[Users] engine-backup --restore (was: Problems accesing the database)

[Yedidyah Bar David]

----- Original Message -----
> From: "Juan Pablo Lorier" <jplorier at gmail.com>
> To: "Yedidyah Bar David" <didi at redhat.com>
> Cc: "Sahina Bose" <sabose at redhat.com>, "users" <users at ovirt.org>
> Sent: Wednesday, February 12, 2014 7:55:35 PM
> Subject: Re: [Users] Problems accesing the database
> 
> Hi Yedidyah,
> 
> But If I run engine-setup and then engine-backup restore shuldn't it
> import the data to the existing db created by engine-setup?
> That's shown everywhere so I thought it's a valid way to migrate

No.

There is a specific case in which this works automatically:
All on the same host:
1. engine-setup
2. engine-backup --mode=backup
(perhaps do other stuff here)
3. engine-cleanup
4. engine-backup --mode=restore

Why does this work? Because 'engine-cleanup', since 3.3, does not drop
the database nor user inside postgres. So when restore tries to access
this database using this user and password it succeeds.

In general, if you do the restore on another machine, and do there
'engine-setup; engine-cleanup' as a quick-postgres-provisioning-tool,
you end up almost ready, but not quite - because the password is random,
and therefore different between the installations. In principle you could
have provided just the password to restore, but we decided that if you
need to change the credentials, you should pass all of them (except for
defaults).

Hope this clarifies,
-- 
Didi