Cluster discovery

On startup, you will need to specify whether a StorageOS node should bootstrap a new cluster or join an existing cluster. In order for a bootstrapping node to join or create a cluster, the node needs to know where to find the other nodes in the cluster. The node is informed of other nodes in the cluster via the JOIN environment variable.

Cluster Initialisation - Using StorageOS Operator

For standard installs, the StorageOS operator will automatically populate the JOIN variable with appropriate values. For users with advanced requirements, the operator allows specification of a custom JOIN variable.

Cluster Initialisation - Advanced/Custom Installations

StorageOS offers a public discovery service, which is a convenient way to pass clustering information to the StorageOS node.

# Create a cluster discovery token. This token is not used after initialization
$ storageos cluster create

# Add the returned cluster ID token to the JOIN variable

Alternatively, you can specify the IP addresses of nodes to join. If you provide a list of node IPs any new node joining the cluster will attempt to contact the node IPs specified. This means that if all the nodes in the JOIN are unavailable that new nodes will be unable to join the cluster.

# Specify a node to connect to in an existing cluster

# Specify a list of nodes to attempt to connect to, in left-to-right order

# Specify both the discovery service and IP addresses, tried left-to-right

The JOIN command line argument is always required, even in clusters with only one node. A blank JOIN variable will result in a non-functional cluster. This is to prevent non-obvious split-brain scenarios in multi-node clusters, where JOIN was mistakenly omitted.

# Create a one-node cluster; note that replicas are unavailable.