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1 | [[chapter_pvecm]] | |
2 | ifdef::manvolnum[] | |
3 | pvecm(1) | |
4 | ======== | |
5 | :pve-toplevel: | |
6 | ||
7 | NAME | |
8 | ---- | |
9 | ||
10 | pvecm - Proxmox VE Cluster Manager | |
11 | ||
12 | SYNOPSIS | |
13 | -------- | |
14 | ||
15 | include::pvecm.1-synopsis.adoc[] | |
16 | ||
17 | DESCRIPTION | |
18 | ----------- | |
19 | endif::manvolnum[] | |
20 | ||
21 | ifndef::manvolnum[] | |
22 | Cluster Manager | |
23 | =============== | |
24 | :pve-toplevel: | |
25 | endif::manvolnum[] | |
26 | ||
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 | |
29 | http://www.corosync.org[Corosync Cluster Engine] for reliable group | |
30 | communication, and such clusters can consist of up to 32 physical nodes | |
31 | (probably more, dependent on network latency). | |
32 | ||
33 | `pvecm` can be used to create a new cluster, join nodes to a cluster, | |
34 | leave the cluster, get status information and do various other cluster | |
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 | |
37 | nodes. | |
38 | ||
39 | Grouping nodes into a cluster has the following advantages: | |
40 | ||
41 | * Centralized, web based management | |
42 | ||
43 | * Multi-master clusters: each node can do all management task | |
44 | ||
45 | * `pmxcfs`: database-driven file system for storing configuration files, | |
46 | replicated in real-time on all nodes using `corosync`. | |
47 | ||
48 | * Easy migration of virtual machines and containers between physical | |
49 | hosts | |
50 | ||
51 | * Fast deployment | |
52 | ||
53 | * Cluster-wide services like firewall and HA | |
54 | ||
55 | ||
56 | Requirements | |
57 | ------------ | |
58 | ||
59 | * All nodes must be in the same network as `corosync` uses IP Multicast | |
60 | to communicate between nodes (also see | |
61 | http://www.corosync.org[Corosync Cluster Engine]). Corosync uses UDP | |
62 | ports 5404 and 5405 for cluster communication. | |
63 | + | |
64 | NOTE: Some switches do not support IP multicast by default and must be | |
65 | manually enabled first. | |
66 | ||
67 | * Date and time have to be synchronized. | |
68 | ||
69 | * SSH tunnel on TCP port 22 between nodes is used. | |
70 | ||
71 | * If you are interested in High Availability, you need to have at | |
72 | least three nodes for reliable quorum. All nodes should have the | |
73 | same version. | |
74 | ||
75 | * We recommend a dedicated NIC for the cluster traffic, especially if | |
76 | you use shared storage. | |
77 | ||
78 | NOTE: It is not possible to mix Proxmox VE 3.x and earlier with | |
79 | Proxmox VE 4.0 cluster nodes. | |
80 | ||
81 | ||
82 | Preparing Nodes | |
83 | --------------- | |
84 | ||
85 | First, install {PVE} on all nodes. Make sure that each node is | |
86 | installed with the final hostname and IP configuration. Changing the | |
87 | hostname and IP is not possible after cluster creation. | |
88 | ||
89 | Currently the cluster creation has to be done on the console, so you | |
90 | need to login via `ssh`. | |
91 | ||
92 | [[pvecm_create_cluster]] | |
93 | Create the Cluster | |
94 | ------------------ | |
95 | ||
96 | Login via `ssh` to the first {pve} node. Use a unique name for your cluster. | |
97 | This name cannot be changed later. | |
98 | ||
99 | hp1# pvecm create YOUR-CLUSTER-NAME | |
100 | ||
101 | CAUTION: The cluster name is used to compute the default multicast | |
102 | address. Please use unique cluster names if you run more than one | |
103 | cluster inside your network. | |
104 | ||
105 | To check the state of your cluster use: | |
106 | ||
107 | hp1# pvecm status | |
108 | ||
109 | Multiple Clusters In Same Network | |
110 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
111 | ||
112 | It is possible to create multiple clusters in the same physical or logical | |
113 | network. Each cluster must have a unique name, which is used to generate the | |
114 | cluster's multicast group address. As long as no duplicate cluster names are | |
115 | configured in one network segment, the different clusters won't interfere with | |
116 | each other. | |
117 | ||
118 | If multiple clusters operate in a single network it may be beneficial to setup | |
119 | an IGMP querier and enable IGMP Snooping in said network. This may reduce the | |
120 | load of the network significantly because multicast packets are only delivered | |
121 | to endpoints of the respective member nodes. | |
122 | ||
123 | ||
124 | [[pvecm_join_node_to_cluster]] | |
125 | Adding Nodes to the Cluster | |
126 | --------------------------- | |
127 | ||
128 | Login via `ssh` to the node you want to add. | |
129 | ||
130 | hp2# pvecm add IP-ADDRESS-CLUSTER | |
131 | ||
