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80c0adcb | 1 | [[chapter_pveceph]] |
0840a663 | 2 | ifdef::manvolnum[] |
b2f242ab DM |
3 | pveceph(1) |
4 | ========== | |
404a158e | 5 | :pve-toplevel: |
0840a663 DM |
6 | |
7 | NAME | |
8 | ---- | |
9 | ||
21394e70 | 10 | pveceph - Manage Ceph Services on Proxmox VE Nodes |
0840a663 | 11 | |
49a5e11c | 12 | SYNOPSIS |
0840a663 DM |
13 | -------- |
14 | ||
15 | include::pveceph.1-synopsis.adoc[] | |
16 | ||
17 | DESCRIPTION | |
18 | ----------- | |
19 | endif::manvolnum[] | |
0840a663 | 20 | ifndef::manvolnum[] |
fe93f133 DM |
21 | Manage Ceph Services on Proxmox VE Nodes |
22 | ======================================== | |
49d3ad91 | 23 | :pve-toplevel: |
0840a663 DM |
24 | endif::manvolnum[] |
25 | ||
1ff5e4e8 | 26 | [thumbnail="screenshot/gui-ceph-status.png"] |
8997dd6e | 27 | |
a474ca1f AA |
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. | |
c994e4e5 DM |
36 | |
37 | Ceph is a distributed object store and file system designed to provide | |
1d54c3b4 AA |
38 | excellent performance, reliability and scalability. |
39 | ||
04ba9b24 TL |
40 | .Some advantages of Ceph on {pve} are: |
41 | - Easy setup and management with CLI and GUI support | |
a474ca1f AA |
42 | - Thin provisioning |
43 | - Snapshots support | |
44 | - Self healing | |
a474ca1f AA |
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 | |
a474ca1f AA |
50 | - Open source |
51 | ||
1d54c3b4 AA |
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 | |
c994e4e5 DM |
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. | |
21394e70 DM |
57 | |
58 | To simplify management, we provide 'pveceph' - a tool to install and | |
59 | manage {ceph} services on {pve} nodes. | |
60 | ||
127ca409 | 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: |
1d54c3b4 AA |
62 | - Ceph Monitor (ceph-mon) |
63 | - Ceph Manager (ceph-mgr) | |
64 | - Ceph OSD (ceph-osd; Object Storage Daemon) | |
65 | ||
477fbcfb AA |
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]. | |
1d54c3b4 | 70 | |
21394e70 DM |
71 | |
72 | Precondition | |
73 | ------------ | |
74 | ||
76f6eca4 AA |
75 | To build a hyper-converged Proxmox + Ceph Cluster there should be at least |
76 | three (preferably) identical servers for the setup. | |
21394e70 DM |
77 | |
78 | Check also the recommendations from | |
1d54c3b4 | 79 | http://docs.ceph.com/docs/luminous/start/hardware-recommendations/[Ceph's website]. |
21394e70 | 80 | |
76f6eca4 | 81 | .CPU |
2f19a6b0 TL |
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. | |
76f6eca4 AA |
85 | |
86 | .Memory | |
87 | Especially in a hyper-converged setup, the memory consumption needs to be | |
2f19a6b0 TL |
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. | |
76f6eca4 AA |
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 | ||
2f19a6b0 TL |
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. | |
76f6eca4 AA |
101 | |
102 | Further, estimate your bandwidth needs. While one HDD might not saturate a 1 Gb | |
2f19a6b0 TL |
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. | |
76f6eca4 AA |
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 | ||
2f19a6b0 | 115 | In general SSDs will provide more IOPs than spinning disks. This fact and the |
76f6eca4 | 116 | higher cost may make a xref:pve_ceph_device_classes[class based] separation of |
2f19a6b0 | 117 | pools appealing. Another possibility to speedup OSDs is to use a faster disk |
352c803f TL |
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. | |
76f6eca4 AA |
122 | |
123 | Aside from the disk type, Ceph best performs with an even sized and distributed | |
2f19a6b0 TL |
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. | |
76f6eca4 | 130 | |
a474ca1f | 131 | .Avoid RAID |
86be506d | 132 | As Ceph handles data object redundancy and multiple parallel writes to disks |
c78756be | 133 | (OSDs) on its own, using a RAID controller normally doesn’t improve |
86be506d TL |
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. | |
a474ca1f AA |
139 | |
140 | WARNING: Avoid RAID controller, use host bus adapter (HBA) instead. | |
