Vinay, if the Hadoop docs are not clear in this regard, can you please create a jira to add these details?
On Fri, Nov 16, 2012 at 12:31 AM, Vinayakumar B <vinayakuma...@huawei.com>wrote: > Hi,**** > > ** ** > > If you are moving from NonHA (single master) to HA, then follow the below > steps.**** > > **1. **Configure the another namenode’s configuration in the > running namenode and all datanode’s configurations. And configure logical > *fs.defaultFS***** > > **2. **Configure the shared storage related configuration.**** > > **3. **Stop the running NameNode and all datanodes.**** > > **4. **Execute ‘hdfs namenode –initializeSharedEdits’ from the > existing namenode installation, to transfer the edits to shared storage.** > ** > > **5. **Now format zkfc using ‘hdfs zkfc –formatZK’ and start zkfc > using ‘hadoop-daemon.sh start zkfc’**** > > **6. **Now restart the namenode from existing installation. If all > configurations are fine, then NameNode should start successfully as > STANDBY, then zkfc will make it to ACTIVE.**** > > ** ** > > **7. **Now install the NameNode in another machine (master2) with > same configuration, except ‘dfs.ha.namenode.id’.**** > > **8. **Now instead of format, you need to copy the name dir > contents from another namenode (master1) to master2’s name dir. For this > you are having 2 options.**** > > **a. **Execute ‘hdfs namenode -bootStrapStandby’ from the master2 > installation.**** > > **b. **Using ‘scp’ copy entire contents of name dir from master1 to > master2’s name dir.**** > > **9. **Now start the zkfc for second namenode ( No need to do zkfc > format now). Also start the namenode (master2)**** > > ** ** > > Regards,**** > > Vinay-**** > > *From:* Uma Maheswara Rao G [mailto:mahesw...@huawei.com] > *Sent:* Friday, November 16, 2012 1:26 PM > *To:* user@hadoop.apache.org > *Subject:* RE: High Availability - second namenode (master2) issue: > Incompatible namespaceIDs**** > > ** ** > > If you format namenode, you need to cleanup storage directories of > DataNode as well if that is having some data already. DN also will have > namespace ID saved and compared with NN namespaceID. if you format NN, then > namespaceID will be changed and DN may have still older namespaceID. So, > just cleaning the data in DN would be fine.**** > > **** > > Regards,**** > > Uma**** > ------------------------------ > > *From:* hadoop hive [hadooph...@gmail.com] > *Sent:* Friday, November 16, 2012 1:15 PM > *To:* user@hadoop.apache.org > *Subject:* Re: High Availability - second namenode (master2) issue: > Incompatible namespaceIDs**** > > Seems like you havn't format your cluster (if its 1st time made). **** > > On Fri, Nov 16, 2012 at 9:58 AM, a...@hsk.hk <a...@hsk.hk> wrote:**** > > Hi, **** > > ** ** > > Please help!**** > > ** ** > > I have installed a Hadoop Cluster with a single master (master1) and have > HBase running on the HDFS. Now I am setting up the second master > (master2) in order to form HA. When I used JPS to check the cluster, I > found :**** > > ** ** > > 2782 Jps**** > > 2126 NameNode**** > > 2720 SecondaryNameNode**** > > i.e. The datanode on this server could not be started**** > > ** ** > > In the log file, found: **** > > 2012-11-16 10:28:44,851 ERROR > org.apache.hadoop.hdfs.server.datanode.DataNode: java.io.IOException: > Incompatible namespaceIDs in /app/hadoop/tmp/dfs/data: namenode namespaceID > = 1356148070; datanode namespaceID = 1151604993**** > > ** ** > > ** ** > > ** ** > > One of the possible solutions to fix this issue is to: stop the cluster, > reformat the NameNode, restart the cluster.**** > > QUESTION: As I already have HBASE running on the cluster, if I reformat > the NameNode, do I need to reinstall the entire HBASE? I don't mind to have > all data lost as I don't have many data in HBASE and HDFS, however I don't > want to re-install HBASE again.**** > > ** ** > > ** ** > > On the other hand, I have tried another solution: stop the DataNode, edit > the namespaceID in current/VERSION (i.e. set namespaceID=1151604993), > restart the datanode, it doesn't work:**** > > Warning: $HADOOP_HOME is deprecated.**** > > starting master2, logging to > /usr/local/hadoop-1.0.4/libexec/../logs/hadoop-hduser-master2-master2.out* > *** > > Exception in thread "main" java.lang.NoClassDefFoundError: master2**** > > Caused by: java.lang.ClassNotFoundException: master2**** > > at java.net.URLClassLoader$1.run(URLClassLoader.java:202)**** > > at java.security.AccessController.doPrivileged(Native Method)**** > > at java.net.URLClassLoader.findClass(URLClassLoader.java:190)**** > > at java.lang.ClassLoader.loadClass(ClassLoader.java:306)**** > > at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)**** > > at java.lang.ClassLoader.loadClass(ClassLoader.java:247)**** > > Could not find the main class: master2. Program will exit.**** > > QUESTION: Any other solutions?**** > > ** ** > > ** ** > > ** ** > > Thanks**** > > ** ** > > ** ** > > ** ** > > **** > > ** ** > > ** ** > > ** ** > -- http://hortonworks.com/download/
