[Beowulf] Contents of Compute Nodes Images vs. Login Node Images

[Ryan Novosielski]

> On Oct 23, 2018, at 2:10 PM, Greg Lindahl <lindahl at pbm.com> wrote:
> 
> On Tue, Oct 23, 2018 at 05:48:00PM +0000, Ryan Novosielski wrote:
> 
>> We’re getting some complaints that there’s not enough stuff in the
>> compute node images, and that we should just boot compute nodes to
>> the login node image
> 
> It's probably worth your while sitting down with your users and
> learning how they want to use the tool, instead of telling them.

In general, good advice; not totally applicable here. An example would be that we’re frequently asked to install things by users that are already installed, just a different way (by modules, or whatever else) than the user is used to or that the steps in their documentation said (eg. “Can you please run the following: yum install whatever — I tried but I don’t have root access.” Management sometimes reads these and says “why do we keep getting these requests, just install everything.” We also have another group that works more closely with users, have identified cases where “it works on the login node” and often extrapolate the solution without relaying the problem (or understanding the architecture). We’ll get to the bottom of that, but I wanted to know more generally what sites are doing.

Our node images are in RAM, generally, so putting a bunch of extra stuff in them for no good reason does have an impact, although it’s less than it was when installed memory was lower, and it also all needs to be transferred on a cold start.

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