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1 | [[chapter_pveceph]] | |
2 | ifdef::manvolnum[] | |
3 | pveceph(1) | |
4 | ========== | |
5 | :pve-toplevel: | |
6 | ||
7 | NAME | |
8 | ---- | |
9 | ||
10 | pveceph - Manage Ceph Services on Proxmox VE Nodes | |
11 | ||
12 | SYNOPSIS | |
13 | -------- | |
14 | ||
15 | include::pveceph.1-synopsis.adoc[] | |
16 | ||
17 | DESCRIPTION | |
18 | ----------- | |
19 | endif::manvolnum[] | |
20 | ifndef::manvolnum[] | |
21 | Deploy Hyper-Converged Ceph Cluster | |
22 | =================================== | |
23 | :pve-toplevel: | |
24 | endif::manvolnum[] | |
25 | ||
26 | [thumbnail="screenshot/gui-ceph-status.png"] | |
27 | ||
28 | {pve} unifies your compute and storage systems, i.e. you can use the same | |
29 | physical nodes within a cluster for both computing (processing VMs and | |
30 | containers) and replicated storage. The traditional silos of compute and | |
31 | storage resources can be wrapped up into a single hyper-converged appliance. | |
32 | Separate storage networks (SANs) and connections via network attached storages | |
33 | (NAS) disappear. With the integration of Ceph, an open source software-defined | |
34 | storage platform, {pve} has the ability to run and manage Ceph storage directly | |
35 | on the hypervisor nodes. | |
36 | ||
37 | Ceph is a distributed object store and file system designed to provide | |
38 | excellent performance, reliability and scalability. | |
39 | ||
40 | .Some advantages of Ceph on {pve} are: | |
41 | - Easy setup and management with CLI and GUI support | |
42 | - Thin provisioning | |
43 | - Snapshots support | |
44 | - Self healing | |
45 | - Scalable to the exabyte level | |
46 | - Setup pools with different performance and redundancy characteristics | |
47 | - Data is replicated, making it fault tolerant | |
48 | - Runs on economical commodity hardware | |
49 | - No need for hardware RAID controllers | |
50 | - Open source | |
51 | ||
52 | For small to mid sized deployments, it is possible to install a Ceph server for | |
53 | RADOS Block Devices (RBD) directly on your {pve} cluster nodes, see | |
54 | xref:ceph_rados_block_devices[Ceph RADOS Block Devices (RBD)]. Recent | |
55 | hardware has plenty of CPU power and RAM, so running storage services | |
56 | and VMs on the same node is possible. | |
57 | ||
58 | To simplify management, we provide 'pveceph' - a tool to install and | |
59 | manage {ceph} services on {pve} nodes. | |
60 | ||
61 | .Ceph consists of a couple of Daemons footnote:[Ceph intro https://docs.ceph.com/docs/{ceph_codename}/start/intro/], for use as a RBD storage: | |
62 | - Ceph Monitor (ceph-mon) | |
63 | - Ceph Manager (ceph-mgr) | |
64 | - Ceph OSD (ceph-osd; Object Storage Daemon) | |
65 | ||
66 | TIP: We highly recommend to get familiar with Ceph's architecture | |
67 | footnote:[Ceph architecture https://docs.ceph.com/docs/{ceph_codename}/architecture/] | |
68 | and vocabulary | |
69 | footnote:[Ceph glossary https://docs.ceph.com/docs/{ceph_codename}/glossary]. | |
70 | ||
71 | ||
72 | Precondition | |
73 | ------------ | |
74 | ||
75 | To build a hyper-converged Proxmox + Ceph Cluster there should be at least | |
76 | three (preferably) identical servers for the setup. | |
77 | ||
78 | Check also the recommendations from | |
79 | https://docs.ceph.com/docs/{ceph_codename}/start/hardware-recommendations/[Ceph's website]. | |
80 | ||
81 | .CPU | |
82 | Higher CPU core frequency reduce latency and should be preferred. As a simple | |
83 | rule of thumb, you should assign a CPU core (or thread) to each Ceph service to | |
84 | provide enough resources for stable and durable Ceph performance. | |
85 | ||
86 | .Memory | |
87 | Especially in a hyper-converged setup, the memory consumption needs to be | |
88 | carefully monitored. In addition to the intended workload from virtual machines | |
89 | and containers, Ceph needs enough memory available to provide excellent and | |
90 | stable performance. | |
91 | ||
92 | As a rule of thumb, for roughly **1 TiB of data, 1 GiB of memory** will be used | |
93 | by an OSD. Especially during recovery, rebalancing or backfilling. | |
94 | ||
95 | The daemon itself will use additional memory. The Bluestore backend of the | |
96 | daemon requires by default **3-5 GiB of memory** (adjustable). In contrast, the | |
97 | legacy Filestore backend uses the OS page cache and the memory consumption is | |
98 | generally related to PGs of an OSD daemon. | |
99 | ||
100 | .Network | |
101 | We recommend a network bandwidth of at least 10 GbE or more, which is used | |