132 | For `IP-ADDRESS-CLUSTER` use the IP from an existing cluster node. | |
133 | ||
134 | CAUTION: A new node cannot hold any VMs, because you would get | |
135 | conflicts about identical VM IDs. Also, all existing configuration in | |
136 | `/etc/pve` is overwritten when you join a new node to the cluster. To | |
137 | workaround, use `vzdump` to backup and restore to a different VMID after | |
138 | adding the node to the cluster. | |
139 | ||
140 | To check the state of cluster: | |
141 | ||
142 | # pvecm status | |
143 | ||
144 | .Cluster status after adding 4 nodes | |
145 | ---- | |
146 | hp2# pvecm status | |
147 | Quorum information | |
148 | ~~~~~~~~~~~~~~~~~~ | |
149 | Date: Mon Apr 20 12:30:13 2015 | |
150 | Quorum provider: corosync_votequorum | |
151 | Nodes: 4 | |
152 | Node ID: 0x00000001 | |
153 | Ring ID: 1928 | |
154 | Quorate: Yes | |
155 | ||
156 | Votequorum information | |
157 | ~~~~~~~~~~~~~~~~~~~~~~ | |
158 | Expected votes: 4 | |
159 | Highest expected: 4 | |
160 | Total votes: 4 | |
161 | Quorum: 2 | |
162 | Flags: Quorate | |
163 | ||
164 | Membership information | |
165 | ~~~~~~~~~~~~~~~~~~~~~~ | |
166 | Nodeid Votes Name | |
167 | 0x00000001 1 192.168.15.91 | |
168 | 0x00000002 1 192.168.15.92 (local) | |
169 | 0x00000003 1 192.168.15.93 | |
170 | 0x00000004 1 192.168.15.94 | |
171 | ---- | |
172 | ||
173 | If you only want the list of all nodes use: | |
174 | ||
175 | # pvecm nodes | |
176 | ||
177 | .List nodes in a cluster | |
178 | ---- | |
179 | hp2# pvecm nodes | |
180 | ||
181 | Membership information | |
182 | ~~~~~~~~~~~~~~~~~~~~~~ | |
183 | Nodeid Votes Name | |
184 | 1 1 hp1 | |
185 | 2 1 hp2 (local) | |
186 | 3 1 hp3 | |
187 | 4 1 hp4 | |
188 | ---- | |
189 | ||
190 | [[adding-nodes-with-separated-cluster-network]] | |
191 | Adding Nodes With Separated Cluster Network | |
192 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
193 | ||
194 | When adding a node to a cluster with a separated cluster network you need to | |
195 | use the 'ringX_addr' parameters to set the nodes address on those networks: | |
196 | ||
197 | [source,bash] | |
198 | ---- | |
199 | pvecm add IP-ADDRESS-CLUSTER -ring0_addr IP-ADDRESS-RING0 | |
200 | ---- | |
201 | ||
202 | If you want to use the Redundant Ring Protocol you will also want to pass the | |
203 | 'ring1_addr' parameter. | |
204 | ||
205 | ||
206 | Remove a Cluster Node | |
207 | --------------------- | |
208 | ||
209 | CAUTION: Read carefully the procedure before proceeding, as it could | |
210 | not be what you want or need. | |
211 | ||
212 | Move all virtual machines from the node. Make sure you have no local | |
213 | data or backups you want to keep, or save them accordingly. | |
214 | In the following example we will remove the node hp4 from the cluster. | |
215 | ||
216 | Log in to a *different* cluster node (not hp4), and issue a `pvecm nodes` | |
217 | command to identify the node ID to remove: | |
218 | ||
219 | ---- | |
220 | hp1# pvecm nodes | |
221 | ||
222 | Membership information | |
223 | ~~~~~~~~~~~~~~~~~~~~~~ | |
224 | Nodeid Votes Name | |
225 | 1 1 hp1 (local) | |
226 | 2 1 hp2 | |
227 | 3 1 hp3 | |
228 | 4 1 hp4 | |
229 | ---- | |
230 | ||
231 | ||
232 | At this point you must power off hp4 and | |
233 | make sure that it will not power on again (in the network) as it | |
234 | is. | |
235 | ||
236 | IMPORTANT: As said above, it is critical to power off the node | |
237 | *before* removal, and make sure that it will *never* power on again | |
238 | (in the existing cluster network) as it is. | |
239 | If you power on the node as it is, your cluster will be screwed up and | |
240 | it could be difficult to restore a clean cluster state. | |
241 | ||
242 | After powering off the node hp4, we can safely remove it from the cluster. | |
243 | ||
244 | hp1# pvecm delnode hp4 | |
245 | ||
246 | If the operation succeeds no output is returned, just check the node | |
247 | list again with `pvecm nodes` or `pvecm status`. You should see | |
248 | something like: | |
249 | ||
250 | ---- | |
251 | hp1# pvecm status | |
252 | ||
253 | Quorum information | |
254 | ~~~~~~~~~~~~~~~~~~ | |
255 | Date: Mon Apr 20 12:44:28 2015 | |
256 | Quorum provider: corosync_votequorum | |
257 | Nodes: 3 | |
258 | Node ID: 0x00000001 | |
259 | Ring ID: 1992 | |
260 | Quorate: Yes | |
261 | ||
262 | Votequorum information | |
263 | ~~~~~~~~~~~~~~~~~~~~~~ | |
264 | Expected votes: 3 | |
265 | Highest expected: 3 | |
266 | Total votes: 3 | |
267 | Quorum: 3 | |
268 | Flags: Quorate | |
269 | ||
270 | Membership information | |
271 | ~~~~~~~~~~~~~~~~~~~~~~ | |
272 | Nodeid Votes Name | |
273 | 0x00000001 1 192.168.15.90 (local) | |
274 | 0x00000002 1 192.168.15.91 | |
