Great writeup Benoit. In Ambari 2.1.0, the host_name will exist in only the hosts table, and all other tables will reference a host_id as FK. https://issues.apache.org/jira/browse/AMBARI-10167
Thanks, Alejandro From: Benoit Perroud <[email protected]<mailto:[email protected]>> Reply-To: "[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>> Date: Monday, April 20, 2015 at 12:42 PM To: "[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>> Subject: Re: Change hostname on running cluster I did it earlier this year with Ambari 1.7 and postgresql. As noticed earlier, no master processes was running on the nodes I renamed. Provided without guarantees : http://www.swiss-scalability.com/2015/01/rename-host-in-ambari-170.html 2015-04-19 13:22 GMT+02:00 Frank Eisenhauer <[email protected]<mailto:[email protected]>>: Seems like renaming a host is more complex than expected, especially in my case, where I have to rename the hosts with the master services like the namenode, hbase master etc. I'm currently considering to install the test lab from scratch and migrate the "old" lab to the newly installed one. On Sunday, April 19, 2015, Alejandro Fernandez <[email protected]<mailto:[email protected]>> wrote: Renaming a host also has implications because NameNode and other services can still have references to the old name in several configs. If the host has no master components, then it's definitely easier. The following steps can be used to change host name in the Ambari database, so please use at your own risk. 1. Stop all services through Ambari UI. 2. Stop ambari-server on Ambari server host from command line, run: > ambari-server stop 3. Stop ambari-agent on all of the hosts from command line, run: > ambari-agent stop This is done to make sure that operation safer. 4. Backup database on the Ambari server from command line, please run: > mkdir /var/db_backup > cd /var/db_backup Postgres > pg_dump -U ambari ambari > ambari1.sql (default password: bigdata) > pg_dump -U mapred ambarirca > ambarirca1.sql (default password: mapred) MySQL In Linux, the MySQL databases are stored in /var/lib/mysql by default. > mysqldump -u ambari ambari > ambari1.sql (default password: bigdata) 5. Replace all occurrences of old hostname with new hostname. For example: > sed 's/old-hostname/new-hostname/g' ambari1.sql > ambari2.sql > sed 's/old-hostname/new-hostname/g' ambarirca1.sql > ambarirca2.sql (not > needed when using MySQL) Warning: Use tools that are appropriate for you. Please be careful to not accidentally replace unintended strings in the database data. 6. Clean up Ambari database from command line, please run: > ambari-server reset 7. Recreate Ambari database from command line, please run: Postgres > su postgres -c 'psql -c "drop database ambari" ' > su postgres -c 'psql -c "drop database ambarirca" ' > su postgres -c 'psql -c "create database ambari" ' > su postgres -c 'psql -c "create database ambarirca" ' MySQL > mysql -u ambari -pbigdata (or other password) mysql> DROP DATABASE ambari; mysql> CREATE DATABASE ambari; mysql> exit; 8. Load into Ambari database with the modified database generated in step 5 and run the following commands: Postgres > su postgres -c 'psql -f ambari2.sql -d ambari' > su postgres -c 'psql -f ambarirca2.sql -d ambarirca' MySQL > mysql -u ambari -pbigdata ambari < ambari2.sql (default password: bigdata) 9. Start ambari-server on Ambari server host from command line, please run: > ambari-server start 10. Start ambari-agent on all of the hosts from command line, please run: > ambari-agent start 11. Verify that Ambari shows new host name. 12.Restart all services through Ambari UI, this will cause all components to pick up any changes in configs. Note: This procedure does not modify any database that is used by Hadoop components such as Hive metastore database or Oozie database. If database access were granted to old hosts, you may need to grant permissions to the new host before starting the Hadoop service. Thanks, Alejandro On 4/18/15, 1:16 PM, "Yusaku Sako" <[email protected]> wrote: Just FYI... What I've seen folks do is dump the database, keep a backup, replace all occurrences of the old hostname to the new hostname in the dump file, then reimport. Yusaku On 4/18/15 9:51 AM, "Sumit Mohanty" <[email protected]> wrote: +Alejandro In theory, you can stop ambari-server, modify all occurrences of the hostname and that should be it. There is not first class support for it. Alejandro, did you look at the possibility of manually changing all host names to rename a host (https://issues.apache.org/jira/browse/AMBARI-10167) -Sumit ________________________________________ From: Frank Eisenhauer <[email protected]> Sent: Saturday, April 18, 2015 12:31 AM To: Ambari User Subject: Change hostname on running cluster Hi All, we have a running hadoop cluster where we unfortunately have a hostname in uppercase, e.g. SRV-HADOOP01.BIGDATA.LOCAL. As of Ambari 1.7 we are experiencing a lot of side effects which are presumably caused by the hostnames in uppercase. I would like to rename the particular hosts(e.g. srv-hadoop01.bigdata.local), so that there are only hosts with lowercase names in the cluster. Is it possible to change the hostname? I came across a few blogs, but in general renaming hostnames seems not to be recommended. Has anyone performed a hostname change? Many thanks in advance.
