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d8742b0c DM |
1 | ifdef::manvolnum[] |
2 | PVE({manvolnum}) | |
3 | ================ | |
4 | include::attributes.txt[] | |
5 | ||
5f09af76 DM |
6 | :pve-toplevel: |
7 | ||
d8742b0c DM |
8 | NAME |
9 | ---- | |
10 | ||
74026b8f | 11 | pvecm - Proxmox VE Cluster Manager |
d8742b0c | 12 | |
49a5e11c | 13 | SYNOPSIS |
d8742b0c DM |
14 | -------- |
15 | ||
16 | include::pvecm.1-synopsis.adoc[] | |
17 | ||
18 | DESCRIPTION | |
19 | ----------- | |
20 | endif::manvolnum[] | |
21 | ||
22 | ifndef::manvolnum[] | |
23 | Cluster Manager | |
24 | =============== | |
25 | include::attributes.txt[] | |
26 | endif::manvolnum[] | |
27 | ||
5f09af76 DM |
28 | ifdef::wiki[] |
29 | :pve-toplevel: | |
30 | endif::wiki[] | |
31 | ||
8c1189b6 FG |
32 | The {PVE} cluster manager `pvecm` is a tool to create a group of |
33 | physical servers. Such a group is called a *cluster*. We use the | |
8a865621 | 34 | http://www.corosync.org[Corosync Cluster Engine] for reliable group |
5eba0743 | 35 | communication, and such clusters can consist of up to 32 physical nodes |
8a865621 DM |
36 | (probably more, dependent on network latency). |
37 | ||
8c1189b6 | 38 | `pvecm` can be used to create a new cluster, join nodes to a cluster, |
8a865621 | 39 | leave the cluster, get status information and do various other cluster |
e300cf7d FG |
40 | related tasks. The **P**rox**m**o**x** **C**luster **F**ile **S**ystem (``pmxcfs'') |
41 | is used to transparently distribute the cluster configuration to all cluster | |
8a865621 DM |
42 | nodes. |
43 | ||
44 | Grouping nodes into a cluster has the following advantages: | |
45 | ||
46 | * Centralized, web based management | |
47 | ||
5eba0743 | 48 | * Multi-master clusters: each node can do all management task |
8a865621 | 49 | |
8c1189b6 FG |
50 | * `pmxcfs`: database-driven file system for storing configuration files, |
51 | replicated in real-time on all nodes using `corosync`. | |
8a865621 | 52 | |
5eba0743 | 53 | * Easy migration of virtual machines and containers between physical |
8a865621 DM |
54 | hosts |
55 | ||
56 | * Fast deployment | |
57 | ||
58 | * Cluster-wide services like firewall and HA | |
59 | ||
60 | ||
61 | Requirements | |
62 | ------------ | |
63 | ||
8c1189b6 | 64 | * All nodes must be in the same network as `corosync` uses IP Multicast |
8a865621 | 65 | to communicate between nodes (also see |
ceabe189 | 66 | http://www.corosync.org[Corosync Cluster Engine]). Corosync uses UDP |
ff72a2ba | 67 | ports 5404 and 5405 for cluster communication. |
ceabe189 DM |
68 | + |
69 | NOTE: Some switches do not support IP multicast by default and must be | |
70 | manually enabled first. | |
8a865621 DM |
71 | |
72 | * Date and time have to be synchronized. | |
73 | ||
ceabe189 | 74 | * SSH tunnel on TCP port 22 between nodes is used. |
8a865621 | 75 | |
ceabe189 DM |
76 | * If you are interested in High Availability, you need to have at |
77 | least three nodes for reliable quorum. All nodes should have the | |
78 | same version. | |
8a865621 DM |
79 | |
80 | * We recommend a dedicated NIC for the cluster traffic, especially if | |
81 | you use shared storage. | |
82 | ||
83 | NOTE: It is not possible to mix Proxmox VE 3.x and earlier with | |
ceabe189 | 84 | Proxmox VE 4.0 cluster nodes. |
8a865621 DM |
85 | |
86 | ||
ceabe189 DM |
87 | Preparing Nodes |
88 | --------------- | |
8a865621 DM |
89 | |
90 | First, install {PVE} on all nodes. Make sure that each node is | |
91 | installed with the final hostname and IP configuration. Changing the | |
92 | hostname and IP is not possible after cluster creation. | |
93 | ||
94 | Currently the cluster creation has to be done on the console, so you | |
8c1189b6 | 95 | need to login via `ssh`. |
8a865621 | 96 | |
8a865621 | 97 | Create the Cluster |
ceabe189 | 98 | ------------------ |
8a865621 | 99 | |
8c1189b6 FG |
100 | Login via `ssh` to the first {pve} node. Use a unique name for your cluster. |
101 | This name cannot be changed later. | |
8a865621 DM |
102 | |
103 | hp1# pvecm create YOUR-CLUSTER-NAME | |
104 | ||
63f956c8 DM |
105 | CAUTION: The cluster name is used to compute the default multicast |
106 | address. Please use unique cluster names if you run more than one | |