102 | exclusively for Ceph. A meshed network setup | |
103 | footnote:[Full Mesh Network for Ceph {webwiki-url}Full_Mesh_Network_for_Ceph_Server] | |
104 | is also an option if there are no 10 GbE switches available. | |
105 | ||
106 | The volume of traffic, especially during recovery, will interfere with other | |
107 | services on the same network and may even break the {pve} cluster stack. | |
108 | ||
109 | Further, estimate your bandwidth needs. While one HDD might not saturate a 1 Gb | |
110 | link, multiple HDD OSDs per node can, and modern NVMe SSDs will even saturate | |
111 | 10 Gbps of bandwidth quickly. Deploying a network capable of even more bandwidth | |
112 | will ensure that it isn't your bottleneck and won't be anytime soon, 25, 40 or | |
113 | even 100 GBps are possible. | |
114 | ||
115 | .Disks | |
116 | When planning the size of your Ceph cluster, it is important to take the | |
117 | recovery time into consideration. Especially with small clusters, the recovery | |
118 | might take long. It is recommended that you use SSDs instead of HDDs in small | |
119 | setups to reduce recovery time, minimizing the likelihood of a subsequent | |
120 | failure event during recovery. | |
121 | ||
122 | In general SSDs will provide more IOPs than spinning disks. This fact and the | |
123 | higher cost may make a xref:pve_ceph_device_classes[class based] separation of | |
124 | pools appealing. Another possibility to speedup OSDs is to use a faster disk | |
125 | as journal or DB/**W**rite-**A**head-**L**og device, see | |
126 | xref:pve_ceph_osds[creating Ceph OSDs]. If a faster disk is used for multiple | |
127 | OSDs, a proper balance between OSD and WAL / DB (or journal) disk must be | |
128 | selected, otherwise the faster disk becomes the bottleneck for all linked OSDs. | |
129 | ||
130 | Aside from the disk type, Ceph best performs with an even sized and distributed | |
131 | amount of disks per node. For example, 4 x 500 GB disks with in each node is | |
132 | better than a mixed setup with a single 1 TB and three 250 GB disk. | |
133 | ||
134 | One also need to balance OSD count and single OSD capacity. More capacity | |
135 | allows to increase storage density, but it also means that a single OSD | |
136 | failure forces ceph to recover more data at once. | |
137 | ||
138 | .Avoid RAID | |
139 | As Ceph handles data object redundancy and multiple parallel writes to disks | |
140 | (OSDs) on its own, using a RAID controller normally doesn’t improve | |
141 | performance or availability. On the contrary, Ceph is designed to handle whole | |
142 | disks on it's own, without any abstraction in between. RAID controller are not | |
143 | designed for the Ceph use case and may complicate things and sometimes even | |
144 | reduce performance, as their write and caching algorithms may interfere with | |
145 | the ones from Ceph. | |
146 | ||
147 | WARNING: Avoid RAID controller, use host bus adapter (HBA) instead. | |
148 | ||
149 | NOTE: Above recommendations should be seen as a rough guidance for choosing | |
150 | hardware. Therefore, it is still essential to adapt it to your specific needs, | |
151 | test your setup and monitor health and performance continuously. | |
152 | ||
153 | [[pve_ceph_install_wizard]] | |
154 | Initial Ceph installation & configuration | |
155 | ----------------------------------------- | |
156 | ||
157 | [thumbnail="screenshot/gui-node-ceph-install.png"] | |
158 | ||
159 | With {pve} you have the benefit of an easy to use installation wizard | |
160 | for Ceph. Click on one of your cluster nodes and navigate to the Ceph | |
161 | section in the menu tree. If Ceph is not already installed you will be | |
162 | offered to do so now. | |
163 | ||
164 | The wizard is divided into different sections, where each needs to be | |
165 | finished successfully in order to use Ceph. After starting the installation | |
166 | the wizard will download and install all required packages from {pve}'s ceph | |
167 | repository. | |
168 | ||
169 | After finishing the first step, you will need to create a configuration. | |
170 | This step is only needed once per cluster, as this configuration is distributed | |
171 | automatically to all remaining cluster members through {pve}'s clustered | |
172 | xref:chapter_pmxcfs[configuration file system (pmxcfs)]. | |
173 | ||
174 | The configuration step includes the following settings: | |
175 | ||
176 | * *Public Network:* You should setup a dedicated network for Ceph, this | |
177 | setting is required. Separating your Ceph traffic is highly recommended, | |
