Migrating to HA Components

Apcera Platform Enterprise Edition release 2.2.x and 2.4.x update several components for high-availability. For existing clusters, to take advantage of these component upgrades, you must migrate the Orchestrator-managed Apcera component from a single server (usually on the "singleton" or "spof" host) to a redundant n-wise scaled service on 1 or more "central" hosts. See the sizing guidelines for details.

Migration procedure

  1. Prerequisites:

  2. Update cluster config for the first migration deploy:

    Make the tag suitable on the "central" hosts where scaled components live.
    - Examine the “suitable_tags” list for the "spof" server and/or "singelton" server to determine the tag for the service.
    - Copy this tag to the “suitable_tags” list for the “central” server. (DO NOT remove the tag yet.)

    • Update the number of hosts the component should run on from one to central-clustered-host-count + 1.
      • This will cause the component to be scaled to all the central hosts, and leave the spof instance in place.
  3. First deploy:

    • Dry run a deploy, verify its doing what you expect:
      - The graph should show the tag being added to all of the central host.
      - The graph should NOT show the tag being removed from the spof or singelton hosts.
    • Run the deploy
    • When done the component should exist both on the spof/singleton host and on all the central hosts.
  4. Update the cluster config for the second migration deploy:
    • Remove the tag from “suitable_tags” list for the spof/singelton host
    • Reduced the deployed number by 1.
  5. Second deploy:

    • Dry run a deploy.
      • Use the graph to verify that Orchestrator will remove the tag from the spof/singeton host.
    • Run the deploy.
    • Verify the component now only exists on the central hosts.
      • It should no longer be installed or running on the spof/singelton server.
  6. Third deploy:

    • A third deploy will be required, with no configuration change, to remove the ​monitoring​ of the component that was removed in the second deploy.