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bde0e57d | 1 | [[chapter_pvecm]] |
d8742b0c | 2 | ifdef::manvolnum[] |
b2f242ab DM |
3 | pvecm(1) |
4 | ======== | |
5f09af76 DM |
5 | :pve-toplevel: |
6 | ||
d8742b0c DM |
7 | NAME |
8 | ---- | |
9 | ||
74026b8f | 10 | pvecm - Proxmox VE Cluster Manager |
d8742b0c | 11 | |
49a5e11c | 12 | SYNOPSIS |
d8742b0c DM |
13 | -------- |
14 | ||
15 | include::pvecm.1-synopsis.adoc[] | |
16 | ||
17 | DESCRIPTION | |
18 | ----------- | |
19 | endif::manvolnum[] | |
20 | ||
21 | ifndef::manvolnum[] | |
22 | Cluster Manager | |
23 | =============== | |
5f09af76 | 24 | :pve-toplevel: |
194d2f29 | 25 | endif::manvolnum[] |
5f09af76 | 26 | |
8c1189b6 FG |
27 | The {PVE} cluster manager `pvecm` is a tool to create a group of |
28 | physical servers. Such a group is called a *cluster*. We use the | |
8a865621 | 29 | http://www.corosync.org[Corosync Cluster Engine] for reliable group |
5eba0743 | 30 | communication, and such clusters can consist of up to 32 physical nodes |
8a865621 DM |
31 | (probably more, dependent on network latency). |
32 | ||
8c1189b6 | 33 | `pvecm` can be used to create a new cluster, join nodes to a cluster, |
8a865621 | 34 | leave the cluster, get status information and do various other cluster |
e300cf7d FG |
35 | related tasks. The **P**rox**m**o**x** **C**luster **F**ile **S**ystem (``pmxcfs'') |
36 | is used to transparently distribute the cluster configuration to all cluster | |
8a865621 DM |
37 | nodes. |
38 | ||
39 | Grouping nodes into a cluster has the following advantages: | |
40 | ||
41 | * Centralized, web based management | |
42 | ||
6d3c0b34 | 43 | * Multi-master clusters: each node can do all management tasks |
8a865621 | 44 | |
8c1189b6 FG |
45 | * `pmxcfs`: database-driven file system for storing configuration files, |
46 | replicated in real-time on all nodes using `corosync`. | |
8a865621 | 47 | |
5eba0743 | 48 | * Easy migration of virtual machines and containers between physical |
8a865621 DM |
49 | hosts |
50 | ||
51 | * Fast deployment | |
52 | ||
53 | * Cluster-wide services like firewall and HA | |
54 | ||
55 | ||
56 | Requirements | |
57 | ------------ | |
58 | ||
a9e7c3aa SR |
59 | * All nodes must be able to connect to each other via UDP ports 5404 and 5405 |
60 | for corosync to work. | |
8a865621 DM |
61 | |
62 | * Date and time have to be synchronized. | |
63 | ||
ceabe189 | 64 | * SSH tunnel on TCP port 22 between nodes is used. |
8a865621 | 65 | |
ceabe189 DM |
66 | * If you are interested in High Availability, you need to have at |
67 | least three nodes for reliable quorum. All nodes should have the | |
68 | same version. | |
8a865621 DM |
69 | |
70 | * We recommend a dedicated NIC for the cluster traffic, especially if | |
71 | you use shared storage. | |
72 | ||
d4a9910f DL |
73 | * Root password of a cluster node is required for adding nodes. |
74 | ||
e4b62d04 TL |
75 | NOTE: It is not possible to mix {pve} 3.x and earlier with {pve} 4.X cluster |
76 | nodes. | |
77 | ||
6cab1704 TL |
78 | NOTE: While it's possible to mix {pve} 4.4 and {pve} 5.0 nodes, doing so is |
79 | not supported as production configuration and should only used temporarily | |
80 | during upgrading the whole cluster from one to another major version. | |
8a865621 | 81 | |
a9e7c3aa SR |
82 | NOTE: Running a cluster of {pve} 6.x with earlier versions is not possible. The |
83 | cluster protocol (corosync) between {pve} 6.x and earlier versions changed | |
84 | fundamentally. The corosync 3 packages for {pve} 5.4 are only intended for the | |
85 | upgrade procedure to {pve} 6.0. | |
86 | ||
8a865621 | 87 | |
ceabe189 DM |
88 | Preparing Nodes |
89 | --------------- | |
8a865621 DM |
90 | |
91 | First, install {PVE} on all nodes. Make sure that each node is | |
92 | installed with the final hostname and IP configuration. Changing the | |
93 | hostname and IP is not possible after cluster creation. | |
94 | ||
a9e7c3aa SR |
95 | While it's common to reference all nodenames and their IPs in `/etc/hosts` (or |
96 | make their names resolvable through other means), this is not necessary for a | |
97 | cluster to work. It may be useful however, as you can then connect from one node | |
98 | to the other with SSH via the easier to remember node name (see also | |
99 | xref:pvecm_corosync_addresses[Link Address Types]). Note that we always | |
100 | recommend to reference nodes by their IP addresses in the cluster configuration. | |
101 | ||
9a7396aa | 102 | |
11202f1d | 103 | [[pvecm_create_cluster]] |
6cab1704 TL |
104 | Create a Cluster |
105 | ---------------- | |
106 | ||
107 | You can either create a cluster on the console (login via `ssh`), or through | |
108 | the API using the {pve} Webinterface (__Datacenter -> Cluster__). | |
8a865621 | 109 | |
6cab1704 TL |
110 | NOTE: Use a unique name for your cluster. This name cannot be changed later. |
111 | The cluster name follows the same rules as node names. | |
3e380ce0 | 112 | |
6cab1704 | 113 | [[pvecm_cluster_create_via_gui]] |
3e380ce0 SR |
114 | Create via Web GUI |
115 | ~~~~~~~~~~~~~~~~~~ | |
116 | ||
24398259 SR |
117 | [thumbnail="screenshot/gui-cluster-create.png"] |
118 | ||
3e380ce0 SR |
119 | Under __Datacenter -> Cluster__, click on *Create Cluster*. Enter the cluster |
120 | name and select a network connection from the dropdown to serve as the main | |
121 | cluster network (Link 0). It defaults to the IP resolved via the node's | |
122 | hostname. | |
123 | ||
124 | To add a second link as fallback, you can select the 'Advanced' checkbox and | |
125 | choose an additional network interface (Link 1, see also | |
126 | xref:pvecm_redundancy[Corosync Redundancy]). | |
127 | ||
6cab1704 TL |
128 | NOTE: Ensure the network selected for the cluster communication is not used for |
129 | any high traffic loads like those of (network) storages or live-migration. | |
130 | While the cluster network itself produces small amounts of data, it is very | |
131 | sensitive to latency. Check out full | |
132 | xref:pvecm_cluster_network_requirements[cluster network requirements]. | |
133 | ||
134 | [[pvecm_cluster_create_via_cli]] | |
3e380ce0 SR |
135 | Create via Command Line |
136 | ~~~~~~~~~~~~~~~~~~~~~~~ | |
137 | ||
138 | Login via `ssh` to the first {pve} node and run the following command: | |
8a865621 | 139 | |
c15cdfba TL |
140 | ---- |
141 | hp1# pvecm create CLUSTERNAME | |
142 | ---- | |
8a865621 | 143 | |
3e380ce0 | 144 | To check the state of the new cluster use: |
8a865621 | 145 | |
c15cdfba | 146 | ---- |
8a865621 | 147 | hp1# pvecm status |
c15cdfba | 148 | ---- |
8a865621 | 149 | |
dd1aa0e0 TL |
150 | Multiple Clusters In Same Network |
151 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
152 | ||
153 | It is possible to create multiple clusters in the same physical or logical | |
3e380ce0 SR |
154 | network. Each such cluster must have a unique name to avoid possible clashes in |
155 | the cluster communication stack. This also helps avoid human confusion by making | |
156 | clusters clearly distinguishable. | |
dd1aa0e0 TL |
157 | |
158 | While the bandwidth requirement of a corosync cluster is relatively low, the | |