275 | 0x00000003 1 192.168.15.92 | |
276 | ---- | |
277 | ||
278 | If, for whatever reason, you want that this server joins the same | |
279 | cluster again, you have to | |
280 | ||
281 | * reinstall {pve} on it from scratch | |
282 | ||
283 | * then join it, as explained in the previous section. | |
284 | ||
285 | [[pvecm_separate_node_without_reinstall]] | |
286 | Separate A Node Without Reinstalling | |
287 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
288 | ||
289 | CAUTION: This is *not* the recommended method, proceed with caution. Use the | |
290 | above mentioned method if you're unsure. | |
291 | ||
292 | You can also separate a node from a cluster without reinstalling it from | |
293 | scratch. But after removing the node from the cluster it will still have | |
294 | access to the shared storages! This must be resolved before you start removing | |
295 | the node from the cluster. A {pve} cluster cannot share the exact same | |
296 | storage with another cluster, as storage locking doesn't work over cluster | |
297 | boundary. Further, it may also lead to VMID conflicts. | |
298 | ||
299 | Its suggested that you create a new storage where only the node which you want | |
300 | to separate has access. This can be an new export on your NFS or a new Ceph | |
301 | pool, to name a few examples. Its just important that the exact same storage | |
302 | does not gets accessed by multiple clusters. After setting this storage up move | |
303 | all data from the node and its VMs to it. Then you are ready to separate the | |
304 | node from the cluster. | |
305 | ||
306 | WARNING: Ensure all shared resources are cleanly separated! You will run into | |
307 | conflicts and problems else. | |
308 | ||
309 | First stop the corosync and the pve-cluster services on the node: | |
310 | [source,bash] | |
311 | ---- | |
312 | systemctl stop pve-cluster | |
313 | systemctl stop corosync | |
314 | ---- | |
315 | ||
316 | Start the cluster filesystem again in local mode: | |
317 | [source,bash] | |
318 | ---- | |
319 | pmxcfs -l | |
320 | ---- | |
321 | ||
322 | Delete the corosync configuration files: | |
323 | [source,bash] | |
324 | ---- | |
325 | rm /etc/pve/corosync.conf | |
326 | rm /etc/corosync/* | |
327 | ---- | |
328 | ||
329 | You can now start the filesystem again as normal service: | |
330 | [source,bash] | |
331 | ---- | |
332 | killall pmxcfs | |
333 | systemctl start pve-cluster | |
334 | ---- | |
335 | ||
336 | The node is now separated from the cluster. You can deleted it from a remaining | |
337 | node of the cluster with: | |
338 | [source,bash] | |
339 | ---- | |
340 | pvecm delnode oldnode | |
341 | ---- | |
342 | ||
343 | If the command failed, because the remaining node in the cluster lost quorum | |
344 | when the now separate node exited, you may set the expected votes to 1 as a workaround: | |
345 | [source,bash] | |
346 | ---- | |
347 | pvecm expected 1 | |
348 | ---- | |
349 | ||
350 | And the repeat the 'pvecm delnode' command. | |
351 | ||
352 | Now switch back to the separated node, here delete all remaining files left | |
353 | from the old cluster. This ensures that the node can be added to another | |
354 | cluster again without problems. | |
355 | ||
356 | [source,bash] | |
357 | ---- | |
358 | rm /var/lib/corosync/* | |
359 | ---- | |
360 | ||
361 | As the configuration files from the other nodes are still in the cluster | |
362 | filesystem you may want to clean those up too. Remove simply the whole | |
363 | directory recursive from '/etc/pve/nodes/NODENAME', but check three times that | |
364 | you used the correct one before deleting it. | |
365 | ||
366 | CAUTION: The nodes SSH keys are still in the 'authorized_key' file, this means | |
367 | the nodes can still connect to each other with public key authentication. This | |
368 | should be fixed by removing the respective keys from the | |
369 | '/etc/pve/priv/authorized_keys' file. | |
370 | ||
371 | Quorum | |
372 | ------ | |
373 | ||
374 | {pve} use a quorum-based technique to provide a consistent state among | |
375 | all cluster nodes. | |
376 | ||
377 | [quote, from Wikipedia, Quorum (distributed computing)] | |
378 | ____ | |
379 | A quorum is the minimum number of votes that a distributed transaction | |
380 | has to obtain in order to be allowed to perform an operation in a | |
381 | distributed system. | |
382 | ____ | |
383 | ||
384 | In case of network partitioning, state changes requires that a | |
385 | majority of nodes are online. The cluster switches to read-only mode | |
386 | if it loses quorum. | |
387 | ||
388 | NOTE: {pve} assigns a single vote to each node by default. | |
389 | ||
390 | Cluster Network | |