141 | ||
76f6eca4 | 142 | NOTE: Above recommendations should be seen as a rough guidance for choosing |
2f19a6b0 TL |
143 | hardware. Therefore, it is still essential to adapt it to your specific needs, |
144 | test your setup and monitor health and performance continuously. | |
76f6eca4 | 145 | |
2394c306 TM |
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 | |
6a711e64 TL |
154 | section in the menu tree. If Ceph is not already installed you will be |
155 | offered to do so now. | |
2394c306 TM |
156 | |
157 | The wizard is divided into different sections, where each needs to be | |
6a711e64 TL |
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. | |
2394c306 TM |
161 | |
162 | After finishing the first step, you will need to create a configuration. | |
6a711e64 TL |
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)]. | |
2394c306 TM |
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, | |
6a711e64 TL |
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. | |
2394c306 TM |
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 | |
6a711e64 | 186 | for I/O to be marked as complete. |
2394c306 | 187 | |
6a711e64 | 188 | Additionally you need to choose your first monitor node, this is required. |
2394c306 TM |
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. | |
21394e70 | 199 | |
58f95dd7 | 200 | [[pve_ceph_install]] |
21394e70 DM |
201 | Installation of Ceph Packages |
202 | ----------------------------- | |
2394c306 TM |
203 | Use {pve} Ceph installation wizard (recommended) or run the following |
204 | command on each node: | |
21394e70 DM |
205 | |
206 | [source,bash] | |
207 | ---- | |
19920184 | 208 | pveceph install |
21394e70 DM |
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 | Creating initial Ceph configuration | |
216 | ----------------------------------- | |
217 | ||
1ff5e4e8 | 218 | [thumbnail="screenshot/gui-ceph-config.png"] |
8997dd6e | 219 | |
2394c306 TM |
220 | Use the {pve} Ceph installation wizard (recommended) or run the |
221 | following command on one node: | |
21394e70 DM |
222 | |
223 | [source,bash] | |
224 | ---- | |
225 | pveceph init --network 10.10.10.0/24 | |
226 | ---- | |
227 | ||
2394c306 TM |
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. | |
21394e70 DM |
234 | |
235 | ||
d9a27ee1 | 236 | [[pve_ceph_monitors]] |
21394e70 DM |
237 | Creating Ceph Monitors |
238 | ---------------------- | |
239 | ||
1ff5e4e8 | 240 | [thumbnail="screenshot/gui-ceph-monitor.png"] |
8997dd6e | 241 | |
1d54c3b4 AA |
242 | The Ceph Monitor (MON) |
243 | footnote:[Ceph Monitor http://docs.ceph.com/docs/luminous/start/intro/] | |
a474ca1f | 244 | maintains a master copy of the cluster map. For high availability you need to |
2394c306 | 245 | have at least 3 monitors. One monitor will already be installed if you |
620d6725 | 246 | used the installation wizard. You won't need more than 3 monitors as long |
2394c306 TM |
247 | as your cluster is small to midsize, only really large clusters will |
248 | need more than that. | |
1d54c3b4 AA |
249 | |
250 | On each node where you want to place a monitor (three monitors are recommended), | |
251 | create it by using the 'Ceph -> Monitor' tab in the GUI or run. | |
21394e70 DM |
252 | |
253 | ||
254 | [source,bash] | |
255 | ---- | |
d1fdb121 | 256 | pveceph mon create |
21394e70 DM |
257 | ---- |
258 | ||
1d54c3b4 AA |
259 | This will also install the needed Ceph Manager ('ceph-mgr') by default. If you |
260 | do not want to install a manager, specify the '-exclude-manager' option. | |
261 | ||
262 | ||
0e38a564 AA |
263 | Destroying Ceph Monitor |
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 | ||
1d54c3b4 AA |
280 | [[pve_ceph_manager]] |
281 | Creating Ceph Manager | |
282 | ---------------------- | |
283 | ||
a474ca1f | 284 | The Manager daemon runs alongside the monitors, providing an interface for |
1d54c3b4 AA |
285 | monitoring the cluster. Since the Ceph luminous release the |
286 | ceph-mgr footnote:[Ceph Manager http://docs.ceph.com/docs/luminous/mgr/] daemon | |
