[ClusterLabs] heartbeat rings questions

[Jan Friesse]

On 13/07/2021 19:07, Kiril Pashin wrote:
> Hi , thanks for the quick reply.
> I have a couple of follow up questions below in blue below
> 
>      On 12/07/2021 23:27, Kiril Pashin wrote:
>       > Hi ,
>       > is it valid to use the same network adapter interface on the same host to be
>       > part of multiple
>       > heart beat rings ?
> 
>      There should be no problem from technical side, but I wouldn't call this
>      use case "valid". Idea of multiple rings is to have multiple independent
>      connections between nodes - something what one nic simply doesn't provide.
> 
>       > The scenario is hostA has eth0 ( ip 192.10.10.1 ) interface and hostB has
>      eth0 (
>       > 192.20.20.1 ) and eth1 ( 192.20.20.2 ) .
> 
>      This is unsupported configuration
>      Can you clarify here why this is unsupported, you mentioned above that there
>      should be no problem from a technical side ?
> 
>       > Are there any restrictions to form two heartbeat rings { eth0, eth0 } and {
>       > eth0, eth1 }
> 
>      Technically only restriction is based on IP. But to make it reliable one
>      should use multiple NICs with multiple links and multiple switches.
> 
> I understand that its not as reliable as using multiple NICs, you mention the
> only restriction is based on IP . Is there a doc
> mentioning such restrictions ?

Closest is probably https://access.redhat.com/articles/3068841

Regards,
   Honza


> 
> 
>       > as well as create a nozzle device to be able to ping hostA in case eth0
>      or eth1
>       > go down on hostB
> 
>      It is definitively possible to create noozle device which will allow to
>      ping hostA in case some of nic fails, but not in the way described in
>      config snip. Noozle device should have different IP subnet (noozle is
>      basically yet another network card).
>      I made up the example in thisemail, however , i assumed all the IPs in the
>      examle are
>      are using 24 bits for the subnet netmaskso the nozzle is on a different
>      subnet 192.168.10
>      Can you clarify the problem with my config snip ?
> 
>       > nodelist {
>       >       node {
>       >           ring0_addr: 192.10.10.1
>       >           ring1_addr: 192.10.10.1
>       >           name: node1
>       >           nodeid: 1
>       >       }
>       >       node {
>       >           ring0_addr: 192.20.20.1
>       >           ring1_addr: 192.20.20.2
>       >           name: node2
>       >           nodeid: 2
>       >       }
>       > }
>       > nozzle {
>       >           name: noz01
>       >           ipaddr: 192.168.10.0
>       >           ipprefix: 24
>       > }
> 
>      This config will definitively not work.
> 
>      Regards,
>          Honza
> 
>       > Thanks,
>       > Kiril Pashin
>       > DB2 Purescale Development & Support
>       > kirilp at ca.ibm.com
>       >
>       >
>       >
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