107 | cluster inside your network. | |
108 | ||
8a865621 DM |
109 | To check the state of your cluster use: |
110 | ||
111 | hp1# pvecm status | |
112 | ||
113 | ||
114 | Adding Nodes to the Cluster | |
ceabe189 | 115 | --------------------------- |
8a865621 | 116 | |
8c1189b6 | 117 | Login via `ssh` to the node you want to add. |
8a865621 DM |
118 | |
119 | hp2# pvecm add IP-ADDRESS-CLUSTER | |
120 | ||
121 | For `IP-ADDRESS-CLUSTER` use the IP from an existing cluster node. | |
122 | ||
5eba0743 | 123 | CAUTION: A new node cannot hold any VMs, because you would get |
7980581f | 124 | conflicts about identical VM IDs. Also, all existing configuration in |
8c1189b6 FG |
125 | `/etc/pve` is overwritten when you join a new node to the cluster. To |
126 | workaround, use `vzdump` to backup and restore to a different VMID after | |
7980581f | 127 | adding the node to the cluster. |
8a865621 DM |
128 | |
129 | To check the state of cluster: | |
130 | ||
131 | # pvecm status | |
132 | ||
ceabe189 | 133 | .Cluster status after adding 4 nodes |
8a865621 DM |
134 | ---- |
135 | hp2# pvecm status | |
136 | Quorum information | |
137 | ~~~~~~~~~~~~~~~~~~ | |
138 | Date: Mon Apr 20 12:30:13 2015 | |
139 | Quorum provider: corosync_votequorum | |
140 | Nodes: 4 | |
141 | Node ID: 0x00000001 | |
142 | Ring ID: 1928 | |
143 | Quorate: Yes | |
144 | ||
145 | Votequorum information | |
146 | ~~~~~~~~~~~~~~~~~~~~~~ | |
147 | Expected votes: 4 | |
148 | Highest expected: 4 | |
149 | Total votes: 4 | |
150 | Quorum: 2 | |
151 | Flags: Quorate | |
152 | ||
153 | Membership information | |
154 | ~~~~~~~~~~~~~~~~~~~~~~ | |
155 | Nodeid Votes Name | |
156 | 0x00000001 1 192.168.15.91 | |
157 | 0x00000002 1 192.168.15.92 (local) | |
158 | 0x00000003 1 192.168.15.93 | |
159 | 0x00000004 1 192.168.15.94 | |
160 | ---- | |
161 | ||
162 | If you only want the list of all nodes use: | |
163 | ||
164 | # pvecm nodes | |
165 | ||
5eba0743 | 166 | .List nodes in a cluster |
8a865621 DM |
167 | ---- |
168 | hp2# pvecm nodes | |
169 | ||
170 | Membership information | |
171 | ~~~~~~~~~~~~~~~~~~~~~~ | |
172 | Nodeid Votes Name | |
173 | 1 1 hp1 | |
174 | 2 1 hp2 (local) | |
175 | 3 1 hp3 | |
176 | 4 1 hp4 | |
177 | ---- | |
178 | ||
e4ec4154 TL |
179 | Adding Nodes With Separated Cluster Network |
180 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
181 | ||
182 | When adding a node to a cluster with a separated cluster network you need to | |
183 | use the 'ringX_addr' parameters to set the nodes address on those networks: | |
184 | ||
185 | [source,bash] | |
4d19cb00 | 186 | ---- |
e4ec4154 | 187 | pvecm add IP-ADDRESS-CLUSTER -ring0_addr IP-ADDRESS-RING0 |
4d19cb00 | 188 | ---- |
e4ec4154 TL |
189 | |
190 | If you want to use the Redundant Ring Protocol you will also want to pass the | |
191 | 'ring1_addr' parameter. | |
192 | ||
8a865621 DM |
193 | |
194 | Remove a Cluster Node | |
ceabe189 | 195 | --------------------- |
8a865621 DM |
196 | |
197 | CAUTION: Read carefully the procedure before proceeding, as it could | |
198 | not be what you want or need. | |
199 | ||
200 | Move all virtual machines from the node. Make sure you have no local | |
201 | data or backups you want to keep, or save them accordingly. | |
202 | ||
8c1189b6 | 203 | Log in to one remaining node via ssh. Issue a `pvecm nodes` command to |
7980581f | 204 | identify the node ID: |
8a865621 DM |
205 | |
206 | ---- | |
207 | hp1# pvecm status | |
208 | ||
209 | Quorum information | |
210 | ~~~~~~~~~~~~~~~~~~ | |
211 | Date: Mon Apr 20 12:30:13 2015 | |
212 | Quorum provider: corosync_votequorum | |
213 | Nodes: 4 | |
214 | Node ID: 0x00000001 | |
215 | Ring ID: 1928 | |
216 | Quorate: Yes | |
217 | ||
218 | Votequorum information | |
219 | ~~~~~~~~~~~~~~~~~~~~~~ | |
220 | Expected votes: 4 | |
221 | Highest expected: 4 | |
222 | Total votes: 4 | |
223 | Quorum: 2 | |
224 | Flags: Quorate | |
225 | ||
226 | Membership information | |
227 | ~~~~~~~~~~~~~~~~~~~~~~ | |
228 | Nodeid Votes Name | |
229 | 0x00000001 1 192.168.15.91 (local) | |
230 | 0x00000002 1 192.168.15.92 | |
231 | 0x00000003 1 192.168.15.93 | |
232 | 0x00000004 1 192.168.15.94 | |
233 | ---- | |
234 | ||
235 | IMPORTANT: at this point you must power off the node to be removed and | |
