X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=pveceph.adoc;h=20e1883e3b92223b4fe109973fc4ab55ab5eaabc;hb=d986fd9040a6a18868ca3333707505b54016f37c;hp=67a0dba248a0fcfcb2240dc72e95377e9d7ff1c6;hpb=07fef357a9f83feb8be6c5f5f067cedfdb87cf6f;p=pve-docs.git diff --git a/pveceph.adoc b/pveceph.adoc index 67a0dba..20e1883 100644 --- a/pveceph.adoc +++ b/pveceph.adoc @@ -25,19 +25,30 @@ endif::manvolnum[] [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 (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. +{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. +.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 @@ -47,10 +58,7 @@ 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 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) @@ -65,13 +73,24 @@ 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 recommended. 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/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 ----------------------------- @@ -101,7 +120,7 @@ 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 @@ -116,8 +135,8 @@ Creating Ceph Monitors The Ceph Monitor (MON) footnote:[Ceph Monitor http://docs.ceph.com/docs/luminous/start/intro/] -maintains a master copy of the cluster map. For HA you need to have at least 3 -monitors. +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. @@ -136,7 +155,7 @@ do not want to install a manager, specify the '-exclude-manager' option. Creating Ceph Manager ---------------------- -The Manager daemon runs alongside the monitors. It provides interfaces for +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 @@ -167,14 +186,24 @@ pveceph createosd /dev/sd[X] 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/]. In -Ceph luminous this store is the default when creating OSDs. +footnote:[Ceph Bluestore http://ceph.com/community/new-luminous-bluestore/]. +This is the default when creating OSDs in Ceph luminous. [source,bash] ---- @@ -182,18 +211,18 @@ 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. +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 '-wal_dev' option. +through the '-journal_dev' option. The WAL is placed with the DB, if not +specified separately. [source,bash] ---- -pveceph createosd /dev/sd[X] -wal_dev /dev/sd[Y] +pveceph createosd /dev/sd[X] -journal_dev /dev/sd[Y] ---- NOTE: The DB stores BlueStore’s internal metadata and the WAL is BlueStore’s @@ -221,7 +250,7 @@ If you want to use a dedicated SSD journal disk: [source,bash] ---- -pveceph createosd /dev/sd[X] -journal_dev /dev/sd[Y] +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 @@ -229,7 +258,7 @@ 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 @@ -262,9 +291,9 @@ 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. +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 @@ -284,6 +313,85 @@ operation footnote:[Ceph pool operation http://docs.ceph.com/docs/luminous/rados/operations/pools/] manual. +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]). + +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 -----------