This is my patch https://github.com/apache/zookeeper/pull/546
One question: I would like to force the cluster to change leader in HierarchicalQuorumTest, so that I can test that JMX will reflect the new status of the group. Any idea about how to bounce the leader ? Cheers Enrico Il giorno mer 20 giu 2018 alle ore 13:45 Enrico Olivelli < eolive...@gmail.com> ha scritto: > This is my JIRA > I am going to work on a patch > > https://issues.apache.org/jira/browse/ZOOKEEPER-3066 > > Enrico > > Il gio 10 mag 2018, 19:47 Andor Molnar <an...@cloudera.com> ha scritto: > >> "in order to guess which is the leader I have to ask to all of the three >> nodes in the cluster" >> >> That's correct. >> >> Regards, >> Andor >> >> >> >> On Thu, May 10, 2018 at 4:07 AM, Enrico Olivelli <eolive...@gmail.com> >> wrote: >> >> > Il giorno mer 9 mag 2018 alle ore 20:24 Patrick Hunt <ph...@apache.org> >> ha >> > scritto: >> > >> > > iiuc what you are interested in the information is already available. >> The >> > > beans have a "state" attribute which indicates following vs leading. >> > > >> > > Try attaching a jconsole to the running servers, use the "mbeans" tab >> and >> > > open org.apache.ZooKeeperService -> replicatedserver -> replica -> >> > > attributes, you'll see the "state" attribute there. >> > > >> > >> > >> > Patrick, >> > I can't find this information. >> > If I log into a "follower" I get this info only for the 'current >> replica' >> > >> > Example, I have three peers, the first one is a "Follower", on JMX I >> have >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_1 - ClientAddress >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_1 - >> ElectionAddress >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_1 - LearnerType >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_1 - Name >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_1 - QuorumAddress >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_1 - State = >> > following >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_1 - ConfigVersion >> > ..... >> > >> > >> > >> > for other peers I see only >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_2 - ClientAddress >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_2 - >> ElectionAddress >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_2 - LearnerType >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_2 - Name >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_2 - QuorumAddress >> > >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_3 - ClientAddress >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_3 - >> ElectionAddress >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_3 - LearnerType >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_3 - Name >> > o.a.ZookKeeperService - ReplicatedServer_id1 - replica_3 - QuorumAddress >> > >> > >> > so quering only this server I cannot guess which is the current leader, >> the >> > only information I can extract is: >> > - I am a follower >> > - We are a cluster of three >> > - Every of the three is a PARTECIPANT (no observers) >> > >> > in order to guess which is the leader I have to ask to all of the three >> > nodes in the cluster >> > >> > Am I missing something ? I am running 3.5.3-BETA >> > >> > Enrico >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > > >> > > Patrick >> > > >> > > On Wed, May 9, 2018 at 8:02 AM, Enrico Olivelli <eolive...@gmail.com> >> > > wrote: >> > > >> > > > Thank you Edward >> > > > >> > > > I will pack all together and send out a patch as soon as I have >> time. >> > > > I am running 3.5 in production and given than an RC for 3.5.4 is >> going >> > to >> > > > be cut soon I will have to wait for 3.5.5 and I assume it won't be >> > > > immediate. >> > > > >> > > > Cheers >> > > > Enrico >> > > > >> > > > Il giorno mer 9 mag 2018 alle ore 14:37 Edward Ribeiro < >> > > > edward.ribe...@gmail.com> ha scritto: >> > > > >> > > > > Sent before finishing the previous email. Only to complement, the >> > > > > findLeader() could have been as below, but this change is only a >> > nitty >> > > > > detail and totally irrelevant to the questions you are asking. :) >> > > > > >> > > > > /** >> > > > > * Returns the address of the node we think is the leader. >> > > > > */ >> > > > > protected QuorumServer findLeader() { >> > > > > >> > > > > // Find the leader by id >> > > > > long currentLeader = self.getCurrentVote().getId(); >> > > > > >> > > > > QuorumServer leaderServer = self.getView().get(currentLeader); >> > > > > >> > > > > if (leaderServer == null) { >> > > > > LOG.warn("Couldn't find the leader with id = {}", >> > > currentLeader); >> > > > > } >> > > > > return leaderServer; >> > > > > } >> > > > > >> > > > > Edward >> > > > > >> > > > > On Wed, May 9, 2018 at 9:29 AM, Edward Ribeiro < >> > > edward.ribe...