159 | latency of packages and the package per second (PPS) rate is the limiting | |
160 | factor. Different clusters in the same network can compete with each other for | |
161 | these resources, so it may still make sense to use separate physical network | |
162 | infrastructure for bigger clusters. | |
8a865621 | 163 | |
11202f1d | 164 | [[pvecm_join_node_to_cluster]] |
8a865621 | 165 | Adding Nodes to the Cluster |
ceabe189 | 166 | --------------------------- |
8a865621 | 167 | |
3e380ce0 SR |
168 | CAUTION: A node that is about to be added to the cluster cannot hold any guests. |
169 | All existing configuration in `/etc/pve` is overwritten when joining a cluster, | |
170 | since guest IDs could be conflicting. As a workaround create a backup of the | |
171 | guest (`vzdump`) and restore it as a different ID after the node has been added | |
172 | to the cluster. | |
173 | ||
6cab1704 TL |
174 | Join Node to Cluster via GUI |
175 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
3e380ce0 | 176 | |
24398259 SR |
177 | [thumbnail="screenshot/gui-cluster-join-information.png"] |
178 | ||
3e380ce0 SR |
179 | Login to the web interface on an existing cluster node. Under __Datacenter -> |
180 | Cluster__, click the button *Join Information* at the top. Then, click on the | |
181 | button *Copy Information*. Alternatively, copy the string from the 'Information' | |
182 | field manually. | |
183 | ||
24398259 SR |
184 | [thumbnail="screenshot/gui-cluster-join.png"] |
185 | ||
3e380ce0 SR |
186 | Next, login to the web interface on the node you want to add. |
187 | Under __Datacenter -> Cluster__, click on *Join Cluster*. Fill in the | |
6cab1704 TL |
188 | 'Information' field with the 'Join Information' text you copied earlier. |
189 | Most settings required for joining the cluster will be filled out | |
190 | automatically. For security reasons, the cluster password has to be entered | |
191 | manually. | |
3e380ce0 SR |
192 | |
193 | NOTE: To enter all required data manually, you can disable the 'Assisted Join' | |
194 | checkbox. | |
195 | ||
6cab1704 TL |
196 | After clicking the *Join* button, the cluster join process will start |
197 | immediately. After the node joined the cluster its current node certificate | |
198 | will be replaced by one signed from the cluster certificate authority (CA), | |
199 | that means the current session will stop to work after a few seconds. You might | |
200 | then need to force-reload the webinterface and re-login with the cluster | |
201 | credentials. | |
3e380ce0 | 202 | |
6cab1704 | 203 | Now your node should be visible under __Datacenter -> Cluster__. |
3e380ce0 | 204 | |
6cab1704 TL |
205 | Join Node to Cluster via Command Line |
206 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
3e380ce0 | 207 | |
6cab1704 | 208 | Login via `ssh` to the node you want to join into an existing cluster. |
8a865621 | 209 | |
c15cdfba | 210 | ---- |
8a865621 | 211 | hp2# pvecm add IP-ADDRESS-CLUSTER |
c15cdfba | 212 | ---- |
8a865621 | 213 | |
270757a1 | 214 | For `IP-ADDRESS-CLUSTER` use the IP or hostname of an existing cluster node. |
a9e7c3aa | 215 | An IP address is recommended (see xref:pvecm_corosync_addresses[Link Address Types]). |
8a865621 | 216 | |
8a865621 | 217 | |
a9e7c3aa | 218 | To check the state of the cluster use: |
8a865621 | 219 | |
c15cdfba | 220 | ---- |
8a865621 | 221 | # pvecm status |
c15cdfba | 222 | ---- |
8a865621 | 223 | |
ceabe189 | 224 | .Cluster status after adding 4 nodes |
8a865621 DM |
225 | ---- |
226 | hp2# pvecm status | |
227 | Quorum information | |
228 | ~~~~~~~~~~~~~~~~~~ | |
229 | Date: Mon Apr 20 12:30:13 2015 | |
230 | Quorum provider: corosync_votequorum | |
231 | Nodes: 4 | |
232 | Node ID: 0x00000001 | |
a9e7c3aa | 233 | Ring ID: 1/8 |
8a865621 DM |
234 | Quorate: Yes |
235 | ||
236 | Votequorum information | |
237 | ~~~~~~~~~~~~~~~~~~~~~~ | |
238 | Expected votes: 4 | |
239 | Highest expected: 4 | |
240 | Total votes: 4 | |
91f3edd0 | 241 | Quorum: 3 |
8a865621 DM |
242 | Flags: Quorate |
243 | ||
244 | Membership information | |
245 | ~~~~~~~~~~~~~~~~~~~~~~ | |
246 | Nodeid Votes Name | |
247 | 0x00000001 1 192.168.15.91 | |
248 | 0x00000002 1 192.168.15.92 (local) | |
249 | 0x00000003 1 192.168.15.93 | |
250 | 0x00000004 1 192.168.15.94 | |
251 | ---- | |
252 | ||
253 | If you only want the list of all nodes use: | |
254 | ||
c15cdfba | 255 | ---- |
8a865621 | 256 | # pvecm nodes |
c15cdfba | 257 | ---- |
8a865621 | 258 | |
5eba0743 | 259 | .List nodes in a cluster |
8a865621 DM |
260 | ---- |
261 | hp2# pvecm nodes | |
262 | ||
263 | Membership information | |
264 | ~~~~~~~~~~~~~~~~~~~~~~ | |
265 | Nodeid Votes Name | |
266 | 1 1 hp1 | |
267 | 2 1 hp2 (local) | |
268 | 3 1 hp3 | |
269 | 4 1 hp4 | |
270 | ---- | |
271 | ||
3254bfdd | 272 | [[pvecm_adding_nodes_with_separated_cluster_network]] |
e4ec4154 TL |
273 | Adding Nodes With Separated Cluster Network |
274 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
275 | ||
276 | When adding a node to a cluster with a separated cluster network you need to | |
a9e7c3aa | 277 | use the 'link0' parameter to set the nodes address on that network: |
e4ec4154 TL |
278 | |
279 | [source,bash] | |
4d19cb00 | 280 | ---- |
a9e7c3aa | 281 | pvecm add IP-ADDRESS-CLUSTER -link0 LOCAL-IP-ADDRESS-LINK0 |
4d19cb00 | 282 | ---- |
e4ec4154 | 283 | |
a9e7c3aa SR |
284 | If you want to use the built-in xref:pvecm_redundancy[redundancy] of the |
285 | kronosnet transport layer, also use the 'link1' parameter. | |
e4ec4154 | 286 | |
3e380ce0 SR |
287 | Using the GUI, you can select the correct interface from the corresponding 'Link 0' |
288 | and 'Link 1' fields in the *Cluster Join* dialog. | |
8a865621 DM |
289 | |
290 | Remove a Cluster Node | |
ceabe189 | 291 | --------------------- |
8a865621 DM |
292 | |
293 | CAUTION: Read carefully the procedure before proceeding, as it could | |
294 | not be what you want or need. | |
295 | ||
296 | Move all virtual machines from the node. Make sure you have no local | |
297 | data or backups you want to keep, or save them accordingly. | |
e8503c6c | 298 | In the following example we will remove the node hp4 from the cluster. |
8a865621 | 299 | |
e8503c6c EK |
300 | Log in to a *different* cluster node (not hp4), and issue a `pvecm nodes` |
301 | command to identify the node ID to remove: | |
8a865621 DM |
302 | |
303 | ---- | |
304 | hp1# pvecm nodes | |
305 | ||
306 | Membership information | |
307 | ~~~~~~~~~~~~~~~~~~~~~~ | |
308 | Nodeid Votes Name | |
309 | 1 1 hp1 (local) | |
310 | 2 1 hp2 | |
311 | 3 1 hp3 | |
312 | 4 1 hp4 | |
313 | ---- | |
314 | ||
e8503c6c EK |
315 | |
316 | At this point you must power off hp4 and | |
317 | make sure that it will not power on again (in the network) as it | |
318 | is. | |
319 | ||
320 | IMPORTANT: As said above, it is critical to power off the node | |
321 | *before* removal, and make sure that it will *never* power on again | |
322 | (in the existing cluster network) as it is. | |
323 | If you power on the node as it is, your cluster will be screwed up and | |
