clustvirt - Libvirt cluster manager

Clustered virtualization has gotten to complicated. We have a great system for it built into the Linux kernel, with shared software stacks between whatever base distro you want to use.

Every other option has buy in, and buzzwords. I want something truly simple that can manage virtual machines on multiple hosts, integrating with existing tools, running from one/all of the hosts, a raspberry pi, or as a guest machine on the cluster itself.

The mission: Talk to libvirt hosts, coordinate them, manage them, and let people take their clusters back.

Overall goals:

• HA Cluster resource manager (simpler then existing options, just for libvirt)
  • Share secrets
  • Share VM configs
  • know what VM is running on what cluster host
  • trigger migrations of hosts
  • most simple quorum algorithm possible, ability to run 2 hosts reliably, up to ?? hosts without worry
    • Simplest quorum: If the controller can't reach it, it's down.
• Shared Network management
• Shared storage managment
  • Does not include clustered storage configuration
  • Can use different clustered storage systems (just not configure them directly)
• Reliable backup and snapshotting
  • The tools exist for this, just needs to be exposed
• Install on any libvirt system, as long as the basic requirements are met as far as compatibility is concerned
  • Should be able to have hosts on RedHat, Rocky, Arch, Ubuntu, Debian, whatever without worry
• Cloud-init configuration help to create useful and reusable cloud-init files, that don't need to be used by the system only. It's a standard, use it.

Existing tools and libraries to use

• [https://pkg.go.dev/libvirt.org/go/libvirt] Go Bindings for libvirt
  • Not sure if it can be used without libvirt existing on the system it's running on. Worth a try.

Roadmap

• Create simple daemon that can run on 1 or more hosts that will keep track of things
  • Libvirt daemon
    • Host Capabilities
    • Migration Capabilities
    • Secret management
    • Storage pool management
    • Volume management
    • Guest management
    • Connection management (to other libvirt hosts)
• Create a simple WebUI with HTMX to monitor that stuff
• Add the ability to manage that stuff once we can monitor it, through the WebUI.

Special XMLNS definitions

Domain

• xmlns:clustvirt="https://git.staur.ca/stobbsm/clustvirt"

<metadata>
    <clustvirt:data xmlns:clustvirt="https://git.staur.ca/stobbsm/clustvirt/">
        <clustvirt:created>true</clustvirt:created>
        <clustvirt:managed>true</clustvirt:managed>
        <clustvirt:currentHost>host01</clustvirt:currentHost>
        <clustvirt:origHost>host02</clustvirt:origHost>
        <clustvirt:baseGuest>rocky-9-base</clustvirt:baseGuest>
    </clustvirt:data>
</metadata>