287 | is required. During monitor installation the ceph manager will be installed as | |
288 | well. | |
289 | ||
290 | NOTE: It is recommended to install the Ceph Manager on the monitor nodes. For | |
291 | high availability install more then one manager. | |
292 | ||
293 | [source,bash] | |
294 | ---- | |
d1fdb121 | 295 | pveceph mgr create |
1d54c3b4 AA |
296 | ---- |
297 | ||
21394e70 | 298 | |
549350fe AA |
299 | Destroying Ceph Manager |
300 | ---------------------- | |
301 | ||
302 | To remove a Ceph Manager via the GUI first select a node in the tree view and | |
303 | go to the **Ceph -> Monitor** panel. Select the Manager and click the | |
304 | **Destroy** button. | |
305 | ||
306 | To remove a Ceph Monitor via the CLI first connect to the node on which the | |
307 | Manager is running. Then execute the following command: | |
308 | [source,bash] | |
309 | ---- | |
310 | pveceph mgr destroy | |
311 | ---- | |
312 | ||
313 | NOTE: A Ceph cluster can function without a Manager, but certain functions like | |
314 | the cluster status or usage require a running Manager. | |
315 | ||
316 | ||
d9a27ee1 | 317 | [[pve_ceph_osds]] |
21394e70 DM |
318 | Creating Ceph OSDs |
319 | ------------------ | |
320 | ||
1ff5e4e8 | 321 | [thumbnail="screenshot/gui-ceph-osd-status.png"] |
8997dd6e | 322 | |
21394e70 DM |
323 | via GUI or via CLI as follows: |
324 | ||
325 | [source,bash] | |
326 | ---- | |
d1fdb121 | 327 | pveceph osd create /dev/sd[X] |
21394e70 DM |
328 | ---- |
329 | ||
1d54c3b4 AA |
330 | TIP: We recommend a Ceph cluster size, starting with 12 OSDs, distributed evenly |
331 | among your, at least three nodes (4 OSDs on each node). | |
332 | ||
a474ca1f | 333 | If the disk was used before (eg. ZFS/RAID/OSD), to remove partition table, boot |
9bddef40 | 334 | sector and any OSD leftover the following command should be sufficient. |
a474ca1f AA |
335 | |
336 | [source,bash] | |
337 | ---- | |
9bddef40 | 338 | ceph-volume lvm zap /dev/sd[X] --destroy |
a474ca1f AA |
339 | ---- |
340 | ||
9bddef40 | 341 | WARNING: The above command will destroy data on the disk! |
1d54c3b4 AA |
342 | |
343 | Ceph Bluestore | |
344 | ~~~~~~~~~~~~~~ | |
21394e70 | 345 | |
1d54c3b4 AA |
346 | Starting with the Ceph Kraken release, a new Ceph OSD storage type was |
347 | introduced, the so called Bluestore | |
a474ca1f | 348 | footnote:[Ceph Bluestore http://ceph.com/community/new-luminous-bluestore/]. |
9bddef40 | 349 | This is the default when creating OSDs since Ceph Luminous. |
21394e70 DM |
350 | |
351 | [source,bash] | |
352 | ---- | |
d1fdb121 | 353 | pveceph osd create /dev/sd[X] |
1d54c3b4 AA |
354 | ---- |
355 | ||
1e834cb2 | 356 | .Block.db and block.wal |
1d54c3b4 AA |
357 | |
358 | If you want to use a separate DB/WAL device for your OSDs, you can specify it | |
9bddef40 | 359 | through the '-db_dev' and '-wal_dev' options. The WAL is placed with the DB, if not |
a474ca1f | 360 | specified separately. |
1d54c3b4 AA |
361 | |
362 | [source,bash] | |
363 | ---- | |
d1fdb121 | 364 | pveceph osd create /dev/sd[X] -db_dev /dev/sd[Y] -wal_dev /dev/sd[Z] |
1d54c3b4 AA |
365 | ---- |
366 | ||
9bddef40 DC |
367 | You can directly choose the size for those with the '-db_size' and '-wal_size' |
368 | paremeters respectively. If they are not given the following values (in order) | |
369 | will be used: | |
370 | ||
352c803f TL |
371 | * bluestore_block_{db,wal}_size from ceph configuration... |
372 | ** ... database, section 'osd' | |
373 | ** ... database, section 'global' | |
374 | ** ... file, section 'osd' | |
375 | ** ... file, section 'global' | |
9bddef40 DC |
376 | * 10% (DB)/1% (WAL) of OSD size |
377 | ||
1d54c3b4 | 378 | NOTE: The DB stores BlueStore’s internal metadata and the WAL is BlueStore’s |
ee4a0e96 | 379 | internal journal or write-ahead log. It is recommended to use a fast SSD or |
1d54c3b4 AA |
380 | NVRAM for better performance. |
381 | ||
382 | ||
383 | Ceph Filestore | |
9bddef40 DC |
384 | ~~~~~~~~~~~~~~ |
385 | ||
352c803f | 386 | Before Ceph Luminous, Filestore was used as default storage type for Ceph OSDs. |