236 | make sure that it will not power on again (in the network) as it | |
237 | is. | |
238 | ||
239 | ---- | |
240 | hp1# pvecm nodes | |
241 | ||
242 | Membership information | |
243 | ~~~~~~~~~~~~~~~~~~~~~~ | |
244 | Nodeid Votes Name | |
245 | 1 1 hp1 (local) | |
246 | 2 1 hp2 | |
247 | 3 1 hp3 | |
248 | 4 1 hp4 | |
249 | ---- | |
250 | ||
251 | Log in to one remaining node via ssh. Issue the delete command (here | |
8c1189b6 | 252 | deleting node `hp4`): |
8a865621 DM |
253 | |
254 | hp1# pvecm delnode hp4 | |
255 | ||
256 | If the operation succeeds no output is returned, just check the node | |
8c1189b6 | 257 | list again with `pvecm nodes` or `pvecm status`. You should see |
8a865621 DM |
258 | something like: |
259 | ||
260 | ---- | |
261 | hp1# pvecm status | |
262 | ||
263 | Quorum information | |
264 | ~~~~~~~~~~~~~~~~~~ | |
265 | Date: Mon Apr 20 12:44:28 2015 | |
266 | Quorum provider: corosync_votequorum | |
267 | Nodes: 3 | |
268 | Node ID: 0x00000001 | |
269 | Ring ID: 1992 | |
270 | Quorate: Yes | |
271 | ||
272 | Votequorum information | |
273 | ~~~~~~~~~~~~~~~~~~~~~~ | |
274 | Expected votes: 3 | |
275 | Highest expected: 3 | |
276 | Total votes: 3 | |
277 | Quorum: 3 | |
278 | Flags: Quorate | |
279 | ||
280 | Membership information | |
281 | ~~~~~~~~~~~~~~~~~~~~~~ | |
282 | Nodeid Votes Name | |
283 | 0x00000001 1 192.168.15.90 (local) | |
284 | 0x00000002 1 192.168.15.91 | |
285 | 0x00000003 1 192.168.15.92 | |
286 | ---- | |
287 | ||
288 | IMPORTANT: as said above, it is very important to power off the node | |
289 | *before* removal, and make sure that it will *never* power on again | |
290 | (in the existing cluster network) as it is. | |
291 | ||
292 | If you power on the node as it is, your cluster will be screwed up and | |
293 | it could be difficult to restore a clean cluster state. | |
294 | ||
295 | If, for whatever reason, you want that this server joins the same | |
296 | cluster again, you have to | |
297 | ||
26ca7ff5 | 298 | * reinstall {pve} on it from scratch |
8a865621 DM |
299 | |
300 | * then join it, as explained in the previous section. | |
d8742b0c | 301 | |
555e966b TL |
302 | Separate A Node Without Reinstalling |
303 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
304 | ||
305 | CAUTION: This is *not* the recommended method, proceed with caution. Use the | |
306 | above mentioned method if you're unsure. | |
307 | ||
308 | You can also separate a node from a cluster without reinstalling it from | |
309 | scratch. But after removing the node from the cluster it will still have | |
310 | access to the shared storages! This must be resolved before you start removing | |
311 | the node from the cluster. A {pve} cluster cannot share the exact same | |
312 | storage with another cluster, as it leads to VMID conflicts. | |
313 | ||
3be22308 TL |
314 | Its suggested that you create a new storage where only the node which you want |
315 | to separate has access. This can be an new export on your NFS or a new Ceph | |
316 | pool, to name a few examples. Its just important that the exact same storage | |
317 | does not gets accessed by multiple clusters. After setting this storage up move | |
318 | all data from the node and its VMs to it. Then you are ready to separate the | |
319 | node from the cluster. | |
555e966b TL |
320 | |
321 | WARNING: Ensure all shared resources are cleanly separated! You will run into | |
322 | conflicts and problems else. | |
323 | ||
324 | First stop the corosync and the pve-cluster services on the node: | |
325 | [source,bash] | |
4d19cb00 | 326 | ---- |
555e966b TL |
327 | systemctl stop pve-cluster |
328 | systemctl stop corosync | |
4d19cb00 | 329 | ---- |
555e966b TL |
330 | |
331 | Start the cluster filesystem again in local mode: | |
332 | [source,bash] | |
4d19cb00 | 333 | ---- |
555e966b | 334 | pmxcfs -l |
4d19cb00 | 335 | ---- |
555e966b TL |
336 | |
337 | Delete the corosync configuration files: | |
338 | [source,bash] | |
4d19cb00 | 339 | ---- |
555e966b TL |
340 | rm /etc/pve/corosync.conf |
341 | rm /etc/corosync/* | |
4d19cb00 | 342 | ---- |
555e966b TL |
343 | |
344 | You can now start the filesystem again as normal service: | |
345 | [source,bash] | |
4d19cb00 | 346 | ---- |
555e966b TL |
