title: Loading lustre kernel modules on AWS linux
body: <p>I'm trying to load lustre modules into a Linux instance running Linux 4.15.0-1040-aws and a 18.04 Ubuntu disk image (the 18.04 AMI).</p>
  
  <p>I've downloaded and installed (i.e. dpkg -i) the lustre client debs for 18.04 from <a href="https://downloads.whamcloud.com/public/lustre/lustre-2.12.2/ubuntu1804/client/" rel="nofollow noreferrer">Ubuntu 18.04 - Lustre 2.12.2</a>:</p>
  
  <pre><code>- lustre-client-modules-4.15.0-45-generic_2.12.2-1_amd64.deb
  - lustre-client-utils_2.12.2-1_amd64.deb
  </code></pre>
  
  <p>The .ko module files get installed in /lib/modules/4.15.0-45-generic/updates/fs/, but they're not picked up by default by modprobe, because they're outside my kernel's default lookup path: /lib/modules/4.15.0-1040-aws. </p>
  
  <p>Is there a way to get them loaded, or does my kernel need to match exactly what is provided by the deb? Are users expected to muck around with writing custom lustre .conf files for modprobe?</p>
  
  <p><strong>Edit</strong></p>
  
  <p>I think the answer is probably that the kernel needs to precisely match the modules -- which may require recompilation of the module source code. I've eventually managed to install the lustre client on a linux 4.14.123-111.109.amzn2.x86_64, but that's running on "Amazon Linux 2" image (not ubuntu 18.04), and I had to use the command <code>amazon-linux-extras install -y lustre2.10</code>.</p>
  
  <p>The other thing which I'd not initially realized, is that amazon's Lustre FSx is only compatible with Lustre client 2.10.5 and 2.10.6 (see note at the top of <a href="https://docs.aws.amazon.com/fsx/latest/LustreGuide/install-lustre-client.html" rel="nofollow noreferrer">this page</a>), in case that matters. Tricky.</p>