Good question. Wouldn't just killing the leader do the job? Regards, Norbert
On Thu, Jun 21, 2018 at 3:51 AM Enrico Olivelli <[email protected]> wrote: > 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 < > [email protected]> 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 <[email protected]> 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 <[email protected]> > >> wrote: > >> > >> > Il giorno mer 9 mag 2018 alle ore 20:24 Patrick Hunt < > [email protected]> > >> 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 < > [email protected]> > >> > > 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 < > >> > > > [email protected]> 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 < > >> > > [email protected] > >> > > > > > >> > > > > 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 < > >> > [email protected] > >> > > > > >> > > > > > 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 < > >> > > > > >> [email protected]> 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 < > [email protected]> > >> > > 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 < > >> > [email protected]> > >> > > > > >> 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 > > >