347 | killall pmxcfs |
348 | systemctl start pve-cluster | |
4d19cb00 | 349 | ---- |
555e966b TL |
350 | |
351 | The node is now separated from the cluster. You can deleted it from a remaining | |
352 | node of the cluster with: | |
353 | [source,bash] | |
4d19cb00 | 354 | ---- |
555e966b | 355 | pvecm delnode oldnode |
4d19cb00 | 356 | ---- |
555e966b TL |
357 | |
358 | If the command failed, because the remaining node in the cluster lost quorum | |
359 | when the now separate node exited, you may set the expected votes to 1 as a workaround: | |
360 | [source,bash] | |
4d19cb00 | 361 | ---- |
555e966b | 362 | pvecm expected 1 |
4d19cb00 | 363 | ---- |
555e966b TL |
364 | |
365 | And the repeat the 'pvecm delnode' command. | |
366 | ||
367 | Now switch back to the separated node, here delete all remaining files left | |
368 | from the old cluster. This ensures that the node can be added to another | |
369 | cluster again without problems. | |
370 | ||
371 | [source,bash] | |
4d19cb00 | 372 | ---- |
555e966b | 373 | rm /var/lib/corosync/* |
4d19cb00 | 374 | ---- |
555e966b TL |
375 | |
376 | As the configuration files from the other nodes are still in the cluster | |
377 | filesystem you may want to clean those up too. Remove simply the whole | |
378 | directory recursive from '/etc/pve/nodes/NODENAME', but check three times that | |
379 | you used the correct one before deleting it. | |
380 | ||
381 | CAUTION: The nodes SSH keys are still in the 'authorized_key' file, this means | |
382 | the nodes can still connect to each other with public key authentication. This | |
383 | should be fixed by removing the respective keys from the | |
384 | '/etc/pve/priv/authorized_keys' file. | |
d8742b0c | 385 | |
806ef12d DM |
386 | Quorum |
387 | ------ | |
388 | ||
389 | {pve} use a quorum-based technique to provide a consistent state among | |
390 | all cluster nodes. | |
391 | ||
392 | [quote, from Wikipedia, Quorum (distributed computing)] | |
393 | ____ | |
394 | A quorum is the minimum number of votes that a distributed transaction | |
395 | has to obtain in order to be allowed to perform an operation in a | |
396 | distributed system. | |
397 | ____ | |
398 | ||
399 | In case of network partitioning, state changes requires that a | |
400 | majority of nodes are online. The cluster switches to read-only mode | |
5eba0743 | 401 | if it loses quorum. |
806ef12d DM |
402 | |
403 | NOTE: {pve} assigns a single vote to each node by default. | |
404 | ||
e4ec4154 TL |
405 | Cluster Network |
406 | --------------- | |
407 | ||
408 | The cluster network is the core of a cluster. All messages sent over it have to | |
409 | be delivered reliable to all nodes in their respective order. In {pve} this | |
410 | part is done by corosync, an implementation of a high performance low overhead | |
411 | high availability development toolkit. It serves our decentralized | |
412 | configuration file system (`pmxcfs`). | |
413 | ||
414 | [[cluster-network-requirements]] | |
415 | Network Requirements | |
416 | ~~~~~~~~~~~~~~~~~~~~ | |
417 | This needs a reliable network with latencies under 2 milliseconds (LAN | |
418 | performance) to work properly. While corosync can also use unicast for | |
419 | communication between nodes its **highly recommended** to have a multicast | |
420 | capable network. The network should not be used heavily by other members, | |
421 | ideally corosync runs on its own network. | |
422 | *never* share it with network where storage communicates too. | |
423 | ||
424 | Before setting up a cluster it is good practice to check if the network is fit | |
425 | for that purpose. | |
426 | ||
427 | * Ensure that all nodes are in the same subnet. This must only be true for the | |
428 | network interfaces used for cluster communication (corosync). | |
429 | ||
430 | * Ensure all nodes can reach each other over those interfaces, using `ping` is | |
431 | enough for a basic test. | |
432 | ||
433 | * Ensure that multicast works in general and a high package rates. This can be | |
434 | done with the `omping` tool. The final "%loss" number should be < 1%. | |
435 | [source,bash] | |
436 | ---- | |
437 | omping -c 10000 -i 0.001 -F -q NODE1-IP NODE2-IP ... | |
438 | ---- | |
439 | ||
