Upgrade a Multiple Server Environment

This document provides high level processes for upgrading a multiple-server environment, in support of the recent addition of the latest generation AWS instance types such as M3s, C3s and C4s. These processes support upgrades from:

  • Engine Yard Gentoo 2009 to 2009 (stable-v2 to stable-v2)
  • Engine Yard Gentoo 12.11 to 12.11 (stable-v4 to stable-v4)

... for these instance types:

  • AWS M3
  • AWS C3
  • AWS C4

Tip: Use the tools and documentation (which are linked-to in the process steps) to save time.

This document includes these sections:

  • Multiple-server environment upgrade using promotion tools
  • FAQs
  • Troubleshooting
  • More information

Multiple-server environment upgrade using promotion tools

This is a relatively easy, medium-downtime method to upgrade a multi-server environment's instance types using application and database promotion tools.

To upgrade your application's instance types

  1. Check the environment status:

    • Ensure that you have good backups for your environment.
    • Check the environment's app takeover preference configuration setting to be sure it is set to Boot from snapshot.
  2. Review the upgrade information page.

    Check the stack version. If the stack release is:

    • Far behind (i.e., more than a few weeks), be sure and test in a cloned staging environment before you continue upgrading.
    • Not up to date, upgrade the environment's stack release.
    • Up to date, then you can upgrade in place (continue with the steps below).
  3. Add an application slave with the instance type and size you need.
  4. Promote the app slave to app master.
  5. Add a database replica with the instance type and size you need.
  6. Promote the database replica to database master.

    (You will enable the maintenance page as a part of the database promotion process.)

  7. Add utility instances as needed, with the instance types and sizes you need. Migrate as required:
    • Utility data
    • Utility services
  8. Verify that your application is working as expected.

FAQs

You might have these questions about upgrades.

Do I need to do all this for weekly cookbook / stack upgrades?

No; minor weekly upgrades have the same upgrade process as usual: Click Upgrade on your environment.

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