391 | --------------- | |
392 | ||
393 | The cluster network is the core of a cluster. All messages sent over it have to | |
394 | be delivered reliable to all nodes in their respective order. In {pve} this | |
395 | part is done by corosync, an implementation of a high performance low overhead | |
396 | high availability development toolkit. It serves our decentralized | |
397 | configuration file system (`pmxcfs`). | |
398 | ||
399 | [[cluster-network-requirements]] | |
400 | Network Requirements | |
401 | ~~~~~~~~~~~~~~~~~~~~ | |
402 | This needs a reliable network with latencies under 2 milliseconds (LAN | |
403 | performance) to work properly. While corosync can also use unicast for | |
404 | communication between nodes its **highly recommended** to have a multicast | |
405 | capable network. The network should not be used heavily by other members, | |
406 | ideally corosync runs on its own network. | |
407 | *never* share it with network where storage communicates too. | |
408 | ||
409 | Before setting up a cluster it is good practice to check if the network is fit | |
410 | for that purpose. | |
411 | ||
412 | * Ensure that all nodes are in the same subnet. This must only be true for the | |
413 | network interfaces used for cluster communication (corosync). | |
414 | ||
415 | * Ensure all nodes can reach each other over those interfaces, using `ping` is | |
416 | enough for a basic test. | |
417 | ||
418 | * Ensure that multicast works in general and a high package rates. This can be | |
419 | done with the `omping` tool. The final "%loss" number should be < 1%. | |
420 | + | |
421 | [source,bash] | |
422 | ---- | |
423 | omping -c 10000 -i 0.001 -F -q NODE1-IP NODE2-IP ... | |
424 | ---- | |
425 | ||
426 | * Ensure that multicast communication works over an extended period of time. | |
427 | This uncovers problems where IGMP snooping is activated on the network but | |
428 | no multicast querier is active. This test has a duration of around 10 | |
429 | minutes. | |
430 | + | |
431 | [source,bash] | |
432 | ---- | |
433 | omping -c 600 -i 1 -q NODE1-IP NODE2-IP ... | |
434 | ---- | |
435 | ||
436 | Your network is not ready for clustering if any of these test fails. Recheck | |
437 | your network configuration. Especially switches are notorious for having | |
438 | multicast disabled by default or IGMP snooping enabled with no IGMP querier | |
439 | active. | |
440 | ||
441 | In smaller cluster its also an option to use unicast if you really cannot get | |
442 | multicast to work. | |
443 | ||
444 | Separate Cluster Network | |
445 | ~~~~~~~~~~~~~~~~~~~~~~~~ | |
446 | ||
447 | When creating a cluster without any parameters the cluster network is generally | |
448 | shared with the Web UI and the VMs and its traffic. Depending on your setup | |
449 | even storage traffic may get sent over the same network. Its recommended to | |
450 | change that, as corosync is a time critical real time application. | |
451 | ||
452 | Setting Up A New Network | |
453 | ^^^^^^^^^^^^^^^^^^^^^^^^ | |
454 | ||
455 | First you have to setup a new network interface. It should be on a physical | |
456 | separate network. Ensure that your network fulfills the | |
457 | <<cluster-network-requirements,cluster network requirements>>. | |
458 | ||
459 | Separate On Cluster Creation | |
460 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
461 | ||
462 | This is possible through the 'ring0_addr' and 'bindnet0_addr' parameter of | |
463 | the 'pvecm create' command used for creating a new cluster. | |
464 | ||
465 | If you have setup an additional NIC with a static address on 10.10.10.1/25 | |
466 | and want to send and receive all cluster communication over this interface | |
467 | you would execute: | |
468 | ||
469 | [source,bash] | |
470 | ---- | |
471 | pvecm create test --ring0_addr 10.10.10.1 --bindnet0_addr 10.10.10.0 | |
472 | ---- | |
473 | ||
474 | To check if everything is working properly execute: | |
475 | [source,bash] | |
476 | ---- | |
477 | systemctl status corosync | |
478 | ---- | |
479 | ||
480 | Afterwards, proceed as descripted in the section to | |
481 | <<adding-nodes-with-separated-cluster-network,add nodes with a separated cluster network>>. | |
482 | ||
483 | [[separate-cluster-net-after-creation]] | |
484 | Separate After Cluster Creation | |
485 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
486 | ||
487 | You can do this also if you have already created a cluster and want to switch | |
488 | its communication to another network, without rebuilding the whole cluster. | |
489 | This change may lead to short durations of quorum loss in the cluster, as nodes | |
490 | have to restart corosync and come up one after the other on the new network. | |