440 | * Ensure that multicast communication works over an extended period of time. | |
441 | This covers up problems where IGMP snooping is activated on the network but | |
442 | no multicast querier is active. This test has a duration of around 10 | |
443 | minutes. | |
444 | [source,bash] | |
4d19cb00 | 445 | ---- |
e4ec4154 | 446 | omping -c 600 -i 1 -q NODE1-IP NODE2-IP ... |
4d19cb00 | 447 | ---- |
e4ec4154 TL |
448 | |
449 | Your network is not ready for clustering if any of these test fails. Recheck | |
450 | your network configuration. Especially switches are notorious for having | |
451 | multicast disabled by default or IGMP snooping enabled with no IGMP querier | |
452 | active. | |
453 | ||
454 | In smaller cluster its also an option to use unicast if you really cannot get | |
455 | multicast to work. | |
456 | ||
457 | Separate Cluster Network | |
458 | ~~~~~~~~~~~~~~~~~~~~~~~~ | |
459 | ||
460 | When creating a cluster without any parameters the cluster network is generally | |
461 | shared with the Web UI and the VMs and its traffic. Depending on your setup | |
462 | even storage traffic may get sent over the same network. Its recommended to | |
463 | change that, as corosync is a time critical real time application. | |
464 | ||
465 | Setting Up A New Network | |
466 | ^^^^^^^^^^^^^^^^^^^^^^^^ | |
467 | ||
468 | First you have to setup a new network interface. It should be on a physical | |
469 | separate network. Ensure that your network fulfills the | |
470 | <<cluster-network-requirements,cluster network requirements>>. | |
471 | ||
472 | Separate On Cluster Creation | |
473 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
474 | ||
475 | This is possible through the 'ring0_addr' and 'bindnet0_addr' parameter of | |
476 | the 'pvecm create' command used for creating a new cluster. | |
477 | ||
478 | If you have setup a additional NIC with a static address on 10.10.10.1/25 | |
479 | and want to send and receive all cluster communication over this interface | |
480 | you would execute: | |
481 | ||
482 | [source,bash] | |
4d19cb00 | 483 | ---- |
e4ec4154 | 484 | pvecm create test --ring0_addr 10.10.10.1 --bindnet0_addr 10.10.10.0 |
4d19cb00 | 485 | ---- |
e4ec4154 TL |
486 | |
487 | To check if everything is working properly execute: | |
488 | [source,bash] | |
4d19cb00 | 489 | ---- |
e4ec4154 | 490 | systemctl status corosync |
4d19cb00 | 491 | ---- |
e4ec4154 TL |
492 | |
493 | [[separate-cluster-net-after-creation]] | |
494 | Separate After Cluster Creation | |
495 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
496 | ||
497 | You can do this also if you have already created a cluster and want to switch | |
498 | its communication to another network, without rebuilding the whole cluster. | |
499 | This change may lead to short durations of quorum loss in the cluster, as nodes | |
500 | have to restart corosync and come up one after the other on the new network. | |
501 | ||
502 | Check how to <<edit-corosync-conf,edit the corosync.conf file>> first. | |
503 | The open it and you should see a file similar to: | |
504 | ||
505 | ---- | |
506 | logging { | |
507 | debug: off | |
508 | to_syslog: yes | |
509 | } | |
510 | ||
511 | nodelist { | |
512 | ||
513 | node { | |
514 | name: due | |
515 | nodeid: 2 | |
516 | quorum_votes: 1 | |
517 | ring0_addr: due | |
518 | } | |
519 | ||
520 | node { | |
521 | name: tre | |
522 | nodeid: 3 | |
523 | quorum_votes: 1 | |
524 | ring0_addr: tre | |
525 | } | |
526 | ||
527 | node { | |
528 | name: uno | |
529 | nodeid: 1 | |
530 | quorum_votes: 1 | |
531 | ring0_addr: uno | |
532 | } | |
533 | ||
534 | } | |
535 | ||
536 | quorum { | |
537 | provider: corosync_votequorum | |
538 | } | |
539 | ||
540 | totem { | |
541 | cluster_name: thomas-testcluster | |
542 | config_version: 3 | |
543 | ip_version: ipv4 | |
544 | secauth: on | |
545 | version: 2 | |
546 | interface { | |
547 | bindnetaddr: 192.168.30.50 | |
548 | ringnumber: 0 | |
549 | } | |
550 | ||
551 | } | |
552 | ---- | |
553 | ||
554 | The first you want to do is add the 'name' properties in the node entries if | |
555 | you do not see them already. Those *must* match the node name. | |
556 | ||
557 | Then replace the address from the 'ring0_addr' properties with the new | |