324 | it could be difficult to restore a clean cluster state. | |
325 | ||
326 | After powering off the node hp4, we can safely remove it from the cluster. | |
8a865621 | 327 | |
c15cdfba | 328 | ---- |
8a865621 | 329 | hp1# pvecm delnode hp4 |
c15cdfba | 330 | ---- |
8a865621 DM |
331 | |
332 | If the operation succeeds no output is returned, just check the node | |
8c1189b6 | 333 | list again with `pvecm nodes` or `pvecm status`. You should see |
8a865621 DM |
334 | something like: |
335 | ||
336 | ---- | |
337 | hp1# pvecm status | |
338 | ||
339 | Quorum information | |
340 | ~~~~~~~~~~~~~~~~~~ | |
341 | Date: Mon Apr 20 12:44:28 2015 | |
342 | Quorum provider: corosync_votequorum | |
343 | Nodes: 3 | |
344 | Node ID: 0x00000001 | |
a9e7c3aa | 345 | Ring ID: 1/8 |
8a865621 DM |
346 | Quorate: Yes |
347 | ||
348 | Votequorum information | |
349 | ~~~~~~~~~~~~~~~~~~~~~~ | |
350 | Expected votes: 3 | |
351 | Highest expected: 3 | |
352 | Total votes: 3 | |
91f3edd0 | 353 | Quorum: 2 |
8a865621 DM |
354 | Flags: Quorate |
355 | ||
356 | Membership information | |
357 | ~~~~~~~~~~~~~~~~~~~~~~ | |
358 | Nodeid Votes Name | |
359 | 0x00000001 1 192.168.15.90 (local) | |
360 | 0x00000002 1 192.168.15.91 | |
361 | 0x00000003 1 192.168.15.92 | |
362 | ---- | |
363 | ||
a9e7c3aa SR |
364 | If, for whatever reason, you want this server to join the same cluster again, |
365 | you have to | |
8a865621 | 366 | |
26ca7ff5 | 367 | * reinstall {pve} on it from scratch |
8a865621 DM |
368 | |
369 | * then join it, as explained in the previous section. | |
d8742b0c | 370 | |
41925ede SR |
371 | NOTE: After removal of the node, its SSH fingerprint will still reside in the |
372 | 'known_hosts' of the other nodes. If you receive an SSH error after rejoining | |
9121b45b TL |
373 | a node with the same IP or hostname, run `pvecm updatecerts` once on the |
374 | re-added node to update its fingerprint cluster wide. | |
41925ede | 375 | |
38ae8db3 | 376 | [[pvecm_separate_node_without_reinstall]] |
555e966b TL |
377 | Separate A Node Without Reinstalling |
378 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
379 | ||
380 | CAUTION: This is *not* the recommended method, proceed with caution. Use the | |
381 | above mentioned method if you're unsure. | |
382 | ||
383 | You can also separate a node from a cluster without reinstalling it from | |
384 | scratch. But after removing the node from the cluster it will still have | |
385 | access to the shared storages! This must be resolved before you start removing | |
386 | the node from the cluster. A {pve} cluster cannot share the exact same | |
2ea5c4a5 TL |
387 | storage with another cluster, as storage locking doesn't work over cluster |
388 | boundary. Further, it may also lead to VMID conflicts. | |
555e966b | 389 | |
3be22308 | 390 | Its suggested that you create a new storage where only the node which you want |
a9e7c3aa | 391 | to separate has access. This can be a new export on your NFS or a new Ceph |
3be22308 TL |
392 | pool, to name a few examples. Its just important that the exact same storage |
393 | does not gets accessed by multiple clusters. After setting this storage up move | |
394 | all data from the node and its VMs to it. Then you are ready to separate the | |
395 | node from the cluster. | |
555e966b | 396 | |
a9e7c3aa SR |
397 | WARNING: Ensure all shared resources are cleanly separated! Otherwise you will |
398 | run into conflicts and problems. | |
555e966b TL |
399 | |
400 | First stop the corosync and the pve-cluster services on the node: | |
401 | [source,bash] | |
4d19cb00 | 402 | ---- |
555e966b TL |
403 | systemctl stop pve-cluster |
404 | systemctl stop corosync | |
4d19cb00 | 405 | ---- |
555e966b TL |
406 | |
407 | Start the cluster filesystem again in local mode: | |
408 | [source,bash] | |
4d19cb00 | 409 | ---- |
555e966b | 410 | pmxcfs -l |
4d19cb00 | 411 | ---- |
555e966b TL |
412 | |
413 | Delete the corosync configuration files: | |
414 | [source,bash] | |
4d19cb00 | 415 | ---- |
555e966b TL |
416 | rm /etc/pve/corosync.conf |
417 | rm /etc/corosync/* | |
4d19cb00 | 418 | ---- |
555e966b TL |
419 | |
420 | You can now start the filesystem again as normal service: | |
421 | [source,bash] | |
4d19cb00 | 422 | ---- |
555e966b TL |
423 | killall pmxcfs |
424 | systemctl start pve-cluster | |
4d19cb00 | 425 | ---- |
555e966b TL |
426 | |
427 | The node is now separated from the cluster. You can deleted it from a remaining | |
428 | node of the cluster with: | |
429 | [source,bash] | |
4d19cb00 | 430 | ---- |
555e966b | 431 | pvecm delnode oldnode |
4d19cb00 | 432 | ---- |
555e966b TL |
433 | |
434 | If the command failed, because the remaining node in the cluster lost quorum | |
435 | when the now separate node exited, you may set the expected votes to 1 as a workaround: | |
436 | [source,bash] | |
4d19cb00 | 437 | ---- |
555e966b | 438 | pvecm expected 1 |
4d19cb00 | 439 | ---- |
555e966b | 440 | |
96d698db | 441 | And then repeat the 'pvecm delnode' command. |
555e966b TL |
442 | |
443 | Now switch back to the separated node, here delete all remaining files left | |
444 | from the old cluster. This ensures that the node can be added to another | |
445 | cluster again without problems. | |
446 | ||
447 | [source,bash] | |
4d19cb00 | 448 | ---- |
555e966b | 449 | rm /var/lib/corosync/* |
4d19cb00 | 450 | ---- |
555e966b TL |
451 | |
452 | As the configuration files from the other nodes are still in the cluster | |
453 | filesystem you may want to clean those up too. Remove simply the whole | |
454 | directory recursive from '/etc/pve/nodes/NODENAME', but check three times that | |
455 | you used the correct one before deleting it. | |
456 | ||
457 | CAUTION: The nodes SSH keys are still in the 'authorized_key' file, this means | |
458 | the nodes can still connect to each other with public key authentication. This | |
459 | should be fixed by removing the respective keys from the | |
460 | '/etc/pve/priv/authorized_keys' file. | |
d8742b0c | 461 | |
a9e7c3aa | 462 | |
806ef12d DM |
463 | Quorum |
464 | ------ | |
465 | ||
466 | {pve} use a quorum-based technique to provide a consistent state among | |
467 | all cluster nodes. | |
468 | ||
469 | [quote, from Wikipedia, Quorum (distributed computing)] | |
470 | ____ | |
471 | A quorum is the minimum number of votes that a distributed transaction | |
472 | has to obtain in order to be allowed to perform an operation in a | |
473 | distributed system. | |
474 | ____ | |
475 | ||
476 | In case of network partitioning, state changes requires that a | |
477 | majority of nodes are online. The cluster switches to read-only mode | |
5eba0743 | 478 | if it loses quorum. |
806ef12d DM |
479 | |
480 | NOTE: {pve} assigns a single vote to each node by default. | |
481 | ||
a9e7c3aa | 482 | |
e4ec4154 TL |
483 | Cluster Network |
484 | --------------- | |
485 | ||
486 | The cluster network is the core of a cluster. All messages sent over it have to | |
a9e7c3aa SR |
487 | be delivered reliably to all nodes in their respective order. In {pve} this |
488 | part is done by corosync, an implementation of a high performance, low overhead | |