178 | because it could lead to troubles with other latency dependent services, | |
179 | e.g., cluster communication may decrease Ceph's performance, if not done. | |
180 | ||
181 | [thumbnail="screenshot/gui-node-ceph-install-wizard-step2.png"] | |
182 | ||
183 | * *Cluster Network:* As an optional step you can go even further and | |
184 | separate the xref:pve_ceph_osds[OSD] replication & heartbeat traffic | |
185 | as well. This will relieve the public network and could lead to | |
186 | significant performance improvements especially in big clusters. | |
187 | ||
188 | You have two more options which are considered advanced and therefore | |
189 | should only changed if you are an expert. | |
190 | ||
191 | * *Number of replicas*: Defines the how often a object is replicated | |
192 | * *Minimum replicas*: Defines the minimum number of required replicas | |
193 | for I/O to be marked as complete. | |
194 | ||
195 | Additionally you need to choose your first monitor node, this is required. | |
196 | ||
197 | That's it, you should see a success page as the last step with further | |
198 | instructions on how to go on. You are now prepared to start using Ceph, | |
199 | even though you will need to create additional xref:pve_ceph_monitors[monitors], | |
200 | create some xref:pve_ceph_osds[OSDs] and at least one xref:pve_ceph_pools[pool]. | |
201 | ||
202 | The rest of this chapter will guide you on how to get the most out of | |
203 | your {pve} based Ceph setup, this will include aforementioned and | |
204 | more like xref:pveceph_fs[CephFS] which is a very handy addition to your | |
205 | new Ceph cluster. | |
206 | ||
207 | [[pve_ceph_install]] | |
208 | Installation of Ceph Packages | |
209 | ----------------------------- | |
210 | Use {pve} Ceph installation wizard (recommended) or run the following | |
211 | command on each node: | |
212 | ||
213 | [source,bash] | |
214 | ---- | |
215 | pveceph install | |
216 | ---- | |
217 | ||
218 | This sets up an `apt` package repository in | |
219 | `/etc/apt/sources.list.d/ceph.list` and installs the required software. | |
220 | ||
221 | ||
222 | Create initial Ceph configuration | |
223 | --------------------------------- | |
224 | ||
225 | [thumbnail="screenshot/gui-ceph-config.png"] | |
226 | ||
227 | Use the {pve} Ceph installation wizard (recommended) or run the | |
228 | following command on one node: | |
229 | ||
230 | [source,bash] | |
231 | ---- | |
232 | pveceph init --network 10.10.10.0/24 | |
233 | ---- | |
234 | ||
235 | This creates an initial configuration at `/etc/pve/ceph.conf` with a | |
236 | dedicated network for ceph. That file is automatically distributed to | |
237 | all {pve} nodes by using xref:chapter_pmxcfs[pmxcfs]. The command also | |
238 | creates a symbolic link from `/etc/ceph/ceph.conf` pointing to that file. | |
239 | So you can simply run Ceph commands without the need to specify a | |
240 | configuration file. | |
241 | ||
242 | ||
243 | [[pve_ceph_monitors]] | |
244 | Ceph Monitor | |
245 | ----------- | |
246 | The Ceph Monitor (MON) | |
247 | footnote:[Ceph Monitor https://docs.ceph.com/docs/{ceph_codename}/start/intro/] | |
248 | maintains a master copy of the cluster map. For high availability you need to | |
249 | have at least 3 monitors. One monitor will already be installed if you | |
250 | used the installation wizard. You won't need more than 3 monitors as long | |
251 | as your cluster is small to midsize, only really large clusters will | |
252 | need more than that. | |
253 | ||
254 | ||
255 | [[pveceph_create_mon]] | |
256 | Create Monitors | |
257 | ~~~~~~~~~~~~~~~ | |
258 | ||
259 | [thumbnail="screenshot/gui-ceph-monitor.png"] | |
260 | ||
261 | On each node where you want to place a monitor (three monitors are recommended), | |
262 | create it by using the 'Ceph -> Monitor' tab in the GUI or run. | |
263 | ||
264 | ||
265 | [source,bash] | |
266 | ---- | |
267 | pveceph mon create | |
268 | ---- | |
269 | ||
270 | [[pveceph_destroy_mon]] | |
271 | Destroy Monitors | |
272 | ~~~~~~~~~~~~~~~~ | |
273 | ||
274 | To remove a Ceph Monitor via the GUI first select a node in the tree view and | |
275 | go to the **Ceph -> Monitor** panel. Select the MON and click the **Destroy** | |
276 | button. | |
277 | ||
278 | To remove a Ceph Monitor via the CLI first connect to the node on which the MON | |
279 | is running. Then execute the following command: | |
280 | [source,bash] | |
281 | ---- | |
282 | pveceph mon destroy | |
283 | ---- | |
284 | ||
285 | NOTE: At least three Monitors are needed for quorum. | |
286 | ||
287 | ||
288 | [[pve_ceph_manager]] | |
289 | Ceph Manager | |