558 | addresses. You may use plain IP addresses or also hostnames here. If you use | |
559 | hostnames ensure that they are resolvable from all nodes. | |
560 | ||
561 | In my example I want to switch my cluster communication to the 10.10.10.1/25 | |
562 | network. So I replace all 'ring0_addr' respectively. I also set the bindetaddr | |
563 | in the totem section of the config to an address of the new network. It can be | |
564 | any address from the subnet configured on the new network interface. | |
565 | ||
566 | After you increased the 'config_version' property the new configuration file | |
567 | should look like: | |
568 | ||
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: 10.10.10.2 | |
583 | } | |
584 | ||
585 | node { | |
586 | name: tre | |
587 | nodeid: 3 | |
588 | quorum_votes: 1 | |
589 | ring0_addr: 10.10.10.3 | |
590 | } | |
591 | ||
592 | node { | |
593 | name: uno | |
594 | nodeid: 1 | |
595 | quorum_votes: 1 | |
596 | ring0_addr: 10.10.10.1 | |
597 | } | |
598 | ||
599 | } | |
600 | ||
601 | quorum { | |
602 | provider: corosync_votequorum | |
603 | } | |
604 | ||
605 | totem { | |
606 | cluster_name: thomas-testcluster | |
607 | config_version: 4 | |
608 | ip_version: ipv4 | |
609 | secauth: on | |
610 | version: 2 | |
611 | interface { | |
612 | bindnetaddr: 10.10.10.1 | |
613 | ringnumber: 0 | |
614 | } | |
615 | ||
616 | } | |
617 | ---- | |
618 | ||
619 | Now after a final check whether all changed information is correct we save it | |
620 | and see again the <<edit-corosync-conf,edit corosync.conf file>> section to | |
621 | learn how to bring it in effect. | |
622 | ||
623 | As our change cannot be enforced live from corosync we have to do an restart. | |
624 | ||
625 | On a single node execute: | |
626 | [source,bash] | |
4d19cb00 | 627 | ---- |
e4ec4154 | 628 | systemctl restart corosync |
4d19cb00 | 629 | ---- |
e4ec4154 TL |
630 | |
631 | Now check if everything is fine: | |
632 | ||
633 | [source,bash] | |
4d19cb00 | 634 | ---- |
e4ec4154 | 635 | systemctl status corosync |
4d19cb00 | 636 | ---- |
e4ec4154 TL |
637 | |
638 | If corosync runs again correct restart corosync also on all other nodes. | |
639 | They will then join the cluster membership one by one on the new network. | |
640 | ||
641 | Redundant Ring Protocol | |
642 | ~~~~~~~~~~~~~~~~~~~~~~~ | |
643 | To avoid a single point of failure you should implement counter measurements. | |
644 | This can be on the hardware and operating system level through network bonding. | |
645 | ||
646 | Corosync itself offers also a possibility to add redundancy through the so | |
647 | called 'Redundant Ring Protocol'. This protocol allows running a second totem | |
648 | ring on another network, this network should be physically separated from the | |
649 | other rings network to actually increase availability. | |
650 | ||
651 | RRP On Cluster Creation | |
652 | ~~~~~~~~~~~~~~~~~~~~~~~ | |
653 | ||
654 | The 'pvecm create' command provides the additional parameters 'bindnetX_addr', | |
655 | 'ringX_addr' and 'rrp_mode', can be used for RRP configuration. | |
656 | ||
657 | NOTE: See the <<corosync-conf-glossary,glossary>> if you do not know what each parameter means. | |
658 | ||
659 | So if you have two networks, one on the 10.10.10.1/24 and the other on the | |
660 | 10.10.20.1/24 subnet you would execute: | |
661 | ||
662 | [source,bash] | |
4d19cb00 | 663 | ---- |
e4ec4154 TL |
664 | pvecm create CLUSTERNAME -bindnet0_addr 10.10.10.1 -ring0_addr 10.10.10.1 \ |
665 | -bindnet1_addr 10.10.20.1 -ring1_addr 10.10.20.1 | |
4d19cb00 | 666 | ---- |
e4ec4154 TL |
667 | |
668 | RRP On A Created Cluster | |
669 | ~~~~~~~~~~~~~~~~~~~~~~~~ | |
670 | ||
671 | When enabling an already running cluster to use RRP you will take similar steps | |
672 | as describe in <<separate-cluster-net-after-creation,separating the cluster | |
673 | network>>. You just do it on another ring. | |
674 | ||
675 | First add a new `interface` subsection in the `totem` section, set its | |
676 | `ringnumber` property to `1`. Set the interfaces `bindnetaddr` property to an | |
677 | address of the subnet you have configured for your new ring. | |
678 | Further set the `rrp_mode` to `passive`, this is the only stable mode. | |
679 | ||
