# 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"`

```xml
<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>
```

### Open Source Projects

The following projects are being used as part of ClustVirt.
Only those being used directly are listed, not the dependencies.

#### Go

| Library | Use | License |
| ---     | --- | ---     |
| [xdg](https://github.com/adrg/xdg)                   | XDG paths                          | MIT |
| [spf13/viper](https://github.com/spf13/viper)        | Configuration                      | MIT |
| [spf13](https://github.com/spf13/cobra)              | Command Pattern CLI                | Apache 2.0 |
| [go-chart/v2](https://github.com/wcharczuk/go-chart) | Chart generation                   | MIT |
| [libvirt](https://libvirt.org/go/libvirt)            | Communications with Libvirtd       | MIT |
| [libvirtxml](https://libvirt.org/go/libvirtxml)      | Libvirt XML parsing and generation | MIT |
| [templ](https://github.com/a-h/templ)                | HTML Templating Engine             | MIT |
| [chi/v5](https://github.com/go-chi/chi)              | HTTP Routing                       | MIT |

#### Node NPM

| Library | Use | License |
| ---     | --- | ------- |
| [tailwindcss](https://tailwindcss.com)       | CSS UI library           | MIT     |
| [tailwindcss/forms](https://tailwindcss.com) | CSS UI library for forms | MIT     |