What: The Linux Foundation will be upgrading Gerrit to the latest stable
release (3.1.x)

When: Saturday February 29, 2020 @ 13:00 - 16:30 UTC (05:00 - 08:30 PT)

Why: We've been testing the latest version of Gerrit on the LF system
for over 2 months now. We are reasonably confident that there will be no
degradation in system performance. However, ODL is one of our largest
Gerrit instances and you have a history of helping us work out the
wrinkles in our large deployment scenarios so you've targeted as our
next upgrade target.

Impact: Gerrit will be offline for all or part of the window as we do
the following:

* Convert the remaining database to NoteDB
* Upgrade to Gerrit 3.0.x
* Upgrade to Gerrit 3.1.x
* Rebuild all indexes

Jenkins will be put into shutdown mode prior to this and jobs will
either be stopped if they will complete in the middle of the window or
allowed to finish if they can complete before we take Gerrit offline.

What will people see with the change:

* The "old" Gerrit UI will no longer be available, it has been
deprecated since Gerrit 2.14 and 2.15 made the new UI the default. With
Gerrit 3 the old "GWT" UI is not available at all

* The use of refs/publish no longer works, if you are using a git-review
that is older than 1.28 you must upgrade or git-review will stop working
for you

* Git protocol v2 is now supported by Gerrit

* The transition to NoteDB means that _all_ comments, votes, and other
metadata that was previously stored in the DB are now available to
people to look at directly themselves as they will be stored in magic
refs inside the repo.

* NoteDB brings in the following new features:
- "hashtags" aka extra topics
- patchset descriptions

* We will be enabling _full_ replication to GitHub of all refs instead
of just the merged refs. This will mean that the GitHub replicas will
become 100% full backups of not just the merged code, but all proposed
changes along with the comments and voting, making it possible for
someone to pull a mirror clone from GitHub (or our Gerrit) and insert it
into a private Gerrit to inspect. A note on this, while we'll be
enabling this, it may take a day or two before the full replication
finishes as we're talking many thousands of new refs that have to stream
out to GitHub. For those concerned that this may become a privacy leak,
it is no more so than what already exists with the public repositories.
We will continue to _not_ replicate the All-Projects or All-Users
repositories.

For those wishing to follow the progress of the maintenance you may
subscribe to the status page about it here [0]

-Andy-

[0] https://status.linuxfoundation.org/incidents/8t8qhtt52bdt