680 | Then add to each node entry in the `nodelist` section its new `ring1_addr` | |
681 | property with the nodes additional ring address. | |
682 | ||
683 | So if you have two networks, one on the 10.10.10.1/24 and the other on the | |
684 | 10.10.20.1/24 subnet, the final configuration file should look like: | |
685 | ||
686 | ---- | |
687 | totem { | |
688 | cluster_name: tweak | |
689 | config_version: 9 | |
690 | ip_version: ipv4 | |
691 | rrp_mode: passive | |
692 | secauth: on | |
693 | version: 2 | |
694 | interface { | |
695 | bindnetaddr: 10.10.10.1 | |
696 | ringnumber: 0 | |
697 | } | |
698 | interface { | |
699 | bindnetaddr: 10.10.20.1 | |
700 | ringnumber: 1 | |
701 | } | |
702 | } | |
703 | ||
704 | nodelist { | |
705 | node { | |
706 | name: pvecm1 | |
707 | nodeid: 1 | |
708 | quorum_votes: 1 | |
709 | ring0_addr: 10.10.10.1 | |
710 | ring1_addr: 10.10.20.1 | |
711 | } | |
712 | ||
713 | node { | |
714 | name: pvecm2 | |
715 | nodeid: 2 | |
716 | quorum_votes: 1 | |
717 | ring0_addr: 10.10.10.2 | |
718 | ring1_addr: 10.10.20.2 | |
719 | } | |
720 | ||
721 | [...] # other cluster nodes here | |
722 | } | |
723 | ||
724 | [...] # other remaining config sections here | |
725 | ||
726 | ---- | |
727 | ||
728 | Bring it in effect like described in the <<edit-corosync-conf,edit the | |
729 | corosync.conf file>> section. | |
730 | ||
731 | This is a change which cannot take live in effect and needs at least a restart | |
732 | of corosync. Recommended is a restart of the whole cluster. | |
733 | ||
734 | If you cannot reboot the whole cluster ensure no High Availability services are | |
735 | configured and the stop the corosync service on all nodes. After corosync is | |
736 | stopped on all nodes start it one after the other again. | |
737 | ||
738 | Corosync Configuration | |
739 | ---------------------- | |
740 | ||
741 | The `/ect/pve/corosync.conf` file plays a central role in {pve} cluster. It | |
742 | controls the cluster member ship and its network. | |
743 | For reading more about it check the corosync.conf man page: | |
744 | [source,bash] | |
4d19cb00 | 745 | ---- |
e4ec4154 | 746 | man corosync.conf |
4d19cb00 | 747 | ---- |
e4ec4154 TL |
748 | |
749 | For node membership you should always use the `pvecm` tool provided by {pve}. | |
750 | You may have to edit the configuration file manually for other changes. | |
751 | Here are a few best practice tips for doing this. | |
752 | ||
753 | [[edit-corosync-conf]] | |
754 | Edit corosync.conf | |
755 | ~~~~~~~~~~~~~~~~~~ | |
756 | ||
757 | Editing the corosync.conf file can be not always straight forward. There are | |
758 | two on each cluster, one in `/etc/pve/corosync.conf` and the other in | |
759 | `/etc/corosync/corosync.conf`. Editing the one in our cluster file system will | |
760 | propagate the changes to the local one, but not vice versa. | |
761 | ||
762 | The configuration will get updated automatically as soon as the file changes. | |
763 | This means changes which can be integrated in a running corosync will take | |
764 | instantly effect. So you should always make a copy and edit that instead, to | |
765 | avoid triggering some unwanted changes by an in between safe. | |
766 | ||
767 | [source,bash] | |
4d19cb00 | 768 | ---- |
e4ec4154 | 769 | cp /etc/pve/corosync.conf /etc/pve/corosync.conf.new |
4d19cb00 | 770 | ---- |
e4ec4154 TL |
771 | |
772 | Then open the Config file with your favorite editor, `nano` and `vim.tiny` are | |
773 | preinstalled on {pve} for example. | |
774 | ||
775 | NOTE: Always increment the 'config_version' number on configuration changes, | |
776 | omitting this can lead to problems. | |
777 | ||
778 | After making the necessary changes create another copy of the current working | |
779 | configuration file. This serves as a backup if the new configuration fails to | |
780 | apply or makes problems in other ways. | |
781 | ||
782 | [source,bash] | |
4d19cb00 | 783 | ---- |
e4ec4154 | 784 | cp /etc/pve/corosync.conf /etc/pve/corosync.conf.bak |
4d19cb00 | 785 | ---- |
e4ec4154 TL |
786 | |
787 | Then move the new configuration file over the old one: | |
788 | [source,bash] | |
4d19cb00 | 789 | ---- |
e4ec4154 | 790 | mv /etc/pve/corosync.conf.new /etc/pve/corosync.conf |
4d19cb00 | 791 | ---- |
e4ec4154 TL |
