Cluster metadata

Dataproc sets special metadata values for the instances that run in your cluster:

Metadata key	Value
`dataproc-bucket`	Name of the cluster's staging bucket
`dataproc-region`	Region of the cluster's endpoint
`dataproc-worker-count`	Number of worker nodes in the cluster. The value is `0` for single node clusters.
`dataproc-cluster-name`	Name of the cluster
`dataproc-cluster-uuid`	UUID of the cluster
`dataproc-role`	Instance's role, either `Master` or `Worker`
`dataproc-master`	Hostname of the first master node. The value is either `[CLUSTER_NAME]-m` in a standard or single node cluster, or `[CLUSTER_NAME]-m-0` in a high-availability cluster, where `[CLUSTER_NAME]` is the name of your cluster.
`dataproc-master-additional`	Comma-separated list of hostnames for the additional master nodes in a high-availability cluster, for example, `[CLUSTER_NAME]-m-1,[CLUSTER_NAME]-m-2` in a cluster that has 3 master nodes.

You can use these values to customize the behavior of initialization actions.

You can also use the --metadata flag of the gcloud dataproc clusters create command in the gcloud CLI to provide your own custom metadata:

gcloud dataproc clusters create cluster-name \
    --region=region \
    --metadata=name1=value1,name2=value2... \
    ... other flags ...