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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 | ||
5eba0743 | 43 | * Multi-master clusters: each node can do all management task |
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 | ||
78 | NOTE: While it's possible for {pve} 4.4 and {pve} 5.0 this is not supported as | |
79 | production configuration and should only used temporarily during upgrading the | |
80 | 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 | ||
30101530 TL |
95 | Currently the cluster creation can either be done on the console (login via |
96 | `ssh`) or the API, which we have a GUI implementation for (__Datacenter -> | |
97 | Cluster__). | |
8a865621 | 98 | |
a9e7c3aa SR |
99 | While it's common to reference all nodenames and their IPs in `/etc/hosts` (or |
100 | make their names resolvable through other means), this is not necessary for a | |
101 | cluster to work. It may be useful however, as you can then connect from one node | |
102 | to the other with SSH via the easier to remember node name (see also | |
103 | xref:pvecm_corosync_addresses[Link Address Types]). Note that we always | |
104 | recommend to reference nodes by their IP addresses in the cluster configuration. | |
105 | ||
9a7396aa | 106 | |
11202f1d | 107 | [[pvecm_create_cluster]] |
8a865621 | 108 | Create the Cluster |
ceabe189 | 109 | ------------------ |
8a865621 | 110 | |
8c1189b6 | 111 | Login via `ssh` to the first {pve} node. Use a unique name for your cluster. |
9a7396aa TL |
112 | This name cannot be changed later. The cluster name follows the same rules as |
113 | node names. | |
8a865621 | 114 | |
c15cdfba TL |
115 | ---- |
116 | hp1# pvecm create CLUSTERNAME | |
117 | ---- | |
8a865621 | 118 | |
a9e7c3aa SR |
119 | NOTE: It is possible to create multiple clusters in the same physical or logical |
120 | network. Use unique cluster names if you do so. To avoid human confusion, it is | |
121 | also recommended to choose different names even if clusters do not share the | |
122 | cluster network. | |
63f956c8 | 123 | |
8a865621 DM |
124 | To check the state of your cluster use: |
125 | ||
c15cdfba | 126 | ---- |
8a865621 | 127 | hp1# pvecm status |
c15cdfba | 128 | ---- |
8a865621 | 129 | |
dd1aa0e0 TL |
130 | Multiple Clusters In Same Network |
131 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
132 | ||
133 | It is possible to create multiple clusters in the same physical or logical | |
134 | network. Each such cluster must have a unique name, this does not only helps | |
135 | admins to distinguish on which cluster they currently operate, it is also | |
136 | required to avoid possible clashes in the cluster communication stack. | |
137 | ||
138 | While the bandwidth requirement of a corosync cluster is relatively low, the | |
139 | latency of packages and the package per second (PPS) rate is the limiting | |
140 | factor. Different clusters in the same network can compete with each other for | |
141 | these resources, so it may still make sense to use separate physical network | |
142 | infrastructure for bigger clusters. | |
8a865621 | 143 | |
11202f1d | 144 | [[pvecm_join_node_to_cluster]] |
8a865621 | 145 | Adding Nodes to the Cluster |
ceabe189 | 146 | --------------------------- |
8a865621 | 147 | |
8c1189b6 | 148 | Login via `ssh` to the node you want to add. |
8a865621 | 149 | |
c15cdfba | 150 | ---- |
8a865621 | 151 | hp2# pvecm add IP-ADDRESS-CLUSTER |
c15cdfba | 152 | ---- |
8a865621 | 153 | |
270757a1 | 154 | For `IP-ADDRESS-CLUSTER` use the IP or hostname of an existing cluster node. |
a9e7c3aa | 155 | An IP address is recommended (see xref:pvecm_corosync_addresses[Link Address Types]). |
8a865621 | 156 | |
5eba0743 | 157 | CAUTION: A new node cannot hold any VMs, because you would get |
7980581f | 158 | conflicts about identical VM IDs. Also, all existing configuration in |
8c1189b6 FG |
159 | `/etc/pve` is overwritten when you join a new node to the cluster. To |
160 | workaround, use `vzdump` to backup and restore to a different VMID after | |
7980581f | 161 | adding the node to the cluster. |
8a865621 | 162 | |
a9e7c3aa | 163 | To check the state of the cluster use: |
8a865621 | 164 | |
c15cdfba | 165 | ---- |
8a865621 | 166 | # pvecm status |
c15cdfba | 167 | ---- |
8a865621 | 168 | |
ceabe189 | 169 | .Cluster status after adding 4 nodes |
8a865621 DM |
170 | ---- |
171 | hp2# pvecm status | |
172 | Quorum information | |
173 | ~~~~~~~~~~~~~~~~~~ | |
174 | Date: Mon Apr 20 12:30:13 2015 | |
175 | Quorum provider: corosync_votequorum | |
176 | Nodes: 4 | |
177 | Node ID: 0x00000001 | |
a9e7c3aa | 178 | Ring ID: 1/8 |
8a865621 DM |
179 | Quorate: Yes |
180 | ||
181 | Votequorum information | |
182 | ~~~~~~~~~~~~~~~~~~~~~~ | |
183 | Expected votes: 4 | |
184 | Highest expected: 4 | |
185 | Total votes: 4 | |
91f3edd0 | 186 | Quorum: 3 |
8a865621 DM |
187 | Flags: Quorate |
188 | ||
189 | Membership information | |
190 | ~~~~~~~~~~~~~~~~~~~~~~ | |
191 | Nodeid Votes Name | |
192 | 0x00000001 1 192.168.15.91 | |
193 | 0x00000002 1 192.168.15.92 (local) | |
194 | 0x00000003 1 192.168.15.93 | |
195 | 0x00000004 1 192.168.15.94 | |
196 | ---- | |
197 | ||
198 | If you only want the list of all nodes use: | |
199 | ||
c15cdfba | 200 | ---- |
8a865621 | 201 | # pvecm nodes |
c15cdfba | 202 | ---- |
8a865621 | 203 | |
5eba0743 | 204 | .List nodes in a cluster |
8a865621 DM |
205 | ---- |
206 | hp2# pvecm nodes | |
207 | ||
208 | Membership information | |
209 | ~~~~~~~~~~~~~~~~~~~~~~ | |
210 | Nodeid Votes Name | |
211 | 1 1 hp1 | |
212 | 2 1 hp2 (local) | |
213 | 3 1 hp3 | |
214 | 4 1 hp4 | |
215 | ---- | |
216 | ||
3254bfdd | 217 | [[pvecm_adding_nodes_with_separated_cluster_network]] |
e4ec4154 TL |
218 | Adding Nodes With Separated Cluster Network |
219 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
220 | ||
221 | When adding a node to a cluster with a separated cluster network you need to | |
a9e7c3aa | 222 | use the 'link0' parameter to set the nodes address on that network: |
e4ec4154 TL |
223 | |
224 | [source,bash] | |
4d19cb00 | 225 | ---- |
a9e7c3aa | 226 | pvecm add IP-ADDRESS-CLUSTER -link0 LOCAL-IP-ADDRESS-LINK0 |
4d19cb00 | 227 | ---- |
e4ec4154 | 228 | |
a9e7c3aa SR |
229 | If you want to use the built-in xref:pvecm_redundancy[redundancy] of the |