491 | ||
492 | Check how to <<edit-corosync-conf,edit the corosync.conf file>> first. | |
493 | The open it and you should see a file similar to: | |
494 | ||
495 | ---- | |
496 | logging { | |
497 | debug: off | |
498 | to_syslog: yes | |
499 | } | |
500 | ||
501 | nodelist { | |
502 | ||
503 | node { | |
504 | name: due | |
505 | nodeid: 2 | |
506 | quorum_votes: 1 | |
507 | ring0_addr: due | |
508 | } | |
509 | ||
510 | node { | |
511 | name: tre | |
512 | nodeid: 3 | |
513 | quorum_votes: 1 | |
514 | ring0_addr: tre | |
515 | } | |
516 | ||
517 | node { | |
518 | name: uno | |
519 | nodeid: 1 | |
520 | quorum_votes: 1 | |
521 | ring0_addr: uno | |
522 | } | |
523 | ||
524 | } | |
525 | ||
526 | quorum { | |
527 | provider: corosync_votequorum | |
528 | } | |
529 | ||
530 | totem { | |
531 | cluster_name: thomas-testcluster | |
532 | config_version: 3 | |
533 | ip_version: ipv4 | |
534 | secauth: on | |
535 | version: 2 | |
536 | interface { | |
537 | bindnetaddr: 192.168.30.50 | |
538 | ringnumber: 0 | |
539 | } | |
540 | ||
541 | } | |
542 | ---- | |
543 | ||
544 | The first you want to do is add the 'name' properties in the node entries if | |
545 | you do not see them already. Those *must* match the node name. | |
546 | ||
547 | Then replace the address from the 'ring0_addr' properties with the new | |
548 | addresses. You may use plain IP addresses or also hostnames here. If you use | |
549 | hostnames ensure that they are resolvable from all nodes. | |
550 | ||
551 | In my example I want to switch my cluster communication to the 10.10.10.1/25 | |
552 | network. So I replace all 'ring0_addr' respectively. I also set the bindnetaddr | |
553 | in the totem section of the config to an address of the new network. It can be | |
554 | any address from the subnet configured on the new network interface. | |
555 | ||
556 | After you increased the 'config_version' property the new configuration file | |
557 | should look like: | |
558 | ||
559 | ---- | |
560 | ||
561 | logging { | |
562 | debug: off | |
563 | to_syslog: yes | |
564 | } | |
565 | ||
566 | nodelist { | |
567 | ||
568 | node { | |
569 | name: due | |
570 | nodeid: 2 | |
571 | quorum_votes: 1 | |
572 | ring0_addr: 10.10.10.2 | |
573 | } | |
574 | ||
575 | node { | |
576 | name: tre | |
577 | nodeid: 3 | |
578 | quorum_votes: 1 | |
579 | ring0_addr: 10.10.10.3 | |
580 | } | |
581 | ||
582 | node { | |
583 | name: uno | |
584 | nodeid: 1 | |
585 | quorum_votes: 1 | |
586 | ring0_addr: 10.10.10.1 | |
587 | } | |
588 | ||
589 | } | |
590 | ||
591 | quorum { | |
592 | provider: corosync_votequorum | |
593 | } | |
594 | ||
595 | totem { | |
596 | cluster_name: thomas-testcluster | |
597 | config_version: 4 | |
598 | ip_version: ipv4 | |
599 | secauth: on | |
600 | version: 2 | |
601 | interface { | |
602 | bindnetaddr: 10.10.10.1 | |
603 | ringnumber: 0 | |
604 | } | |
605 | ||
606 | } | |
607 | ---- | |
608 | ||
609 | Now after a final check whether all changed information is correct we save it | |
610 | and see again the <<edit-corosync-conf,edit corosync.conf file>> section to | |
611 | learn how to bring it in effect. | |
612 | ||
613 | As our change cannot be enforced live from corosync we have to do an restart. | |
614 | ||
615 | On a single node execute: | |
616 | [source,bash] | |
617 | ---- | |
618 | systemctl restart corosync | |
619 | ---- | |
620 | ||
621 | Now check if everything is fine: | |
622 | ||
623 | [source,bash] | |
624 | ---- | |
625 | systemctl status corosync | |
626 | ---- | |
627 | ||
628 | If corosync runs again correct restart corosync also on all other nodes. | |
629 | They will then join the cluster membership one by one on the new network. | |
630 | ||
631 | [[pvecm_rrp]] | |
632 | Redundant Ring Protocol | |
633 | ~~~~~~~~~~~~~~~~~~~~~~~ | |
634 | To avoid a single point of failure you should implement counter measurements. | |
635 | This can be on the hardware and operating system level through network bonding. | |
636 | ||
637 | Corosync itself offers also a possibility to add redundancy through the so | |
638 | called 'Redundant Ring Protocol'. This protocol allows running a second totem | |
639 | ring on another network, this network should be physically separated from the | |
640 | other rings network to actually increase availability. | |
641 | ||
642 | RRP On Cluster Creation | |
643 | ~~~~~~~~~~~~~~~~~~~~~~~ | |
644 | ||
645 | The 'pvecm create' command provides the additional parameters 'bindnetX_addr', | |
646 | 'ringX_addr' and 'rrp_mode', can be used for RRP configuration. | |
647 | ||
648 | NOTE: See the <<corosync-conf-glossary,glossary>> if you do not know what each parameter means. | |
649 | ||
