StorageOS Feature labels

Feature labels are a powerful and flexible way to control storage features, especially when combined with rules.

Labels can be applied to various StorageOS artefacts. Applying specific feature labels triggers compression, replication and other storage features. No feature labels are present by default.

StorageOS Node labels

Nodes do not have any feature labels present by default. When StorageOS is run within Kubernetes with the Cluster Operator, any node labels set on Kubernetes nodes are available within StorageOS. Node labels may also be set with the CLI or UI.

Feature Label Values Description
Deployment type strings [computeonly,mixed] Specifies whether a node should be computeonly where it only acts as a client and does not host volume data locally, or mixed (the default), where the node can operate in both client and server modes.
Region iaas/region string Set automatically in AWS, Azure and GCE. e.g. eu-west-1. Not currently used by StorageOS but available for use in rules.
Failure domain iaas/failure-domain string Used to spread master and replicas across different failure domains. Set automatically in AWS, Azure and GCE, e.g. eu-west-1b
Update domain iaas/update-domain string Set by some cloud providers to perform sequential updates/reboots. Not currently used by StorageOS but available for use in rules.
Size iaas/size string The node hardware configuration, as set by the cloud provider, e.g. m5d.xlarge. Not currently used by StorageOS but available for use in rules.

To add a label to a node:

storageos node update --label-add nodename

StorageOS Pod Labels

Feature Label Values Description
Fencing true / false Enables StorageOS fencing of pods on unavailable nodes. For more information about fencing prerequisites please see the Fencing operations page.

To add the fencing label to a pod use kubectl:

kubectl label pod <POD_NAME> key=value
kubectl label pod mydb-pod

StorageOS Pool labels

Pools do not have any labels present by default.

Feature Label Values Description
Overcommitment integers [+] Sets the percentage of overcommitment allowed for the pool (see here).

To add overcommit labels to a pool:

storageos pool update --label-add default

StorageOS Volume labels

Volumes do not have any feature labels present by default

Feature Label Values Description
Caching true / false Switches off caching.
Compression true / false Switches off compression of data at rest and in transit.
Encryption true / false Enables volume encryption, more details here
Failure mode strings [soft,hard,alwayson] Soft failure mode works together with the failure tolerance. Hard is a mode where any loss in desired replicas count will mark volume as unavailable. AlwaysOn is a mode where as long as master is alive volume will be writable.
Failure tolerance integers [0, 4] Specifies how many failed replicas to tolerate, defaults to (Replicas - 1) if Replicas > 0, so if there are 2 replicas it will default to 1.
Placement Node hostname or uuid Requests master volume placement on the specified node. Will use another node if request can’t be satisfied.
QoS true / false Deprioritizes traffic by reducing the rate of disk I/O, when true.
Replication integers [0, 5] Replicates entire volume across nodes. Typically 1 replica is sufficient (2 copies of the data); more than 2 replicas is not recommended.

To create a volume with a feature label:

storageos volume create --label --label volumename

When using the Kubernetes CSI driver (available from Kubernetes 1.10), volume labels can also be added to the parameters section of the StorageClass. This means that all volumes created with the specific StorageClass will have StorageOS volume labels applied to them.

For example the StorageClass below will create ext4 formatted volumes with a single StorageOS replica, in the default pool.

kind: StorageClass
  name: storageos-replicated
    fsType: ext4
    pool: default "1"
provisioner: storageos