Upgrade best practices

The following list outlines recommended best practices for upgrading high-availability Control Center deployments:

  1. Download a copy of the Control Center Release Notes for this release and review its contents. The latest information is included in that document.
  2. Upgrade only what needs upgrading. For example, you can update some components independently. For more information, see the following appendices:
  3. Compare the Docker images that accompany this release with the images that accompany the installed release, and determine whether the image files need to be downloaded and installed. For more information, see Releases and image tags.
  4. The contents of /etc/default/serviced on the master nodes must be identical. Use a utility like sum to compare the files quickly.
  5. On delegate hosts, most of the upgrade steps are identical. Use screen, tmux, or a similar program to establish sessions on each delegate host and perform the steps at the same time.
  6. Review and verify the settings in delegate host configuration files (/etc/default/serviced) before starting the upgrade. Ideally, the settings on all delegate hosts are identical, except on ZooKeeper nodes and delegate hosts that do not mount the DFS.
  7. Review the procedures in this guide before performing them. Every effort is made to avoid mistakes and anticipate needs; nevertheless, the instructions may be incorrect or inadequate for some requirements or environments.
  8. Download and stage the required files for your upgrade. For more information, see Downloading and staging required files.