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AWS ParallelCluster - changing compute node config after cluster creation


I have created a Slurm cluster on Ubuntu 20.04 using AWS ParallelCluster.

I then made a bunch of manual changes to the head/login node. I want to make a couple of small changes to the compute nodes as well (just install a couple of apt packages).

I know that I should treat the cluster as ephemeral and the way to make changes should be to use pcluster to change the cloudformation stack that generates the cluster. But in this case I am just trying to demo something and I've already invested time in making changes to the head node - I'm looking for a more quick and dirty solution with my existing cluster.

So what I am wondering is, is there any way to modify the compute instances short of recreating this cluster? For example, could I change the AMI that is used to launch these instances, or set/modify the user data or launch template that is run when they start?


2 Answers

PCluster use "Launch Template" to start EC2 resource when submitting jobs. You can find a Launch Template name like "<ClusterName>-<Partition-NodeList>", try to change it.

answered 5 months ago

The suggested alternative is to use a custom bootstrap script to install the required software in your compute nodes.

If you're using ParallelCluster 3.x you can also think to update the AMI of the compute nodes, through the CustomAmi configuration parameter (the compute fleet must be stopped to be able to perform this update).

answered 5 months ago

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