On Oct 28, 2010, at 2:53 AM, Dan Frincu wrote:
> Hi,
>
> Andreas Ntaflos wrote:
>>
>> Hi,
>>
>> first time poster, short time Pacemaker user. I don't think this is a
>> very difficult question to answer but I seem to be feeding Google the
>> wrong search terms. I am using Pacemaker 1.0.8 and Corosync 1.2.0 on
>> Ubuntu 10.04.1 Server.
>>
>> Short version: How do I configure multiple independent two-node clusters
>> where the nodes are all on the same subnet? Only the two nodes that form
>> the cluster should see that cluster's resources and not any other.
>>
>> Is this possible? Where should I look for more and detailed information?
>>
> You need to specify different multicast sockets for this to work. Under the
> /etc/corosync/corosync.conf you have the interface statements. Even if all
> servers are in the same subnet, you can "split them apart" by defining unique
> multicast sockets.
> An example should be useful. Let's say that you have only one interface
> statement in the corosync file.
> interface {
> ringnumber: 0
> bindnetaddr: 192.168.1.0
> mcastaddr: 239.192.168.1
> mcastport: 5405
> }
> The multicast socket in this case is 239.192.168.1:5405. All nodes that
> should be in the same cluster should use the same multicast socket. In your
> case, the first two nodes should use the same multicast socket. How about the
> other two nodes? Use another unique multicast socket.
> interface {
> ringnumber: 0
> bindnetaddr: 192.168.1.0
> mcastaddr: 239.192.168.112
> mcastport: 5405
> }
> Now the multicast socket is 239.192.168.112:5405. It's unique, the network
> address is the same, but you add this config (edit according to your
> environment, this is just an example) to your other two nodes. So you have
> cluster1 formed out of node1 and node2 linked to 239.192.168.1:5405 and
> cluster2 formed out of node3 and node4 linked to 239.192.168.112:5405.
>
> This way, the clusters don't _see_ each other, so you can reuse the resource
> ID's and see only two nodes per cluster.
Out of curiosity, RFC2365 defines "local scope" multicast space 239.255.0.0/16
and "organizational local scope" 239.192.0.0/14.
Seems most examples for pacemaker cluster use later. But since most clusters
are not spread across different subnets, wouldn't it be more appropriate to use
the former?
Thanks,
Vadym
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