[DRBD-user] Failover problem with LINSTORPlugin.pm for Proxmox

[Wanja Schonecke]

Hi there,

i hope this is the right place for my question.

i'm running an Proxmox-Cluster with Linstor and just two real nodes.
There is a third node (RaspberryPi) just running corosync for Quorum to
work.
   
Everything is working fine, except for failover when one of the two real
nodes fails.
The remaining node is not able to start any VM.
The Proxmox HA tries to start the VM on the remaining node and runs into
a timeout after 60 seconds.
I traced it back to the Linstor plugin on line 479.
Where there is:
wait_connect_resource($volname);

Which does:
run_command(
        [ 'drbdsetup', 'wait-connect-resource', $resource ],
        errmsg => "Could not wait until replication established for
($resource)",
        timeout => 60 # could use --wfc-timeout, but hey when we already
do it proxmoxy...
    );
   
I'm fairly new to DRBD but i read:
wait-connect-resource - Wait until all connections are establised.

That sounds like this command will wait for connection with the peer
node, which isn't available at this time as it just failed.
As the ressource is available on this node at this time in secondary
mode, i wonder if the plugin shouldn't just switch it to primary,
instead.   
If i comment out line 479 in LINSTORPlugin.pm, Proxmox HA is able to
start all my VM on the remaining node, if the peer node fails.

So my cluster would work just fine in any cases i tested, if i just
leave line 479 commented out.
But i',m not sure if i will run into any other problems if i leave it
like that and i have no clue what this line is for.
So it would be good to know, what this command is doing there and if
there is any other solution for my problem.


My Proxmox-Versions are:
proxmox-ve: 5.3-1 (running kernel: 4.15.18-9-pve)
pve-manager: 5.3-7 (running version: 5.3-7/e8ed1e22)
pve-kernel-4.15: 5.2-12
pve-kernel-4.15.18-9-pve: 4.15.18-30
pve-kernel-4.15.17-1-pve: 4.15.17-9
corosync: 2.4.4-pve1

Linstor:
linstor 0.7.3;


Thanks in advance
Wanja



-- 
Mit freundlichen Grüßen
Wanja Schonecke