virsh and/or lxc is all I ever use. All that cloud stuff, docker, kub-whatever is overkill to run a few VMs or containers at a small scale on-prem. KISS.
In terms of speed, how is virt-builder compare to say Terraform?
Terraform is dog slow sometimes due to cloud provisioning. Would be nice to just be able to build the VM locally then push the AMI/VHD into AWS or Azure.
virt-builder can usually build out a disk image in 15-60 seconds if the template has already been downloaded and you're running on baremetal. Might be 120 seconds if you have to use nested KVM or TCG.
$ virt-builder fedora-33
[ 1.5] Downloading: http://builder.libguestfs.org/fedora-33.xz
[ 2.3] Planning how to build this image
[ 2.3] Uncompressing
[ 8.6] Opening the new disk
[ 13.8] Setting a random seed
[ 13.8] Setting passwords
virt-builder: Setting random password of root to mZbPJw9d1ZHgowBk
[ 14.8] Finishing off
Output file: fedora-33.img
Output size: 6.0G
Output format: raw
Total usable space: 6.0G
Free space: 4.7G (79%)
I don't know how Terraform works, but `virt-builder` will cache the xz-compressed template images locally on your first pull. So for example, if you build a Fedora image:
$ virt-builder fedora-32 --size 10G --format qcow2
You might want to give it a whirl and see if it satisfies your needs; `virt-builder` should be available on most major Linux distributions.
• virsh — This[1] is libvirt's shell interface; and gives you access to the rich set of libvirt APIs.
• virt-builder — Use this for rapidly building minimal or customized virtual machines; it's greatly flexible; check out its man page[2]. And here's[3] a quick example that connects both virt-builder and virsh together.
• virt-install — Use this if you don't like the default build of the template images from virt-builder; it lets you create "headless" servers via 'kickstart' and Linux OS trees from the command-line.
• guestfish and libguestfs suite[4] — This rich set of tools help you in a variety of use-cases: repairing your broken disk images, editing, cloning, debugging disk images, and more. It has saved my behind a lot of times.
• qemu-img[5] – This Swiss Army knife lets you powerfully manipulate disk images (QCOW2, raw, et al) offline. Example operations include: create images, backing chains, offline snapshots, disk image merging, ability to convert disk images from one format to another, and more.
[1] https://libvirt.org/manpages/virsh.html
[2] https://libguestfs.org/virt-builder.1.html
[3] https://developer.fedoraproject.org/tools/virt-builder/about...
[4] http://libguestfs.org/
[5] https://qemu.readthedocs.io/en/latest/tools/qemu-img.html