9bddef40 | 387 | Starting with Ceph Nautilus, {pve} does not support creating such OSDs with |
352c803f TL |
388 | 'pveceph' anymore. If you still want to create filestore OSDs, use |
389 | 'ceph-volume' directly. | |
1d54c3b4 AA |
390 | |
391 | [source,bash] | |
392 | ---- | |
9bddef40 | 393 | ceph-volume lvm create --filestore --data /dev/sd[X] --journal /dev/sd[Y] |
21394e70 DM |
394 | ---- |
395 | ||
be2d137e AA |
396 | Destroying Ceph OSDs |
397 | -------------------- | |
398 | ||
399 | To remove an OSD via the GUI first select a {PVE} node in the tree view and go | |
400 | to the **Ceph -> OSD** panel. Select the OSD to destroy. Next click the **OUT** | |
401 | button. Once the OSD status changed from `in` to `out` click the **STOP** | |
402 | button. As soon as the status changed from `up` to `down` select **Destroy** | |
403 | from the `More` drop-down menu. | |
404 | ||
405 | To remove an OSD via the CLI run the following commands. | |
406 | [source,bash] | |
407 | ---- | |
408 | ceph osd out <ID> | |
409 | systemctl stop ceph-osd@<ID>.service | |
410 | ---- | |
411 | NOTE: The first command instructs Ceph not to include the OSD in the data | |
412 | distribution. The second command stops the OSD service. Until this time, no | |
413 | data is lost. | |
414 | ||
415 | The following command destroys the OSD. Specify the '-cleanup' option to | |
416 | additionally destroy the partition table. | |
417 | [source,bash] | |
418 | ---- | |
419 | pveceph osd destroy <ID> | |
420 | ---- | |
421 | WARNING: The above command will destroy data on the disk! | |
422 | ||
423 | ||
07fef357 | 424 | [[pve_ceph_pools]] |
1d54c3b4 AA |
425 | Creating Ceph Pools |
426 | ------------------- | |
21394e70 | 427 | |
1ff5e4e8 | 428 | [thumbnail="screenshot/gui-ceph-pools.png"] |
8997dd6e | 429 | |
1d54c3b4 | 430 | A pool is a logical group for storing objects. It holds **P**lacement |
90682f35 | 431 | **G**roups (`PG`, `pg_num`), a collection of objects. |
1d54c3b4 | 432 | |
90682f35 TL |
433 | When no options are given, we set a default of **128 PGs**, a **size of 3 |
434 | replicas** and a **min_size of 2 replicas** for serving objects in a degraded | |
435 | state. | |
1d54c3b4 | 436 | |
5a54ef44 | 437 | NOTE: The default number of PGs works for 2-5 disks. Ceph throws a |
90682f35 | 438 | 'HEALTH_WARNING' if you have too few or too many PGs in your cluster. |
1d54c3b4 AA |
439 | |
440 | It is advised to calculate the PG number depending on your setup, you can find | |
a474ca1f AA |
441 | the formula and the PG calculator footnote:[PG calculator |
442 | http://ceph.com/pgcalc/] online. While PGs can be increased later on, they can | |
443 | never be decreased. | |
1d54c3b4 AA |
444 | |
445 | ||
446 | You can create pools through command line or on the GUI on each PVE host under | |
447 | **Ceph -> Pools**. | |
448 | ||
449 | [source,bash] | |
450 | ---- | |
d1fdb121 | 451 | pveceph pool create <name> |
1d54c3b4 AA |
452 | ---- |
453 | ||
620d6725 FE |
454 | If you would like to automatically also get a storage definition for your pool, |
455 | mark the checkbox "Add storages" in the GUI or use the command line option | |
456 | '--add_storages' at pool creation. | |
21394e70 | 457 | |
1d54c3b4 AA |
458 | Further information on Ceph pool handling can be found in the Ceph pool |
459 | operation footnote:[Ceph pool operation | |
460 | http://docs.ceph.com/docs/luminous/rados/operations/pools/] | |
461 | manual. | |
21394e70 | 462 | |
76f6eca4 | 463 | [[pve_ceph_device_classes]] |
9fad507d AA |
464 | Ceph CRUSH & device classes |
465 | --------------------------- | |
466 | The foundation of Ceph is its algorithm, **C**ontrolled **R**eplication | |
467 | **U**nder **S**calable **H**ashing | |
468 | (CRUSH footnote:[CRUSH https://ceph.com/wp-content/uploads/2016/08/weil-crush-sc06.pdf]). | |
469 | ||
470 | CRUSH calculates where to store to and retrieve data from, this has the | |
471 | advantage that no central index service is needed. CRUSH works with a map of | |
472 | OSDs, buckets (device locations) and rulesets (data replication) for pools. | |
