You need the following: - active namenode + zkfc - standby namenode + zkfc - pool of journal nodes (odd number, 3 or more) - pool of zookeeper nodes (odd number, 3 or more)
As the journal nodes hold the namesystem transactions they should not be co-located with the namenodes in case of failure. I distribute the journal and zookeeper nodes across the hosts running datanodes or as Harsh says you could co-locate them on dedicated hosts. ZKFC does not monitor the JobTracker. Regards, Craig On Dec 28, 2012 9:25 AM, "ESGLinux" <[email protected]> wrote: > Hi, > > well, If I have understand you I can configure my NN HA cluster this way: > > - Active NameNode + 1 ZKFC daemon + Journal Node > - Standby NameNode + 1 ZKFC daemon + Journal Node > - JobTracker node + 1 ZKFC daemon + Journal Node, > > Is this right? > > Thanks in advance, > > ESGLinux, > > 2012/12/27 Harsh J <[email protected]> > >> Hi, >> >> There are two different things here: Automatic Failover and Quorum >> Journal Manager. The former, used via a ZooKeeper Failover Controller, >> is to manage failovers automatically (based on health checks of NNs). >> The latter, used via a set of Journal Nodes, is a medium of shared >> storage for namesystem transactions that helps enable HA. >> >> In a typical deployment, you want 3 or more (odd) JournalNodes for >> reliable HA, preferably on nodes of their own if possible (like you >> would for typical ZooKeepers, and you may co-locate with those as >> well) and one ZKFC for each NameNode (connected to the same ZK >> quorum). >> >> On Thu, Dec 27, 2012 at 5:33 PM, ESGLinux <[email protected]> wrote: >> > Hi all, >> > >> > I have a doubt about how to deploy the Zookeeper in a NN HA cluster, >> > >> > As far as I know, I need at least three nodes to run three ZooKeeper >> > FailOver Controller (ZKFC). I plan to put these 3 daemons this way: >> > >> > - Active NameNode + 1 ZKFC daemon >> > - Standby NameNode + 1 ZKFC daemon >> > - JobTracker node + 1 ZKFC daemon, (is this right?) >> > >> > so the quorum is formed with these three nodes. The nodes that runs a >> > namenode are right because the ZKFC monitors it, but what does the third >> > daemon? >> > >> > as I read from this url: >> > >> https://ccp.cloudera.com/display/CDH4DOC/Software+Configuration+for+Quorum-based+Storage#SoftwareConfigurationforQuorum-basedStorage-AutomaticFailoverConfiguration >> > >> > this daemons are only related with NameNodes, (Health monitoring - the >> ZKFC >> > pings its local NameNode on a periodic basis with a health-check >> command.) >> > so what does the third ZKFC? I used the jobtracker node but I could use >> > another node without any daemon on it... >> > >> > Thanks in advance, >> > >> > ESGLInux, >> > >> > >> > >> >> >> >> -- >> Harsh J >> > >
