On Tue, May 11, 2021 at 10:50 AM Alastair Basden <a.g.bas...@durham.ac.uk> wrote: > > Hi Andrei, all, > > So, what I want to achieve is that if both nodes are up, node1 > preferentially has drbd as master. If that node fails, then node2 should > become master. If node1 then comes back online, it should become master > again. > > I also want to avoid node3 and node4 ever running drbd, since they don't > have the disks. > > For the link below about promotion scores, what is the pcs command to > achieve this? I'm unfamiliar with where the xml goes... >
I do not normally use PCS so am not familiar with its syntax. I assume there should be documentation that describes how to define location constraints with rules. Maybe someone who is familiar with it can provide an example. > > > I notice that drbd9 has an auto promotion feature, perhaps that would help > here, and so I can forget about configuring drbd in pacemaker? Is that > how it is supposed to work? i.e. I can just concentrate on the overlying > file system. > > Sorry that I'm being a bit slow about all this. > > Thanks, > Alastair. > > On Tue, 11 May 2021, Andrei Borzenkov wrote: > > > [EXTERNAL EMAIL] > > > > On 10.05.2021 20:36, Alastair Basden wrote: > >> Hi Andrei, > >> > >> Thanks. So, in summary, I need to: > >> pcs resource create resourcedrbd0 ocf:linbit:drbd drbd_resource=disk0 op > >> monitor interval=60s > >> pcs resource master resourcedrbd0Clone resourcedrbd0 master-max=1 > >> master-node-max=1 clone-max=2 clone-node-max=1 notify=true > >> > >> pcs constraint location resourcedrb0Clone prefers node1=100 > >> pcs constraint location resourcedrb0Clone prefers node2=50 > >> pcs constraint location resourcedrb0Clone avoids node3 > >> pcs constraint location resourcedrb0Clone avoids node4 > >> > >> Does this mean that it will prefer to run as master on node1, and slave > >> on node2? > > > > No. I already told you so. > > > >> If not, how can I achieve that? > >> > > > > DRBD resource agents sets master scores based on disk state. If you > > statically override this decision you are risking promoting stale copy > > which means data loss (I do not know if agent allows it, hopefully not; > > but then it will continue to attempt to promote wrong copy and > > eventually fail). But if you insist, it is documented: > > > > https://clusterlabs.org/pacemaker/doc/en-US/Pacemaker/2.0/html/Pacemaker_Explained/s-promotion-scores.html > > > > Also statically biasing one single node means workload will be relocated > > every time node becomes available, which usually implies additional > > downtime. That is something normally avoided (which is why resource > > stickiness exists). > > _______________________________________________ > > Manage your subscription: > > https://lists.clusterlabs.org/mailman/listinfo/users > > > > ClusterLabs home: https://www.clusterlabs.org/ > >_______________________________________________ > Manage your subscription: > https://lists.clusterlabs.org/mailman/listinfo/users > > ClusterLabs home: https://www.clusterlabs.org/ _______________________________________________ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/