473 | ||
474 | NOTE: Further information can be found in the Ceph documentation, under the | |
475 | section CRUSH map footnote:[CRUSH map http://docs.ceph.com/docs/luminous/rados/operations/crush-map/]. | |
476 | ||
477 | This map can be altered to reflect different replication hierarchies. The object | |
478 | replicas can be separated (eg. failure domains), while maintaining the desired | |
479 | distribution. | |
480 | ||
481 | A common use case is to use different classes of disks for different Ceph pools. | |
482 | For this reason, Ceph introduced the device classes with luminous, to | |
483 | accommodate the need for easy ruleset generation. | |
484 | ||
485 | The device classes can be seen in the 'ceph osd tree' output. These classes | |
486 | represent their own root bucket, which can be seen with the below command. | |
487 | ||
488 | [source, bash] | |
489 | ---- | |
490 | ceph osd crush tree --show-shadow | |
491 | ---- | |
492 | ||
493 | Example output form the above command: | |
494 | ||
495 | [source, bash] | |
496 | ---- | |
497 | ID CLASS WEIGHT TYPE NAME | |
498 | -16 nvme 2.18307 root default~nvme | |
499 | -13 nvme 0.72769 host sumi1~nvme | |
500 | 12 nvme 0.72769 osd.12 | |
501 | -14 nvme 0.72769 host sumi2~nvme | |
502 | 13 nvme 0.72769 osd.13 | |
503 | -15 nvme 0.72769 host sumi3~nvme | |
504 | 14 nvme 0.72769 osd.14 | |
505 | -1 7.70544 root default | |
506 | -3 2.56848 host sumi1 | |
507 | 12 nvme 0.72769 osd.12 | |
508 | -5 2.56848 host sumi2 | |
509 | 13 nvme 0.72769 osd.13 | |
510 | -7 2.56848 host sumi3 | |
511 | 14 nvme 0.72769 osd.14 | |
512 | ---- | |
513 | ||
514 | To let a pool distribute its objects only on a specific device class, you need | |
515 | to create a ruleset with the specific class first. | |
516 | ||
517 | [source, bash] | |
518 | ---- | |
519 | ceph osd crush rule create-replicated <rule-name> <root> <failure-domain> <class> | |
520 | ---- | |
521 | ||
522 | [frame="none",grid="none", align="left", cols="30%,70%"] | |
523 | |=== | |
524 | |<rule-name>|name of the rule, to connect with a pool (seen in GUI & CLI) | |
525 | |<root>|which crush root it should belong to (default ceph root "default") | |
526 | |<failure-domain>|at which failure-domain the objects should be distributed (usually host) | |
527 | |<class>|what type of OSD backing store to use (eg. nvme, ssd, hdd) | |
528 | |=== | |
529 | ||
530 | Once the rule is in the CRUSH map, you can tell a pool to use the ruleset. | |
531 | ||
532 | [source, bash] | |
533 | ---- | |
534 | ceph osd pool set <pool-name> crush_rule <rule-name> | |
535 | ---- | |
536 | ||
537 | TIP: If the pool already contains objects, all of these have to be moved | |
538 | accordingly. Depending on your setup this may introduce a big performance hit on | |
539 | your cluster. As an alternative, you can create a new pool and move disks | |
540 | separately. | |
541 | ||
542 | ||
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543 | Ceph Client |
544 | ----------- | |
545 | ||
1ff5e4e8 | 546 | [thumbnail="screenshot/gui-ceph-log.png"] |
8997dd6e | 547 | |
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548 | You can then configure {pve} to use such pools to store VM or |
549 | Container images. Simply use the GUI too add a new `RBD` storage (see | |
550 | section xref:ceph_rados_block_devices[Ceph RADOS Block Devices (RBD)]). | |
551 | ||
620d6725 | 552 | You also need to copy the keyring to a predefined location for an external Ceph |
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553 | cluster. If Ceph is installed on the Proxmox nodes itself, then this will be |
554 | done automatically. | |
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555 | |
556 | NOTE: The file name needs to be `<storage_id> + `.keyring` - `<storage_id>` is | |
557 | the expression after 'rbd:' in `/etc/pve/storage.cfg` which is | |
558 | `my-ceph-storage` in the following example: | |
559 | ||
560 | [source,bash] | |
561 | ---- | |
562 | mkdir /etc/pve/priv/ceph | |
563 | cp /etc/ceph/ceph.client.admin.keyring /etc/pve/priv/ceph/my-ceph-storage.keyring | |
