Starting an Ozone Cluster

Before we boot up the Ozone cluster, we need to initialize both SCM and Ozone Manager.

ozone scm --init

This allows SCM to create the cluster Identity and initialize its state. The init command is similar to Namenode format. Init command is executed only once, that allows SCM to create all the required on-disk structures to work correctly.

ozone --daemon start scm

Once we know SCM is up and running, we can create an Object Store for our use. This is done by running the following command.

ozone om --init

Once Ozone manager has created the Object Store, we are ready to run the name services.

ozone --daemon start om

At this point Ozone’s name services, the Ozone manager, and the block service SCM is both running. Please note: If SCM is not running om --init command will fail. SCM start will fail if on-disk data structures are missing. So please make sure you have done both scm --init and om --init commands.

Now we need to start the data nodes. Please run the following command on each datanode.

ozone --daemon start datanode

At this point SCM, Ozone Manager and data nodes are up and running.

Congratulations!, You have set up a functional ozone cluster.

If you want to make your life simpler, you can just run

ozone scm --init
ozone om --init
start-ozone.sh

This assumes that you have set up the slaves file correctly and ssh configuration that allows ssh-ing to all data nodes. This is the same as the HDFS configuration, so please refer to HDFS documentation on how to set this up.