Migrating an existing installation to hosted engine

[Yedidyah Bar David]

Hi all,

A message with the same subject was sent to arch around a month ago, see [1].

In short, it suggested two approaches:
1. Use p2v (or v2v)
2. Clean install of OS/engine software and use backup/restore.

Following that, I pushed a few changes for engine-backup and engine-setup,
with the intention of doing, briefly:
1. hosted-engine --deploy on new host
2. Install OS/software on new vm
3. backup on old engine machine
4. On new vm, do restore, which only restores the database and files,
followed by engine-setup, which will fix whatever else needs to be fixed.

Some of the changes are still pending, and are under some controversy. See
[2], [3], [4].

A more detailed description of the suggested migration path is in [5].

What do you think?

Should engine-setup do as little as possible to the system, or as much as
needed to save the admin from any manual work?

Should engine-setup doing an upgrade do the same as a new setup, or just
whatever that's needed to adapt the config/database to the new code?

A specific example: if admin chose during initial setup to automatically
configure the firewall (iptables/firewalld), should upgrade update it again,
or not touch it?

Should engine-backup do all these things when doing a restore?

Should we have some other utility to do these things?

Should we merely document them and let the admin do this manually?

[1] http://lists.ovirt.org/pipermail/arch/2013-October/001677.html
[2] https://bugzilla.redhat.com/1024707
[3] http://gerrit.ovirt.org/20736
[4] http://gerrit.ovirt.org/20737
[5] http://www.ovirt.org/Migrate_to_Hosted_Engine
-- 
Didi