e4ec4154 TL |
489 | high availability development toolkit. It serves our decentralized |
490 | configuration file system (`pmxcfs`). | |
491 | ||
3254bfdd | 492 | [[pvecm_cluster_network_requirements]] |
e4ec4154 TL |
493 | Network Requirements |
494 | ~~~~~~~~~~~~~~~~~~~~ | |
495 | This needs a reliable network with latencies under 2 milliseconds (LAN | |
a9e7c3aa SR |
496 | performance) to work properly. The network should not be used heavily by other |
497 | members, ideally corosync runs on its own network. Do not use a shared network | |
498 | for corosync and storage (except as a potential low-priority fallback in a | |
499 | xref:pvecm_redundancy[redundant] configuration). | |
e4ec4154 | 500 | |
a9e7c3aa SR |
501 | Before setting up a cluster, it is good practice to check if the network is fit |
502 | for that purpose. To make sure the nodes can connect to each other on the | |
503 | cluster network, you can test the connectivity between them with the `ping` | |
504 | tool. | |
e4ec4154 | 505 | |
a9e7c3aa SR |
506 | If the {pve} firewall is enabled, ACCEPT rules for corosync will automatically |
507 | be generated - no manual action is required. | |
e4ec4154 | 508 | |
a9e7c3aa SR |
509 | NOTE: Corosync used Multicast before version 3.0 (introduced in {pve} 6.0). |
510 | Modern versions rely on https://kronosnet.org/[Kronosnet] for cluster | |
511 | communication, which, for now, only supports regular UDP unicast. | |
e4ec4154 | 512 | |
a9e7c3aa SR |
513 | CAUTION: You can still enable Multicast or legacy unicast by setting your |
514 | transport to `udp` or `udpu` in your xref:pvecm_edit_corosync_conf[corosync.conf], | |
515 | but keep in mind that this will disable all cryptography and redundancy support. | |
516 | This is therefore not recommended. | |
e4ec4154 TL |
517 | |
518 | Separate Cluster Network | |
519 | ~~~~~~~~~~~~~~~~~~~~~~~~ | |
520 | ||
a9e7c3aa SR |
521 | When creating a cluster without any parameters the corosync cluster network is |
522 | generally shared with the Web UI and the VMs and their traffic. Depending on | |
523 | your setup, even storage traffic may get sent over the same network. Its | |
524 | recommended to change that, as corosync is a time critical real time | |
525 | application. | |
e4ec4154 TL |
526 | |
527 | Setting Up A New Network | |
528 | ^^^^^^^^^^^^^^^^^^^^^^^^ | |
529 | ||
a9e7c3aa | 530 | First you have to set up a new network interface. It should be on a physically |
e4ec4154 | 531 | separate network. Ensure that your network fulfills the |
3254bfdd | 532 | xref:pvecm_cluster_network_requirements[cluster network requirements]. |
e4ec4154 TL |
533 | |
534 | Separate On Cluster Creation | |
535 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
536 | ||
a9e7c3aa SR |
537 | This is possible via the 'linkX' parameters of the 'pvecm create' |
538 | command used for creating a new cluster. | |
e4ec4154 | 539 | |
a9e7c3aa SR |
540 | If you have set up an additional NIC with a static address on 10.10.10.1/25, |
541 | and want to send and receive all cluster communication over this interface, | |
e4ec4154 TL |
542 | you would execute: |
543 | ||
544 | [source,bash] | |
4d19cb00 | 545 | ---- |
a9e7c3aa | 546 | pvecm create test --link0 10.10.10.1 |
4d19cb00 | 547 | ---- |
e4ec4154 TL |
548 | |
549 | To check if everything is working properly execute: | |
550 | [source,bash] | |
4d19cb00 | 551 | ---- |
e4ec4154 | 552 | systemctl status corosync |
4d19cb00 | 553 | ---- |
e4ec4154 | 554 | |
a9e7c3aa | 555 | Afterwards, proceed as described above to |
3254bfdd | 556 | xref:pvecm_adding_nodes_with_separated_cluster_network[add nodes with a separated cluster network]. |
82d52451 | 557 | |
3254bfdd | 558 | [[pvecm_separate_cluster_net_after_creation]] |
e4ec4154 TL |
559 | Separate After Cluster Creation |
560 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
561 | ||
a9e7c3aa | 562 | You can do this if you have already created a cluster and want to switch |
e4ec4154 TL |
563 | its communication to another network, without rebuilding the whole cluster. |
564 | This change may lead to short durations of quorum loss in the cluster, as nodes | |
565 | have to restart corosync and come up one after the other on the new network. | |
566 | ||
3254bfdd | 567 | Check how to xref:pvecm_edit_corosync_conf[edit the corosync.conf file] first. |
a9e7c3aa | 568 | Then, open it and you should see a file similar to: |
e4ec4154 TL |
569 | |
570 | ---- | |
571 | logging { | |
572 | debug: off | |
573 | to_syslog: yes | |
574 | } | |
575 | ||
576 | nodelist { | |
577 | ||
578 | node { | |
579 | name: due | |
580 | nodeid: 2 | |
581 | quorum_votes: 1 | |
582 | ring0_addr: due | |
583 | } | |
584 | ||
585 | node { | |
586 | name: tre | |
587 | nodeid: 3 | |
588 | quorum_votes: 1 | |
589 | ring0_addr: tre | |
590 | } | |
591 | ||
592 | node { | |
593 | name: uno | |
594 | nodeid: 1 | |
595 | quorum_votes: 1 | |
596 | ring0_addr: uno | |
597 | } | |
598 | ||
599 | } | |
600 | ||
601 | quorum { | |
602 | provider: corosync_votequorum | |
603 | } | |
604 | ||
605 | totem { | |
a9e7c3aa | 606 | cluster_name: testcluster |
e4ec4154 | 607 | config_version: 3 |
a9e7c3aa | 608 | ip_version: ipv4-6 |
e4ec4154 TL |
609 | secauth: on |
610 | version: 2 | |
611 | interface { | |
a9e7c3aa | 612 | linknumber: 0 |
e4ec4154 TL |
613 | } |
614 | ||
615 | } | |
616 | ---- | |
617 | ||
a9e7c3aa SR |
618 | NOTE: `ringX_addr` actually specifies a corosync *link address*, the name "ring" |
619 | is a remnant of older corosync versions that is kept for backwards | |
620 | compatibility. | |
621 | ||
622 | The first thing you want to do is add the 'name' properties in the node entries | |
623 | if you do not see them already. Those *must* match the node name. | |
e4ec4154 | 624 | |
a9e7c3aa SR |
625 | Then replace all addresses from the 'ring0_addr' properties of all nodes with |
626 | the new addresses. You may use plain IP addresses or hostnames here. If you use | |
270757a1 | 627 | hostnames ensure that they are resolvable from all nodes. (see also |
a9e7c3aa | 628 | xref:pvecm_corosync_addresses[Link Address Types]) |
e4ec4154 | 629 | |
a9e7c3aa SR |
630 | In this example, we want to switch the cluster communication to the |
631 | 10.10.10.1/25 network. So we replace all 'ring0_addr' respectively. | |
e4ec4154 | 632 | |
a9e7c3aa SR |
633 | NOTE: The exact same procedure can be used to change other 'ringX_addr' values |
634 | as well, although we recommend to not change multiple addresses at once, to make | |
635 | it easier to recover if something goes wrong. | |
636 | ||
637 | After we increase the 'config_version' property, the new configuration file | |
e4ec4154 TL |
638 | should look like: |
639 | ||
640 | ---- | |
e4ec4154 TL |
641 | logging { |
642 | debug: off | |
643 | to_syslog: yes | |
644 | } | |
645 | ||
646 | nodelist { | |
647 | ||
648 | node { | |
649 | name: due | |
650 | nodeid: 2 | |
651 | quorum_votes: 1 | |
652 | ring0_addr: 10.10.10.2 | |
653 | } | |
654 | ||
655 | node { | |
656 | name: tre | |
657 | nodeid: 3 | |
658 | quorum_votes: 1 | |
659 | ring0_addr: 10.10.10.3 | |
660 | } | |
661 | ||
