question Re: How to specify multiple fencing methods in dfs.ha.fencing.methods in Archives of Support Questions (Read Only)

How to specify multiple fencing methods in dfs.ha.fencing.methods

KuldeepK — Wed, 16 Mar 2016 01:35:01 GMT

This is new question based on answers provided at https://community.hortonworks.com/questions/23046/question-on-hdfs-automatic-failover.html

Question - If I need to define multiple fencing methods in dfs.ha.fencing.methods (hdfs-site.xml), how should I do that? Is that even possible? I tried putting comma separated values, semi colon separated, colon separated but nothing worked(I got parsing error in ZKFC logs)

Please suggest.

Re: How to specify multiple fencing methods in dfs.ha.fencing.methods

KuldeepK — Wed, 16 Mar 2016 01:46:20 GMT

More info - according to this link, value of dfs.ha.fencing.methods shows 2 fencing methods, each one is on new line. I believe we cannot enter it using ambari UI. Not sure if that link has valid and verified information.

Re: How to specify multiple fencing methods in dfs.ha.fencing.methods

hosako — Wed, 16 Mar 2016 10:30:38 GMT

https://hadoop.apache.org/docs/r2.7.1/hadoop-project-dist/hadoop-hdfs/HDFSHighAvailabilityWithQJM.html

According to above link, it seems it accepts carriage-return-separated list.

Re: How to specify multiple fencing methods in dfs.ha.fencing.methods

KuldeepK — Wed, 16 Mar 2016 10:52:19 GMT

Nevermind! I have figured out the problem.

Many Thanks to @Hajime and @Sagar Shimpi for helping me here.

To add multiple fencing methods we need to run below command from Ambari Server

/var/lib/ambari-server/resources/scripts/configs.sh -u admin -p admin set <ambari-host> <cluster-name> hdfs-site dfs.ha.fencing.methods  "sshfence\\nshell(/bin/true)"

I think this is a bug with Ambari, I will make sure to file a Ambari BUG for this today.

Re: How to specify multiple fencing methods in dfs.ha.fencing.methods

KuldeepK — Wed, 16 Mar 2016 10:53:33 GMT

Thanks @Hajime - It was a real hint for solving this issue