X-Git-Url: https://git.proxmox.com/?p=pve-docs.git;a=blobdiff_plain;f=pveceph.adoc;h=20e1883e3b92223b4fe109973fc4ab55ab5eaabc;hp=7fb86b123b9e5e91812d00ab189884f59f875145;hb=19b04e775fea4645a075fc4263272c3614795eda;hpb=c994e4e5326512204e108b62779f03809c42e58c diff --git a/pveceph.adoc b/pveceph.adoc index 7fb86b1..20e1883 100644 --- a/pveceph.adoc +++ b/pveceph.adoc @@ -18,24 +18,39 @@ DESCRIPTION ----------- endif::manvolnum[] ifndef::manvolnum[] -pveceph - Manage Ceph Services on Proxmox VE Nodes -================================================== +Manage Ceph Services on Proxmox VE Nodes +======================================== +:pve-toplevel: endif::manvolnum[] -{pve} unifies your compute and storage systems, i.e. you can use the -same physical nodes within a cluster for both computing (processing -VMs and containers) and replicated storage. The traditional silos of -compute and storage resources can be wrapped up into a single -hyper-converged appliance. Separate storage networks (SANs) and -connections via network (NAS) disappear. With the integration of Ceph, -an open source software-defined storage platform, {pve} has the -ability to run and manage Ceph storage directly on the hypervisor -nodes. +[thumbnail="gui-ceph-status.png"] + +{pve} unifies your compute and storage systems, i.e. you can use the same +physical nodes within a cluster for both computing (processing VMs and +containers) and replicated storage. The traditional silos of compute and +storage resources can be wrapped up into a single hyper-converged appliance. +Separate storage networks (SANs) and connections via network attached storages +(NAS) disappear. With the integration of Ceph, an open source software-defined +storage platform, {pve} has the ability to run and manage Ceph storage directly +on the hypervisor nodes. Ceph is a distributed object store and file system designed to provide -excellent performance, reliability and scalability. For smaller -deployments, it is possible to install a Ceph server for RADOS Block -Devices (RBD) directly on your {pve} cluster nodes, see +excellent performance, reliability and scalability. + +.Some advantages of Ceph on {pve} are: +- Easy setup and management with CLI and GUI support +- Thin provisioning +- Snapshots support +- Self healing +- Scalable to the exabyte level +- Setup pools with different performance and redundancy characteristics +- Data is replicated, making it fault tolerant +- Runs on economical commodity hardware +- No need for hardware RAID controllers +- Open source + +For small to mid sized deployments, it is possible to install a Ceph server for +RADOS Block Devices (RBD) directly on your {pve} cluster nodes, see xref:ceph_rados_block_devices[Ceph RADOS Block Devices (RBD)]. Recent hardware has plenty of CPU power and RAM, so running storage services and VMs on the same node is possible. @@ -43,6 +58,14 @@ and VMs on the same node is possible. To simplify management, we provide 'pveceph' - a tool to install and manage {ceph} services on {pve} nodes. +.Ceph consists of a couple of Daemons footnote:[Ceph intro http://docs.ceph.com/docs/master/start/intro/], for use as a RBD storage: +- Ceph Monitor (ceph-mon) +- Ceph Manager (ceph-mgr) +- Ceph OSD (ceph-osd; Object Storage Daemon) + +TIP: We recommend to get familiar with the Ceph vocabulary. +footnote:[Ceph glossary http://docs.ceph.com/docs/luminous/glossary] + Precondition ------------ @@ -50,12 +73,23 @@ Precondition To build a Proxmox Ceph Cluster there should be at least three (preferably) identical servers for the setup. -A 10Gb network, exclusively used for Ceph, is recommmended. A meshed -network setup is also an option if there are no 10Gb switches -available, see {webwiki-url}Full_Mesh_Network_for_Ceph_Server[wiki] . +A 10Gb network, exclusively used for Ceph, is recommended. A meshed network +setup is also an option if there are no 10Gb switches available, see our wiki +article footnote:[Full Mesh Network for Ceph {webwiki-url}Full_Mesh_Network_for_Ceph_Server] . Check also the recommendations