@gmail.com >> > > > > >> > > > > wrote: >> > > > > >> > > > > > Hi Enrico, >> > > > > > >> > > > > > Well, I am not an expert on QuorumPeer either (not an expert on >> > > > anything, >> > > > > > really), but maybe it's the variable and method below? >> > > > > > >> > > > > > ----------------- QuorumPeer ------------------ >> > > > > > >> > > > > > /** >> > > > > > * This is who I think the leader currently is. >> > > > > > */ >> > > > > > volatile private Vote currentVote; >> > > > > > >> > > > > > public synchronized Vote getCurrentVote(){ >> > > > > > return currentVote; >> > > > > > } >> > > > > > >> > > > > > --------------------------------------- >> > > > > > >> > > > > > >> > > > > > Then it's a matter of calling >> quorumPeer.getCurrentVote().getId() >> > and >> > > > > > quorumPeer.getServerState()? >> > > > > > >> > > > > > Btw, the Learner class has this handy method below (self is a >> > > > > QuorumPeer): >> > > > > > >> > > > > > ---------------- Learner -------------------- >> > > > > > >> > > > > > /** >> > > > > > * Returns the address of the node we think is the leader. >> > > > > > */ >> > > > > > protected QuorumServer findLeader() { >> > > > > > QuorumServer leaderServer = null; >> > > > > > // Find the leader by id >> > > > > > Vote current = self.getCurrentVote(); >> > > > > > for (QuorumServer s : self.getView().values()) { >> > > > > > if (s.id == current.getId()) { >> > > > > > leaderServer = s; >> > > > > > break; >> > > > > > } >> > > > > > } >> > > > > > if (leaderServer == null) { >> > > > > > LOG.warn("Couldn't find the leader with id = " >> > > > > > + current.getId()); >> > > > > > } >> > > > > > return leaderServer; >> > > > > > } >> > > > > > >> > > > > > --------------------------------------- >> > > > > > >> > > > > > By the way, as a side note, the map traversal could be changed >> by: >> > > > > > >> > > > > > ---------------------------- >> > > > > > >> > > > > > if (self.getView().contains(current.getId()) { >> > > > > > >> > > > > > } >> > > > > > >> > > > > > --------------------------- >> > > > > > >> > > > > > >> > > > > > >> > > > > > You can see above this method the quorumPeer.getView() returns a >> > > > Map<sid, >> > > > > > QuorumServer> as below: >> > > > > > >> > > > > > -------------QuorumPeer --------- >> > > > > > >> > > > > > /** >> > > > > > * A 'view' is a node's current opinion of the membership of the >> > > entire >> > > > > > * ensemble. >> > > > > > */ >> > > > > > public Map<Long,QuorumPeer.QuorumServer> getView() { >> > > > > > return Collections.unmodifiableMap(getQuorumVerifier(). >> > > > > > getAllMembers()); >> > > > > > } >> > > > > > >> > > > > > ----------------------------- >> > > > > > >> > > > > > >> > > > > > And then it retrieves the QuorumServer that has many more >> > information >> > > > > > about the node besides the sid (InetSocketAddress, hostname, >> etc). >> > :) >> > > > > > >> > > > > > >> > > > > > Cheers, >> > > > > > Edward >> > > > > > >> > > > > > On Wed, May 9, 2018 at 8:50 AM, Enrico Olivelli < >> > eolive...@gmail.com >> > > > >> > > > > > wrote: >> > > > > > >> > > > > >> So I am trying to create a patch in order to expose on JMX the >> id >> > of >> > > > the >> > > > > >> current "leader" (on the JVM of a follower) >> > > > > >> >> > > > > >> I am trying to find in ZK which is the variable which holds >> the ID >> > > of >> > > > > the >> > > > > >> current leader. >> > > > > >> I am new to the internal of QuorumPeer >> > > > > >> >> > > > > >> Can someone give me some hint ? >> > > > > >> >> > > > > >> Enrico >> > > > > >> >> > > > > >> Il giorno mar 8 mag 2018 alle ore 10:08 Ansel Zandegran < >> > > > > >> ansel.zandeg...@infor.com> ha scritto: >> > > > > >> >> > > > > >> > Hi, >> > > > > >> > That is possible with 4 letter commands. We are using it >> now. In >> > > > 3.5.x >> > > > > >> it >> > > > > >> > is going to be removed in favour of admin server (embedded >> web >> > > > > server). >> > > > > >> > We are running in an environment where it’s not possible to >> run >> > > JMX >> > > > or >> > > > > >> > embedded web servers. >> > > > > >> > >> > > > > >> > So I am wondering if there is another way? It would be nice >> to >> > > have >> > > > > this >> > > > > >> > info as a znode. >> > > > > >> > >> > > > > >> > Best regards, >> > > > > >> > Ansel >> > > > > >> > >> > > > > >> > > On 8 May 2018, at 09:55, Flavio Junqueira <f...@apache.org> >> > > wrote: >> > > > > >> > > >> > > > > >> > > Hi Enrico, >> > > > > >> > > >> > > > > >> > > You can determine the state of a server it via 4-letter >> > > commands. >> > > > > >> Would >> > > > > >> > that work for you? >> > > > > >> > > >> > > > > >> > > -Flavio >> > > > > >> > > >> > > > > >> > >> On 8 May 2018, at 09:09, Enrico Olivelli < >> > eolive...@gmail.com> >> > > > > >> wrote: >> > > > > >> > >> >> > > > > >> > >> Hi, >> > > > > >> > >> is there any way to see in JMX which is the leader of a >> > > ZooKeeper >> > > > > >> > cluster? >> > > > > >> > >> >> > > > > >> > >> My problem is: given access to any of the nodes of the >> > cluster >> > > I >> > > > > >> want to >> > > > > >> > >> know from JMX which is the current leader. >> > > > > >> > >> It seems to me that this information is not available, you >> > can >> > > > know >> > > > > >> > only if >> > > > > >> > >> the local node is Leader or Follower. >> > > > > >> > >> >> > > > > >> > >> Cheers >> > > > > >> > >> Enrico >> > > > > >> > > >> > > > > >> > >> > > > > >> > >> > > > > >> >> > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> > -- > > > -- Enrico Olivelli >