230 | kronosnet transport layer, also use the 'link1' parameter. | |
e4ec4154 | 231 | |
8a865621 DM |
232 | |
233 | Remove a Cluster Node | |
ceabe189 | 234 | --------------------- |
8a865621 DM |
235 | |
236 | CAUTION: Read carefully the procedure before proceeding, as it could | |
237 | not be what you want or need. | |
238 | ||
239 | Move all virtual machines from the node. Make sure you have no local | |
240 | data or backups you want to keep, or save them accordingly. | |
e8503c6c | 241 | In the following example we will remove the node hp4 from the cluster. |
8a865621 | 242 | |
e8503c6c EK |
243 | Log in to a *different* cluster node (not hp4), and issue a `pvecm nodes` |
244 | command to identify the node ID to remove: | |
8a865621 DM |
245 | |
246 | ---- | |
247 | hp1# pvecm nodes | |
248 | ||
249 | Membership information | |
250 | ~~~~~~~~~~~~~~~~~~~~~~ | |
251 | Nodeid Votes Name | |
252 | 1 1 hp1 (local) | |
253 | 2 1 hp2 | |
254 | 3 1 hp3 | |
255 | 4 1 hp4 | |
256 | ---- | |
257 | ||
e8503c6c EK |
258 | |
259 | At this point you must power off hp4 and | |
260 | make sure that it will not power on again (in the network) as it | |
261 | is. | |
262 | ||
263 | IMPORTANT: As said above, it is critical to power off the node | |
264 | *before* removal, and make sure that it will *never* power on again | |
265 | (in the existing cluster network) as it is. | |
266 | If you power on the node as it is, your cluster will be screwed up and | |
267 | it could be difficult to restore a clean cluster state. | |
268 | ||
269 | After powering off the node hp4, we can safely remove it from the cluster. | |
8a865621 | 270 | |
c15cdfba | 271 | ---- |
8a865621 | 272 | hp1# pvecm delnode hp4 |
c15cdfba | 273 | ---- |
8a865621 DM |
274 | |
275 | If the operation succeeds no output is returned, just check the node | |
8c1189b6 | 276 | list again with `pvecm nodes` or `pvecm status`. You should see |
8a865621 DM |
277 | something like: |
278 | ||
279 | ---- | |
280 | hp1# pvecm status | |
281 | ||
282 | Quorum information | |
283 | ~~~~~~~~~~~~~~~~~~ | |
284 | Date: Mon Apr 20 12:44:28 2015 | |
285 | Quorum provider: corosync_votequorum | |
286 | Nodes: 3 | |
287 | Node ID: 0x00000001 | |
a9e7c3aa | 288 | Ring ID: 1/8 |
8a865621 DM |
289 | Quorate: Yes |
290 | ||
291 | Votequorum information | |
292 | ~~~~~~~~~~~~~~~~~~~~~~ | |
293 | Expected votes: 3 | |
294 | Highest expected: 3 | |
295 | Total votes: 3 | |
91f3edd0 | 296 | Quorum: 2 |
8a865621 DM |
297 | Flags: Quorate |
298 | ||
299 | Membership information | |
300 | ~~~~~~~~~~~~~~~~~~~~~~ | |
301 | Nodeid Votes Name | |
302 | 0x00000001 1 192.168.15.90 (local) | |
303 | 0x00000002 1 192.168.15.91 | |
304 | 0x00000003 1 192.168.15.92 | |
305 | ---- | |
306 | ||
a9e7c3aa SR |
307 | If, for whatever reason, you want this server to join the same cluster again, |
308 | you have to | |
8a865621 | 309 | |
26ca7ff5 | 310 | * reinstall {pve} on it from scratch |
8a865621 DM |
311 | |
312 | * then join it, as explained in the previous section. | |
d8742b0c | 313 | |
41925ede SR |
314 | NOTE: After removal of the node, its SSH fingerprint will still reside in the |
315 | 'known_hosts' of the other nodes. If you receive an SSH error after rejoining | |
9121b45b TL |
316 | a node with the same IP or hostname, run `pvecm updatecerts` once on the |
317 | re-added node to update its fingerprint cluster wide. | |
41925ede | 318 | |
38ae8db3 | 319 | [[pvecm_separate_node_without_reinstall]] |
555e966b TL |
320 | Separate A Node Without Reinstalling |
321 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
322 | ||
323 | CAUTION: This is *not* the recommended method, proceed with caution. Use the | |
324 | above mentioned method if you're unsure. | |
325 | ||
326 | You can also separate a node from a cluster without reinstalling it from | |
327 | scratch. But after removing the node from the cluster it will still have | |
328 | access to the shared storages! This must be resolved before you start removing | |
329 | the node from the cluster. A {pve} cluster cannot share the exact same | |
2ea5c4a5 TL |
330 | storage with another cluster, as storage locking doesn't work over cluster |
331 | boundary. Further, it may also lead to VMID conflicts. | |
555e966b | 332 | |
3be22308 | 333 | Its suggested that you create a new storage where only the node which you want |
a9e7c3aa | 334 | to separate has access. This can be a new export on your NFS or a new Ceph |
3be22308 TL |
335 | pool, to name a few examples. Its just important that the exact same storage |
336 | does not gets accessed by multiple clusters. After setting this storage up move | |
337 | all data from the node and its VMs to it. Then you are ready to separate the | |
338 | node from the cluster. | |
555e966b | 339 | |
a9e7c3aa SR |
340 | WARNING: Ensure all shared resources are cleanly separated! Otherwise you will |
341 | run into conflicts and problems. | |
555e966b TL |
342 | |
343 | First stop the corosync and the pve-cluster services on the node: | |
344 | [source,bash] | |
4d19cb00 | 345 | ---- |
555e966b TL |
346 | systemctl stop pve-cluster |
347 | systemctl stop corosync | |
4d19cb00 | 348 | ---- |
555e966b TL |
349 | |
350 | Start the cluster filesystem again in local mode: | |
351 | [source,bash] | |
4d19cb00 | 352 | ---- |
555e966b | 353 | pmxcfs -l |
4d19cb00 | 354 | ---- |
555e966b TL |
355 | |
356 | Delete the corosync configuration files: | |
357 | [source,bash] | |
4d19cb00 | 358 | ---- |
555e966b TL |
359 | rm /etc/pve/corosync.conf |
360 | rm /etc/corosync/* | |
4d19cb00 | 361 | ---- |
555e966b TL |
362 | |
363 | You can now start the filesystem again as normal service: | |
364 | [source,bash] | |
4d19cb00 | 365 | ---- |
555e966b TL |
366 | killall pmxcfs |
367 | systemctl start pve-cluster | |
4d19cb00 | 368 | ---- |
555e966b TL |
369 | |
370 | The node is now separated from the cluster. You can deleted it from a remaining | |
371 | node of the cluster with: | |
372 | [source,bash] | |
4d19cb00 | 373 | ---- |
555e966b | 374 | pvecm delnode oldnode |
4d19cb00 | 375 | ---- |
555e966b TL |
376 | |
377 | If the command failed, because the remaining node in the cluster lost quorum | |
378 | when the now separate node exited, you may set the expected votes to 1 as a workaround: | |
379 | [source,bash] | |
