How can I change yarn.nodemanager.local-dirs to point to file:/// (high performance NFS mount point)

[#1]

Hi,

I'm trying to change the "yarn.nodemanager.local-dirs" to point to "file:///fast_nfs/yarn/local". This is indeed a high-performance NFS mount-point that all the nodes in my cluster have.

When I try to change it in Ambari I can't and the message "Must be a slash or drive at the start, and must not contain white spaces" is displayed.

If I manually change the /etc/hadoop/conf/yarn-site.xml in all the nodes, after restarting YARN the "file:///" is removed from that option.

I want to have all the shuffle happening in my high-performance NFS array instead of in HDFS.

How can I change this behaviour in HDP?

[#2 · Accepted solution]

@Raul Pingarrón

The culprit is "file:/// "you should get a was to create a mount point /fast_nfs/yarn/local, hence the message "Must be a slash or drive ........" like te list below

/hadoop/yarn/local,/opt/hadoop/yarn/local,/usr/hadoop/yarn/local,/var/hadoop/yarn/local

Hope that helps

[#3]

@Geoffrey Shelton Okot you're absolutely right! Thank you a lot.

I was struggling to understand why I was loosing containers the first time I used "/fast_nfs/yarn/local (was getting "file not found" error messages) and then the tiredness made me think of using hdfs:/// instead...and I ended up sending this dumb question.

My initial problem was caused by the fact that I was using the same NFS filesystem and path for all the nodes. After mounting /fast_nfs/nodeXXX/ on each node (where nodeXXX contains the yarn/local subdir) and adjusting permissions it worked perfectly (note that node1 gets /fast_nfs/node001 mounted as /scratch, node2 gets /fast_nfs/node002 mounted as /scratch and so on, so I'm using /fast_nfs as the NFS filesystem and mounting subdirs for each node..and defined yarn.nodemanager.local-dir as "/scratch/yarn/local")