Cluster Storage Pools¶
Services can use volume
resources to:
Abstract the disks and filesystems layout, which are hosting specificities, from the service deployment. A development cluster can for example define pools on a ceph cluster, while a production cluster can define pools on fc arrays.
Enable service redeployment while retaining the data.
In this case the translation from volumes to disks and filesystems is delegated to the storage pool drivers.
Pools are defined in the node configuration. Each pool is identified by its name (the section suffix). For example, a pool#tank
section defines a pool named tank
.
The default
pool always exist, even if not defined in the node configuration. If not explicitely changed, the default
pool driver is directory
.
Volumes¶
A volume resource drives a volume object, automatically created upon service provisioning if not already existing.
The volume is hosted in the same namespace than its users.
If not explicitely set, the volume object name is
<consumer name>-vol-<volume resource index>
. For example, asvc1
service with avolume#1
resource will create asvc1-vol-1
volume object.A volume object can be referenced by multiple services in the same namespace.
On provision, a service adds itself as a child of the volume objects mapped via volume resources. Due to this parent/child relation, stopping a volume object is delayed until all its consumers are stopped.
On unprovision, a service removes itself from the children list of the volume objects mapped via volume resources.
A consumer service instance stop also stops its node-affine volume object instances if the consumer service is the only child of the volume service.
A consumer service instance start always tries to start its node-affine volume object instances.
Volume Resources Keywords¶
- volume
- blocking_post_provision
- blocking_post_start
- blocking_post_startstandby
- blocking_post_stop
- blocking_post_unprovision
- blocking_pre_provision
- blocking_pre_start
- blocking_pre_startstandby
- blocking_pre_stop
- blocking_pre_unprovision
- comment
- configs
- directories
- dirperm
- disable
- encap
- group
- monitor
- name
- nodes
- optional
- perm
- pg_blkio_weight
- pg_cpu_quota
- pg_cpu_shares
- pg_cpus
- pg_mem_limit
- pg_mem_oom_control
- pg_mem_swappiness
- pg_mems
- pg_vmem_limit
- post_provision
- post_start
- post_startstandby
- post_stop
- post_unprovision
- pre_provision
- pre_start
- pre_startstandby
- pre_stop
- pre_unprovision
- provision
- provision_requires
- restart
- restart_delay
- secrets
- shared
- signal
- standby
- start_requires
- stop_requires
- subset
- tags
- unprovision
- unprovision_requires
- user
- access
- format
- pool
- size
- type
Access Modes¶
roo
Read Only Oncerwo
Read Write Once (default)rox
Read Only from multiple instancesrwx
Read Write from multiple instances
Access Mode to Volume Topology¶
..x
access modes imply the volume is configured in a flex topology (active on all service nodes)...o
access modes imply the volume is configured in a failover topology (active on only one service node).
Volume Resource Parameter Requirements¶
..x + shared=true format=false
requires a shared block storage (SAN array, a rados blockdev gateway, …)..x + shared=true format=true
requires either a shared block storage (SAN array, a rados blockdev gateway, …) plus a cluster filesystem (gfs2, ocfs, …), or a distributed cluster filesystem (CephFS, GlusterFS, NAS, …)
Pool Selector¶
A volume resource requires a size and capabilities from the pool, via its size
, access
, shared
and format
keywords.
If pool
is not set explicitely to a pool name, the pool selector will return the available pool matching those criteria with the most free space.
Pool Drivers¶
directory¶
Capabilities¶
rox, rwx, roo, rwo
Layout¶
A volume object from this type of pool contains:
a fs.directory resource, with
path
set to<pool head>/<volume fqdn>
.
drbd¶
Capabilities¶
rox, rwx, shared, blk, roo, rwo
Layout¶
A volume object from this type of pool contains:
If a vg is defined in the pool configuration,
a fs resource, with
dev
set to the drbd device patha drbd resource, layered over a logical volume of the pool vg
a lv resource
If a zpool is defined in the pool configuration,
a fs resource, with
dev
set to the drbd device patha drbd resource, layered over a zvol of the pool zpool
a zvol resource
If the pool configuration has neither vg nor zpool set,
a fs resource, with
dev
set to the drbd device patha drbd resource, layered over a logical volume
a lv resource
a vg resource
a loop resource, with image file hosted in the pool defined
path
or in<PATHVAR>/pool/<poolname>/
freenas¶
Capabilities¶
roo, rwo, shared, blk, iscsi
Layout¶
A volume object from this type of pool contains:
a disk.disk resource named, with
name
set to<volume fqdn>
If the consumer has format=true
(default), the volume object also contains:
a fs.<pool fs_type> resource, with
mnt
set to/srv/<volume fqdn>
loop¶
Capabilities¶
rox, rwx, roo, rwo, blk
Layout¶
A volume object from this type of pool contains:
a disk.loop resource, with
file
set to<pool head>/<volume fqdn>.img
If the consumer has format=true
(default), the volume object also contains:
a fs.<pool fs_type> resource, with
mnt
set to/srv/<volume fqdn>
symmetrix¶
Capabilities¶
roo, rwo, shared, blk, fc
Layout¶
A volume object from this type of pool contains:
a disk.disk resource named, with
name
set to<volume fqdn>
If the consumer has format=true
(default), the volume object also contains:
a fs.<pool fs_type> resource, with
mnt
set to/srv/<volume fqdn>
vg¶
Capabilities¶
rox, rwx, roo, rwo, blk, snap
Layout¶
A volume object from this type of pool contains:
a disk.lv resource, with
name
set to<volume fqdn>
If the consumer has format=true
(default), the volume object also contains:
a fs.<pool fs_type> resource, with
mnt
set to/srv/<volume fqdn>
zpool¶
Capabilities¶
rox, rwx, roo, rwo, blk, snap
Layout¶
A volume object from this type of pool contains:
a fs.zfs resource, with
name
set to<pool>/<volume fqdn>
andmnt
set to/srv/<volume fqdn>
.
