hadoop/hadoop-hdds/docs/content/RealCluster.md

---
title: Starting an Ozone Cluster
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   main:
      parent: Starting
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---
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Before we boot up the Ozone cluster, we need to initialize both SCM and Ozone Manager.

{{< highlight bash >}}
ozone scm --init
{{< /highlight >}}
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.
{{< highlight bash >}}
ozone --daemon start scm
{{< /highlight >}}

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.

{{< highlight bash >}}
ozone om --init
{{< /highlight >}}


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

{{< highlight bash >}}
ozone --daemon start om
{{< /highlight >}}

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.
{{< highlight bash >}}
ozone --daemon start datanode
{{< /highlight >}}

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
{{< highlight bash >}}
ozone scm --init
ozone om --init
start-ozone.sh
{{< /highlight >}}
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.