StarCluster - Mailing List Archive

Re: Adding New NFS Volumes to Cluster

From: Jennifer Staab <no email>
Date: Wed, 27 Aug 2014 22:41:27 -0400

I going to assume are using NFS for volumes mounted on the master node
of your cluster, the answer is different if you are using NFS between
your cluster and an EC2 outside your cluster but within the same VPC.

You should be able to use the config file to set the volumes you want
mounted and call them in your cluster template. Noting that you can
only have one cluster with that mounted volume at any one time. If your
volume is mounted to another cluster (running or not), it cannot be
mounted to the new cluster you create (thought this might be the issue
you are having).
[cluster YourClusterTemplate]
VOLUMES = YourVolume
# Sections starting with "volume" define your EBS volumes
[volume YourVolume]
VOLUME_ID = vol-xxxxxxxxx
MOUNT_PATH = /YourMountPath

Now if you have a running cluster and you want to mount other volumes
that are seen by all nodes on that cluster there is a way to do this,
but it requires you have the "crossmnt" option specified in
"/etc/exports" for "/home" and/or "/YourMountPath". I edited my version
of Starcluster so that the "crossmnt" option was automatically set so
that I could mount underneath the volumes that were mounted via
starcluster config.
LIKE /etc/exports:
/home YourCluster(async,no_root_squash,no_subtree_check,rw,crossmnt)
/opt/sge6 YourCluster(async,no_root_squash,no_subtree_check,rw)

Then you can simply use the AWS console to attach your new volume to the
running Master node. Next login to the the Master node and use the
"mount" command to mount the newly attached volume underneath an already
mounted volume LIKE "mount /dev/xvdXX/ home/NewVolume" OR "mount
/dev/xvdXX /YourMountPath/NewVolume". This trick only works if you have
"crossmnt" option set in /etc/exports. If you edit /etc/exports to add
"crossmnt" option you will have to run "exportfs -r" or restart NFS on
Master node to reload /etc/exports file.The command "lsblk" should show
you the new volumes all mounted. Admittedly I haven't personally tried
to mount under /home -- I just suggested it should work since
StarCluster software automatically shares /home among all nodes of the
cluster. One hard fast AWS rule is that an EBS volume can only be
mounted to one EC2 at a time, this is why the EBS volume is attached and
mounted to the Master node, and NFS is used to allow the volume to be
seen by all nodes of the cluster.

Hope this helps,


On 8/27/14 7:26 PM, Dave Lin wrote:
> I was trying to figure out the best way to add new volumes (NFS
> mounted) to a running cluster.
> I searched through the archives and found this open feature request
> 1) Is there a suggested process or plugin for doing this?
> 2) One way I've been doing this is to just modify the config,
> terminate and restart the cluster. When I tried to restart the cluster
> after modifying the config, the new volumes didn't seem to get
> mounted. Is the restart supposed to read the config again?
> Thanks in advance,
> Dave
> _______________________________________________
> StarCluster mailing list
Received on Wed Aug 27 2014 - 22:41:30 EDT
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