290 | ------------ | |
291 | The Manager daemon runs alongside the monitors. It provides an interface to | |
292 | monitor the cluster. Since the Ceph luminous release at least one ceph-mgr | |
293 | footnote:[Ceph Manager https://docs.ceph.com/docs/{ceph_codename}/mgr/] daemon is | |
294 | required. | |
295 | ||
296 | [[pveceph_create_mgr]] | |
297 | Create Manager | |
298 | ~~~~~~~~~~~~~~ | |
299 | ||
300 | Multiple Managers can be installed, but at any time only one Manager is active. | |
301 | ||
302 | [source,bash] | |
303 | ---- | |
304 | pveceph mgr create | |
305 | ---- | |
306 | ||
307 | NOTE: It is recommended to install the Ceph Manager on the monitor nodes. For | |
308 | high availability install more then one manager. | |
309 | ||
310 | ||
311 | [[pveceph_destroy_mgr]] | |
312 | Destroy Manager | |
313 | ~~~~~~~~~~~~~~~ | |
314 | ||
315 | To remove a Ceph Manager via the GUI first select a node in the tree view and | |
316 | go to the **Ceph -> Monitor** panel. Select the Manager and click the | |
317 | **Destroy** button. | |
318 | ||
319 | To remove a Ceph Monitor via the CLI first connect to the node on which the | |
320 | Manager is running. Then execute the following command: | |
321 | [source,bash] | |
322 | ---- | |
323 | pveceph mgr destroy | |
324 | ---- | |
325 | ||
326 | NOTE: A Ceph cluster can function without a Manager, but certain functions like | |
327 | the cluster status or usage require a running Manager. | |
328 | ||
329 | ||
330 | [[pve_ceph_osds]] | |
331 | Ceph OSDs | |
332 | --------- | |
333 | Ceph **O**bject **S**torage **D**aemons are storing objects for Ceph over the | |
334 | network. It is recommended to use one OSD per physical disk. | |
335 | ||
336 | NOTE: By default an object is 4 MiB in size. | |
337 | ||
338 | [[pve_ceph_osd_create]] | |
339 | Create OSDs | |
340 | ~~~~~~~~~~~ | |
341 | ||
342 | [thumbnail="screenshot/gui-ceph-osd-status.png"] | |
343 | ||
344 | via GUI or via CLI as follows: | |
345 | ||
346 | [source,bash] | |
347 | ---- | |
348 | pveceph osd create /dev/sd[X] | |
349 | ---- | |
350 | ||
351 | TIP: We recommend a Ceph cluster size, starting with 12 OSDs, distributed | |
352 | evenly among your, at least three nodes (4 OSDs on each node). | |
353 | ||
354 | If the disk was used before (eg. ZFS/RAID/OSD), to remove partition table, boot | |
355 | sector and any OSD leftover the following command should be sufficient. | |
356 | ||
357 | [source,bash] | |
358 | ---- | |
359 | ceph-volume lvm zap /dev/sd[X] --destroy | |
360 | ---- | |
361 | ||
362 | WARNING: The above command will destroy data on the disk! | |
363 | ||
364 | .Ceph Bluestore | |
365 | ||
366 | Starting with the Ceph Kraken release, a new Ceph OSD storage type was | |
367 | introduced, the so called Bluestore | |
368 | footnote:[Ceph Bluestore https://ceph.com/community/new-luminous-bluestore/]. | |
369 | This is the default when creating OSDs since Ceph Luminous. | |
370 | ||
371 | [source,bash] | |
372 | ---- | |
373 | pveceph osd create /dev/sd[X] | |
374 | ---- | |
375 | ||
376 | .Block.db and block.wal | |
377 | ||
378 | If you want to use a separate DB/WAL device for your OSDs, you can specify it | |
379 | through the '-db_dev' and '-wal_dev' options. The WAL is placed with the DB, if | |
380 | not specified separately. | |
381 | ||
382 | [source,bash] | |
383 | ---- | |
384 | pveceph osd create /dev/sd[X] -db_dev /dev/sd[Y] -wal_dev /dev/sd[Z] | |
385 | ---- | |
386 | ||
387 | You can directly choose the size for those with the '-db_size' and '-wal_size' | |
388 | parameters respectively. If they are not given the following values (in order) | |
389 | will be used: | |
390 | ||
391 | * bluestore_block_{db,wal}_size from ceph configuration... | |
392 | ** ... database, section 'osd' | |
393 | ** ... database, section 'global' | |
394 | ** ... file, section 'osd' | |
395 | ** ... file, section 'global' | |
396 | * 10% (DB)/1% (WAL) of OSD size | |
397 | ||
398 | NOTE: The DB stores BlueStore’s internal metadata and the WAL is BlueStore’s | |
399 | internal journal or write-ahead log. It is recommended to use a fast SSD or | |
400 | NVRAM for better performance. | |
401 | ||
402 | ||
403 | .Ceph Filestore | |
404 | ||
405 | Before Ceph Luminous, Filestore was used as default storage type for Ceph OSDs. | |
406 | Starting with Ceph Nautilus, {pve} does not support creating such OSDs with | |
407 | 'pveceph' anymore. If you still want to create filestore OSDs, use | |
408 | 'ceph-volume' directly. | |
409 | ||
410 | [source,bash] | |
411 | ---- | |
412 | ceph-volume lvm create --filestore --data /dev/sd[X] --journal /dev/sd[Y] | |