662 | node { | |
663 | name: uno | |
664 | nodeid: 1 | |
665 | quorum_votes: 1 | |
666 | ring0_addr: 10.10.10.1 | |
667 | } | |
668 | ||
669 | } | |
670 | ||
671 | quorum { | |
672 | provider: corosync_votequorum | |
673 | } | |
674 | ||
675 | totem { | |
a9e7c3aa | 676 | cluster_name: testcluster |
e4ec4154 | 677 | config_version: 4 |
a9e7c3aa | 678 | ip_version: ipv4-6 |
e4ec4154 TL |
679 | secauth: on |
680 | version: 2 | |
681 | interface { | |
a9e7c3aa | 682 | linknumber: 0 |
e4ec4154 TL |
683 | } |
684 | ||
685 | } | |
686 | ---- | |
687 | ||
a9e7c3aa SR |
688 | Then, after a final check if all changed information is correct, we save it and |
689 | once again follow the xref:pvecm_edit_corosync_conf[edit corosync.conf file] | |
690 | section to bring it into effect. | |
e4ec4154 | 691 | |
a9e7c3aa SR |
692 | The changes will be applied live, so restarting corosync is not strictly |
693 | necessary. If you changed other settings as well, or notice corosync | |
694 | complaining, you can optionally trigger a restart. | |
e4ec4154 TL |
695 | |
696 | On a single node execute: | |
a9e7c3aa | 697 | |
e4ec4154 | 698 | [source,bash] |
4d19cb00 | 699 | ---- |
e4ec4154 | 700 | systemctl restart corosync |
4d19cb00 | 701 | ---- |
e4ec4154 TL |
702 | |
703 | Now check if everything is fine: | |
704 | ||
705 | [source,bash] | |
4d19cb00 | 706 | ---- |
e4ec4154 | 707 | systemctl status corosync |
4d19cb00 | 708 | ---- |
e4ec4154 TL |
709 | |
710 | If corosync runs again correct restart corosync also on all other nodes. | |
711 | They will then join the cluster membership one by one on the new network. | |
712 | ||
3254bfdd | 713 | [[pvecm_corosync_addresses]] |
270757a1 SR |
714 | Corosync addresses |
715 | ~~~~~~~~~~~~~~~~~~ | |
716 | ||
a9e7c3aa SR |
717 | A corosync link address (for backwards compatibility denoted by 'ringX_addr' in |
718 | `corosync.conf`) can be specified in two ways: | |
270757a1 SR |
719 | |
720 | * **IPv4/v6 addresses** will be used directly. They are recommended, since they | |
721 | are static and usually not changed carelessly. | |
722 | ||
723 | * **Hostnames** will be resolved using `getaddrinfo`, which means that per | |
724 | default, IPv6 addresses will be used first, if available (see also | |
725 | `man gai.conf`). Keep this in mind, especially when upgrading an existing | |
726 | cluster to IPv6. | |
727 | ||
728 | CAUTION: Hostnames should be used with care, since the address they | |
729 | resolve to can be changed without touching corosync or the node it runs on - | |
730 | which may lead to a situation where an address is changed without thinking | |
731 | about implications for corosync. | |
732 | ||
733 | A seperate, static hostname specifically for corosync is recommended, if | |
734 | hostnames are preferred. Also, make sure that every node in the cluster can | |
735 | resolve all hostnames correctly. | |
736 | ||
737 | Since {pve} 5.1, while supported, hostnames will be resolved at the time of | |
738 | entry. Only the resolved IP is then saved to the configuration. | |
739 | ||
740 | Nodes that joined the cluster on earlier versions likely still use their | |
741 | unresolved hostname in `corosync.conf`. It might be a good idea to replace | |
742 | them with IPs or a seperate hostname, as mentioned above. | |
743 | ||
e4ec4154 | 744 | |
a9e7c3aa SR |
745 | [[pvecm_redundancy]] |
746 | Corosync Redundancy | |
747 | ------------------- | |
e4ec4154 | 748 | |
a9e7c3aa SR |
749 | Corosync supports redundant networking via its integrated kronosnet layer by |
750 | default (it is not supported on the legacy udp/udpu transports). It can be | |
751 | enabled by specifying more than one link address, either via the '--linkX' | |
3e380ce0 SR |
752 | parameters of `pvecm`, in the GUI as **Link 1** (while creating a cluster or |
753 | adding a new node) or by specifying more than one 'ringX_addr' in | |
754 | `corosync.conf`. | |
e4ec4154 | 755 | |
a9e7c3aa SR |
756 | NOTE: To provide useful failover, every link should be on its own |
757 | physical network connection. | |
e4ec4154 | 758 | |
a9e7c3aa SR |
759 | Links are used according to a priority setting. You can configure this priority |
760 | by setting 'knet_link_priority' in the corresponding interface section in | |
761 | `corosync.conf`, or, preferrably, using the 'priority' parameter when creating | |
762 | your cluster with `pvecm`: | |
e4ec4154 | 763 | |
4d19cb00 | 764 | ---- |
a9e7c3aa | 765 | # pvecm create CLUSTERNAME --link0 10.10.10.1,priority=20 --link1 10.20.20.1,priority=15 |
4d19cb00 | 766 | ---- |
e4ec4154 | 767 | |
a9e7c3aa SR |
768 | This would cause 'link1' to be used first, since it has the lower priority. |
769 | ||
770 | If no priorities are configured manually (or two links have the same priority), | |
771 | links will be used in order of their number, with the lower number having higher | |
772 | priority. | |
773 | ||
774 | Even if all links are working, only the one with the highest priority will see | |
775 | corosync traffic. Link priorities cannot be mixed, i.e. links with different | |
776 | priorities will not be able to communicate with each other. | |
e4ec4154 | 777 | |
a9e7c3aa SR |
778 | Since lower priority links will not see traffic unless all higher priorities |
779 | have failed, it becomes a useful strategy to specify even networks used for | |
780 | other tasks (VMs, storage, etc...) as low-priority links. If worst comes to | |
781 | worst, a higher-latency or more congested connection might be better than no | |
782 | connection at all. | |
e4ec4154 | 783 | |
a9e7c3aa SR |
784 | Adding Redundant Links To An Existing Cluster |
785 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
e4ec4154 | 786 | |
a9e7c3aa SR |
787 | To add a new link to a running configuration, first check how to |
788 | xref:pvecm_edit_corosync_conf[edit the corosync.conf file]. | |
e4ec4154 | 789 | |
a9e7c3aa SR |
790 | Then, add a new 'ringX_addr' to every node in the `nodelist` section. Make |
791 | sure that your 'X' is the same for every node you add it to, and that it is | |
792 | unique for each node. | |
793 | ||
794 | Lastly, add a new 'interface', as shown below, to your `totem` | |
795 | section, replacing 'X' with your link number chosen above. | |
796 | ||
797 | Assuming you added a link with number 1, the new configuration file could look | |
798 | like this: | |
e4ec4154 TL |
799 | |
800 | ---- | |
a9e7c3aa SR |
801 | logging { |
802 | debug: off | |
803 | to_syslog: yes | |
e4ec4154 TL |
804 | } |
805 | ||
806 | nodelist { | |
a9e7c3aa | 807 | |
e4ec4154 | 808 | node { |
a9e7c3aa SR |
809 | name: due |
810 | nodeid: 2 | |
e4ec4154 | 811 | quorum_votes: 1 |
a9e7c3aa SR |
812 | ring0_addr: 10.10.10.2 |
813 | ring1_addr: 10.20.20.2 | |
e4ec4154 TL |
814 | } |
815 | ||
a9e7c3aa SR |
816 | node { |
817 | name: tre | |
818 | nodeid: 3 | |
e4ec4154 | 819 | quorum_votes: 1 |
a9e7c3aa SR |
820 | ring0_addr: 10.10.10.3 |
821 | ring1_addr: 10.20.20.3 | |
e4ec4154 TL |
822 | } |
823 | ||
a9e7c3aa SR |
824 | node { |
825 | name: uno | |
826 | nodeid: 1 | |
827 | quorum_votes: 1 | |
828 | ring0_addr: 10.10.10.1 | |
