[ovirt-users] I broke my ovirt real good....

[Alexander Wels]

On Thursday, April 12, 2018 6:26:07 PM EDT ~Stack~ wrote:
> Greetings,
> 
> So I did a over-confident-admin-makes-rookie-mistake. I changed a bunch
> of things all back-to-back and thus don't actually know what broke. :-D
> 
> The only two real "big" changes were:
> * Upgrade from 4.2.1 to 4.2.2
> * change my ovirtmgmt network
> 
> The update I followed the upgrade procedures and I thought it all went
> pretty well. Because I am moving it from a testing into what I hope will
> be a more heavily used environment, I changed my ovirtmgmt network from
> 192.168.100.0/24 to 192.168.101.0/24 via the web-gui.
> 
> That was a touch tricker than just a change as I had to poke the
> management engine host to be reachable on both network for a while, then
> it just seemed OK.
> 
> What's happening is:
> * I can no longer migrate a vm from one host to the other.
> * If I try to do a "reinstall" it dies.
> * There is some serious network lag between my hosts on a 10Gb network.
> * I've got all kinds of python2.4 failures in my vdsm and mom logs.
> 
> Those are least the biggies.
> 
> So while I was planning on moving this to a more active use case, right
> now - it is all still my play ground. I would REALLY hate to lose the
> VM's but everything else can go and be rebuilt.
> 
> Given that I've somehow really broke this system pretty good, would it
> be more advisable to blow away and rebuild it ALL or can I simply delete
> the hypervisor hosts and rebuild them?
> 
> Thoughts?
> 
> Thanks!
> ~Stack~

As long as you don't destroy the data on your data domain you can rebuild the 
engine and hosts and then import the existing data domain without too many 
issues. I have destroyed my engine database many times, and I am still using 
the same VMs from the same data domain.

Here is what I do when I mess up my database to the point I have to make a new 
one:

1. Recreate the engine and database, so that I have basically have an empty 
engine with no hosts and VMs.
1.1 (Optional) make a new DC that is not default. and add a cluster.
2. Add my hosts (I only have 2 so that is quick and easy).
3. Add a throw away data domain (This is needed to get the DC up so I can 
import the existing data domain).
4. Import (NOT new, import) the existing data domain.
5. Do to Storage->Storage Domains->VM import and import the VMs I want.
6. Same for templates and disks if needed.
7. After you have imported the VMs/Templates/Disks you can detach and remove 
the throw away data domain and the one you imported becomes the master domain.

Note if you want to move VMs between your play ground and more serious system 
you can simply detach your data domain from the play ground, then attach it to 
the serious engine (so you have 2 engines, one play ground and one serious) 
and import which VMs you want. That way you won't run into issues with 
configuring networks and stuff like you experienced.