Since Hawkular is still primarily in development mode upgrading dependencies, including databases, is fairly painless. Metrics 0.8.0 however was included in OpenShift 3.1, which means upgrading Cassandra in Metrics is going to be more involved than upgrading the parent pom and upgrading our dev environments, e.g., changing ccm cluster. The following is a brief description of the steps that need to be performed,


  1. Run nodetool drain
  2. Shut down the node
  3. Back up configuration and data files
  4. Install new version of Cassandra
  5. Apply configuration changes (from old version) to new version. This would include files like cassandra.yaml, cassandra-env.sh, etc.
  6. Start the node
  7. Run nodetool upgradesstables
  8. Repeat for each node in the cluster

These steps can be performed as a rolling upgrade; however, no application schema changes should be made until the upgrade is complete and until cluster reports schema agreement.

With respect to OpenShift, how much of this needs to be automated? Matt, can you share some insights here? I would like to figure out sooner rather than later how much work we think is involved.

Thanks

- John