |
1872 | before attempting to start the next container to give the current | |
1873 | container time to begin initialization and reduce overloading the host | |
1874 | system. After starting the members of the "onboot" group, the LXC system | |
1875 | will proceed to boot containers with lxc.start.auto == 1 which are not | |
1876 | members of any group (the NULL group) and proceed as with the onboot | |
1877 | group. | |
1878 | </para> | |
1879 | ||
1880 | </refsect2> | |
7c661726 MP |
1881 | |
1882 | <refsect2> | |
1883 | <title>Container Environment</title> | |
1884 | <para> | |
c464fd7e SG |
1885 | If you want to pass environment variables into the container (that |
1886 | is, environment variables which will be available to init and all of | |
1887 | its descendents), you can use <command>lxc.environment</command> | |
1888 | parameters to do so. Be careful that you do not pass in anything | |
1889 | sensitive; any process in the container which doesn't have its | |
1890 | environment scrubbed will have these variables available to it, and | |
1891 | environment variables are always available via | |
1892 | <command>/proc/PID/environ</command>. | |
7c661726 MP |
1893 | </para> |
1894 | ||
1895 | <para> | |
1896 | This configuration parameter can be specified multiple times; once | |
1897 | for each environment variable you wish to configure. | |
1898 | </para> | |
1899 | ||
1900 | <variablelist> | |
c464fd7e SG |
1901 | <varlistentry> |
1902 | <term> | |
1903 | <option>lxc.environment</option> | |
1904 | </term> | |
1905 | <listitem> | |
1906 | <para> | |
1907 | Specify an environment variable to pass into the container. | |
1908 | Example: | |
1909 | </para> | |
1910 | <programlisting> | |
1911 | lxc.environment = APP_ENV=production | |
1912 | lxc.environment = SYSLOG_SERVER=192.0.2.42 | |
1913 | </programlisting> | |
1914 | </listitem> | |
1915 | </varlistentry> | |
7c661726 MP |
1916 | </variablelist> |
1917 | </refsect2> | |
1918 | ||
55fc19a1 SG |
1919 | </refsect1> |
1920 | ||
1921 | <refsect1> | |
1922 | <title>Examples</title> | |
1923 | <para> | |
c464fd7e SG |
1924 | In addition to the few examples given below, you will find |
1925 | some other examples of configuration file in @DOCDIR@/examples | |
55fc19a1 SG |
1926 | </para> |
1927 | <refsect2> | |
1928 | <title>Network</title> | |
1929 | <para>This configuration sets up a container to use a veth pair | |
c464fd7e SG |
1930 | device with one side plugged to a bridge br0 (which has been |
1931 | configured before on the system by the administrator). The | |
1932 | virtual network device visible in the container is renamed to | |
1933 | eth0.</para> | |
55fc19a1 | 1934 | <programlisting> |
c464fd7e | 1935 | lxc.utsname = myhostname |
7fa3f2e9 | 1936 | lxc.net.0.type = veth |
1937 | lxc.net.0.flags = up | |
1938 | lxc.net.0.link = br0 | |
1939 | lxc.net.0.name = eth0 | |
1940 | lxc.net.0.hwaddr = 4a:49:43:49:79:bf | |
1941 | lxc.net.0.ipv4 = 10.2.3.5/24 10.2.3.255 | |
1942 | lxc.net.0.ipv6 = 2003:db8:1:0:214:1234:fe0b:3597 | |
55fc19a1 SG |
1943 | </programlisting> |
1944 | </refsect2> | |
1945 | ||
1946 | <refsect2> | |
1947 | <title>UID/GID mapping</title> | |
1948 | <para>This configuration will map both user and group ids in the | |
1949 | range 0-9999 in the container to the ids 100000-109999 on the host. | |
1950 | </para> | |
1951 | <programlisting> | |
c464fd7e SG |
1952 | lxc.id_map = u 0 100000 10000 |
1953 | lxc.id_map = g 0 100000 10000 | |
55fc19a1 SG |
1954 | </programlisting> |
1955 | </refsect2> | |
1956 | ||
1957 | <refsect2> | |
1958 | <title>Control group</title> | |
1959 | <para>This configuration will setup several control groups for | |
1960 | the application, cpuset.cpus restricts usage of the defined cpu, | |
1961 | cpus.share prioritize the control group, devices.allow makes | |
