[Linux-cluster] question about failoverdomains

[Digimer]

On 07/14/2011 11:42 AM, Budai Laszlo wrote:
> Hi all,
> 
> Please somebody tell me what is the behavior for the following
> failoverdomains configuration:
> 
> <failoverdomains>
>   <failoverdomain name="dom1" ordered="0" restricted="0">
>       <failoverdomainnode name="pnl-p" priority="1"/>
>    </failoverdomain>
>    <failoverdomain name="dom2">
>       <failoverdomainnode name="psd-p" priority="1"/>
>    </failoverdomain>
> </failoverdomains>
> 
> 
> This is a two node cluster. the idea is to create a configuration where
> some of the services prefer to run on one node, and other on the other node.
> For this I would have created two prioritized failover domains with the
> priorities set in such a way that in one domain the one node has higher
> priority than the other.
> 
> My question related to this setup is:
> if a node fails (let suppose pnl-p fails) then the services which are
> configured to use dom1 will migrate to node psd-p. What will happen when
> the node recovers? will that service fail back to that node?
> 
> Thank you,
> Laszlo

These two domains will not offer failover. The domain contains only one
node, so any services set to use either domain will only run on that
given node. This is useful the cluster to starting local service (ie:
clvmd, gfs2, etc).

To get an ordered domain, define both nodes within a given domain, set
'ordered="1"' and then set different 'priority="<int>"'. The node with
the lower priority will be the "preferred node" and the other will be
the fall-back.

Pay attention to the "nofailback" option as well.

See: https://fedorahosted.org/cluster/wiki/RGManager

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