4d19cb00 | 380 | ---- |
555e966b | 381 | pvecm expected 1 |
4d19cb00 | 382 | ---- |
555e966b | 383 | |
96d698db | 384 | And then repeat the 'pvecm delnode' command. |
555e966b TL |
385 | |
386 | Now switch back to the separated node, here delete all remaining files left | |
387 | from the old cluster. This ensures that the node can be added to another | |
388 | cluster again without problems. | |
389 | ||
390 | [source,bash] | |
4d19cb00 | 391 | ---- |
555e966b | 392 | rm /var/lib/corosync/* |
4d19cb00 | 393 | ---- |
555e966b TL |
394 | |
395 | As the configuration files from the other nodes are still in the cluster | |
396 | filesystem you may want to clean those up too. Remove simply the whole | |
397 | directory recursive from '/etc/pve/nodes/NODENAME', but check three times that | |
398 | you used the correct one before deleting it. | |
399 | ||
400 | CAUTION: The nodes SSH keys are still in the 'authorized_key' file, this means | |
401 | the nodes can still connect to each other with public key authentication. This | |
402 | should be fixed by removing the respective keys from the | |
403 | '/etc/pve/priv/authorized_keys' file. | |
d8742b0c | 404 | |
a9e7c3aa | 405 | |
806ef12d DM |
406 | Quorum |
407 | ------ | |
408 | ||
409 | {pve} use a quorum-based technique to provide a consistent state among | |
410 | all cluster nodes. | |
411 | ||
412 | [quote, from Wikipedia, Quorum (distributed computing)] | |
413 | ____ | |
414 | A quorum is the minimum number of votes that a distributed transaction | |
415 | has to obtain in order to be allowed to perform an operation in a | |
416 | distributed system. | |
417 | ____ | |
418 | ||
419 | In case of network partitioning, state changes requires that a | |
420 | majority of nodes are online. The cluster switches to read-only mode | |
5eba0743 | 421 | if it loses quorum. |
806ef12d DM |
422 | |
423 | NOTE: {pve} assigns a single vote to each node by default. | |
424 | ||
a9e7c3aa | 425 | |
e4ec4154 TL |
426 | Cluster Network |
427 | --------------- | |
428 | ||
429 | The cluster network is the core of a cluster. All messages sent over it have to | |
a9e7c3aa SR |
430 | be delivered reliably to all nodes in their respective order. In {pve} this |
431 | part is done by corosync, an implementation of a high performance, low overhead | |
e4ec4154 TL |
432 | high availability development toolkit. It serves our decentralized |
433 | configuration file system (`pmxcfs`). | |
434 | ||
3254bfdd | 435 | [[pvecm_cluster_network_requirements]] |
e4ec4154 TL |
436 | Network Requirements |
437 | ~~~~~~~~~~~~~~~~~~~~ | |
438 | This needs a reliable network with latencies under 2 milliseconds (LAN | |
a9e7c3aa SR |
439 | performance) to work properly. The network should not be used heavily by other |
440 | members, ideally corosync runs on its own network. Do not use a shared network | |
441 | for corosync and storage (except as a potential low-priority fallback in a | |
442 | xref:pvecm_redundancy[redundant] configuration). | |
e4ec4154 | 443 | |
a9e7c3aa SR |
444 | Before setting up a cluster, it is good practice to check if the network is fit |
445 | for that purpose. To make sure the nodes can connect to each other on the | |
446 | cluster network, you can test the connectivity between them with the `ping` | |
447 | tool. | |
e4ec4154 | 448 | |
a9e7c3aa SR |
449 | If the {pve} firewall is enabled, ACCEPT rules for corosync will automatically |
450 | be generated - no manual action is required. | |
e4ec4154 | 451 | |
a9e7c3aa SR |
452 | NOTE: Corosync used Multicast before version 3.0 (introduced in {pve} 6.0). |
453 | Modern versions rely on https://kronosnet.org/[Kronosnet] for cluster | |
454 | communication, which, for now, only supports regular UDP unicast. | |
e4ec4154 | 455 | |
a9e7c3aa SR |
456 | CAUTION: You can still enable Multicast or legacy unicast by setting your |
457 | transport to `udp` or `udpu` in your xref:pvecm_edit_corosync_conf[corosync.conf], | |
458 | but keep in mind that this will disable all cryptography and redundancy support. | |
459 | This is therefore not recommended. | |
e4ec4154 TL |
460 | |
461 | Separate Cluster Network | |
462 | ~~~~~~~~~~~~~~~~~~~~~~~~ | |
463 | ||
a9e7c3aa SR |
464 | When creating a cluster without any parameters the corosync cluster network is |
465 | generally shared with the Web UI and the VMs and their traffic. Depending on | |
466 | your setup, even storage traffic may get sent over the same network. Its | |
467 | recommended to change that, as corosync is a time critical real time | |
468 | application. | |
e4ec4154 TL |
469 | |
470 | Setting Up A New Network | |
471 | ^^^^^^^^^^^^^^^^^^^^^^^^ | |
472 | ||
a9e7c3aa | 473 | First you have to set up a new network interface. It should be on a physically |
e4ec4154 | 474 | separate network. Ensure that your network fulfills the |
3254bfdd | 475 | xref:pvecm_cluster_network_requirements[cluster network requirements]. |
e4ec4154 TL |
476 | |
477 | Separate On Cluster Creation | |
478 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
479 | ||
a9e7c3aa SR |
480 | This is possible via the 'linkX' parameters of the 'pvecm create' |
481 | command used for creating a new cluster. | |
e4ec4154 | 482 | |
a9e7c3aa SR |
483 | If you have set up an additional NIC with a static address on 10.10.10.1/25, |
484 | and want to send and receive all cluster communication over this interface, | |
e4ec4154 TL |
485 | you would execute: |
486 | ||
487 | [source,bash] | |
4d19cb00 | 488 | ---- |
a9e7c3aa | 489 | pvecm create test --link0 10.10.10.1 |
4d19cb00 | 490 | ---- |
e4ec4154 TL |
491 | |
492 | To check if everything is working properly execute: | |
493 | [source,bash] | |
4d19cb00 | 494 | ---- |
e4ec4154 | 495 | systemctl status corosync |
4d19cb00 | 496 | ---- |
e4ec4154 | 497 | |
a9e7c3aa | 498 | Afterwards, proceed as described above to |
3254bfdd | 499 | xref:pvecm_adding_nodes_with_separated_cluster_network[add nodes with a separated cluster network]. |
82d52451 | 500 | |
3254bfdd | 501 | [[pvecm_separate_cluster_net_after_creation]] |
e4ec4154 TL |
502 | Separate After Cluster Creation |
503 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
504 | ||
a9e7c3aa | 505 | You can do this if you have already created a cluster and want to switch |
e4ec4154 TL |