413 | ---- | |
414 | ||
415 | [[pve_ceph_osd_destroy]] | |
416 | Destroy OSDs | |
417 | ~~~~~~~~~~~~ | |
418 | ||
419 | To remove an OSD via the GUI first select a {PVE} node in the tree view and go | |
420 | to the **Ceph -> OSD** panel. Select the OSD to destroy. Next click the **OUT** | |
421 | button. Once the OSD status changed from `in` to `out` click the **STOP** | |
422 | button. As soon as the status changed from `up` to `down` select **Destroy** | |
423 | from the `More` drop-down menu. | |
424 | ||
425 | To remove an OSD via the CLI run the following commands. | |
426 | [source,bash] | |
427 | ---- | |
428 | ceph osd out <ID> | |
429 | systemctl stop ceph-osd@<ID>.service | |
430 | ---- | |
431 | NOTE: The first command instructs Ceph not to include the OSD in the data | |
432 | distribution. The second command stops the OSD service. Until this time, no | |
433 | data is lost. | |
434 | ||
435 | The following command destroys the OSD. Specify the '-cleanup' option to | |
436 | additionally destroy the partition table. | |
437 | [source,bash] | |
438 | ---- | |
439 | pveceph osd destroy <ID> | |
440 | ---- | |
441 | WARNING: The above command will destroy data on the disk! | |
442 | ||
443 | ||
444 | [[pve_ceph_pools]] | |
445 | Ceph Pools | |
446 | ---------- | |
447 | A pool is a logical group for storing objects. It holds **P**lacement | |
448 | **G**roups (`PG`, `pg_num`), a collection of objects. | |
449 | ||
450 | ||
451 | Create Pools | |
452 | ~~~~~~~~~~~~ | |
453 | ||
454 | [thumbnail="screenshot/gui-ceph-pools.png"] | |
455 | ||
456 | When no options are given, we set a default of **128 PGs**, a **size of 3 | |
457 | replicas** and a **min_size of 2 replicas** for serving objects in a degraded | |
458 | state. | |
459 | ||
460 | NOTE: The default number of PGs works for 2-5 disks. Ceph throws a | |
461 | 'HEALTH_WARNING' if you have too few or too many PGs in your cluster. | |
462 | ||
463 | It is advised to calculate the PG number depending on your setup, you can find | |
464 | the formula and the PG calculator footnote:[PG calculator | |
465 | https://ceph.com/pgcalc/] online. From Ceph Nautilus onwards it is possible to | |
466 | increase and decrease the number of PGs later on footnote:[Placement Groups | |
467 | https://docs.ceph.com/docs/{ceph_codename}/rados/operations/placement-groups/]. | |
468 | ||
469 | ||
470 | You can create pools through command line or on the GUI on each PVE host under | |
471 | **Ceph -> Pools**. | |
472 | ||
473 | [source,bash] | |
474 | ---- | |
475 | pveceph pool create <name> | |
476 | ---- | |
477 | ||
478 | If you would like to automatically also get a storage definition for your pool, | |
479 | mark the checkbox "Add storages" in the GUI or use the command line option | |
480 | '--add_storages' at pool creation. | |
481 | ||
482 | Further information on Ceph pool handling can be found in the Ceph pool | |
483 | operation footnote:[Ceph pool operation | |
484 | https://docs.ceph.com/docs/{ceph_codename}/rados/operations/pools/] | |
485 | manual. | |
486 | ||
487 | ||
488 | Destroy Pools | |
489 | ~~~~~~~~~~~~~ | |
490 | ||
491 | To destroy a pool via the GUI select a node in the tree view and go to the | |
492 | **Ceph -> Pools** panel. Select the pool to destroy and click the **Destroy** | |
493 | button. To confirm the destruction of the pool you need to enter the pool name. | |
494 | ||
495 | Run the following command to destroy a pool. Specify the '-remove_storages' to | |
496 | also remove the associated storage. | |
497 | [source,bash] | |
498 | ---- | |
499 | pveceph pool destroy <name> | |
500 | ---- | |
501 | ||
502 | NOTE: Deleting the data of a pool is a background task and can take some time. | |
503 | You will notice that the data usage in the cluster is decreasing. | |
504 | ||
505 | [[pve_ceph_device_classes]] | |
506 | Ceph CRUSH & device classes | |
507 | --------------------------- | |
508 | The foundation of Ceph is its algorithm, **C**ontrolled **R**eplication | |
509 | **U**nder **S**calable **H**ashing | |
510 | (CRUSH footnote:[CRUSH https://ceph.com/wp-content/uploads/2016/08/weil-crush-sc06.pdf]). | |
511 | ||
512 | CRUSH calculates where to store to and retrieve data from, this has the | |
513 | advantage that no central index service is needed. CRUSH works with a map of | |
514 | OSDs, buckets (device locations) and rulesets (data replication) for pools. | |
515 | ||
516 | NOTE: Further information can be found in the Ceph documentation, under the | |
517 | section CRUSH map footnote:[CRUSH map https://docs.ceph.com/docs/{ceph_codename}/rados/operations/crush-map/]. | |