650 | So if you have two networks, one on the 10.10.10.1/24 and the other on the | |
651 | 10.10.20.1/24 subnet you would execute: | |
652 | ||
653 | [source,bash] | |
654 | ---- | |
655 | pvecm create CLUSTERNAME -bindnet0_addr 10.10.10.1 -ring0_addr 10.10.10.1 \ | |
656 | -bindnet1_addr 10.10.20.1 -ring1_addr 10.10.20.1 | |
657 | ---- | |
658 | ||
659 | RRP On Existing Clusters | |
660 | ~~~~~~~~~~~~~~~~~~~~~~~~ | |
661 | ||
662 | You will take similar steps as described in | |
663 | <<separate-cluster-net-after-creation,separating the cluster network>> to | |
664 | enable RRP on an already running cluster. The single difference is, that you | |
665 | will add `ring1` and use it instead of `ring0`. | |
666 | ||
667 | First add a new `interface` subsection in the `totem` section, set its | |
668 | `ringnumber` property to `1`. Set the interfaces `bindnetaddr` property to an | |
669 | address of the subnet you have configured for your new ring. | |
670 | Further set the `rrp_mode` to `passive`, this is the only stable mode. | |
671 | ||
672 | Then add to each node entry in the `nodelist` section its new `ring1_addr` | |
673 | property with the nodes additional ring address. | |
674 | ||
675 | So if you have two networks, one on the 10.10.10.1/24 and the other on the | |
676 | 10.10.20.1/24 subnet, the final configuration file should look like: | |
677 | ||
678 | ---- | |
679 | totem { | |
680 | cluster_name: tweak | |
681 | config_version: 9 | |
682 | ip_version: ipv4 | |
683 | rrp_mode: passive | |
684 | secauth: on | |
685 | version: 2 | |
686 | interface { | |
687 | bindnetaddr: 10.10.10.1 | |
688 | ringnumber: 0 | |
689 | } | |
690 | interface { | |
691 | bindnetaddr: 10.10.20.1 | |
692 | ringnumber: 1 | |
693 | } | |
694 | } | |
695 | ||
696 | nodelist { | |
697 | node { | |
698 | name: pvecm1 | |
699 | nodeid: 1 | |
700 | quorum_votes: 1 | |
701 | ring0_addr: 10.10.10.1 | |
702 | ring1_addr: 10.10.20.1 | |
703 | } | |
704 | ||
705 | node { | |
706 | name: pvecm2 | |
707 | nodeid: 2 | |
708 | quorum_votes: 1 | |
709 | ring0_addr: 10.10.10.2 | |
710 | ring1_addr: 10.10.20.2 | |
711 | } | |
712 | ||
713 | [...] # other cluster nodes here | |
714 | } | |
715 | ||
716 | [...] # other remaining config sections here | |
717 | ||
718 | ---- | |
719 | ||
720 | Bring it in effect like described in the | |
721 | <<edit-corosync-conf,edit the corosync.conf file>> section. | |
722 | ||
723 | This is a change which cannot take live in effect and needs at least a restart | |
724 | of corosync. Recommended is a restart of the whole cluster. | |
725 | ||
726 | If you cannot reboot the whole cluster ensure no High Availability services are | |
727 | configured and the stop the corosync service on all nodes. After corosync is | |
728 | stopped on all nodes start it one after the other again. | |
729 | ||
730 | Corosync Configuration | |
731 | ---------------------- | |
732 | ||
733 | The `/etc/pve/corosync.conf` file plays a central role in {pve} cluster. It | |
734 | controls the cluster member ship and its network. | |
735 | For reading more about it check the corosync.conf man page: | |
736 | [source,bash] | |
737 | ---- | |
738 | man corosync.conf | |
739 | ---- | |
740 | ||
741 | For node membership you should always use the `pvecm` tool provided by {pve}. | |
742 | You may have to edit the configuration file manually for other changes. | |
743 | Here are a few best practice tips for doing this. | |
744 | ||
745 | [[edit-corosync-conf]] | |
746 | Edit corosync.conf | |
747 | ~~~~~~~~~~~~~~~~~~ | |
748 | ||
749 | Editing the corosync.conf file can be not always straight forward. There are | |
750 | two on each cluster, one in `/etc/pve/corosync.conf` and the other in | |
751 | `/etc/corosync/corosync.conf`. Editing the one in our cluster file system will | |
752 | propagate the changes to the local one, but not vice versa. | |
753 | ||
754 | The configuration will get updated automatically as soon as the file changes. | |
755 | This means changes which can be integrated in a running corosync will take | |
756 | instantly effect. So you should always make a copy and edit that instead, to | |
757 | avoid triggering some unwanted changes by an in between safe. | |
758 | ||
759 | [source,bash] | |
760 | ---- | |
761 | cp /etc/pve/corosync.conf /etc/pve/corosync.conf.new | |
762 | ---- | |
763 | ||
764 | Then open the Config file with your favorite editor, `nano` and `vim.tiny` are | |
765 | preinstalled on {pve} for example. | |
766 | ||
767 | NOTE: Always increment the 'config_version' number on configuration changes, | |
768 | omitting this can lead to problems. | |
769 | ||
770 | After making the necessary changes create another copy of the current working | |