506 | its communication to another network, without rebuilding the whole cluster. |
507 | This change may lead to short durations of quorum loss in the cluster, as nodes | |
508 | have to restart corosync and come up one after the other on the new network. | |
509 | ||
3254bfdd | 510 | Check how to xref:pvecm_edit_corosync_conf[edit the corosync.conf file] first. |
a9e7c3aa | 511 | Then, open it and you should see a file similar to: |
e4ec4154 TL |
512 | |
513 | ---- | |
514 | logging { | |
515 | debug: off | |
516 | to_syslog: yes | |
517 | } | |
518 | ||
519 | nodelist { | |
520 | ||
521 | node { | |
522 | name: due | |
523 | nodeid: 2 | |
524 | quorum_votes: 1 | |
525 | ring0_addr: due | |
526 | } | |
527 | ||
528 | node { | |
529 | name: tre | |
530 | nodeid: 3 | |
531 | quorum_votes: 1 | |
532 | ring0_addr: tre | |
533 | } | |
534 | ||
535 | node { | |
536 | name: uno | |
537 | nodeid: 1 | |
538 | quorum_votes: 1 | |
539 | ring0_addr: uno | |
540 | } | |
541 | ||
542 | } | |
543 | ||
544 | quorum { | |
545 | provider: corosync_votequorum | |
546 | } | |
547 | ||
548 | totem { | |
a9e7c3aa | 549 | cluster_name: testcluster |
e4ec4154 | 550 | config_version: 3 |
a9e7c3aa | 551 | ip_version: ipv4-6 |
e4ec4154 TL |
552 | secauth: on |
553 | version: 2 | |
554 | interface { | |
a9e7c3aa | 555 | linknumber: 0 |
e4ec4154 TL |
556 | } |
557 | ||
558 | } | |
559 | ---- | |
560 | ||
a9e7c3aa SR |
561 | NOTE: `ringX_addr` actually specifies a corosync *link address*, the name "ring" |
562 | is a remnant of older corosync versions that is kept for backwards | |
563 | compatibility. | |
564 | ||
565 | The first thing you want to do is add the 'name' properties in the node entries | |
566 | if you do not see them already. Those *must* match the node name. | |
e4ec4154 | 567 | |
a9e7c3aa SR |
568 | Then replace all addresses from the 'ring0_addr' properties of all nodes with |
569 | the new addresses. You may use plain IP addresses or hostnames here. If you use | |
270757a1 | 570 | hostnames ensure that they are resolvable from all nodes. (see also |
a9e7c3aa | 571 | xref:pvecm_corosync_addresses[Link Address Types]) |
e4ec4154 | 572 | |
a9e7c3aa SR |
573 | In this example, we want to switch the cluster communication to the |
574 | 10.10.10.1/25 network. So we replace all 'ring0_addr' respectively. | |
e4ec4154 | 575 | |
a9e7c3aa SR |
576 | NOTE: The exact same procedure can be used to change other 'ringX_addr' values |
577 | as well, although we recommend to not change multiple addresses at once, to make | |
578 | it easier to recover if something goes wrong. | |
579 | ||
580 | After we increase the 'config_version' property, the new configuration file | |
e4ec4154 TL |
581 | should look like: |
582 | ||
583 | ---- | |
e4ec4154 TL |
584 | logging { |
585 | debug: off | |
586 | to_syslog: yes | |
587 | } | |
588 | ||
589 | nodelist { | |
590 | ||
591 | node { | |
592 | name: due | |
593 | nodeid: 2 | |
594 | quorum_votes: 1 | |
595 | ring0_addr: 10.10.10.2 | |
596 | } | |
597 | ||
598 | node { | |
599 | name: tre | |
600 | nodeid: 3 | |
601 | quorum_votes: 1 | |
602 | ring0_addr: 10.10.10.3 | |
603 | } | |
604 | ||
605 | node { | |
606 | name: uno | |
607 | nodeid: 1 | |
608 | quorum_votes: 1 | |
609 | ring0_addr: 10.10.10.1 | |
610 | } | |
611 | ||
612 | } | |
613 | ||
614 | quorum { | |
615 | provider: corosync_votequorum | |
616 | } | |
617 | ||
618 | totem { | |
a9e7c3aa | 619 | cluster_name: testcluster |
e4ec4154 | 620 | config_version: 4 |
a9e7c3aa | 621 | ip_version: ipv4-6 |
e4ec4154 TL |
622 | secauth: on |
623 | version: 2 | |
624 | interface { | |
a9e7c3aa | 625 | linknumber: 0 |
e4ec4154 TL |
626 | } |
627 | ||
628 | } | |
629 | ---- | |
630 | ||
a9e7c3aa SR |
631 | Then, after a final check if all changed information is correct, we save it and |
632 | once again follow the xref:pvecm_edit_corosync_conf[edit corosync.conf file] | |
633 | section to bring it into effect. | |
e4ec4154 | 634 | |
a9e7c3aa SR |
635 | The changes will be applied live, so restarting corosync is not strictly |
636 | necessary. If you changed other settings as well, or notice corosync | |
637 | complaining, you can optionally trigger a restart. | |
e4ec4154 TL |
638 | |
639 | On a single node execute: | |
a9e7c3aa | 640 | |
e4ec4154 | 641 | [source,bash] |
4d19cb00 | 642 | ---- |
e4ec4154 | 643 | systemctl restart corosync |
4d19cb00 | 644 | ---- |
e4ec4154 TL |
645 | |
646 | Now check if everything is fine: | |
647 | ||
648 | [source,bash] | |
4d19cb00 | 649 | ---- |
e4ec4154 | 650 | systemctl status corosync |
4d19cb00 | 651 | ---- |
e4ec4154 TL |
652 | |
653 | If corosync runs again correct restart corosync also on all other nodes. | |
654 | They will then join the cluster membership one by one on the new network. | |
655 | ||
3254bfdd | 656 | [[pvecm_corosync_addresses]] |
270757a1 SR |
657 | Corosync addresses |
658 | ~~~~~~~~~~~~~~~~~~ | |
659 | ||
a9e7c3aa SR |
660 | A corosync link address (for backwards compatibility denoted by 'ringX_addr' in |
661 | `corosync.conf`) can be specified in two ways: | |
270757a1 SR |
662 | |
663 | * **IPv4/v6 addresses** will be used directly. They are recommended, since they | |
664 | are static and usually not changed carelessly. | |
665 | ||
666 | * **Hostnames** will be resolved using `getaddrinfo`, which means that per | |
667 | default, IPv6 addresses will be used first, if available (see also | |
668 | `man gai.conf`). Keep this in mind, especially when upgrading an existing | |
669 | cluster to IPv6. | |
670 | ||
671 | CAUTION: Hostnames should be used with care, since the address they | |
672 | resolve to can be changed without touching corosync or the node it runs on - | |
673 | which may lead to a situation where an address is changed without thinking | |
674 | about implications for corosync. | |
675 | ||
676 | A seperate, static hostname specifically for corosync is recommended, if | |
677 | hostnames are preferred. Also, make sure that every node in the cluster can | |
678 | resolve all hostnames correctly. | |
679 | ||
680 | Since {pve} 5.1, while supported, hostnames will be resolved at the time of | |
681 | entry. Only the resolved IP is then saved to the configuration. | |
682 | ||
683 | Nodes that joined the cluster on earlier versions likely still use their | |