829 | ring1_addr: 10.20.20.1 | |
830 | } | |
831 | ||
832 | } | |
833 | ||
834 | quorum { | |
835 | provider: corosync_votequorum | |
836 | } | |
837 | ||
838 | totem { | |
839 | cluster_name: testcluster | |
840 | config_version: 4 | |
841 | ip_version: ipv4-6 | |
842 | secauth: on | |
843 | version: 2 | |
844 | interface { | |
845 | linknumber: 0 | |
846 | } | |
847 | interface { | |
848 | linknumber: 1 | |
849 | } | |
e4ec4154 | 850 | } |
a9e7c3aa | 851 | ---- |
e4ec4154 | 852 | |
a9e7c3aa SR |
853 | The new link will be enabled as soon as you follow the last steps to |
854 | xref:pvecm_edit_corosync_conf[edit the corosync.conf file]. A restart should not | |
855 | be necessary. You can check that corosync loaded the new link using: | |
e4ec4154 | 856 | |
a9e7c3aa SR |
857 | ---- |
858 | journalctl -b -u corosync | |
e4ec4154 TL |
859 | ---- |
860 | ||
a9e7c3aa SR |
861 | It might be a good idea to test the new link by temporarily disconnecting the |
862 | old link on one node and making sure that its status remains online while | |
863 | disconnected: | |
e4ec4154 | 864 | |
a9e7c3aa SR |
865 | ---- |
866 | pvecm status | |
867 | ---- | |
868 | ||
869 | If you see a healthy cluster state, it means that your new link is being used. | |
e4ec4154 | 870 | |
e4ec4154 | 871 | |
c21d2cbe OB |
872 | Corosync External Vote Support |
873 | ------------------------------ | |
874 | ||
875 | This section describes a way to deploy an external voter in a {pve} cluster. | |
876 | When configured, the cluster can sustain more node failures without | |
877 | violating safety properties of the cluster communication. | |
878 | ||
879 | For this to work there are two services involved: | |
880 | ||
881 | * a so called qdevice daemon which runs on each {pve} node | |
882 | ||
883 | * an external vote daemon which runs on an independent server. | |
884 | ||
885 | As a result you can achieve higher availability even in smaller setups (for | |
886 | example 2+1 nodes). | |
887 | ||
888 | QDevice Technical Overview | |
889 | ~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
890 | ||
891 | The Corosync Quroum Device (QDevice) is a daemon which runs on each cluster | |
892 | node. It provides a configured number of votes to the clusters quorum | |
893 | subsystem based on an external running third-party arbitrator's decision. | |
894 | Its primary use is to allow a cluster to sustain more node failures than | |
895 | standard quorum rules allow. This can be done safely as the external device | |
896 | can see all nodes and thus choose only one set of nodes to give its vote. | |
51730d56 | 897 | This will only be done if said set of nodes can have quorum (again) when |
c21d2cbe OB |
898 | receiving the third-party vote. |
899 | ||
900 | Currently only 'QDevice Net' is supported as a third-party arbitrator. It is | |
901 | a daemon which provides a vote to a cluster partition if it can reach the | |
902 | partition members over the network. It will give only votes to one partition | |
903 | of a cluster at any time. | |
904 | It's designed to support multiple clusters and is almost configuration and | |
905 | state free. New clusters are handled dynamically and no configuration file | |
906 | is needed on the host running a QDevice. | |
907 | ||
908 | The external host has the only requirement that it needs network access to the | |
909 | cluster and a corosync-qnetd package available. We provide such a package | |
910 | for Debian based hosts, other Linux distributions should also have a package | |
911 | available through their respective package manager. | |
912 | ||
913 | NOTE: In contrast to corosync itself, a QDevice connects to the cluster over | |
a9e7c3aa SR |
914 | TCP/IP. The daemon may even run outside of the clusters LAN and can have longer |
915 | latencies than 2 ms. | |
c21d2cbe OB |
916 | |
917 | Supported Setups | |
918 | ~~~~~~~~~~~~~~~~ | |
919 | ||
920 | We support QDevices for clusters with an even number of nodes and recommend | |
921 | it for 2 node clusters, if they should provide higher availability. | |
922 | For clusters with an odd node count we discourage the use of QDevices | |
923 | currently. The reason for this, is the difference of the votes the QDevice | |
924 | provides for each cluster type. Even numbered clusters get single additional | |
925 | vote, with this we can only increase availability, i.e. if the QDevice | |
926 | itself fails we are in the same situation as with no QDevice at all. | |
927 | ||
928 | Now, with an odd numbered cluster size the QDevice provides '(N-1)' votes -- | |
929 | where 'N' corresponds to the cluster node count. This difference makes | |
930 | sense, if we had only one additional vote the cluster can get into a split | |
931 | brain situation. | |
932 | This algorithm would allow that all nodes but one (and naturally the | |
933 | QDevice itself) could fail. | |
934 | There are two drawbacks with this: | |
935 | ||
936 | * If the QNet daemon itself fails, no other node may fail or the cluster | |
937 | immediately loses quorum. For example, in a cluster with 15 nodes 7 | |
938 | could fail before the cluster becomes inquorate. But, if a QDevice is | |
939 | configured here and said QDevice fails itself **no single node** of | |
940 | the 15 may fail. The QDevice acts almost as a single point of failure in | |
941 | this case. | |
942 | ||
943 | * The fact that all but one node plus QDevice may fail sound promising at | |
944 | first, but this may result in a mass recovery of HA services that would | |
945 | overload the single node left. Also ceph server will stop to provide | |
946 | services after only '((N-1)/2)' nodes are online. | |
947 | ||
948 | If you understand the drawbacks and implications you can decide yourself if | |
949 | you should use this technology in an odd numbered cluster setup. | |
950 | ||
c21d2cbe OB |
951 | QDevice-Net Setup |
952 | ~~~~~~~~~~~~~~~~~ | |
953 | ||
954 | We recommend to run any daemon which provides votes to corosync-qdevice as an | |
e34c3e91 TL |
955 | unprivileged user. {pve} and Debian provides a package which is already |
956 | configured to do so. | |
c21d2cbe OB |
957 | The traffic between the daemon and the cluster must be encrypted to ensure a |
958 | safe and secure QDevice integration in {pve}. | |
959 | ||
960 | First install the 'corosync-qnetd' package on your external server and | |
961 | the 'corosync-qdevice' package on all cluster nodes. | |
962 | ||
963 | After that, ensure that all your nodes on the cluster are online. | |
964 | ||
965 | You can now easily set up your QDevice by running the following command on one | |
966 | of the {pve} nodes: | |
967 | ||
968 | ---- | |
969 | pve# pvecm qdevice setup <QDEVICE-IP> | |
970 | ---- | |
971 | ||
972 | The SSH key from the cluster will be automatically copied to the QDevice. You | |
973 | might need to enter an SSH password during this step. | |
974 | ||
975 | After you enter the password and all the steps are successfully completed, you | |
976 | will see "Done". You can check the status now: | |
977 | ||
978 | ---- | |
979 | pve# pvecm status | |
980 | ||
981 | ... | |