564 | ---- | |
0840a663 | 565 | |
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566 | [[pveceph_fs]] |
567 | CephFS | |
568 | ------ | |
569 | ||
570 | Ceph provides also a filesystem running on top of the same object storage as | |
571 | RADOS block devices do. A **M**eta**d**ata **S**erver (`MDS`) is used to map | |
572 | the RADOS backed objects to files and directories, allowing to provide a | |
573 | POSIX-compliant replicated filesystem. This allows one to have a clustered | |
574 | highly available shared filesystem in an easy way if ceph is already used. Its | |
575 | Metadata Servers guarantee that files get balanced out over the whole Ceph | |
576 | cluster, this way even high load will not overload a single host, which can be | |
d180eb39 | 577 | an issue with traditional shared filesystem approaches, like `NFS`, for |
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578 | example. |
579 | ||
1e834cb2 TL |
580 | [thumbnail="screenshot/gui-node-ceph-cephfs-panel.png"] |
581 | ||
2394c306 | 582 | {pve} supports both, using an existing xref:storage_cephfs[CephFS as storage] |
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583 | to save backups, ISO files or container templates and creating a |
584 | hyper-converged CephFS itself. | |
585 | ||
586 | ||
587 | [[pveceph_fs_mds]] | |
588 | Metadata Server (MDS) | |
589 | ~~~~~~~~~~~~~~~~~~~~~ | |
590 | ||
591 | CephFS needs at least one Metadata Server to be configured and running to be | |
592 | able to work. One can simply create one through the {pve} web GUI's `Node -> | |
593 | CephFS` panel or on the command line with: | |
594 | ||
595 | ---- | |
596 | pveceph mds create | |
597 | ---- | |
598 | ||
599 | Multiple metadata servers can be created in a cluster. But with the default | |
600 | settings only one can be active at any time. If an MDS, or its node, becomes | |
601 | unresponsive (or crashes), another `standby` MDS will get promoted to `active`. | |
602 | One can speed up the hand-over between the active and a standby MDS up by using | |
603 | the 'hotstandby' parameter option on create, or if you have already created it | |
604 | you may set/add: | |
605 | ||
606 | ---- | |
607 | mds standby replay = true | |
608 | ---- | |
609 | ||
610 | in the ceph.conf respective MDS section. With this enabled, this specific MDS | |
611 | will always poll the active one, so that it can take over faster as it is in a | |
3580eb13 | 612 | `warm` state. But naturally, the active polling will cause some additional |
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613 | performance impact on your system and active `MDS`. |
614 | ||
1e834cb2 | 615 | .Multiple Active MDS |
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616 | |
617 | Since Luminous (12.2.x) you can also have multiple active metadata servers | |
618 | running, but this is normally only useful for a high count on parallel clients, | |
619 | as else the `MDS` seldom is the bottleneck. If you want to set this up please | |
620 | refer to the ceph documentation. footnote:[Configuring multiple active MDS | |
127ca409 | 621 | daemons http://docs.ceph.com/docs/luminous/cephfs/multimds/] |
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622 | |
623 | [[pveceph_fs_create]] | |
624 | Create a CephFS | |
625 | ~~~~~~~~~~~~~~~ | |
626 | ||
627 | With {pve}'s CephFS integration into you can create a CephFS easily over the | |
628 | Web GUI, the CLI or an external API interface. Some prerequisites are required | |
629 | for this to work: | |
630 | ||
631 | .Prerequisites for a successful CephFS setup: | |
632 | - xref:pve_ceph_install[Install Ceph packages], if this was already done some | |
633 | time ago you might want to rerun it on an up to date system to ensure that | |
634 | also all CephFS related packages get installed. | |
635 | - xref:pve_ceph_monitors[Setup Monitors] | |
636 | - xref:pve_ceph_monitors[Setup your OSDs] | |
637 | - xref:pveceph_fs_mds[Setup at least one MDS] | |
638 | ||
639 | After this got all checked and done you can simply create a CephFS through | |