518 | ||
519 | This map can be altered to reflect different replication hierarchies. The object | |
520 | replicas can be separated (eg. failure domains), while maintaining the desired | |
521 | distribution. | |
522 | ||
523 | A common use case is to use different classes of disks for different Ceph pools. | |
524 | For this reason, Ceph introduced the device classes with luminous, to | |
525 | accommodate the need for easy ruleset generation. | |
526 | ||
527 | The device classes can be seen in the 'ceph osd tree' output. These classes | |
528 | represent their own root bucket, which can be seen with the below command. | |
529 | ||
530 | [source, bash] | |
531 | ---- | |
532 | ceph osd crush tree --show-shadow | |
533 | ---- | |
534 | ||
535 | Example output form the above command: | |
536 | ||
537 | [source, bash] | |
538 | ---- | |
539 | ID CLASS WEIGHT TYPE NAME | |
540 | -16 nvme 2.18307 root default~nvme | |
541 | -13 nvme 0.72769 host sumi1~nvme | |
542 | 12 nvme 0.72769 osd.12 | |
543 | -14 nvme 0.72769 host sumi2~nvme | |
544 | 13 nvme 0.72769 osd.13 | |
545 | -15 nvme 0.72769 host sumi3~nvme | |
546 | 14 nvme 0.72769 osd.14 | |
547 | -1 7.70544 root default | |
548 | -3 2.56848 host sumi1 | |
549 | 12 nvme 0.72769 osd.12 | |
550 | -5 2.56848 host sumi2 | |
551 | 13 nvme 0.72769 osd.13 | |
552 | -7 2.56848 host sumi3 | |
553 | 14 nvme 0.72769 osd.14 | |
554 | ---- | |
555 | ||
556 | To let a pool distribute its objects only on a specific device class, you need | |
557 | to create a ruleset with the specific class first. | |
558 | ||
559 | [source, bash] | |
560 | ---- | |
561 | ceph osd crush rule create-replicated <rule-name> <root> <failure-domain> <class> | |
562 | ---- | |
563 | ||
564 | [frame="none",grid="none", align="left", cols="30%,70%"] | |
565 | |=== | |
566 | |<rule-name>|name of the rule, to connect with a pool (seen in GUI & CLI) | |
567 | |<root>|which crush root it should belong to (default ceph root "default") | |
568 | |<failure-domain>|at which failure-domain the objects should be distributed (usually host) | |
569 | |<class>|what type of OSD backing store to use (eg. nvme, ssd, hdd) | |
570 | |=== | |
571 | ||
572 | Once the rule is in the CRUSH map, you can tell a pool to use the ruleset. | |
573 | ||
574 | [source, bash] | |
575 | ---- | |
576 | ceph osd pool set <pool-name> crush_rule <rule-name> | |
577 | ---- | |
578 | ||
579 | TIP: If the pool already contains objects, all of these have to be moved | |
580 | accordingly. Depending on your setup this may introduce a big performance hit | |
581 | on your cluster. As an alternative, you can create a new pool and move disks | |
582 | separately. | |
583 | ||
584 | ||
585 | Ceph Client | |
586 | ----------- | |
587 | ||
588 | [thumbnail="screenshot/gui-ceph-log.png"] | |
589 | ||
590 | You can then configure {pve} to use such pools to store VM or | |
591 | Container images. Simply use the GUI too add a new `RBD` storage (see | |
592 | section xref:ceph_rados_block_devices[Ceph RADOS Block Devices (RBD)]). | |
593 | ||
594 | You also need to copy the keyring to a predefined location for an external Ceph | |
595 | cluster. If Ceph is installed on the Proxmox nodes itself, then this will be | |
596 | done automatically. | |
597 | ||
598 | NOTE: The file name needs to be `<storage_id> + `.keyring` - `<storage_id>` is | |
599 | the expression after 'rbd:' in `/etc/pve/storage.cfg` which is | |
600 | `my-ceph-storage` in the following example: | |
601 | ||
602 | [source,bash] | |
603 | ---- | |
604 | mkdir /etc/pve/priv/ceph | |
605 | cp /etc/ceph/ceph.client.admin.keyring /etc/pve/priv/ceph/my-ceph-storage.keyring | |
606 | ---- | |
607 | ||
608 | [[pveceph_fs]] | |
609 | CephFS | |
610 | ------ | |
611 | ||
612 | Ceph provides also a filesystem running on top of the same object storage as | |
613 | RADOS block devices do. A **M**eta**d**ata **S**erver (`MDS`) is used to map | |
614 | the RADOS backed objects to files and directories, allowing to provide a | |
615 | POSIX-compliant replicated filesystem. This allows one to have a clustered | |
616 | highly available shared filesystem in an easy way if ceph is already used. Its | |
617 | Metadata Servers guarantee that files get balanced out over the whole Ceph | |
618 | cluster, this way even high load will not overload a single host, which can be | |
619 | an issue with traditional shared filesystem approaches, like `NFS`, for | |
620 | example. | |
621 | ||
622 | [thumbnail="screenshot/gui-node-ceph-cephfs-panel.png"] | |
623 | ||