from -http://docs.ceph.com/docs/jewel/start/hardware-recommendations/[Ceph's website]. +http://docs.ceph.com/docs/luminous/start/hardware-recommendations/[Ceph's website]. + +.Avoid RAID +As Ceph handles data object redundancy and multiple parallel writes to disks +(OSDs) on its own, using a RAID controller normally doesn’t improve +performance or availability. On the contrary, Ceph is designed to handle whole +disks on it's own, without any abstraction in between. RAID controller are not +designed for the Ceph use case and may complicate things and sometimes even +reduce performance, as their write and caching algorithms may interfere with +the ones from Ceph. + +WARNING: Avoid RAID controller, use host bus adapter (HBA) instead. Installation of Ceph Packages @@ -65,7 +99,7 @@ On each node run the installation script as follows: [source,bash] ---- -pveceph install -version jewel +pveceph install ---- This sets up an `apt` package repository in @@ -75,6 +109,8 @@ This sets up an `apt` package repository in Creating initial Ceph configuration ----------------------------------- +[thumbnail="gui-ceph-config.png"] + After installation of packages, you need to create an initial Ceph configuration on just one node, based on your network (`10.10.10.0/24` in the following example) dedicated for Ceph: @@ -84,18 +120,26 @@ in the following example) dedicated for Ceph: pveceph init --network 10.10.10.0/24 ---- -This creates an initial config at `/etc/pve/ceph.conf`. That file is +This creates an initial configuration at `/etc/pve/ceph.conf`. That file is automatically distributed to all {pve} nodes by using xref:chapter_pmxcfs[pmxcfs]. The command also creates a symbolic link from `/etc/ceph/ceph.conf` pointing to that file. So you can simply run Ceph commands without the need to specify a configuration file. +[[pve_ceph_monitors]] Creating Ceph Monitors ---------------------- -On each node where a monitor is requested (three monitors are recommended) -create it by using the "Ceph" item in the GUI or run. +[thumbnail="gui-ceph-monitor.png"] + +The Ceph Monitor (MON) +footnote:[Ceph Monitor http://docs.ceph.com/docs/luminous/start/intro/] +maintains a master copy of the cluster map. For high availability you need to +have at least 3 monitors. + +On each node where you want to place a monitor (three monitors are recommended), +create it by using the 'Ceph -> Monitor' tab in the GUI or run. [source,bash] @@ -103,10 +147,35 @@ create it by using the "Ceph" item in the GUI or run. pveceph createmon ---- +This will also install the needed Ceph Manager ('ceph-mgr') by default. If you +do not want to install a manager, specify the '-exclude-manager' option. + + +[[pve_ceph_manager]] +Creating Ceph Manager +---------------------- + +The Manager daemon runs alongside the monitors, providing an interface for +monitoring the cluster. Since the Ceph luminous release the +ceph-mgr footnote:[Ceph Manager http://docs.ceph.com/docs/luminous/mgr/] daemon +is required. During monitor installation the ceph manager will be installed as +well. + +NOTE: It is recommended to install the Ceph Manager on the monitor nodes. For +high availability install more then one manager. + +[source,bash] +---- +pveceph createmgr +---- + +[[pve_ceph_osds]] Creating Ceph OSDs ------------------ +[thumbnail="gui-ceph-osd-status.png"] + via GUI or via CLI as follows: [source,bash] @@ -114,17 +183,74 @@ via GUI or via CLI as follows: pveceph createosd /dev/sd[X] ---- -If you want to use a dedicated SSD journal disk: +TIP: We recommend a Ceph cluster size, starting with 12 OSDs, distributed evenly +among your, at least three nodes (4 OSDs on each node). + +If the disk was used before (eg. ZFS/RAID/OSD), to remove partition table, boot +sector and any OSD leftover the following commands should be sufficient. + +[source,bash] +---- +dd if=/dev/zero of=/dev/sd[X] bs=1M count=200 +ceph-disk zap /dev/sd[X] +---- + +WARNING: The above commands will destroy data on the disk! + +Ceph Bluestore +~~~~~~~~~~~~~~ + +Starting with the Ceph Kraken