[Pacemaker] Two node cluster and no hardware device for stonith.

Dejan Muhamedagic dejanmm at fastmail.fm
Fri Feb 6 15:15:44 UTC 2015


Hi,

On Thu, Feb 05, 2015 at 09:18:50AM +0100, Digimer wrote:
> That is the problem that makes geo-clustering very hard to nearly
> impossible. You can look at the Booth option for pacemaker, but that
> requires two (or more) full clusters, plus an arbitrator 3rd

A full cluster can consist of one node only. Hence, it is
possible to have a kind of stretch two-node [multi-site] cluster
based on tickets and managed by booth.

Thanks,

Dejan

> location. Outside of this though, there really is no way to have
> geo/stretch clustering with automatic failover.
> 
> digimer
> 
> On 05/02/15 03:38 AM, Dmitry Koterov wrote:
> >Could you please give a hint: how to use fencing in case the nodes are
> >all in different geo-distributed datacenters? How people do that?
> >Because there could be a network disconnection between datacenters, and
> >we have no chance to send a stonith signal somewhere.
> >
> >On Wednesday, February 4, 2015, Andrea <a.bacchi at codices.com
> ><mailto:a.bacchi at codices.com>> wrote:
> >
> >    Digimer <lists at ...> writes:
> >
> >     >
> >     > That fence failed until the network came back makes your fence method
> >     > less than ideal. Will it eventually fence with the network still
> >    failed?
> >     >
> >     > Most importantly though; Cluster resources blocked while the
> >    fence was
> >     > pending? If so, then your cluster is safe, and that is the most
> >     > important part.
> >     >
> >    Hi Digimer
> >
> >    I'm using for fencing a remote NAS, attached via iscsi target.
> >    During network failure, for example on node2, each node try to fence
> >    other node.
> >    Fencing action on node1 get success, but on node2 fail, because it
> >    can't see
> >    iscsi target(network is down!) .
> >    I thinks it's the reason why node2 doesn't reboot now, because it
> >    can't make
> >    operation on key reservation and watchdog can't check for this.
> >    When network come back, watchdog can check for key registration and
> >    reboot
> >    node2.
> >
> >    For clustered filesystem I planned to use ping resource with location
> >    constraint as described here
> >    http://clusterlabs.org/doc/en-US/Pacemaker/1.0/html/Pacemaker_Explained/ch09s03s03s02.html
> >    If the node can't see iscsi target..then..stop AppServer, Filesystem ecc
> >
> >    But it doesn't works. In the node with network failure i see in the
> >    log that
> >    pingd is set to 0 but Filesystem resource doesn't stop.
> >
> >    I will continue testing...
> >
> >    Thanks
> >    Andrea
> >
> >
> >
> >
> >
> >
> >    _______________________________________________
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> >
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> >
> >
> >
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> >
> >Project Home: http://www.clusterlabs.org
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> >
> 
> 
> -- 
> Digimer
> Papers and Projects: https://alteeve.ca/w/
> What if the cure for cancer is trapped in the mind of a person
> without access to education?
> 
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