624 | {pve} supports both, using an existing xref:storage_cephfs[CephFS as storage] | |
625 | to save backups, ISO files or container templates and creating a | |
626 | hyper-converged CephFS itself. | |
627 | ||
628 | ||
629 | [[pveceph_fs_mds]] | |
630 | Metadata Server (MDS) | |
631 | ~~~~~~~~~~~~~~~~~~~~~ | |
632 | ||
633 | CephFS needs at least one Metadata Server to be configured and running to be | |
634 | able to work. One can simply create one through the {pve} web GUI's `Node -> | |
635 | CephFS` panel or on the command line with: | |
636 | ||
637 | ---- | |
638 | pveceph mds create | |
639 | ---- | |
640 | ||
641 | Multiple metadata servers can be created in a cluster. But with the default | |
642 | settings only one can be active at any time. If an MDS, or its node, becomes | |
643 | unresponsive (or crashes), another `standby` MDS will get promoted to `active`. | |
644 | One can speed up the hand-over between the active and a standby MDS up by using | |
645 | the 'hotstandby' parameter option on create, or if you have already created it | |
646 | you may set/add: | |
647 | ||
648 | ---- | |
649 | mds standby replay = true | |
650 | ---- | |
651 | ||
652 | in the ceph.conf respective MDS section. With this enabled, this specific MDS | |
653 | will always poll the active one, so that it can take over faster as it is in a | |
654 | `warm` state. But naturally, the active polling will cause some additional | |
655 | performance impact on your system and active `MDS`. | |
656 | ||
657 | .Multiple Active MDS | |
658 | ||
659 | Since Luminous (12.2.x) you can also have multiple active metadata servers | |
660 | running, but this is normally only useful for a high count on parallel clients, | |
661 | as else the `MDS` seldom is the bottleneck. If you want to set this up please | |
662 | refer to the ceph documentation. footnote:[Configuring multiple active MDS | |
663 | daemons https://docs.ceph.com/docs/{ceph_codename}/cephfs/multimds/] | |
664 | ||
665 | [[pveceph_fs_create]] | |
666 | Create CephFS | |
667 | ~~~~~~~~~~~~~ | |
668 | ||
669 | With {pve}'s CephFS integration into you can create a CephFS easily over the | |
670 | Web GUI, the CLI or an external API interface. Some prerequisites are required | |
671 | for this to work: | |
672 | ||
673 | .Prerequisites for a successful CephFS setup: | |
674 | - xref:pve_ceph_install[Install Ceph packages], if this was already done some | |
675 | time ago you might want to rerun it on an up to date system to ensure that | |
676 | also all CephFS related packages get installed. | |
677 | - xref:pve_ceph_monitors[Setup Monitors] | |
678 | - xref:pve_ceph_monitors[Setup your OSDs] | |
679 | - xref:pveceph_fs_mds[Setup at least one MDS] | |
680 | ||
681 | After this got all checked and done you can simply create a CephFS through | |
682 | either the Web GUI's `Node -> CephFS` panel or the command line tool `pveceph`, | |
683 | for example with: | |
684 | ||
685 | ---- | |
686 | pveceph fs create --pg_num 128 --add-storage | |
687 | ---- | |
688 | ||
689 | This creates a CephFS named `'cephfs'' using a pool for its data named | |
690 | `'cephfs_data'' with `128` placement groups and a pool for its metadata named | |
691 | `'cephfs_metadata'' with one quarter of the data pools placement groups (`32`). | |
692 | Check the xref:pve_ceph_pools[{pve} managed Ceph pool chapter] or visit the | |
693 | Ceph documentation for more information regarding a fitting placement group | |
694 | number (`pg_num`) for your setup footnote:[Ceph Placement Groups | |
695 | https://docs.ceph.com/docs/{ceph_codename}/rados/operations/placement-groups/]. | |
696 | Additionally, the `'--add-storage'' parameter will add the CephFS to the {pve} | |
697 | storage configuration after it was created successfully. | |
698 | ||
699 | Destroy CephFS | |
700 | ~~~~~~~~~~~~~~ | |
701 | ||
702 | WARNING: Destroying a CephFS will render all its data unusable, this cannot be | |
703 | undone! | |
704 | ||
705 | If you really want to destroy an existing CephFS you first need to stop, or | |
706 | destroy, all metadata servers (`M̀DS`). You can destroy them either over the Web | |
707 | GUI or the command line interface, with: | |
708 | ||
709 | ---- | |
710 | pveceph mds destroy NAME | |
711 | ---- | |
712 | on each {pve} node hosting a MDS daemon. | |
713 | ||
714 | Then, you can remove (destroy) CephFS by issuing a: | |
715 | ||
716 | ---- | |
717 | ceph fs rm NAME --yes-i-really-mean-it | |
718 | ---- | |
719 | on a single node hosting Ceph. After this you may want to remove the created | |
720 | data and metadata pools, this can be done either over the Web GUI or the CLI | |
