Perform Host Maintenance

These steps show how you can perform maintenance actions on hosts without first deleting the associated runner from your Elastic Cloud Enterprise installation. The runner remains a part of your ECE installation throughout these steps but will be offline and the resources it provides will not be available.

You might need to perform host maintenance for one of several reasons:

  • To apply urgent operating system patches or hot fixes
  • To perform regularly scheduled software or hardware upgrades

To perform host maintenance:

  1. Recommended: If the runner holds the allocator role and you have enough spare capacity:

    1. Enable maintenance mode on the allocator.
    2. Move all nodes off the allocator and to other allocators in your installation. Moving all nodes lets you retain the same level of redundancy for highly available clusters and ensures that other clusters without high availability remain available.
    Important

    Skipping Step 1 will affect the availability of clusters with nodes on the allocator. Skip at your own risk.

  2. Disable the Docker daemon:

    • On Ubuntu 14.04:

      sudo service docker stop
    • On Ubuntu 16.04, RHEL 7, and CentOS 7:

      sudo systemctl disable docker
  3. Reboot the host:

    sudo reboot
  4. Perform your maintenance on the host, such as patching the operating system.
  5. Enable the Docker daemon:

    • On Ubuntu 14.04:

      sudo service docker restart
    • On Ubuntu 16.04, RHEL 7, and CentOS 7:

      sudo systemctl enable docker
  6. Reboot the host again:

    sudo reboot
  7. If you enabled maintenance mode in Step 1: Take the allocator out of maintenance mode.

    Tip

    ECE will start using the allocator again as you create new or change existing clusters, but it will not automatically redistribute nodes to an allocator after it becomes available. If you want to move nodes back to the same allocator after host maintenance, you need to manually move the nodes and specify the allocator as a target.

  8. Verify that all ECE services and clusters are back up by checking that the runner shows a green status in the Cloud UI.

After the runner shows a green status in the Cloud UI, it is fully functional again and can be used as before.