684 | unresolved hostname in `corosync.conf`. It might be a good idea to replace | |
685 | them with IPs or a seperate hostname, as mentioned above. | |
686 | ||
e4ec4154 | 687 | |
a9e7c3aa SR |
688 | [[pvecm_redundancy]] |
689 | Corosync Redundancy | |
690 | ------------------- | |
e4ec4154 | 691 | |
a9e7c3aa SR |
692 | Corosync supports redundant networking via its integrated kronosnet layer by |
693 | default (it is not supported on the legacy udp/udpu transports). It can be | |
694 | enabled by specifying more than one link address, either via the '--linkX' | |
695 | parameters of `pvecm` (while creating a cluster or adding a new node) or by | |
696 | specifying more than one 'ringX_addr' in `corosync.conf`. | |
e4ec4154 | 697 | |
a9e7c3aa SR |
698 | NOTE: To provide useful failover, every link should be on its own |
699 | physical network connection. | |
e4ec4154 | 700 | |
a9e7c3aa SR |
701 | Links are used according to a priority setting. You can configure this priority |
702 | by setting 'knet_link_priority' in the corresponding interface section in | |
703 | `corosync.conf`, or, preferrably, using the 'priority' parameter when creating | |
704 | your cluster with `pvecm`: | |
e4ec4154 | 705 | |
4d19cb00 | 706 | ---- |
a9e7c3aa | 707 | # pvecm create CLUSTERNAME --link0 10.10.10.1,priority=20 --link1 10.20.20.1,priority=15 |
4d19cb00 | 708 | ---- |
e4ec4154 | 709 | |
a9e7c3aa SR |
710 | This would cause 'link1' to be used first, since it has the lower priority. |
711 | ||
712 | If no priorities are configured manually (or two links have the same priority), | |
713 | links will be used in order of their number, with the lower number having higher | |
714 | priority. | |
715 | ||
716 | Even if all links are working, only the one with the highest priority will see | |
717 | corosync traffic. Link priorities cannot be mixed, i.e. links with different | |
718 | priorities will not be able to communicate with each other. | |
e4ec4154 | 719 | |
a9e7c3aa SR |
720 | Since lower priority links will not see traffic unless all higher priorities |
721 | have failed, it becomes a useful strategy to specify even networks used for | |
722 | other tasks (VMs, storage, etc...) as low-priority links. If worst comes to | |
723 | worst, a higher-latency or more congested connection might be better than no | |
724 | connection at all. | |
e4ec4154 | 725 | |
a9e7c3aa SR |
726 | Adding Redundant Links To An Existing Cluster |
727 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
e4ec4154 | 728 | |
a9e7c3aa SR |
729 | To add a new link to a running configuration, first check how to |
730 | xref:pvecm_edit_corosync_conf[edit the corosync.conf file]. | |
e4ec4154 | 731 | |
a9e7c3aa SR |
732 | Then, add a new 'ringX_addr' to every node in the `nodelist` section. Make |
733 | sure that your 'X' is the same for every node you add it to, and that it is | |
734 | unique for each node. | |
735 | ||
736 | Lastly, add a new 'interface', as shown below, to your `totem` | |
737 | section, replacing 'X' with your link number chosen above. | |
738 | ||
739 | Assuming you added a link with number 1, the new configuration file could look | |
740 | like this: | |
e4ec4154 TL |
741 | |
742 | ---- | |
a9e7c3aa SR |
743 | logging { |
744 | debug: off | |
745 | to_syslog: yes | |
e4ec4154 TL |
746 | } |
747 | ||
748 | nodelist { | |
a9e7c3aa | 749 | |
e4ec4154 | 750 | node { |
a9e7c3aa SR |
751 | name: due |
752 | nodeid: 2 | |
e4ec4154 | 753 | quorum_votes: 1 |
a9e7c3aa SR |
754 | ring0_addr: 10.10.10.2 |
755 | ring1_addr: 10.20.20.2 | |
e4ec4154 TL |
756 | } |
757 | ||
a9e7c3aa SR |
758 | node { |
759 | name: tre | |
760 | nodeid: 3 | |
e4ec4154 | 761 | quorum_votes: 1 |
a9e7c3aa SR |
762 | ring0_addr: 10.10.10.3 |
763 | ring1_addr: 10.20.20.3 | |
e4ec4154 TL |
764 | } |
765 | ||
a9e7c3aa SR |
766 | node { |
767 | name: uno | |
768 | nodeid: 1 | |
769 | quorum_votes: 1 | |
770 | ring0_addr: 10.10.10.1 | |
771 | ring1_addr: 10.20.20.1 | |
772 | } | |
773 | ||
774 | } | |
775 | ||
776 | quorum { | |
777 | provider: corosync_votequorum | |
778 | } | |
779 | ||
780 | totem { | |
781 | cluster_name: testcluster | |
782 | config_version: 4 | |
783 | ip_version: ipv4-6 | |
784 | secauth: on | |
785 | version: 2 | |
786 | interface { | |
787 | linknumber: 0 | |
788 | } | |
789 | interface { | |
790 | linknumber: 1 | |
791 | } | |
e4ec4154 | 792 | } |
a9e7c3aa | 793 | ---- |
e4ec4154 | 794 | |
a9e7c3aa SR |
795 | The new link will be enabled as soon as you follow the last steps to |
796 | xref:pvecm_edit_corosync_conf[edit the corosync.conf file]. A restart should not | |
797 | be necessary. You can check that corosync loaded the new link using: | |
e4ec4154 | 798 | |
a9e7c3aa SR |
799 | ---- |
800 | journalctl -b -u corosync | |
e4ec4154 TL |
801 | ---- |
802 | ||
a9e7c3aa SR |
803 | It might be a good idea to test the new link by temporarily disconnecting the |
804 | old link on one node and making sure that its status remains online while | |
805 | disconnected: | |
e4ec4154 | 806 | |
a9e7c3aa SR |
807 | ---- |
808 | pvecm status | |
809 | ---- | |
810 | ||
811 | If you see a healthy cluster state, it means that your new link is being used. | |
e4ec4154 | 812 | |
e4ec4154 | 813 | |
c21d2cbe OB |
814 | Corosync External Vote Support |
815 | ------------------------------ | |
816 | ||
817 | This section describes a way to deploy an external voter in a {pve} cluster. | |
818 | When configured, the cluster can sustain more node failures without | |
819 | violating safety properties of the cluster communication. | |
820 | ||
821 | For this to work there are two services involved: | |
822 | ||
823 | * a so called qdevice daemon which runs on each {pve} node | |
824 | ||
825 | * an external vote daemon which runs on an independent server. | |
826 | ||
827 | As a result you can achieve higher availability even in smaller setups (for | |
828 | example 2+1 nodes). | |
829 | ||
830 | QDevice Technical Overview | |
831 | ~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
832 | ||
833 | The Corosync Quroum Device (QDevice) is a daemon which runs on each cluster | |
834 | node. It provides a configured number of votes to the clusters quorum | |
835 | subsystem based on an external running third-party arbitrator's decision. | |
836 | Its primary use is to allow a cluster to sustain more node failures than | |
