[SOLVED] CEPH Mirroring : unable to get monitor info from DNS SRV with service name: ceph-mon

[DC-CA1]

hello all im at last step of configuring a Mirroring ( enabled the deamon service on the site-b node ) .

do i need to have each Cluster on the same CEPH Public network or it can be any other range. as i dont have any communication now on the Public network or Client Network between the cluster. so that may explain the issue if this is needed..

● ceph-rbd-mirror@rbd-mirror.cl3-bl3.service - Ceph rbd mirror daemon Loaded: loaded (/etc/systemd/system/ceph-rbd-mirror@.service; enabled; vendor preset: enabled) Active: active (running) since Sat 2023-05-27 07:58:03 EDT; 1min 15s ago Main PID: 372874 (rbd-mirror) Tasks: 30 Memory: 16.8M CPU: 204ms CGroup: /system.slice/system-ceph\x2drbd\x2dmirror.slice/ceph-rbd-mirror@rbd-mirror.cl3-bl3.service └─372874 /usr/bin/rbd-mirror -f --cluster ceph --id rbd-mirror.cl3-bl3 --setuser root --setgroup root May 27 07:58:03 cl3-bl3 systemd[1]: Started Ceph rbd mirror daemon. May 27 07:58:03 cl3-bl3 rbd-mirror[372874]: unable to get monitor info from DNS SRV with service name: ceph-mon May 27 07:58:03 cl3-bl3 rbd-mirror[372874]: 2023-05-27T07:58:03.266-0400 7f6f7668c800 -1 rbd::mirror::PoolReplayer: 0x55d95ef74f00 init_rados: error connecting to remote peer uuid: 4e1680c4-b28c-4e45-80b> May 27 07:58:33 cl3-bl3 rbd-mirror[372874]: 2023-05-27T07:58:33.274-0400 7f6f7668c800 -1 rbd::mirror::Mirror: 0x55d95e0dca20 update_pool_replayers: restarting failed pool replayer for uuid: 4e1680c4-b28c> May 27 07:58:33 cl3-bl3 rbd-mirror[372874]: unable to get monitor info from DNS SRV with service name: ceph-mon May 27 07:58:33 cl3-bl3 rbd-mirror[372874]: 2023-05-27T07:58:33.362-0400 7f6f7668c800 -1 rbd::mirror::PoolReplayer: 0x55d95ef74f00 init_rados: error connecting to remote peer uuid: 4e1680c4-b28c-4e45-80b> May 27 07:59:03 cl3-bl3 rbd-mirror[372874]: 2023-05-27T07:59:03.371-0400 7f6f7668c800 -1 rbd::mirror::Mirror: 0x55d95e0dca20 update_pool_replayers: restarting failed pool replayer for uuid: 4e1680c4-b28c> May 27 07:59:03 cl3-bl3 rbd-mirror[372874]: unable to get monitor info from DNS SRV with service name: ceph-mon

 

[DC-CA1]

Anyone?

 

[ness1602]

Are you able to ping from one to another and back?

 

[DC-CA1]

There is no step do define the primary ip in the wiki so I assume it read the configuration file copied from the master ceph and it try to connect from public ceph network to public ceph network right ?

So no ceph networks are not reachable actually but each proxmox cluster is accessible from another subnet / vlan

 

[ness1602]

Yeah, ceph external cluster network needs to be able to talk to each other.

 

[DC-CA1]

i still have the same issue, i have each cluster on the same subnet and can ping each node from each cluster.


May 30 15:20:28 cl3-bl3 rbd-mirror[2459329]: unable to get monitor info from DNS SRV with service name: ceph-mon
May 30 15:20:28 cl3-bl3 rbd-mirror[2459329]: 2023-05-30T15:20:28.143-0400 7f9c54370800 -1 rbd::mirror:oolReplayer: 0x556e346bf800 init_rados: error connecting to remote peer

 

[ness1602]

Did you copy the site-a ceph.conf to site-b as in the guide?

 

[DC-CA1]

i was doing my test on another blade intialy and i forgot on the second one i was working to do that command:

ln -s /etc/pve/site-a.conf /etc/ceph/site-a.conf

working like a charm now thx Ness1602

 

[ness1602]

Yeah rbd and cephfs replication is sometimes pain to implement. I still haven't found good way to replicate cephfs.

 

[DC-CA1]

are you aware of a command to enable en entire Pool to replicate automaticaly without having to manually enable each images on the pool ?

 

[ness1602]

It should be rbd mirror pool enable cdata pool .
But it didn't work for me

 

[WLKe]

Try change mon ports in ceph.conf from 6789 to 3300 and restart all mon services.