771 | configuration file. This serves as a backup if the new configuration fails to | |
772 | apply or makes problems in other ways. | |
773 | ||
774 | [source,bash] | |
775 | ---- | |
776 | cp /etc/pve/corosync.conf /etc/pve/corosync.conf.bak | |
777 | ---- | |
778 | ||
779 | Then move the new configuration file over the old one: | |
780 | [source,bash] | |
781 | ---- | |
782 | mv /etc/pve/corosync.conf.new /etc/pve/corosync.conf | |
783 | ---- | |
784 | ||
785 | You may check with the commands | |
786 | [source,bash] | |
787 | ---- | |
788 | systemctl status corosync | |
789 | journalctl -b -u corosync | |
790 | ---- | |
791 | ||
792 | If the change could applied automatically. If not you may have to restart the | |
793 | corosync service via: | |
794 | [source,bash] | |
795 | ---- | |
796 | systemctl restart corosync | |
797 | ---- | |
798 | ||
799 | On errors check the troubleshooting section below. | |
800 | ||
801 | Troubleshooting | |
802 | ~~~~~~~~~~~~~~~ | |
803 | ||
804 | Issue: 'quorum.expected_votes must be configured' | |
805 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
806 | ||
807 | When corosync starts to fail and you get the following message in the system log: | |
808 | ||
809 | ---- | |
810 | [...] | |
811 | corosync[1647]: [QUORUM] Quorum provider: corosync_votequorum failed to initialize. | |
812 | corosync[1647]: [SERV ] Service engine 'corosync_quorum' failed to load for reason | |
813 | 'configuration error: nodelist or quorum.expected_votes must be configured!' | |
814 | [...] | |
815 | ---- | |
816 | ||
817 | It means that the hostname you set for corosync 'ringX_addr' in the | |
818 | configuration could not be resolved. | |
819 | ||
820 | ||
821 | Write Configuration When Not Quorate | |
822 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
823 | ||
824 | If you need to change '/etc/pve/corosync.conf' on an node with no quorum, and you | |
825 | know what you do, use: | |
826 | [source,bash] | |
827 | ---- | |
828 | pvecm expected 1 | |
829 | ---- | |
830 | ||
831 | This sets the expected vote count to 1 and makes the cluster quorate. You can | |
832 | now fix your configuration, or revert it back to the last working backup. | |
833 | ||
834 | This is not enough if corosync cannot start anymore. Here its best to edit the | |
835 | local copy of the corosync configuration in '/etc/corosync/corosync.conf' so | |
836 | that corosync can start again. Ensure that on all nodes this configuration has | |
837 | the same content to avoid split brains. If you are not sure what went wrong | |
838 | it's best to ask the Proxmox Community to help you. | |
839 | ||
840 | ||
841 | [[corosync-conf-glossary]] | |
842 | Corosync Configuration Glossary | |
843 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
844 | ||
845 | ringX_addr:: | |
846 | This names the different ring addresses for the corosync totem rings used for | |
847 | the cluster communication. | |
848 | ||
849 | bindnetaddr:: | |
850 | Defines to which interface the ring should bind to. It may be any address of | |
851 | the subnet configured on the interface we want to use. In general its the | |
852 | recommended to just use an address a node uses on this interface. | |
853 | ||
854 | rrp_mode:: | |
855 | Specifies the mode of the redundant ring protocol and may be passive, active or | |
856 | none. Note that use of active is highly experimental and not official | |
857 | supported. Passive is the preferred mode, it may double the cluster | |
858 | communication throughput and increases availability. | |
859 | ||
860 | ||
861 | Cluster Cold Start | |
862 | ------------------ | |
863 | ||
864 | It is obvious that a cluster is not quorate when all nodes are | |
865 | offline. This is a common case after a power failure. | |
866 | ||
867 | NOTE: It is always a good idea to use an uninterruptible power supply | |
868 | (``UPS'', also called ``battery backup'') to avoid this state, especially if | |
869 | you want HA. | |
870 | ||
871 | On node startup, the `pve-guests` service is started and waits for | |
872 | quorum. Once quorate, it starts all guests which have the `onboot` | |
873 | flag set. | |
874 | ||
875 | When you turn on nodes, or when power comes back after power failure, | |
876 | it is likely that some nodes boots faster than others. Please keep in | |
877 | mind that guest startup is delayed until you reach quorum. | |
878 | ||
879 | ||
880 | Guest Migration | |
881 | --------------- | |
882 | ||
883 | Migrating virtual guests to other nodes is a useful feature in a | |
884 | cluster. There are settings to control the behavior of such | |
885 | migrations. This can be done via the configuration file | |
