Creating a custom RHEL image for MAAS

17 Sep

A little change from our typical programming, today’s post is about how to add an image to an Ubuntu MaaS instance.

So what is a Sr Consultant, specializing in Azure and containerization doing working with Linux in an on-premises environment?

As far-removed as it seems from the norm of what we do at Avanade, there is still a lot of demand for on-prem solutions. Many cases are like ours; we have a large lab full of equipment we’ve already paid for and it makes fiscal sense to do much of our dev work there.

In our lab, we utilize MAAS (Metal as a Service) to manage our hardware. Out of the box (for the free version of MAAS at least), MAAS comes with images for Ubuntu and CENTOS. With the paid version of MAAS, you get Windows and RHEL images as well.

A brief glance around the internet showed that there used to be a tool called MAAS-image-builder that allows for the custom creation of RHEL images. Ubuntu seems to have burried many of the references to this once they started using images as a differentiation between free and paid versions. There are actually a few branches of this, none of which worked out of the box.

The version we eventually got to work was this one:
https://code.launchpad.net/~ltrager/maas-image-builder/update_ks

To make it work, you must build it as per the instructions, and once installed, make a few changes:

1. Add the following to /usr/lib/maas-image-builder/contrib/rhel/rhel7-amd64.ks in the %packages section:

Without the python2-oauthlib.noarch and python2-requests-oauthlib.noarch packages, the install will complete, but MAAS will register it as a failed deployment.

Additionally, as anyone familiar with kickstart files will probably tell you, it’s advisable to create a standard user account, and register your subscription in addition to any other customization you want to add to your image.

One caveat however: Keep in mind that no matter what you do with the part command in your kickstart, it won’t actually make a difference to the final install process in MAAS. MAAS manages storage layouts on its own, and won’t allow a custom storage layout for any OS other than Ubuntu.

Ryan Femling

I’m a Sr Consultant with Avanade specializing in Azure cloud solutions. I have 19 years of IT experience.