I just tested adding a Centos 6.6 and Centos 7 host on a oVirt Cluster and it is not possible:

Not possible to mix RHEL 6.x and 7.x hosts in one cluster. Tried adding RHEL - 6 - 7.el6.centos.12.3 host to a cluster with RHEL - 7 - 1.1503.el7.centos.2.8 hosts.

Using the same data storage for multiple Clusters seems possible.

Thanks for all the help today,

Regards,
Paul

Op do 12 nov. 2015 om 10:52 schreef Paul Groeneweg | Pazion <paul@pazion.nl>:
Hmm, that would be a pity, then I also need a second shared storage.

Anyone tested mixed el6 and el7 cluster on 3.5.5 or 3.6 ?

Met vriendelijke groeten,
Paul Groeneweg


Op do 12 nov. 2015 om 10:48 schreef Gianluca Cecchi <gianluca.cecchi@gmail.com>:
On Thu, Nov 12, 2015 at 10:44 AM, Gianluca Cecchi <gianluca.cecchi@gmail.com> wrote:
On Thu, Nov 12, 2015 at 10:40 AM, Paul Groeneweg | Pazion <paul@pazion.nl> wrote:
OK, I understand, I would need to upgrade my Hosts to go to 3.6.

I think I read somewhere I can't mix EL6 and EL7 hosts in the same cluster, is this true?


You can have a mix of EL6 and EL7 hosts with 3.5 cluster compatibility in place.
But you have to notice that you can do live migrations in direction EL6 --> EL7 but not the reverse.
SO you have to care about this for your migration strategy.
Probably bettere to update at least two hosts to EL7 before beginning to place critical VMs on them.
HIH,
Gianluca 

Opsss, perhaps I'm wro and you have to create a different cluster in the same datacenter and progressively migrate VMs from hosts in first cluster to hosts in second cluster.
At least so it was in 3.5.1.... did it change?

See 
http://lists.ovirt.org/pipermail/users/2015-May/032818.html
and bugzilla
https://bugzilla.redhat.com/show_bug.cgi?id=1150191
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Pazion
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