On Thu, Apr 9, 2009 at 19:15, David Teigland <teigl...@redhat.com> wrote: > On Thu, Apr 09, 2009 at 01:50:18PM +0200, Andrew Beekhof wrote: >> For added fun, a node that restarts quickly enough (think a VM) won't >> even appear to have left (or rejoined) the cluster. >> At the next totem confchg event, It will simply just be there again >> with no indication that anything happened. >> >> At least this is true for the raw corosync/openais membership data, >> perhaps CPG can infer this some other way. > > Cpg should not let a node go away and come back without notice. In practice > I'd expect back to back confchg's: one showing it leave and another showing it > join.
If you mean the raw confchg's that lcrsos see, then nope. Try this, set token: to longer than your node takes to reboot and reboot a node. For physical nodes this isn't a realistic scenario, but VMs can easily boot in 10 seconds or so. > As Chrissie mentioned earlier, cpg shouldn't show the same node both > leaving and joining in a single confchg. In theory I think it would be > legitimate. > > Consider a couple examples. > m: member list, j: joined list, l: left list > > 1. nodes A and B join at once > A gets confchg: m=A,B j=A,B l= > B gets confchg: m=A,B j=A,B l= > > 2. node C joins > A gets confchg: m=A,B,C j=C l= > B gets confchg: m=A,B,C j=C l= > C gets confchg: m=A,B,C j=C l= > > 3. node C leaves and quickly rejoins in a single confchg > A gets confchg: m=A,B,C j=C l=C > B gets confchg: m=A,B,C j=C l=C > C gets confchg: m=A,B,C j=C l=C > > 4. node D joins and quickly leaves (or fails) in a single confchg > A gets confchg: m=A,B,C j=D l=D > B gets confchg: m=A,B,C j=D l=D > C gets confchg: m=A,B,C j=D l=D > D gets confchg: m=A,B,C j=D l=D ?* > > * if D does a quick join+leave it may expect to see this confchg showing it in > the joined list, the left list, and not in the member list. > > Again, the examples in 3 and 4 are, I think, legitimate in theory. In > practice it sounds like they won't occur. > > If a quick leave+join is guaranteed to be visible through cpg, then it must be > possible to observe at the lower level from raw corosync data. > > Dave > > _______________________________________________ Openais mailing list Openais@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/openais