837 | standard quorum rules allow. This can be done safely as the external device | |
838 | can see all nodes and thus choose only one set of nodes to give its vote. | |
51730d56 | 839 | This will only be done if said set of nodes can have quorum (again) when |
c21d2cbe OB |
840 | receiving the third-party vote. |
841 | ||
842 | Currently only 'QDevice Net' is supported as a third-party arbitrator. It is | |
843 | a daemon which provides a vote to a cluster partition if it can reach the | |
844 | partition members over the network. It will give only votes to one partition | |
845 | of a cluster at any time. | |
846 | It's designed to support multiple clusters and is almost configuration and | |
847 | state free. New clusters are handled dynamically and no configuration file | |
848 | is needed on the host running a QDevice. | |
849 | ||
850 | The external host has the only requirement that it needs network access to the | |
851 | cluster and a corosync-qnetd package available. We provide such a package | |
852 | for Debian based hosts, other Linux distributions should also have a package | |
853 | available through their respective package manager. | |
854 | ||
855 | NOTE: In contrast to corosync itself, a QDevice connects to the cluster over | |
a9e7c3aa SR |
856 | TCP/IP. The daemon may even run outside of the clusters LAN and can have longer |
857 | latencies than 2 ms. | |
c21d2cbe OB |
858 | |
859 | Supported Setups | |
860 | ~~~~~~~~~~~~~~~~ | |
861 | ||
862 | We support QDevices for clusters with an even number of nodes and recommend | |
863 | it for 2 node clusters, if they should provide higher availability. | |
864 | For clusters with an odd node count we discourage the use of QDevices | |
865 | currently. The reason for this, is the difference of the votes the QDevice | |
866 | provides for each cluster type. Even numbered clusters get single additional | |
867 | vote, with this we can only increase availability, i.e. if the QDevice | |
868 | itself fails we are in the same situation as with no QDevice at all. | |
869 | ||
870 | Now, with an odd numbered cluster size the QDevice provides '(N-1)' votes -- | |
871 | where 'N' corresponds to the cluster node count. This difference makes | |
872 | sense, if we had only one additional vote the cluster can get into a split | |
873 | brain situation. | |
874 | This algorithm would allow that all nodes but one (and naturally the | |
875 | QDevice itself) could fail. | |
876 | There are two drawbacks with this: | |
877 | ||
878 | * If the QNet daemon itself fails, no other node may fail or the cluster | |
879 | immediately loses quorum. For example, in a cluster with 15 nodes 7 | |
880 | could fail before the cluster becomes inquorate. But, if a QDevice is | |
881 | configured here and said QDevice fails itself **no single node** of | |
882 | the 15 may fail. The QDevice acts almost as a single point of failure in | |
883 | this case. | |
884 | ||
885 | * The fact that all but one node plus QDevice may fail sound promising at | |
886 | first, but this may result in a mass recovery of HA services that would | |
887 | overload the single node left. Also ceph server will stop to provide | |
888 | services after only '((N-1)/2)' nodes are online. | |
889 | ||
890 | If you understand the drawbacks and implications you can decide yourself if | |
891 | you should use this technology in an odd numbered cluster setup. | |
892 | ||
c21d2cbe OB |
893 | QDevice-Net Setup |
894 | ~~~~~~~~~~~~~~~~~ | |
895 | ||
896 | We recommend to run any daemon which provides votes to corosync-qdevice as an | |
e34c3e91 TL |
897 | unprivileged user. {pve} and Debian provides a package which is already |
898 | configured to do so. | |
c21d2cbe OB |
899 | The traffic between the daemon and the cluster must be encrypted to ensure a |
900 | safe and secure QDevice integration in {pve}. | |
901 | ||
902 | First install the 'corosync-qnetd' package on your external server and | |
903 | the 'corosync-qdevice' package on all cluster nodes. | |
904 | ||
905 | After that, ensure that all your nodes on the cluster are online. | |
906 | ||
907 | You can now easily set up your QDevice by running the following command on one | |
908 | of the {pve} nodes: | |
909 | ||
910 | ---- | |
911 | pve# pvecm qdevice setup <QDEVICE-IP> | |
912 | ---- | |
913 | ||
914 | The SSH key from the cluster will be automatically copied to the QDevice. You | |
915 | might need to enter an SSH password during this step. | |
916 | ||
917 | After you enter the password and all the steps are successfully completed, you | |
918 | will see "Done". You can check the status now: | |
919 | ||
920 | ---- | |
921 | pve# pvecm status | |
922 | ||
923 | ... | |
924 | ||
925 | Votequorum information | |
926 | ~~~~~~~~~~~~~~~~~~~~~ | |
927 | Expected votes: 3 | |
928 | Highest expected: 3 | |
929 | Total votes: 3 | |
930 | Quorum: 2 | |
931 | Flags: Quorate Qdevice | |
932 | ||
933 | Membership information | |
934 | ~~~~~~~~~~~~~~~~~~~~~~ | |
935 | Nodeid Votes Qdevice Name | |
936 | 0x00000001 1 A,V,NMW 192.168.22.180 (local) | |
937 | 0x00000002 1 A,V,NMW 192.168.22.181 | |
938 | 0x00000000 1 Qdevice | |
939 | ||
940 | ---- | |
941 | ||
942 | which means the QDevice is set up. | |
943 | ||
c21d2cbe OB |
944 | Frequently Asked Questions |
945 | ~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
946 | ||
947 | Tie Breaking | |
948 | ^^^^^^^^^^^^ | |
949 | ||
00821894 TL |
950 | In case of a tie, where two same-sized cluster partitions cannot see each other |
951 | but the QDevice, the QDevice chooses randomly one of those partitions and | |
c21d2cbe OB |
952 | provides a vote to it. |
953 | ||
d31de328 TL |
954 | Possible Negative Implications |
955 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
956 | ||
00821894 TL |
957 | For clusters with an even node count there are no negative implications when |
958 | setting up a QDevice. If it fails to work, you are as good as without QDevice at | |
959 | all. | |
d31de328 | 960 | |
870c2817 OB |
961 | Adding/Deleting Nodes After QDevice Setup |
962 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
d31de328 TL |
963 | |
964 | If you want to add a new node or remove an existing one from a cluster with a | |
00821894 TL |
