Upgrading from 0.8.2.1 to 0.9.0

First, read CHANGELOG.md to get familiar with the new release.

You must read the entirety of this document before starting the upgrade.

Check replication status

During the upgrade CockroachDB will be running with one less node than usual. Check now to make sure you have enough nodes in your pool to carry out the upgrade and maintain availability.

Pick a lead node

Pick one of your Hot Potato nodes to ‘lead’ the upgrade. This node will carry out database migrations while the other nodes respond to notifications on the old version.

Copy the database

On your lead node create a copy of your database to do the upgrade on. See the cockroach docs for how to do this.

Upgrade host and/or python version

If Hot Potato was running on Xenial, now is an ideal time to upgrade to Bionic. Hot Potato 0.9.0 moves the officially supported Python version to 3.6. Alternatively you can use unofficial builds or backports if an upgrade is not feasible.

Upgrade the lead node

  1. Stop Hot Potato on your lead node.

  2. Deploy the new Hot Potato code.

  3. Update dependencies with Pipenv.

    $ pipenv sync

  4. Update the configuration file to point at the correct (to upgrade) database

  5. Add method and provider settings to the config:

    [MODICA]
ENABLED = true
...

[TWILIO]
ENABLED = true
...

[PUSHOVER]
ENABLED = true
...

[SMS]
ENABLED = true

[PAGER]
ENABLED = true

[APP]
ENABLED = true

  6. Update the database URL in the config file:

    Before:

    [SQLALCHEMY]
DATABASE_URI=cockroachdb://user:pass@server:port/database

    After:

    [COCKROACH]
SERVER=server
PORT=port
DATABASE=database
USERNAME=user
PASSWORD=pass

  7. Install npm

  8. In theme/ run npm install --production to install front-end dependencies

  9. In theme/ run NODE_ENV=production npm run build to build front-end dependencies

  10. Run migrations:

    $ FLASK_APP=app/app.py flask db upgrade

    This may take a long time depending on the size of your database.

  11. Check the migration succeeded, and the database is in a good state

  12. Stop Hot Potato (NOT CockroachDB) on all other nodes and start Hot Potato on the lead node. Consider using Anycast to eliminate service unavailability during this period.

Upgrade all other nodes

  1. Stop Hot Potato

  2. Check out the new code

  3. Update dependencies with Pipenv

  4. Update the configuration file

  5. Install npm and build the front-end dependencies

  6. Start Hot Potato

Catch up the database

If necessary, update the new database with changes made during the upgrade. Currently this must be done manually.