Virtual Pool Driver¶
A virtual pool allow administrators to create complex layouts based on volumes from other pools.
A typical use-case in a virtual pool allocating volumes mirrored over two other volumes allocated from arrays on two different sites.
A virtual pool volume is created from a template volume object the administrator can design at wish to meet its specific needs.
Capabilities¶
Capabilities are user defined.
Pool Commands¶
Pool list¶
# om pool ls
default
freenas
mpool
Pool Status¶
# om pool status
name type caps head vols size used free
|- default directory rox,rwx,roo,rwo /opt/opensvc/var/pool/directory 0 29.0g 3.57g 24.0g
|- freenas freenas roo,rwo,shared,blk,iscsi array://freenas/osvcdata 6 195g 9.37g 185g
`- mpool virtual roo,rox,rwo,rwx,shared templates/mpool 1 - - -
Examples¶
loop pool¶
Pool configuration
om cluster set \
--kw pool#loop.type=loop \
--kw pool#loop.path=/bigfs \
--kw "pool#loop.mkfs_opt=-n ftype=1" \
--kw pool#loop.fs_type=xfs
[pool#loop]
type = loop
path = /bigfs
mkfs_opt = -n ftype=1
fs_type = xfs
The volume resource in the service
[volume#1]
size = 100m
pool = loop
Resulting configuration of the volume object
[disk#1]
size = 104857600
type = loop
file = /bigfs/<fqdn>.img
[fs#1]
type = xfs
dev = {disk#1.exposed_devs[0]}
mnt = /srv/<fqdn>
mkfs_opt = -n ftype=1
zfs pool¶
Pool configuration
om cluster set \
--kw pool#tank.type=zpool \
--kw pool#tank.name=tank \
--kw "pool#tank.mkfs_opt=-o mountpoint=legacy -o dedup=on -o compression=on"
[pool#tank]
type = zpool
name = tank
mkfs_opt = -o mountpoint=legacy -o dedup=on -o compression=on
The volume resource in the service
[volume#1]
size = 100m
pool = tank
Resulting configuration of the volume object
[fs#1]
type = zfs
dev = tank/<fqdn>
mnt = /srv/<fqdn>
mkfs_opt = -o mountpoint=legacy -o dedup=on -o compression=on
virtual pool, mirrored zpool over 2 SAN disks¶
Pools configuration
om cluster set \
--kw pool#freenas1.type=array \
--kw pool#freenas1.array=freenas1 \
--kw pool#freenas1.sparse=true \
--kw pool#freenas1.diskgroup=cluster1 \
--kw pool#freenas2.type=array \
--kw pool#freenas2.array=freenas2 \
--kw pool#freenas2.sparse=true \
--kw pool#freenas2.diskgroup=cluster1 \
--kw pool#mpool.type=virtual \
--kw pool#mpool.template=templates/mpool \
--kw "pool#mpool.capabilities=rox rwx roo rwo shared"
[pool#freenas1]
type = array
array = freenas1
diskgroup = cluster1
sparse = true
[pool#freenas2]
type = array
array = freenas2
diskgroup = cluster1
sparse = true
[pool#mpool]
type = virtual
template = templates/mpool
capabilities = rox rwx roo rwo shared
The volume object template referenced by the vpool
[DEFAULT]
kind = vol
nodes = *
disable = true
[disk#1]
name = {namespace}-{svcname}
type = zpool
vdev = mirror {volume#1.exposed_devs[0]} {volume#2.exposed_devs[0]}
shared = true
[fs#1]
dev = {disk#1.name}
mnt = /srv/{namespace}/{svcname}
type = zfs
shared = true
[fs#2]
dev = {disk#1.name}/data
mnt = {fs#1.mnt}/data
type = zfs
shared = true
[fs#3]
dev = {disk#1.name}/log
mnt = {fs#1.mnt}/log
type = zfs
shared = true
[volume#1]
format = false
name = {svcname}-1
pool = freenas1
size = {env.size}
shared = true
[volume#2]
format = false
name = {svcname}-2
pool = freenas2
size = {env.size}
shared = true
virtual pool, mirrored lv over 2 SAN disks¶
Pools configuration
om cluster set \
--kw pool#freenas1.type=array \
--kw pool#freenas1.array=freenas1 \
--kw pool#freenas1.sparse=true \
--kw pool#freenas1.diskgroup=cluster1 \
--kw pool#freenas2.type=array \
