On 11.05.2021 18:20, Alastair Basden wrote: > Hi, > > So, I think the following would do it: > pcs constraint location resourceClone rule role=master score=100 uname > eq node1 > pcs constraint location resourceClone rule role=master score=50 uname eq > node2 >
Single location constraint may have multiple rules, I would assume pcs supports it. It is certainly supported by crmsh. > But, I'm unsure about uname. In the xml example you showed, it had > #uname. Is that correct, or do I use uname without the hash? > This should be #uname - it is special attribute. > So perhaps: > pcs constraint location resourceClone rule role=master score=50 \#uname > eq node2 > > Cheers, > Alastair. > > On Tue, 11 May 2021, Andrei Borzenkov wrote: > >> [EXTERNAL EMAIL] >> >> 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/ >> > _______________________________________________ > 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/