dlmarion commented on code in PR #456: URL: https://github.com/apache/accumulo-website/pull/456#discussion_r2052822986
########## _docs-2/administration/upgrading.md: ########## @@ -4,6 +4,48 @@ category: administration order: 7 --- +## Changes to the upgrade process + +In upgrade notes for prior releases we have advised that users should ensure that no FATE +transactions exist (see `Upgrading from 1.10 or 2.0 to 2.1` below). This is due to the +fact that the internal serialization of FATE transactions is not guaranteed to be +compatible between versions. Accumulo never provided any tooling around the upgrade process +and left it up the user, which can cause problems if older versions of FATE transactions +exist and the user already deployed the new version of software. The user would have to +re-install the old version of software to remove the FATE transactions. + +Starting with Accumulo 4.0 we are modifying the upgrade process steps in an attempt to +make it easier for the user to validate their instance is ready for upgrade. In earlier +versions the upgrade process would start when the user started the instance with the +new version of software. The process ran entirely in the Manager and it was the users +responsibility to read the upgrade notes to perform any necessary pre-upgrade steps. + +The new upgrade process introduces a new `accumulo upgrade` command which will be used +after shutting down the instance with the old version of software and before starting +the instance with the new version of software. The `upgrade` command has two options, +`--prepare` and `--start`. `--prepare` is designed to be executed by the user after shutting +down the instance. This option will check that the Manager is down, validate that there +are no existing FATE transactions, remove all of the server locks in ZooKeeper, and place +a node in ZooKeeper that will prevent server processes from being started again. If there Review Comment: The node created by `--prepare` just prevents the server processes from starting. If the user decides to abort the upgrade, then they can manually delete this node. These instructions are provided if there are fate transactions. I point this out to say that completing the upgrade is not necessarily the only way to start the server processes again. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: notifications-unsubscr...@accumulo.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
