[debian-mysql] ndbd upgrade question

[Monty Taylor]

Hey guys,

So not all versions of ndbd support upgrading in place. Each release
essentially has a list of zero or more previous versions from which an
upgrade is safe. So I think we need to do something to block an upgrade
attempt until the admin has either had a chance to back things up and/or
tell us somehow that it's ok to upgrade - you know a chance to backup
the data if necessary. If the admin is running cluster as part of a
multi-node cluster, then the upgrade can still work without a backup if
he restarts the upgraded node with --initial to cause it to get data
from the running node.

I'm not sure that all of this can be handled automatically, but I
imagine we want to prevent installing software that then won't start. (I
just did this to myself last night)

Thoughts on a mechanism for doing this? I'm guessing something in a
preinst script. Checking the version compatability is easy, but I'm not
sure the "right" way for an admin to tell us it's ok to go ahead and
upgrade to an incompatible version.

Monty