886 | `datacenter.cfg` or for a specific migration via API or command line | |
887 | parameters. | |
888 | ||
889 | It makes a difference if a Guest is online or offline, or if it has | |
890 | local resources (like a local disk). | |
891 | ||
892 | For Details about Virtual Machine Migration see the | |
893 | xref:qm_migration[QEMU/KVM Migration Chapter] | |
894 | ||
895 | For Details about Container Migration see the | |
896 | xref:pct_migration[Container Migration Chapter] | |
897 | ||
898 | Migration Type | |
899 | ~~~~~~~~~~~~~~ | |
900 | ||
901 | The migration type defines if the migration data should be sent over an | |
902 | encrypted (`secure`) channel or an unencrypted (`insecure`) one. | |
903 | Setting the migration type to insecure means that the RAM content of a | |
904 | virtual guest gets also transferred unencrypted, which can lead to | |
905 | information disclosure of critical data from inside the guest (for | |
906 | example passwords or encryption keys). | |
907 | ||
908 | Therefore, we strongly recommend using the secure channel if you do | |
909 | not have full control over the network and can not guarantee that no | |
910 | one is eavesdropping to it. | |
911 | ||
912 | NOTE: Storage migration does not follow this setting. Currently, it | |
913 | always sends the storage content over a secure channel. | |
914 | ||
915 | Encryption requires a lot of computing power, so this setting is often | |
916 | changed to "unsafe" to achieve better performance. The impact on | |
917 | modern systems is lower because they implement AES encryption in | |
918 | hardware. The performance impact is particularly evident in fast | |
919 | networks where you can transfer 10 Gbps or more. | |
920 | ||
921 | ||
922 | Migration Network | |
923 | ~~~~~~~~~~~~~~~~~ | |
924 | ||
925 | By default, {pve} uses the network in which cluster communication | |
926 | takes place to send the migration traffic. This is not optimal because | |
927 | sensitive cluster traffic can be disrupted and this network may not | |
928 | have the best bandwidth available on the node. | |
929 | ||
930 | Setting the migration network parameter allows the use of a dedicated | |
931 | network for the entire migration traffic. In addition to the memory, | |
932 | this also affects the storage traffic for offline migrations. | |
933 | ||
934 | The migration network is set as a network in the CIDR notation. This | |
935 | has the advantage that you do not have to set individual IP addresses | |
936 | for each node. {pve} can determine the real address on the | |
937 | destination node from the network specified in the CIDR form. To | |
938 | enable this, the network must be specified so that each node has one, | |
939 | but only one IP in the respective network. | |
940 | ||
941 | ||
942 | Example | |
943 | ^^^^^^^ | |
944 | ||
945 | We assume that we have a three-node setup with three separate | |
946 | networks. One for public communication with the Internet, one for | |
947 | cluster communication and a very fast one, which we want to use as a | |
948 | dedicated network for migration. | |
949 | ||
950 | A network configuration for such a setup might look as follows: | |
951 | ||
952 | ---- | |
953 | iface eno1 inet manual | |
954 | ||
955 | # public network | |
956 | auto vmbr0 | |
957 | iface vmbr0 inet static | |
958 | address 192.X.Y.57 | |
959 | netmask 255.255.250.0 | |
960 | gateway 192.X.Y.1 | |
961 | bridge_ports eno1 | |
962 | bridge_stp off | |
963 | bridge_fd 0 | |
964 | ||
965 | # cluster network | |
966 | auto eno2 | |
967 | iface eno2 inet static | |
968 | address 10.1.1.1 | |
969 | netmask 255.255.255.0 | |
970 | ||
971 | # fast network | |
972 | auto eno3 | |
973 | iface eno3 inet static | |
974 | address 10.1.2.1 | |
975 | netmask 255.255.255.0 | |
976 | ---- | |
977 | ||
978 | Here, we will use the network 10.1.2.0/24 as a migration network. For | |
979 | a single migration, you can do this using the `migration_network` | |
980 | parameter of the command line tool: | |
981 | ||
982 | ---- | |
983 | # qm migrate 106 tre --online --migration_network 10.1.2.0/24 | |
984 | ---- | |
985 | ||
986 | To configure this as the default network for all migrations in the | |
987 | cluster, set the `migration` property of the `/etc/pve/datacenter.cfg` | |
988 | file: | |
989 | ||
990 | ---- | |
991 | # use dedicated migration network | |
992 | migration: secure,network=10.1.2.0/24 | |
993 | ---- | |
994 | ||
995 | NOTE: The migration type must always be set when the migration network | |
996 | gets set in `/etc/pve/datacenter.cfg`. | |
997 | ||
998 | ||
999 | ifdef::manvolnum[] | |
1000 | include::pve-copyright.adoc[] | |
1001 | endif::manvolnum[] |