965 | QDevice setup, you need to remove the QDevice first. After that, you can add or |
966 | remove nodes normally. Once you have a cluster with an even node count again, | |
967 | you can set up the QDevice again as described above. | |
870c2817 OB |
968 | |
969 | Removing the QDevice | |
970 | ^^^^^^^^^^^^^^^^^^^^ | |
971 | ||
00821894 TL |
972 | If you used the official `pvecm` tool to add the QDevice, you can remove it |
973 | trivially by running: | |
870c2817 OB |
974 | |
975 | ---- | |
976 | pve# pvecm qdevice remove | |
977 | ---- | |
d31de328 | 978 | |
51730d56 TL |
979 | //Still TODO |
980 | //^^^^^^^^^^ | |
a9e7c3aa | 981 | //There is still stuff to add here |
c21d2cbe OB |
982 | |
983 | ||
e4ec4154 TL |
984 | Corosync Configuration |
985 | ---------------------- | |
986 | ||
a9e7c3aa SR |
987 | The `/etc/pve/corosync.conf` file plays a central role in a {pve} cluster. It |
988 | controls the cluster membership and its network. | |
989 | For further information about it, check the corosync.conf man page: | |
e4ec4154 | 990 | [source,bash] |
4d19cb00 | 991 | ---- |
e4ec4154 | 992 | man corosync.conf |
4d19cb00 | 993 | ---- |
e4ec4154 TL |
994 | |
995 | For node membership you should always use the `pvecm` tool provided by {pve}. | |
996 | You may have to edit the configuration file manually for other changes. | |
997 | Here are a few best practice tips for doing this. | |
998 | ||
3254bfdd | 999 | [[pvecm_edit_corosync_conf]] |
e4ec4154 TL |
1000 | Edit corosync.conf |
1001 | ~~~~~~~~~~~~~~~~~~ | |
1002 | ||
a9e7c3aa SR |
1003 | Editing the corosync.conf file is not always very straightforward. There are |
1004 | two on each cluster node, one in `/etc/pve/corosync.conf` and the other in | |
e4ec4154 TL |
1005 | `/etc/corosync/corosync.conf`. Editing the one in our cluster file system will |
1006 | propagate the changes to the local one, but not vice versa. | |
1007 | ||
1008 | The configuration will get updated automatically as soon as the file changes. | |
1009 | This means changes which can be integrated in a running corosync will take | |
a9e7c3aa SR |
1010 | effect immediately. So you should always make a copy and edit that instead, to |
1011 | avoid triggering some unwanted changes by an in-between safe. | |
e4ec4154 TL |
1012 | |
1013 | [source,bash] | |
4d19cb00 | 1014 | ---- |
e4ec4154 | 1015 | cp /etc/pve/corosync.conf /etc/pve/corosync.conf.new |
4d19cb00 | 1016 | ---- |
e4ec4154 | 1017 | |
a9e7c3aa SR |
1018 | Then open the config file with your favorite editor, `nano` and `vim.tiny` are |
1019 | preinstalled on any {pve} node for example. | |
e4ec4154 TL |
1020 | |
1021 | NOTE: Always increment the 'config_version' number on configuration changes, | |
1022 | omitting this can lead to problems. | |
1023 | ||
1024 | After making the necessary changes create another copy of the current working | |
1025 | configuration file. This serves as a backup if the new configuration fails to | |
1026 | apply or makes problems in other ways. | |
1027 | ||
1028 | [source,bash] | |
4d19cb00 | 1029 | ---- |
e4ec4154 | 1030 | cp /etc/pve/corosync.conf /etc/pve/corosync.conf.bak |
4d19cb00 | 1031 | ---- |
e4ec4154 TL |
1032 | |
1033 | Then move the new configuration file over the old one: | |
1034 | [source,bash] | |
4d19cb00 | 1035 | ---- |
e4ec4154 | 1036 | mv /etc/pve/corosync.conf.new /etc/pve/corosync.conf |
4d19cb00 | 1037 | ---- |
e4ec4154 TL |
1038 | |
1039 | You may check with the commands | |
1040 | [source,bash] | |
4d19cb00 | 1041 | ---- |
e4ec4154 TL |
1042 | systemctl status corosync |
1043 | journalctl -b -u corosync | |
4d19cb00 | 1044 | ---- |
e4ec4154 | 1045 | |
a9e7c3aa | 1046 | If the change could be applied automatically. If not you may have to restart the |
e4ec4154 TL |
1047 | corosync service via: |
1048 | [source,bash] | |
4d19cb00 | 1049 | ---- |
e4ec4154 | 1050 | systemctl restart corosync |
4d19cb00 | 1051 | ---- |
e4ec4154 TL |
1052 | |
1053 | On errors check the troubleshooting section below. | |
1054 | ||
1055 | Troubleshooting | |
1056 | ~~~~~~~~~~~~~~~ | |
1057 | ||
1058 | Issue: 'quorum.expected_votes must be configured' | |
1059 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
1060 | ||
1061 | When corosync starts to fail and you get the following message in the system log: | |
1062 | ||
1063 | ---- | |
1064 | [...] | |
1065 | corosync[1647]: [QUORUM] Quorum provider: corosync_votequorum failed to initialize. | |
1066 | corosync[1647]: [SERV ] Service engine 'corosync_quorum' failed to load for reason | |
1067 | 'configuration error: nodelist or quorum.expected_votes must be configured!' | |
1068 | [...] | |
1069 | ---- | |
1070 | ||
1071 | It means that the hostname you set for corosync 'ringX_addr' in the | |
1072 | configuration could not be resolved. | |
1073 | ||
e4ec4154 TL |
1074 | Write Configuration When Not Quorate |
1075 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
1076 | ||
1077 | If you need to change '/etc/pve/corosync.conf' on an node with no quorum, and you | |
1078 | know what you do, use: | |
1079 | [source,bash] | |
4d19cb00 | 1080 | ---- |
e4ec4154 | 1081 | pvecm expected 1 |
4d19cb00 | 1082 | ---- |
e4ec4154 TL |
1083 | |
1084 | This sets the expected vote count to 1 and makes the cluster quorate. You can | |
1085 | now fix your configuration, or revert it back to the last working backup. | |
1086 | ||
1087 | This is not enough if corosync cannot start anymore. Here its best to edit the | |
1088 | local copy of the corosync configuration in '/etc/corosync/corosync.conf' so | |
1089 | that corosync can start again. Ensure that on all nodes this configuration has | |
1090 | the same content to avoid split brains. If you are not sure what went wrong | |
1091 | it's best to ask the Proxmox Community to help you. | |
1092 | ||
1093 | ||
3254bfdd | 1094 | [[pvecm_corosync_conf_glossary]] |
e4ec4154 TL |
1095 | Corosync Configuration Glossary |
1096 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
1097 | ||
1098 | ringX_addr:: | |
a9e7c3aa SR |
1099 | This names the different link addresses for the kronosnet connections between |
1100 | nodes. | |
e4ec4154 | 1101 | |
806ef12d DM |
1102 | |
1103 | Cluster Cold Start | |
1104 | ------------------ | |
1105 | ||
1106 | It is obvious that a cluster is not quorate when all nodes are | |