982 | ||
983 | Votequorum information | |
984 | ~~~~~~~~~~~~~~~~~~~~~ | |
985 | Expected votes: 3 | |
986 | Highest expected: 3 | |
987 | Total votes: 3 | |
988 | Quorum: 2 | |
989 | Flags: Quorate Qdevice | |
990 | ||
991 | Membership information | |
992 | ~~~~~~~~~~~~~~~~~~~~~~ | |
993 | Nodeid Votes Qdevice Name | |
994 | 0x00000001 1 A,V,NMW 192.168.22.180 (local) | |
995 | 0x00000002 1 A,V,NMW 192.168.22.181 | |
996 | 0x00000000 1 Qdevice | |
997 | ||
998 | ---- | |
999 | ||
1000 | which means the QDevice is set up. | |
1001 | ||
c21d2cbe OB |
1002 | Frequently Asked Questions |
1003 | ~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
1004 | ||
1005 | Tie Breaking | |
1006 | ^^^^^^^^^^^^ | |
1007 | ||
00821894 TL |
1008 | In case of a tie, where two same-sized cluster partitions cannot see each other |
1009 | but the QDevice, the QDevice chooses randomly one of those partitions and | |
c21d2cbe OB |
1010 | provides a vote to it. |
1011 | ||
d31de328 TL |
1012 | Possible Negative Implications |
1013 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
1014 | ||
00821894 TL |
1015 | For clusters with an even node count there are no negative implications when |
1016 | setting up a QDevice. If it fails to work, you are as good as without QDevice at | |
1017 | all. | |
d31de328 | 1018 | |
870c2817 OB |
1019 | Adding/Deleting Nodes After QDevice Setup |
1020 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
d31de328 TL |
1021 | |
1022 | If you want to add a new node or remove an existing one from a cluster with a | |
00821894 TL |
1023 | QDevice setup, you need to remove the QDevice first. After that, you can add or |
1024 | remove nodes normally. Once you have a cluster with an even node count again, | |
1025 | you can set up the QDevice again as described above. | |
870c2817 OB |
1026 | |
1027 | Removing the QDevice | |
1028 | ^^^^^^^^^^^^^^^^^^^^ | |
1029 | ||
00821894 TL |
1030 | If you used the official `pvecm` tool to add the QDevice, you can remove it |
1031 | trivially by running: | |
870c2817 OB |
1032 | |
1033 | ---- | |
1034 | pve# pvecm qdevice remove | |
1035 | ---- | |
d31de328 | 1036 | |
51730d56 TL |
1037 | //Still TODO |
1038 | //^^^^^^^^^^ | |
a9e7c3aa | 1039 | //There is still stuff to add here |
c21d2cbe OB |
1040 | |
1041 | ||
e4ec4154 TL |
1042 | Corosync Configuration |
1043 | ---------------------- | |
1044 | ||
a9e7c3aa SR |
1045 | The `/etc/pve/corosync.conf` file plays a central role in a {pve} cluster. It |
1046 | controls the cluster membership and its network. | |
1047 | For further information about it, check the corosync.conf man page: | |
e4ec4154 | 1048 | [source,bash] |
4d19cb00 | 1049 | ---- |
e4ec4154 | 1050 | man corosync.conf |
4d19cb00 | 1051 | ---- |
e4ec4154 TL |
1052 | |
1053 | For node membership you should always use the `pvecm` tool provided by {pve}. | |
1054 | You may have to edit the configuration file manually for other changes. | |
1055 | Here are a few best practice tips for doing this. | |
1056 | ||
3254bfdd | 1057 | [[pvecm_edit_corosync_conf]] |
e4ec4154 TL |
1058 | Edit corosync.conf |
1059 | ~~~~~~~~~~~~~~~~~~ | |
1060 | ||
a9e7c3aa SR |
1061 | Editing the corosync.conf file is not always very straightforward. There are |
1062 | two on each cluster node, one in `/etc/pve/corosync.conf` and the other in | |
e4ec4154 TL |
1063 | `/etc/corosync/corosync.conf`. Editing the one in our cluster file system will |
1064 | propagate the changes to the local one, but not vice versa. | |
1065 | ||
1066 | The configuration will get updated automatically as soon as the file changes. | |
1067 | This means changes which can be integrated in a running corosync will take | |
a9e7c3aa SR |
1068 | effect immediately. So you should always make a copy and edit that instead, to |
1069 | avoid triggering some unwanted changes by an in-between safe. | |
e4ec4154 TL |
1070 | |
1071 | [source,bash] | |
4d19cb00 | 1072 | ---- |
e4ec4154 | 1073 | cp /etc/pve/corosync.conf /etc/pve/corosync.conf.new |
4d19cb00 | 1074 | ---- |
e4ec4154 | 1075 | |
a9e7c3aa SR |
1076 | Then open the config file with your favorite editor, `nano` and `vim.tiny` are |
1077 | preinstalled on any {pve} node for example. | |
e4ec4154 TL |
1078 | |
1079 | NOTE: Always increment the 'config_version' number on configuration changes, | |
1080 | omitting this can lead to problems. | |
1081 | ||
1082 | After making the necessary changes create another copy of the current working | |
1083 | configuration file. This serves as a backup if the new configuration fails to | |
1084 | apply or makes problems in other ways. | |
1085 | ||
1086 | [source,bash] | |
4d19cb00 | 1087 | ---- |
e4ec4154 | 1088 | cp /etc/pve/corosync.conf /etc/pve/corosync.conf.bak |
4d19cb00 | 1089 | ---- |
e4ec4154 TL |
1090 | |
1091 | Then move the new configuration file over the old one: | |
1092 | [source,bash] | |
4d19cb00 | 1093 | ---- |
e4ec4154 | 1094 | mv /etc/pve/corosync.conf.new /etc/pve/corosync.conf |
4d19cb00 | 1095 | ---- |
e4ec4154 TL |
1096 | |
1097 | You may check with the commands | |
1098 | [source,bash] | |
4d19cb00 | 1099 | ---- |
e4ec4154 TL |
1100 | systemctl status corosync |
1101 | journalctl -b -u corosync | |
4d19cb00 | 1102 | ---- |
e4ec4154 | 1103 | |
a9e7c3aa | 1104 | If the change could be applied automatically. If not you may have to restart the |
e4ec4154 TL |
1105 | corosync service via: |
1106 | [source,bash] | |
4d19cb00 | 1107 | ---- |
e4ec4154 | 1108 | systemctl restart corosync |
4d19cb00 | 1109 | ---- |
e4ec4154 TL |
1110 | |
1111 | On errors check the troubleshooting section below. | |
1112 | ||
1113 | Troubleshooting | |
1114 | ~~~~~~~~~~~~~~~ | |
1115 | ||
1116 | Issue: 'quorum.expected_votes must be configured' | |
1117 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
1118 | ||
1119 | When corosync starts to fail and you get the following message in the system log: | |
1120 | ||
1121 | ---- | |
1122 | [...] | |
1123 | corosync[1647]: [QUORUM] Quorum provider: corosync_votequorum failed to initialize. | |
1124 | corosync[1647]: [SERV ] Service engine 'corosync_quorum' failed to load for reason | |
1125 | 'configuration error: nodelist or quorum.expected_votes must be configured!' | |
1126 | [...] | |
1127 | ---- | |
1128 | ||
1129 | It means that the hostname you set for corosync 'ringX_addr' in the | |
1130 | configuration could not be resolved. | |
1131 | ||
e4ec4154 TL |
1132 | Write Configuration When Not Quorate |
1133 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
1134 | ||
1135 | If you need to change '/etc/pve/corosync.conf' on an node with no quorum, and you | |
1136 | know what you do, use: | |
1137 | [source,bash] | |
4d19cb00 | 1138 | ---- |
e4ec4154 | 1139 | pvecm expected 1 |
4d19cb00 | 1140 | ---- |
e4ec4154 TL |
1141 | |
1142 | This sets the expected vote count to 1 and makes the cluster quorate. You can | |
1143 | now fix your configuration, or revert it back to the last working backup. | |
1144 | ||
6d3c0b34 | 1145 | This is not enough if corosync cannot start anymore. Here it is best to edit the |
e4ec4154 TL |
1146 | local copy of the corosync configuration in '/etc/corosync/corosync.conf' so |
