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