640 | either the Web GUI's `Node -> CephFS` panel or the command line tool `pveceph`, | |
641 | for example with: | |
642 | ||
643 | ---- | |
644 | pveceph fs create --pg_num 128 --add-storage | |
645 | ---- | |
646 | ||
647 | This creates a CephFS named `'cephfs'' using a pool for its data named | |
648 | `'cephfs_data'' with `128` placement groups and a pool for its metadata named | |
649 | `'cephfs_metadata'' with one quarter of the data pools placement groups (`32`). | |
650 | Check the xref:pve_ceph_pools[{pve} managed Ceph pool chapter] or visit the | |
651 | Ceph documentation for more information regarding a fitting placement group | |
652 | number (`pg_num`) for your setup footnote:[Ceph Placement Groups | |
127ca409 | 653 | http://docs.ceph.com/docs/luminous/rados/operations/placement-groups/]. |
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654 | Additionally, the `'--add-storage'' parameter will add the CephFS to the {pve} |
655 | storage configuration after it was created successfully. | |
656 | ||
657 | Destroy CephFS | |
658 | ~~~~~~~~~~~~~~ | |
659 | ||
fa9b4ee1 | 660 | WARNING: Destroying a CephFS will render all its data unusable, this cannot be |
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661 | undone! |
662 | ||
663 | If you really want to destroy an existing CephFS you first need to stop, or | |
620d6725 | 664 | destroy, all metadata servers (`M̀DS`). You can destroy them either over the Web |
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665 | GUI or the command line interface, with: |
666 | ||
667 | ---- | |
668 | pveceph mds destroy NAME | |
669 | ---- | |
670 | on each {pve} node hosting a MDS daemon. | |
671 | ||
672 | Then, you can remove (destroy) CephFS by issuing a: | |
673 | ||
674 | ---- | |
de2f8225 | 675 | ceph fs rm NAME --yes-i-really-mean-it |
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676 | ---- |
677 | on a single node hosting Ceph. After this you may want to remove the created | |
678 | data and metadata pools, this can be done either over the Web GUI or the CLI | |
679 | with: | |
680 | ||
681 | ---- | |
682 | pveceph pool destroy NAME | |
683 | ---- | |
0840a663 | 684 | |
6ff32926 | 685 | |
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686 | Ceph monitoring and troubleshooting |
687 | ----------------------------------- | |
688 | A good start is to continuosly monitor the ceph health from the start of | |
689 | initial deployment. Either through the ceph tools itself, but also by accessing | |
690 | the status through the {pve} link:api-viewer/index.html[API]. | |
6ff32926 | 691 | |
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692 | The following ceph commands below can be used to see if the cluster is healthy |
693 | ('HEALTH_OK'), if there are warnings ('HEALTH_WARN'), or even errors | |
694 | ('HEALTH_ERR'). If the cluster is in an unhealthy state the status commands | |
620d6725 | 695 | below will also give you an overview of the current events and actions to take. |
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696 | |
697 | ---- | |
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698 | # single time output |
699 | pve# ceph -s | |
700 | # continuously output status changes (press CTRL+C to stop) | |
701 | pve# ceph -w | |
6ff32926 AA |
702 | ---- |
703 | ||
704 | To get a more detailed view, every ceph service has a log file under | |
705 | `/var/log/ceph/` and if there is not enough detail, the log level can be | |
706 | adjusted footnote:[Ceph log and debugging http://docs.ceph.com/docs/luminous/rados/troubleshooting/log-and-debug/]. | |
707 | ||
708 | You can find more information about troubleshooting | |
709 | footnote:[Ceph troubleshooting http://docs.ceph.com/docs/luminous/rados/troubleshooting/] | |
620d6725 | 710 | a Ceph cluster on the official website. |
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711 | |
712 | ||
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713 | ifdef::manvolnum[] |
714 | include::pve-copyright.adoc[] | |
715 | endif::manvolnum[] |