KVM Templates

Alex Sage

How is the best way to create a KVM template?

Google Fu doesn't seem to be helping

Francesco Provino

@aaronstuder what is a “kvm template”?

Just script your virt-install and use a script to clone the base image.

black3dynamite

Here's an example of creating templates.
https://dnaeon.github.io/creating-a-template-for-kvm-virtual-machines/

stacksofplates

There's a couple ways. You could either create the VM manually and do your setup and then clone it later, or use virt-builder to pull in pre-built images. I usually go for virt-builder. The images are smaller and have things preset for KVM (like console access on ttyS0).

Just as a side note, one cool thing you can do with your templates is inject updated packages. Just do virt-customize --update --selinux-relabel on your template and it will update the packages inside and relabel SELinux (obv only use if it's a RHEL based VM).

Alex Sage

@stacksofplates Interesting. Can you tell me more about this?

Emad R

@stacksofplates

Is there web portal repo for virt-builder ?

And ever heard of RawHide VM? WTF is that ?

black3dynamite

@emad-r said in KVM Templates:

@stacksofplates

Is there web portal repo for virt-builder ?

http://builder.libguestfs.org/

Emad R

@black3dynamite said in KVM Templates:

@emad-r said in KVM Templates:

@stacksofplates

Is there web portal repo for virt-builder ?

http://builder.libguestfs.org/

Very nice thanks.

stacksofplates

@aaronstuder said in KVM Templates:

@stacksofplates Interesting. Can you tell me more about this?

Which part?

Alex Sage

@stacksofplates building templates using virt-builder

stacksofplates

@aaronstuder said in KVM Templates:

@stacksofplates building templates using virt-builder

Oh. It's pretty simple. virt-builder --list gives you a list of images you can use.

Then just create your template with virt-builder <os> --format <format> imagename.format

Then you can use virt-customize to inject packages, create users, set passwords, etc. Then just clone that for your template.

stacksofplates

After a specific amount of time, it will download a new image and cache it when running virt-builder. I forget what the amount of time is though.

black3dynamite

@stacksofplates That's cool, virt-customize has an option to copy files or directories into the image.

stacksofplates

@black3dynamite said in KVM Templates:

@stacksofplates That's cool, virt-customize has an option to copy files or directories into the image.

Ya, libguestfs has a bunch of cool tools.

black3dynamite

@stacksofplates said in KVM Templates:

@aaronstuder said in KVM Templates:

@stacksofplates building templates using virt-builder

Oh. It's pretty simple. virt-builder --list gives you a list of images you can use.

Then just create your template with virt-builder <os> --format <format> imagename.format

Then you can use virt-customize to inject packages, create users, set passwords, etc. Then just clone that for your template.

Is it necessary to add --selinux-relabel when downloading the VM?

stacksofplates

@black3dynamite said in KVM Templates:

@stacksofplates said in KVM Templates:

@aaronstuder said in KVM Templates:

@stacksofplates building templates using virt-builder

Oh. It's pretty simple. virt-builder --list gives you a list of images you can use.

Then just create your template with virt-builder <os> --format <format> imagename.format

Then you can use virt-customize to inject packages, create users, set passwords, etc. Then just clone that for your template.

Is it necessary to add --selinux-relabel when downloading the VM?

No. That’s all in the image. Only when updating the packages with libguestfstools