Hi, what is the best way to upgrade Mesos cluster from 0.18 to 0.19? I've tried to read all documentation before doing actual upgrade, but I still don't understand a few things.
What should be the quorum size? The --help says that "It is imperative to set this value to be a majority of masters i.e., quorum > (number of masters)/2" I have 4 Mesos masters, which would mean that quorum > 2 -> quorum=3, right? The recover.cpp says that: "we allow a replica in EMPTY status to become VOTING immediately if it finds ALL (i.e., 2 * quorum - 1) replicas are in EMPTY status" So, with quorum = 3 I would need 5 Mesos masters (that's just not clear from the mesos-master --help). quorum=1, mesos-masters=1 quorum=2, mesos-masters=3 quorum=3, mesos-masters=5 quorum=4, mesos-masters=7 Is is possible to have non-even number of Mesos masters? or is it just a bad idea? With 4 masters I got into a situation when: master 1: I0722 11:35:40.708562 12689 replica.cpp:638] Replica in VOTING status received a broadcasted recover request master 2: I0722 11:36:37.593647 7754 replica.cpp:638] Replica in EMPTY status received a broadcasted recover request master 3: I0722 11:35:14.102762 26701 recover.cpp:188] Received a recover response from a replica in STARTING status master 4: I0722 11:35:54.284169 32056 replica.cpp:638] Replica in STARTING status received a broadcasted recover request I0722 11:35:54.284425 32050 recover.cpp:188] Received a recover response from a replica in STARTING status I0722 11:35:54.284788 32057 recover.cpp:188] Received a recover response from a replica in VOTING status I0722 11:35:54.285127 32050 recover.cpp:188] Received a recover response from a replica in EMPTY status And the election algorithm ends up in an endless loop. How can I recover from this? Delete all replica logs from master disk? Start with quorum=1 and increment number of masters? Thanks, Tomas
