This is a good question and to be honest, i really not sure what will happen as we never tested such scenario in which the IPs of the hosts has been changed, but the original hostname don't.

Alona, dan, can you please share your insights here?

Thanks,

On Wed, Sep 27, 2017 at 5:48 PM, Gianluca Cecchi <gianluca.cecchi@gmail.com> wrote:
On Wed, Sep 27, 2017 at 4:25 PM, Michael Burman <mburman@redhat.com> wrote:
Hello Gianluca,

Not sure i fully understood, but, if the host's IP has changes and the vlan then the correct flow will be:

1) Remove the host
2) Edit the management network with vlan tag - the vlan you need/want
3) Add/install the host - make sure you using the correct/new IP(if using IP) or the correct FQDN(if has changed).

Note that doing things manually on the host such as changing ovirtmgmt's configuration without the engine or vdsm may cause problems and will not persist the changes during reboots. If the host's IP has changed or it's FQDN then you must install the host again.

Cheers)

Original situation was:

1 DC
1 Cluster: CLA with 2 hosts: host1 and host2
ovirtmgmt defined on vlan10

engine is an external server on VLAN5 that can reach VLAN10 of hosts
So far so good

Need to add another host that is in another physical server room. Here VLAN10 is not present, so I cannot set ovirtmgmt
If I understand correctly, the VLAN assigned to ovirtmgmt is a DC property: I cannot have different vlans assigned to ovirtmgmt in different clusters of the same DC, correct?

So the path:
Create a second cluster CLB and define on it the logical network ovirtmgmt2 on VLAN20 and set it as the mgmt network for that cluster
Add the new host host3 to CLB.

So far so good: the engine on VLAN5 is able to manage the hosts of CLA ad CLB with their mgmt networks in VLAN10 and VLAN20

Now it is decided to create a new VLAN30 that is transportable across the the 2 physical locations and to have host1, host2, host3 to be part of a new CLC cluster where the mgmt network is now on VLAN30

Can I simplify operations, as many VMs are already in place in CLA and CLB?
So the question arises:

the 3 hosts were added originally using their dns hostname and not their IP address.
Can I change my dns settings so that the engine resolves the hostnames with the new IPs and change vlan of ovirtmgmt?

And if I decide to start from scratch with this new cluster CLC on VLAN30, can I retain my old 3 hostnames (resolving to their new IPs)? How?

Hope I was able to clarify a bit the scenario

Gianluca  






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Michael Burman

Quality engineer - rhv network - redhat israel

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