release, a new Ceph OSD storage type was +introduced, the so called Bluestore +footnote:[Ceph Bluestore http://ceph.com/community/new-luminous-bluestore/]. +This is the default when creating OSDs in Ceph luminous. + +[source,bash] +---- +pveceph createosd /dev/sd[X] +---- + +NOTE: In order to select a disk in the GUI, to be more failsafe, the disk needs +to have a GPT footnoteref:[GPT, GPT partition table +https://en.wikipedia.org/wiki/GUID_Partition_Table] partition table. You can +create this with `gdisk /dev/sd(x)`. If there is no GPT, you cannot select the +disk as DB/WAL. + +If you want to use a separate DB/WAL device for your OSDs, you can specify it +through the '-journal_dev' option. The WAL is placed with the DB, if not +specified separately. + +[source,bash] +---- +pveceph createosd /dev/sd[X] -journal_dev /dev/sd[Y] +---- + +NOTE: The DB stores BlueStore’s internal metadata and the WAL is BlueStore’s +internal journal or write-ahead log. It is recommended to use a fast SSDs or +NVRAM for better performance. + -NOTE: In order to use a dedicated journal disk (SSD), the disk needs -to have a https://en.wikipedia.org/wiki/GUID_Partition_Table[GPT] -partition table. You can create this with `gdisk /dev/sd(x)`. If there -is no GPT, you cannot select the disk as journal. Currently the -journal size is fixed to 5 GB. +Ceph Filestore +~~~~~~~~~~~~~ +Till Ceph luminous, Filestore was used as storage type for Ceph OSDs. It can +still be used and might give better performance in small setups, when backed by +a NVMe SSD or similar. [source,bash] ---- -pveceph createosd /dev/sd[X] -journal_dev /dev/sd[X] +pveceph createosd /dev/sd[X] -bluestore 0 +---- + +NOTE: In order to select a disk in the GUI, the disk needs to have a +GPT footnoteref:[GPT] partition table. You can +create this with `gdisk /dev/sd(x)`. If there is no GPT, you cannot select the +disk as journal. Currently the journal size is fixed to 5 GB. + +If you want to use a dedicated SSD journal disk: + +[source,bash] +---- +pveceph createosd /dev/sd[X] -journal_dev /dev/sd[Y] -bluestore 0 ---- Example: Use /dev/sdf as data disk (4TB) and /dev/sdb is the dedicated SSD @@ -132,43 +258,152 @@ journal disk. [source,bash] ---- -pveceph createosd /dev/sdf -journal_dev /dev/sdb +pveceph createosd /dev/sdf -journal_dev /dev/sdb -bluestore 0 ---- This partitions the disk (data and journal partition), creates filesystems and starts the OSD, afterwards it is running and fully -functional. Please create at least 12 OSDs, distributed among your -nodes (4 OSDs on each node). +functional. + +NOTE: This command refuses to initialize disk when it detects existing data. So +if you want to overwrite a disk you should remove existing data first. You can +do that using: 'ceph-disk zap /dev/sd[X]' + +You can create OSDs containing both journal and data partitions or you +can place the journal on a dedicated SSD. Using a SSD journal disk is +highly recommended to achieve good performance. -It should be noted that this command refuses to initialize disk when -it detects existing data. So if you want to overwrite a disk you -should remove existing data first. You can do that using: + +[[pve_ceph_pools]] +Creating Ceph Pools +------------------- + +[thumbnail="gui-ceph-pools.png"] + +A pool is a logical group for storing objects. It holds **P**lacement +**G**roups (PG), a collection of objects. + +When no options are given, we set a +default of **64 PGs**, a **size of 3 replicas** and a **min_size of 2 replicas** +for serving objects in a degraded state. + +NOTE: The default number of PGs works for 2-6 disks. Ceph throws a +"HEALTH_WARNING" if you have too few or too many PGs in your cluster. + +It is advised to calculate the PG number depending on your setup, you can find +the formula and the PG calculator footnote:[PG calculator +http://ceph.com/pgcalc/] online. While PGs can be increased later on, they can +never be decreased. + + +You can create pools through command line or on the GUI on each PVE host under +**Ceph -> Pools**. [source,bash] ---- -ceph-disk