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Put stuff here that we have to remember when we start packaging up Teak.  Especially important is information that system installers or operators will need to know. Please include your name when you add an item, so that we can get back to you with questions.

Operational

• In LMS and CMS, Celery now uses task protocol 2. (Tim McCormack)

  • Action: Any operator using custom Celery tooling should ensure it is compatible with protocol 2. For other operators, no action is required.

  • Background: Celery 4.0 switched how task messages are structured and the new message format is called protocol 2. The version of Celery we currently use (anything >=4.0) can create and consume both protocol versions and it should be safe to switch between them with zero downtime.

    • By default, Celery 4.0 and higher produce messages in this format, and Celery 3.1.25 and higher can read messages in this format.

    • edx-platform was pinned to protocol 1 during the upgrade to Celery 4, presumably as a precaution. This change is the long-delayed unpinning of the protocol version so that Celery can use its default version.

    • Operators can still override the protocol version using the Django setting CELERY_TASK_PROTOCOL although there is no guarantee that protocol 1 compatibility will be preserved in the future.

Deprecations and Removals

• https://github.com/openedx/public-engineering/issues/32 (Feanil Patel)

  • This is a simplification to how course content is cached. It should be invisible to all end users.

  • Some operators may need to run a management command to re-populate the cache:

    • ./manage.py lms generate_course_blocks --all_courses --settings=devstackproduction