[ClusterLabs] cross DC cluster using public ip?

[Klaus Wenninger]

On 10/13/2016 09:30 AM, Jan Friesse wrote:
> neeraj ch napsal(a):
>> Hello ,
>>
>> We are testing out corosync and pacemaker for DB high availability on
>> the
>> cloud. I was able to set up a cluster with in a DC using corosync 1.4
>> and
>> pacemaker 1.12. It works great and I wanted to try a cross DC cluster. I
>> was using unicast as multicast was disabled by default.
>>
>> I was not sure how Corosync behaves with public IP's but I still went
>> ahead
>> and tried it with both public IP's as well as DNS names. These DNS names
>> resolve as local IP when the other node is with in the same subnet.
>
> Every node has to be able to see every other node. So mixing of public
> and private ips is not going to work (with exception of special case
> where all private ips are in the same network). Also keep in mind
> config file has to be same on all nodes.

Guess reason is that corosync derives an ID from the IP.
So the hostname has to resolve to the same IP on all nodes
and under all circumstances.

>
>
>>
>> while I was using public IP's both the node inside the same subnet as
>> well
>> as outside were unable to connect, except for itself. While using DNS
>> names
>> the membership information showed the nodes within same subnet being
>> connected to while the nodes outside were not connected
>
> This is somehow expected.
>>
>>
>> My corosync config is as follows.
>>
>> totem {
>>        version: 2
>>        secauth: off
>>        threads: 0
>>        interface {
>>
>>                 member {
>>                    memberaddr: <public ip>
>>                 }
>>                member {
>>                    memberaddr: <public ip>
>>                 }
>>                 member {
>>                    memberaddr: <public ip>
>>                 }
>>                 ringnumber: 0
>>                 bindnetaddr: 172.31.0.0
>>                 mcastport: 5405
>>                 ttl: 1
>>        }
>>        transport: udpu
>> }
>>
>> logging {
>>        fileline: off
>>        to_stderr: no
>>        to_logfile: yes
>>        to_syslog: yes
>>        logfile: /var/log/cluster/corosync.log
>>        debug: on
>>        timestamp: on
>>        logger_subsys {
>>                 subsys: AMF
>>                 debug: on
>>        }
>> }
>>
>> service {
>>          # Load the Pacemaker Cluster Resource Manager
>>          name: pacemaker
>>          ver: 1
>> }
>>
>> amf {
>>        mode: disabled
>> }
>>
>>
>> I am checking membership information by using corosync-objctl. I have
>> also
>> tried using public ip as the bind address , that makes the membership
>> from
>
> Just to make sure. This "public" ip is really ip of given machine?
>
>> 1 to 0 as it doesn't add itself.
>>
>> If any one has any suggestion / advice on how to debug or what I am
>> doing
>> wrong . Any help would be very appreciated.
>>
>> Thank you
>>
>>
>>
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>
>
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