721 | with: | |
722 | ||
723 | ---- | |
724 | pveceph pool destroy NAME | |
725 | ---- | |
726 | ||
727 | ||
728 | Ceph maintenance | |
729 | ---------------- | |
730 | ||
731 | Replace OSDs | |
732 | ~~~~~~~~~~~~ | |
733 | ||
734 | One of the common maintenance tasks in Ceph is to replace a disk of an OSD. If | |
735 | a disk is already in a failed state, then you can go ahead and run through the | |
736 | steps in xref:pve_ceph_osd_destroy[Destroy OSDs]. Ceph will recreate those | |
737 | copies on the remaining OSDs if possible. This rebalancing will start as soon | |
738 | as an OSD failure is detected or an OSD was actively stopped. | |
739 | ||
740 | NOTE: With the default size/min_size (3/2) of a pool, recovery only starts when | |
741 | `size + 1` nodes are available. The reason for this is that the Ceph object | |
742 | balancer xref:pve_ceph_device_classes[CRUSH] defaults to a full node as | |
743 | `failure domain'. | |
744 | ||
745 | To replace a still functioning disk, on the GUI go through the steps in | |
746 | xref:pve_ceph_osd_destroy[Destroy OSDs]. The only addition is to wait until | |
747 | the cluster shows 'HEALTH_OK' before stopping the OSD to destroy it. | |
748 | ||
749 | On the command line use the following commands. | |
750 | ---- | |
751 | ceph osd out osd.<id> | |
752 | ---- | |
753 | ||
754 | You can check with the command below if the OSD can be safely removed. | |
755 | ---- | |
756 | ceph osd safe-to-destroy osd.<id> | |
757 | ---- | |
758 | ||
759 | Once the above check tells you that it is save to remove the OSD, you can | |
760 | continue with following commands. | |
761 | ---- | |
762 | systemctl stop ceph-osd@<id>.service | |
763 | pveceph osd destroy <id> | |
764 | ---- | |
765 | ||
766 | Replace the old disk with the new one and use the same procedure as described | |
767 | in xref:pve_ceph_osd_create[Create OSDs]. | |
768 | ||
769 | Trim/Discard | |
770 | ~~~~~~~~~~~~ | |
771 | It is a good measure to run 'fstrim' (discard) regularly on VMs or containers. | |
772 | This releases data blocks that the filesystem isn’t using anymore. It reduces | |
773 | data usage and resource load. Most modern operating systems issue such discard | |
774 | commands to their disks regularly. You only need to ensure that the Virtual | |
775 | Machines enable the xref:qm_hard_disk_discard[disk discard option]. | |
776 | ||
777 | [[pveceph_scrub]] | |
778 | Scrub & Deep Scrub | |
779 | ~~~~~~~~~~~~~~~~~~ | |
780 | Ceph ensures data integrity by 'scrubbing' placement groups. Ceph checks every | |
781 | object in a PG for its health. There are two forms of Scrubbing, daily | |
782 | cheap metadata checks and weekly deep data checks. The weekly deep scrub reads | |
783 | the objects and uses checksums to ensure data integrity. If a running scrub | |
784 | interferes with business (performance) needs, you can adjust the time when | |
785 | scrubs footnote:[Ceph scrubbing https://docs.ceph.com/docs/{ceph_codename}/rados/configuration/osd-config-ref/#scrubbing] | |
786 | are executed. | |
787 | ||
788 | ||
789 | Ceph monitoring and troubleshooting | |
790 | ----------------------------------- | |
791 | A good start is to continuosly monitor the ceph health from the start of | |
792 | initial deployment. Either through the ceph tools itself, but also by accessing | |
793 | the status through the {pve} link:api-viewer/index.html[API]. | |
794 | ||
795 | The following ceph commands below can be used to see if the cluster is healthy | |
796 | ('HEALTH_OK'), if there are warnings ('HEALTH_WARN'), or even errors | |
797 | ('HEALTH_ERR'). If the cluster is in an unhealthy state the status commands | |
798 | below will also give you an overview of the current events and actions to take. | |
799 | ||
800 | ---- | |
801 | # single time output | |
802 | pve# ceph -s | |
803 | # continuously output status changes (press CTRL+C to stop) | |
804 | pve# ceph -w | |
805 | ---- | |
806 | ||
807 | To get a more detailed view, every ceph service has a log file under | |
808 | `/var/log/ceph/` and if there is not enough detail, the log level can be | |
809 | adjusted footnote:[Ceph log and debugging https://docs.ceph.com/docs/{ceph_codename}/rados/troubleshooting/log-and-debug/]. | |
810 | ||
811 | You can find more information about troubleshooting | |
812 | footnote:[Ceph troubleshooting https://docs.ceph.com/docs/{ceph_codename}/rados/troubleshooting/] | |
813 | a Ceph cluster on the official website. | |
814 | ||
815 | ||
816 | ifdef::manvolnum[] | |
817 | include::pve-copyright.adoc[] | |
818 | endif::manvolnum[] |