1962 | usable the specified devices.</para> | |
1963 | <programlisting> | |
c464fd7e SG |
1964 | lxc.cgroup.cpuset.cpus = 0,1 |
1965 | lxc.cgroup.cpu.shares = 1234 | |
1966 | lxc.cgroup.devices.deny = a | |
1967 | lxc.cgroup.devices.allow = c 1:3 rw | |
1968 | lxc.cgroup.devices.allow = b 8:0 rw | |
55fc19a1 SG |
1969 | </programlisting> |
1970 | </refsect2> | |
1971 | ||
1972 | <refsect2> | |
1973 | <title>Complex configuration</title> | |
1974 | <para>This example show a complex configuration making a complex | |
1975 | network stack, using the control groups, setting a new hostname, | |
1976 | mounting some locations and a changing root file system.</para> | |
1977 | <programlisting> | |
c464fd7e | 1978 | lxc.utsname = complex |
7fa3f2e9 | 1979 | lxc.net.0.type = veth |
1980 | lxc.net.0.flags = up | |
1981 | lxc.net.0.link = br0 | |
1982 | lxc.net.0.hwaddr = 4a:49:43:49:79:bf | |
1983 | lxc.net.0.ipv4 = 10.2.3.5/24 10.2.3.255 | |
1984 | lxc.net.0.ipv6 = 2003:db8:1:0:214:1234:fe0b:3597 | |
1985 | lxc.net.0.ipv6 = 2003:db8:1:0:214:5432:feab:3588 | |
1986 | lxc.net.1.type = macvlan | |
1987 | lxc.net.1.flags = up | |
1988 | lxc.net.1.link = eth0 | |
1989 | lxc.net.1.hwaddr = 4a:49:43:49:79:bd | |
1990 | lxc.net.1.ipv4 = 10.2.3.4/24 | |
1991 | lxc.net.1.ipv4 = 192.168.10.125/24 | |
1992 | lxc.net.1.ipv6 = 2003:db8:1:0:214:1234:fe0b:3596 | |
1993 | lxc.net.2.type = phys | |
1994 | lxc.net.2.flags = up | |
1995 | lxc.net.2.link = dummy0 | |
1996 | lxc.net.2.hwaddr = 4a:49:43:49:79:ff | |
1997 | lxc.net.2.ipv4 = 10.2.3.6/24 | |
1998 | lxc.net.2.ipv6 = 2003:db8:1:0:214:1234:fe0b:3297 | |
c464fd7e SG |
1999 | lxc.cgroup.cpuset.cpus = 0,1 |
2000 | lxc.cgroup.cpu.shares = 1234 | |
2001 | lxc.cgroup.devices.deny = a | |
2002 | lxc.cgroup.devices.allow = c 1:3 rw | |
2003 | lxc.cgroup.devices.allow = b 8:0 rw | |
2004 | lxc.mount = /etc/fstab.complex | |
2005 | lxc.mount.entry = /lib /root/myrootfs/lib none ro,bind 0 0 | |
2006 | lxc.rootfs = /mnt/rootfs.complex | |
2007 | lxc.cap.drop = sys_module mknod setuid net_raw | |
2008 | lxc.cap.drop = mac_override | |
55fc19a1 SG |
2009 | </programlisting> |
2010 | </refsect2> | |
2011 | ||
2012 | </refsect1> | |
2013 | ||
2014 | <refsect1> | |
2015 | <title>See Also</title> | |
2016 | <simpara> | |
2017 | <citerefentry> | |
c464fd7e SG |
2018 | <refentrytitle><command>chroot</command></refentrytitle> |
2019 | <manvolnum>1</manvolnum> | |
55fc19a1 SG |
2020 | </citerefentry>, |
2021 | ||
2022 | <citerefentry> | |
c464fd7e SG |
2023 | <refentrytitle><command>pivot_root</command></refentrytitle> |
2024 | <manvolnum>8</manvolnum> | |
55fc19a1 SG |
2025 | </citerefentry>, |
2026 | ||
2027 | <citerefentry> | |
c464fd7e SG |
2028 | <refentrytitle><filename>fstab</filename></refentrytitle> |
2029 | <manvolnum>5</manvolnum> | |
55fc19a1 SG |
2030 | </citerefentry>, |
2031 | ||
2032 | <citerefentry> | |
c464fd7e SG |
2033 | <refentrytitle><filename>capabilities</filename></refentrytitle> |
2034 | <manvolnum>7</manvolnum> | |
55fc19a1 SG |
2035 | </citerefentry> |
2036 | </simpara> | |
2037 | </refsect1> | |
2038 | ||
2039 | &seealso; | |
2040 | ||
2041 | <refsect1> | |
2042 | <title>Author</title> | |
2043 | <para>Daniel Lezcano <email>daniel.lezcano@free.fr</email></para> | |
2044 | </refsect1> | |
2045 | ||
2046 | </refentry> | |
2047 | ||
2048 | <!-- Keep this comment at the end of the file | |
2049 | Local variables: | |
2050 | mode: sgml | |
2051 | sgml-omittag:t | |
2052 | sgml-shorttag:t | |
2053 | sgml-minimize-attributes:nil | |
2054 | sgml-always-quote-attributes:t | |
2055 | sgml-indent-step:2 | |
2056 | sgml-indent-data:t | |
2057 | sgml-parent-document:nil | |
2058 | sgml-default-dtd-file:nil | |
2059 | sgml-exposed-tags:nil | |
2060 | sgml-local-catalogs:nil | |
2061 | sgml-local-ecat-files:nil | |
2062 | End: | |
2063 | --> |