zap /dev/sd[X] +pveceph createpool ---- -You can create OSDs containing both journal and data partitions or you -can place the journal on a dedicated SSD. Using a SSD journal disk is -highly recommended if you expect good performance. +If you would like to automatically get also a storage definition for your pool, +active the checkbox "Add storages" on the GUI or use the command line option +'--add_storages' on pool creation. +Further information on Ceph pool handling can be found in the Ceph pool +operation footnote:[Ceph pool operation +http://docs.ceph.com/docs/luminous/rados/operations/pools/] +manual. -Ceph Pools ----------- +Ceph CRUSH & device classes +--------------------------- +The foundation of Ceph is its algorithm, **C**ontrolled **R**eplication +**U**nder **S**calable **H**ashing +(CRUSH footnote:[CRUSH https://ceph.com/wp-content/uploads/2016/08/weil-crush-sc06.pdf]). -The standard installation creates per default the pool 'rbd', -additional pools can be created via GUI. +CRUSH calculates where to store to and retrieve data from, this has the +advantage that no central index service is needed. CRUSH works with a map of +OSDs, buckets (device locations) and rulesets (data replication) for pools. + +NOTE: Further information can be found in the Ceph documentation, under the +section CRUSH map footnote:[CRUSH map http://docs.ceph.com/docs/luminous/rados/operations/crush-map/]. + +This map can be altered to reflect different replication hierarchies. The object +replicas can be separated (eg. failure domains), while maintaining the desired +distribution. + +A common use case is to use different classes of disks for different Ceph pools. +For this reason, Ceph introduced the device classes with luminous, to +accommodate the need for easy ruleset generation. + +The device classes can be seen in the 'ceph osd tree' output. These classes +represent their own root bucket, which can be seen with the below command. + +[source, bash] +---- +ceph osd crush tree --show-shadow +---- + +Example output form the above command: + +[source, bash] +---- +ID CLASS WEIGHT TYPE NAME +-16 nvme 2.18307 root default~nvme +-13 nvme 0.72769 host sumi1~nvme + 12 nvme 0.72769 osd.12 +-14 nvme 0.72769 host sumi2~nvme + 13 nvme 0.72769 osd.13 +-15 nvme 0.72769 host sumi3~nvme + 14 nvme 0.72769 osd.14 + -1 7.70544 root default + -3 2.56848 host sumi1 + 12 nvme 0.72769 osd.12 + -5 2.56848 host sumi2 + 13 nvme 0.72769 osd.13 + -7 2.56848 host sumi3 + 14 nvme 0.72769 osd.14 +---- + +To let a pool distribute its objects only on a specific device class, you need +to create a ruleset with the specific class first. + +[source, bash] +---- +ceph osd crush rule create-replicated +---- + +[frame="none",grid="none", align="left", cols="30%,70%"] +|=== +||name of the rule, to connect with a pool (seen in GUI & CLI) +||which crush root it should belong to (default ceph root "default") +||at which failure-domain the objects should be distributed (usually host) +||what type of OSD backing store to use (eg. nvme, ssd, hdd) +|=== + +Once the rule is in the CRUSH map, you can tell a pool to use the ruleset. + +[source, bash] +---- +ceph osd pool set crush_rule +---- + +TIP: If the pool already contains objects, all of these have to be moved +accordingly. Depending on your setup this may introduce a big performance hit on +your cluster. As an alternative, you can create a new pool and move disks +separately. Ceph Client ----------- +[thumbnail="gui-ceph-log.png"] + You can then configure {pve} to use such pools to store VM or Container images. Simply use the GUI too add a new `RBD` storage (see section xref:ceph_rados_block_devices[Ceph RADOS Block Devices (RBD)]). -You also need to copy the keyring to a predefined location. +You also need to copy the keyring to a predefined location for a external Ceph +cluster. If Ceph is installed on the Proxmox nodes itself, then this will be +done automatically. NOTE: The file name needs to be ` + `.keyring` - `` is the expression after 'rbd:' in `/etc/pve/storage.cfg` which is