--kw pool#freenas2.array=freenas2 \
--kw pool#freenas2.sparse=true \
--kw pool#freenas2.diskgroup=cluster1 \
--kw pool#mvg.type=virtual \
--kw pool#mvg.template=templates/mvg \
--kw "pool#mvg.capabilities=rox rwx roo rwo shared"
[pool#freenas1]
type = array
array = freenas1
diskgroup = cluster1
sparse = true
[pool#freenas2]
type = array
array = freenas2
diskgroup = cluster1
sparse = true
[pool#mvg]
type = virtual
template = templates/mvg
capabilities = rox rwx roo rwo shared
The volume object template referenced by the vpool
[DEFAULT]
kind = vol
nodes = *
disable = true
[volume#1]
shared = true
size = {env.size}
name = {svcname}-1
pool = freenas
format = false
[volume#2]
shared = true
size = {env.size}
name = {svcname}-2
pool = freenas
format = false
[disk#1]
shared = true
type = vg
name = {namespace}-{svcname}
pvs = {volume#1.exposed_devs[0]} {volume#2.exposed_devs[0]}
[fs#1]
shared = true
mnt = /srv/{namespace}/{svcname}
dev = /dev/{disk#1.name}/root
type = ext4
size = 10m
create_options = -m 1
vg = {namespace}-{svcname}
[fs#2]
shared = true
mnt = {fs#1.mnt}/data
dev = /dev/{disk#1.name}/data
type = ext4
size = 60%FREE
create_options = -m 1
vg = {namespace}-{svcname}
[fs#3]
shared = true
mnt = {fs#1.mnt}/log
dev = /dev/{disk#1.name}/log
type = ext4
size = 40%FREE
create_options = -m 1
vg = {namespace}-{svcname}
virtual pool, mirrored md over 2 SAN disks¶
Pools configuration
om cluster set \
--kw pool#freenas1.type=array \
--kw pool#freenas1.array=freenas1 \
--kw pool#freenas1.sparse=true \
--kw pool#freenas1.diskgroup=cluster1 \
--kw pool#freenas2.type=array \
--kw pool#freenas2.array=freenas2 \
--kw pool#freenas2.sparse=true \
--kw pool#freenas2.diskgroup=cluster1 \
--kw pool#md.type=virtual \
--kw pool#md.template=templates/md \
--kw "pool#md.capabilities=rox rwx roo rwo shared"
[pool#freenas1]
type = array
array = freenas1
diskgroup = cluster1
sparse = true
[pool#freenas2]
type = array
array = freenas2
diskgroup = cluster1
sparse = true
[pool#md]
type = virtual
template = templates/md
capabilities = rox rwx roo rwo shared
The volume object template referenced by the vpool
[DEFAULT]
kind = vol
disable = true
nodes = *
[disk#1]
shared = true
devs = {volume#1.exposed_devs[0]} {volume#2.exposed_devs[0]}
type = md
level = raid1
[disk#2]
shared = true
pvs = {disk#1.exposed_devs[0]}
type = vg
name = {namespace}-{svcname}
[fs#1]
vg = {namespace}-{svcname}
mnt = /srv/{namespace}/{svcname}
dev = /dev/{disk#1.name}/root
shared = true
type = ext4
size = 10m
[fs#2]
vg = {namespace}-{svcname}
mnt = {fs#1.mnt}/data
dev = /dev/{disk#1.name}/data
shared = true
type = ext4
size = 60%FREE
[fs#3]
vg = {namespace}-{svcname}
mnt = {fs#1.mnt}/log
dev = /dev/{disk#1.name}/log
shared = true
type = ext4
size = 40%FREE
[volume#2]
shared = true
size = {env.size}
name = {svcname}-2
pool = freenas
format = false
[volume#1]
shared = true
size = {env.size}
name = {svcname}-1
pool = freenas
format = false
drbd pool¶
Pool configuration
om cluster set \
--kw pool#drbdloop.type=drbd
om cluster set \
--kw pool#drbdvg.type=drbd \
--kw pool#drbdvg.vg=centos
[pool#drbdloop]
type = drbd
[pool#drbdvg]
type = drbd
vg = centos
Example postgres service using a volume from a pool.
[DEFAULT]
nodes = *
orchestrate = ha
[volume#1]
shared = true
size = 200m
name = {name}
[container#1]
type = oci
image = postgres
volume_mounts = {name}/data:/var/lib/postgresql/data
secrets_environment = POSTGRES_PASSWORD=pg/password
rm = true
shared = true