1107 | offline. This is a common case after a power failure. | |
1108 | ||
1109 | NOTE: It is always a good idea to use an uninterruptible power supply | |
8c1189b6 | 1110 | (``UPS'', also called ``battery backup'') to avoid this state, especially if |
806ef12d DM |
1111 | you want HA. |
1112 | ||
204231df | 1113 | On node startup, the `pve-guests` service is started and waits for |
8c1189b6 | 1114 | quorum. Once quorate, it starts all guests which have the `onboot` |
612417fd DM |
1115 | flag set. |
1116 | ||
1117 | When you turn on nodes, or when power comes back after power failure, | |
1118 | it is likely that some nodes boots faster than others. Please keep in | |
1119 | mind that guest startup is delayed until you reach quorum. | |
806ef12d | 1120 | |
054a7e7d | 1121 | |
082ea7d9 TL |
1122 | Guest Migration |
1123 | --------------- | |
1124 | ||
054a7e7d DM |
1125 | Migrating virtual guests to other nodes is a useful feature in a |
1126 | cluster. There are settings to control the behavior of such | |
1127 | migrations. This can be done via the configuration file | |
1128 | `datacenter.cfg` or for a specific migration via API or command line | |
1129 | parameters. | |
1130 | ||
da6c7dee DC |
1131 | It makes a difference if a Guest is online or offline, or if it has |
1132 | local resources (like a local disk). | |
1133 | ||
1134 | For Details about Virtual Machine Migration see the | |
a9e7c3aa | 1135 | xref:qm_migration[QEMU/KVM Migration Chapter]. |
da6c7dee DC |
1136 | |
1137 | For Details about Container Migration see the | |
a9e7c3aa | 1138 | xref:pct_migration[Container Migration Chapter]. |
082ea7d9 TL |
1139 | |
1140 | Migration Type | |
1141 | ~~~~~~~~~~~~~~ | |
1142 | ||
44f38275 | 1143 | The migration type defines if the migration data should be sent over an |
d63be10b | 1144 | encrypted (`secure`) channel or an unencrypted (`insecure`) one. |
082ea7d9 | 1145 | Setting the migration type to insecure means that the RAM content of a |
470d4313 | 1146 | virtual guest gets also transferred unencrypted, which can lead to |
b1743473 DM |
1147 | information disclosure of critical data from inside the guest (for |
1148 | example passwords or encryption keys). | |
054a7e7d DM |
1149 | |
1150 | Therefore, we strongly recommend using the secure channel if you do | |
1151 | not have full control over the network and can not guarantee that no | |
1152 | one is eavesdropping to it. | |
082ea7d9 | 1153 | |
054a7e7d DM |
1154 | NOTE: Storage migration does not follow this setting. Currently, it |
1155 | always sends the storage content over a secure channel. | |
1156 | ||
1157 | Encryption requires a lot of computing power, so this setting is often | |
1158 | changed to "unsafe" to achieve better performance. The impact on | |
1159 | modern systems is lower because they implement AES encryption in | |
b1743473 DM |
1160 | hardware. The performance impact is particularly evident in fast |
1161 | networks where you can transfer 10 Gbps or more. | |
082ea7d9 | 1162 | |
082ea7d9 TL |
1163 | Migration Network |
1164 | ~~~~~~~~~~~~~~~~~ | |
1165 | ||
a9baa444 TL |
1166 | By default, {pve} uses the network in which cluster communication |
1167 | takes place to send the migration traffic. This is not optimal because | |
1168 | sensitive cluster traffic can be disrupted and this network may not | |
1169 | have the best bandwidth available on the node. | |
1170 | ||
1171 | Setting the migration network parameter allows the use of a dedicated | |
1172 | network for the entire migration traffic. In addition to the memory, | |
1173 | this also affects the storage traffic for offline migrations. | |
1174 | ||
1175 | The migration network is set as a network in the CIDR notation. This | |
1176 | has the advantage that you do not have to set individual IP addresses | |
1177 | for each node. {pve} can determine the real address on the | |
1178 | destination node from the network specified in the CIDR form. To | |
1179 | enable this, the network must be specified so that each node has one, | |
1180 | but only one IP in the respective network. | |
1181 | ||
082ea7d9 TL |
1182 | Example |
1183 | ^^^^^^^ | |
1184 | ||
a9baa444 TL |
1185 | We assume that we have a three-node setup with three separate |
1186 | networks. One for public communication with the Internet, one for | |
1187 | cluster communication and a very fast one, which we want to use as a | |
1188 | dedicated network for migration. | |
1189 | ||
1190 | A network configuration for such a setup might look as follows: | |
082ea7d9 TL |
1191 | |
1192 | ---- | |
7a0d4784 | 1193 | iface eno1 inet manual |
082ea7d9 TL |
1194 | |
1195 | # public network | |
1196 | auto vmbr0 | |
1197 | iface vmbr0 inet static | |
1198 | address 192.X.Y.57 | |
1199 | netmask 255.255.250.0 | |
1200 | gateway 192.X.Y.1 | |
7a0d4784 | 1201 | bridge_ports eno1 |
082ea7d9 TL |
1202 | bridge_stp off |
1203 | bridge_fd 0 | |
1204 | ||
1205 | # cluster network | |
7a0d4784 WL |
1206 | auto eno2 |
1207 | iface eno2 inet static | |
082ea7d9 TL |
1208 | address 10.1.1.1 |
1209 | netmask 255.255.255.0 | |
1210 | ||
1211 | # fast network | |
7a0d4784 WL |
1212 | auto eno3 |
1213 | iface eno3 inet static | |
082ea7d9 TL |
1214 | address 10.1.2.1 |
1215 | netmask 255.255.255.0 | |
082ea7d9 TL |
1216 | ---- |
1217 | ||
a9baa444 TL |
1218 | Here, we will use the network 10.1.2.0/24 as a migration network. For |
1219 | a single migration, you can do this using the `migration_network` | |
1220 | parameter of the command line tool: | |
1221 | ||
082ea7d9 | 1222 | ---- |
b1743473 | 1223 | # qm migrate 106 tre --online --migration_network 10.1.2.0/24 |
082ea7d9 TL |
1224 | ---- |
1225 | ||
a9baa444 TL |
1226 | To configure this as the default network for all migrations in the |
1227 | cluster, set the `migration` property of the `/etc/pve/datacenter.cfg` | |
1228 | file: | |
1229 | ||
082ea7d9 | 1230 | ---- |
a9baa444 | 1231 | # use dedicated migration network |
b1743473 | 1232 | migration: secure,network=10.1.2.0/24 |
082ea7d9 TL |
1233 | ---- |
1234 | ||
a9baa444 TL |
1235 | NOTE: The migration type must always be set when the migration network |
1236 | gets set in `/etc/pve/datacenter.cfg`. | |
1237 | ||
806ef12d | 1238 | |
d8742b0c DM |
1239 | ifdef::manvolnum[] |
1240 | include::pve-copyright.adoc[] | |
1241 | endif::manvolnum[] |