[Gluster-users] Geo-replication adding new master node

[David Cunningham]

Hi Aravinda,

We ran a "gluster system:: execute gsec_create" and "georep create
push-pem" with force option as suggested, and then a "gluster volume
geo-replication ... status" reported the two new master nodes as being in
"Created" status. We did a geo-replication "stop" and then "start" and are
pleased to see the two new master nodes are now in "Passive" status. Thank
you for your help!


On Tue, 1 Jun 2021 at 10:06, David Cunningham <dcunningham at voisonics.com>
wrote:

> Hi Aravinda,
>
> Thank you very much - we will give that a try.
>
>
> On Mon, 31 May 2021 at 20:29, Aravinda VK <aravinda at kadalu.io> wrote:
>
>> Hi David,
>>
>> On 31-May-2021, at 10:37 AM, David Cunningham <dcunningham at voisonics.com>
>> wrote:
>>
>> Hello,
>>
>> We have a GlusterFS configuration with mirrored nodes on the master side
>> geo-replicating to mirrored nodes on the secondary side.
>>
>> When geo-replication is initially created it seems to automatically add
>> all the mirrored nodes on the master side as geo-replication master nodes,
>> which is fine. My first question is, if we add a new master side node how
>> can we add it as a geo-replication master?
>> This doesn't seem to happen automatically, according to the output of
>> "gluster volume geo-replication gvol0 secondary::gvol0 status". If we use
>> the normal "gluster volume geo-replication gvol0 secondary::slave-vol
>> create push-pem force" it says that the secondary side volume is not empty,
>> which is true because we're adding a master node to the existing
>> geo-replication.
>>
>>
>> This is not automatic. Run `gluster-georep-sshkey generate` and georep
>> create push-pem with force option to push the keys from new nodes to
>> secondary nodes.
>>
>> You can also try this tool instead of georep create command.
>>
>> https://github.com/aravindavk/gluster-georep-tools
>>
>> $ gluster-georep-setup gvol0 secondary::slave-vol --force
>>
>>
>> My second question is whether we can geo-replicate to multiple nodes on
>> the secondary side? Ideally we would normally have something like:
>> master A -> secondary A
>> master B -> secondary B
>> master C -> secondary C
>> so that any master or secondary node could go offline but geo-replication
>> would keep working.
>>
>>
>> Geo-replication command needs one Secondary node to establish the
>> session. Once session starts, Geo-rep starts one worker process per master
>> brick.
>>
>> These worker processes gets the list of secondary nodes by running the
>> `ssh <secondary-host> gluster volume info <secondary-volume>`. Then Geo-rep
>> distributes the secondary nodes connection in round robin way. For example,
>> if Master volume contains three nodes and secondary volume 3 nodes as you
>> mentioned then Geo-rep makes connection as Master A -> Secondary A, Master
>> B -> Secondary B and Master C -> Secondary C.
>>
>> Secondary node failover: If a node goes down in secondary cluster then
>> Master worker connects to other secondary node and continues replication.
>> One known issue is if the secondary node specified in the Geo-rep create
>> command goes down then it fails to get the Volume info(To get list of
>> secondary nodes). This can be solved by providing the list of secondary
>> nodes as config(Not yet available).
>>
>>
>> Thank you very much in advance.
>>
>> --
>> David Cunningham, Voisonics Limited
>> http://voisonics.com/
>> USA: +1 213 221 1092
>> New Zealand: +64 (0)28 2558 3782
>> ________
>>
>>
>>
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>>
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>>
>>
>> Aravinda Vishwanathapura
>> https://kadalu.io
>>
>>
>>
>>
>
> --
> David Cunningham, Voisonics Limited
> http://voisonics.com/
> USA: +1 213 221 1092
> New Zealand: +64 (0)28 2558 3782
>


-- 
David Cunningham, Voisonics Limited
http://voisonics.com/
USA: +1 213 221 1092
New Zealand: +64 (0)28 2558 3782
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