1147 | that corosync can start again. Ensure that on all nodes this configuration has | |
1148 | the same content to avoid split brains. If you are not sure what went wrong | |
1149 | it's best to ask the Proxmox Community to help you. | |
1150 | ||
1151 | ||
3254bfdd | 1152 | [[pvecm_corosync_conf_glossary]] |
e4ec4154 TL |
1153 | Corosync Configuration Glossary |
1154 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
1155 | ||
1156 | ringX_addr:: | |
a9e7c3aa SR |
1157 | This names the different link addresses for the kronosnet connections between |
1158 | nodes. | |
e4ec4154 | 1159 | |
806ef12d DM |
1160 | |
1161 | Cluster Cold Start | |
1162 | ------------------ | |
1163 | ||
1164 | It is obvious that a cluster is not quorate when all nodes are | |
1165 | offline. This is a common case after a power failure. | |
1166 | ||
1167 | NOTE: It is always a good idea to use an uninterruptible power supply | |
8c1189b6 | 1168 | (``UPS'', also called ``battery backup'') to avoid this state, especially if |
806ef12d DM |
1169 | you want HA. |
1170 | ||
204231df | 1171 | On node startup, the `pve-guests` service is started and waits for |
8c1189b6 | 1172 | quorum. Once quorate, it starts all guests which have the `onboot` |
612417fd DM |
1173 | flag set. |
1174 | ||
1175 | When you turn on nodes, or when power comes back after power failure, | |
1176 | it is likely that some nodes boots faster than others. Please keep in | |
1177 | mind that guest startup is delayed until you reach quorum. | |
806ef12d | 1178 | |
054a7e7d | 1179 | |
082ea7d9 TL |
1180 | Guest Migration |
1181 | --------------- | |
1182 | ||
054a7e7d DM |
1183 | Migrating virtual guests to other nodes is a useful feature in a |
1184 | cluster. There are settings to control the behavior of such | |
1185 | migrations. This can be done via the configuration file | |
1186 | `datacenter.cfg` or for a specific migration via API or command line | |
1187 | parameters. | |
1188 | ||
da6c7dee DC |
1189 | It makes a difference if a Guest is online or offline, or if it has |
1190 | local resources (like a local disk). | |
1191 | ||
1192 | For Details about Virtual Machine Migration see the | |
a9e7c3aa | 1193 | xref:qm_migration[QEMU/KVM Migration Chapter]. |
da6c7dee DC |
1194 | |
1195 | For Details about Container Migration see the | |
a9e7c3aa | 1196 | xref:pct_migration[Container Migration Chapter]. |
082ea7d9 TL |
1197 | |
1198 | Migration Type | |
1199 | ~~~~~~~~~~~~~~ | |
1200 | ||
44f38275 | 1201 | The migration type defines if the migration data should be sent over an |
d63be10b | 1202 | encrypted (`secure`) channel or an unencrypted (`insecure`) one. |
082ea7d9 | 1203 | Setting the migration type to insecure means that the RAM content of a |
470d4313 | 1204 | virtual guest gets also transferred unencrypted, which can lead to |
b1743473 DM |
1205 | information disclosure of critical data from inside the guest (for |
1206 | example passwords or encryption keys). | |
054a7e7d DM |
1207 | |
1208 | Therefore, we strongly recommend using the secure channel if you do | |
1209 | not have full control over the network and can not guarantee that no | |
6d3c0b34 | 1210 | one is eavesdropping on it. |
082ea7d9 | 1211 | |
054a7e7d DM |
1212 | NOTE: Storage migration does not follow this setting. Currently, it |
1213 | always sends the storage content over a secure channel. | |
1214 | ||
1215 | Encryption requires a lot of computing power, so this setting is often | |
1216 | changed to "unsafe" to achieve better performance. The impact on | |
1217 | modern systems is lower because they implement AES encryption in | |
b1743473 DM |
1218 | hardware. The performance impact is particularly evident in fast |
1219 | networks where you can transfer 10 Gbps or more. | |
082ea7d9 | 1220 | |
082ea7d9 TL |
1221 | Migration Network |
1222 | ~~~~~~~~~~~~~~~~~ | |
1223 | ||
a9baa444 TL |
1224 | By default, {pve} uses the network in which cluster communication |
1225 | takes place to send the migration traffic. This is not optimal because | |
1226 | sensitive cluster traffic can be disrupted and this network may not | |
1227 | have the best bandwidth available on the node. | |
1228 | ||
1229 | Setting the migration network parameter allows the use of a dedicated | |
1230 | network for the entire migration traffic. In addition to the memory, | |
1231 | this also affects the storage traffic for offline migrations. | |
1232 | ||
1233 | The migration network is set as a network in the CIDR notation. This | |
1234 | has the advantage that you do not have to set individual IP addresses | |
1235 | for each node. {pve} can determine the real address on the | |
1236 | destination node from the network specified in the CIDR form. To | |
1237 | enable this, the network must be specified so that each node has one, | |
1238 | but only one IP in the respective network. | |
1239 | ||
082ea7d9 TL |
1240 | Example |
1241 | ^^^^^^^ | |
1242 | ||
a9baa444 TL |
1243 | We assume that we have a three-node setup with three separate |
1244 | networks. One for public communication with the Internet, one for | |
1245 | cluster communication and a very fast one, which we want to use as a | |
1246 | dedicated network for migration. | |
1247 | ||
1248 | A network configuration for such a setup might look as follows: | |
082ea7d9 TL |
1249 | |
1250 | ---- | |
7a0d4784 | 1251 | iface eno1 inet manual |
082ea7d9 TL |
1252 | |
1253 | # public network | |
1254 | auto vmbr0 | |
1255 | iface vmbr0 inet static | |
1256 | address 192.X.Y.57 | |
1257 | netmask 255.255.250.0 | |
1258 | gateway 192.X.Y.1 | |
7a0d4784 | 1259 | bridge_ports eno1 |
082ea7d9 TL |
1260 | bridge_stp off |
1261 | bridge_fd 0 | |
1262 | ||
1263 | # cluster network | |
7a0d4784 WL |
1264 | auto eno2 |
1265 | iface eno2 inet static | |
082ea7d9 TL |
1266 | address 10.1.1.1 |
1267 | netmask 255.255.255.0 | |
1268 | ||
1269 | # fast network | |
7a0d4784 WL |
1270 | auto eno3 |
1271 | iface eno3 inet static | |
082ea7d9 TL |
1272 | address 10.1.2.1 |
1273 | netmask 255.255.255.0 | |
082ea7d9 TL |
1274 | ---- |
1275 | ||
a9baa444 TL |
1276 | Here, we will use the network 10.1.2.0/24 as a migration network. For |
1277 | a single migration, you can do this using the `migration_network` | |
1278 | parameter of the command line tool: | |
1279 | ||
082ea7d9 | 1280 | ---- |
b1743473 | 1281 | # qm migrate 106 tre --online --migration_network 10.1.2.0/24 |
082ea7d9 TL |
1282 | ---- |
1283 | ||
a9baa444 TL |
1284 | To configure this as the default network for all migrations in the |
1285 | cluster, set the `migration` property of the `/etc/pve/datacenter.cfg` | |
1286 | file: | |
1287 | ||
082ea7d9 | 1288 | ---- |
a9baa444 | 1289 | # use dedicated migration network |
b1743473 | 1290 | migration: secure,network=10.1.2.0/24 |
082ea7d9 TL |
1291 | ---- |
1292 | ||
a9baa444 TL |
1293 | NOTE: The migration type must always be set when the migration network |
1294 | gets set in `/etc/pve/datacenter.cfg`. | |
1295 | ||
806ef12d | 1296 | |
d8742b0c DM |
1297 | ifdef::manvolnum[] |
1298 | include::pve-copyright.adoc[] | |
1299 | endif::manvolnum[] |