Re-provisioning the cluster
=============================

In the event that an existing Omnia cluster needs a different OS version or a fresh installation, the cluster can be re-provisioned.

**Prerequisite**

* Run the `delete node playbook <deletenode.html#delete-provisioned-node>`_ for every target node.

.. note:: If a re-deployment with no modifications is required, execute the following commands:
    ::
        cd omnia
        ansible-playbook discovery_provision.yml

**Setting up the cluster**

* Insert the new IPs in the existing inventory file as shown below:

*Existing kubernetes inventory*

::

    [kube_control_plane]
    10.5.0.101

    [kube_node]
    10.5.0.102
    10.5.0.103

    [auth_server]
    10.5.0.101

    [etcd]
    10.5.0.110



*Updated kubernetes inventory with the new node information*

::

    [kube_control_plane]
    10.5.0.101

    [kube_node]
    10.5.0.102
    10.5.0.103
    10.5.0.105
    10.5.0.106

    [auth_server]
    10.5.0.101

    [etcd]
    10.5.0.110

*Existing Slurm inventory*

::

    [slurm_control_node]
    10.5.0.101

    [slurm_node]
    10.5.0.102
    10.5.0.103

    [login]
    10.5.0.104

    [auth_server]
    10.5.0.101


*Updated Slurm inventory with the new node information*

::

    [slurm_control_node]
    10.5.0.101

    [slurm_node]
    10.5.0.102
    10.5.0.103
    10.5.0.105
    10.5.0.106

    [login]
    10.5.0.104

    [auth_server]
    10.5.0.101

In the above examples, nodes 10.5.0.105 and 10.5.0.106 have been added to the cluster as compute nodes.

.. note::
    * Do not change the ``kube_control_plane``, ``slurm_control_node`` and/or ``auth_server`` in the existing inventory file. Simply add the new node information in the ``kube_node`` and/or ``slurm_node`` group.
    * When re-running ``omnia.yml`` to add a new node, ensure that the ``input/security_config.yml`` and ``input/omnia_config.yml`` are not edited between runs.

* To install security, job scheduler, and storage tools (NFS, BeeGFS) on the node, run ``omnia.yml``: ::

    ansible-playbook omnia.yml -i inventory