792 | |
793 | You may check with the commands | |
794 | [source,bash] | |
4d19cb00 | 795 | ---- |
e4ec4154 TL |
796 | systemctl status corosync |
797 | journalctl -b -u corosync | |
4d19cb00 | 798 | ---- |
e4ec4154 TL |
799 | |
800 | If the change could applied automatically. If not you may have to restart the | |
801 | corosync service via: | |
802 | [source,bash] | |
4d19cb00 | 803 | ---- |
e4ec4154 | 804 | systemctl restart corosync |
4d19cb00 | 805 | ---- |
e4ec4154 TL |
806 | |
807 | On errors check the troubleshooting section below. | |
808 | ||
809 | Troubleshooting | |
810 | ~~~~~~~~~~~~~~~ | |
811 | ||
812 | Issue: 'quorum.expected_votes must be configured' | |
813 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
814 | ||
815 | When corosync starts to fail and you get the following message in the system log: | |
816 | ||
817 | ---- | |
818 | [...] | |
819 | corosync[1647]: [QUORUM] Quorum provider: corosync_votequorum failed to initialize. | |
820 | corosync[1647]: [SERV ] Service engine 'corosync_quorum' failed to load for reason | |
821 | 'configuration error: nodelist or quorum.expected_votes must be configured!' | |
822 | [...] | |
823 | ---- | |
824 | ||
825 | It means that the hostname you set for corosync 'ringX_addr' in the | |
826 | configuration could not be resolved. | |
827 | ||
828 | ||
829 | Write Configuration When Not Quorate | |
830 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
831 | ||
832 | If you need to change '/etc/pve/corosync.conf' on an node with no quorum, and you | |
833 | know what you do, use: | |
834 | [source,bash] | |
4d19cb00 | 835 | ---- |
e4ec4154 | 836 | pvecm expected 1 |
4d19cb00 | 837 | ---- |
e4ec4154 TL |
838 | |
839 | This sets the expected vote count to 1 and makes the cluster quorate. You can | |
840 | now fix your configuration, or revert it back to the last working backup. | |
841 | ||
842 | This is not enough if corosync cannot start anymore. Here its best to edit the | |
843 | local copy of the corosync configuration in '/etc/corosync/corosync.conf' so | |
844 | that corosync can start again. Ensure that on all nodes this configuration has | |
845 | the same content to avoid split brains. If you are not sure what went wrong | |
846 | it's best to ask the Proxmox Community to help you. | |
847 | ||
848 | ||
849 | [[corosync-conf-glossary]] | |
850 | Corosync Configuration Glossary | |
851 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
852 | ||
853 | ringX_addr:: | |
854 | This names the different ring addresses for the corosync totem rings used for | |
855 | the cluster communication. | |
856 | ||
857 | bindnetaddr:: | |
858 | Defines to which interface the ring should bind to. It may be any address of | |
859 | the subnet configured on the interface we want to use. In general its the | |
860 | recommended to just use an address a node uses on this interface. | |
861 | ||
862 | rrp_mode:: | |
863 | Specifies the mode of the redundant ring protocol and may be passive, active or | |
864 | none. Note that use of active is highly experimental and not official | |
865 | supported. Passive is the preferred mode, it may double the cluster | |
866 | communication throughput and increases availability. | |
867 | ||
806ef12d DM |
868 | |
869 | Cluster Cold Start | |
870 | ------------------ | |
871 | ||
872 | It is obvious that a cluster is not quorate when all nodes are | |
873 | offline. This is a common case after a power failure. | |
874 | ||
875 | NOTE: It is always a good idea to use an uninterruptible power supply | |
8c1189b6 | 876 | (``UPS'', also called ``battery backup'') to avoid this state, especially if |
806ef12d DM |
877 | you want HA. |
878 | ||
8c1189b6 FG |
879 | On node startup, service `pve-manager` is started and waits for |
880 | quorum. Once quorate, it starts all guests which have the `onboot` | |
612417fd DM |
881 | flag set. |
882 | ||
883 | When you turn on nodes, or when power comes back after power failure, | |
884 | it is likely that some nodes boots faster than others. Please keep in | |
885 | mind that guest startup is delayed until you reach quorum. | |
806ef12d DM |
886 | |
887 | ||
d8742b0c DM |
888 | ifdef::manvolnum[] |
889 | include::pve-copyright.adoc[] | |
890 | endif::manvolnum[] |