C Sébastien Han

Stacker! Cepher! What's next?

Use Ansible to Configure Containers

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Typically, when we build a container image we have 2 main files:

  • Dockerfile is the essence of the container, it is what the container is made of, it generally contains packages installation steps and files
  • entrypoint.sh is where we configure the container, during the bootstrap sequence this script will get executed. Usually the entrypoint.sh file contains bash instructions.

So the idea is, instead of relying on bash scripting when writing container’s entrypoint we could call an Ansible to configure it.

Ceph: Properly Remove an OSD

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Sometimes removing OSD, if not done properly can result in double rebalancing. The best practice to remove an OSD involves changing the crush weight to 0.0 as first step.

Ceph Is Moving Outside DevStack Core to a Plugin

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Ceph just moved outside of DevStack in order to comply with the new DevStack’s plugin policy. The code can be found on github. We now have the chance to be on OpenStack Gerrit as well and thus brings all the good things from the OpenStack infra (a CI).

To use it simply create a localrc file with the following:

enable_plugin ceph https://github.com/openstack/devstack-plugin-ceph

A more complete localrc file can be found on Github.

Ceph: Find an OSD Location and Restart It

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When you manage a large cluster, you do not always know where your OSD are located. Sometimes you have issues with PG such as unclean or with OSDs such as slow requests. While looking at your ceph health details you only see where the PGs are acting or on which OSD you have slow requests. Given that you might have tons of OSDs located on a lot of node, it is not straightforward to find and restart them.