113 lines
4.6 KiB
Markdown
113 lines
4.6 KiB
Markdown
# `qemush` - A suckless QEMU wrapper written in shell
|
|
|
|
[](https://nogithub.codeberg.page)
|
|
|
|
## How does it work
|
|
|
|
`qemush` allows to run commands as Unix user `qemu` to manage virtual machines and their disks associated.
|
|
|
|
## Why
|
|
|
|
`qemush` is **daemonless**: no bloaty long running process is needed for `qemush` to work.
|
|
|
|
`qemush` is **lightweight**: it only consists in a shell script to automate repeated tasks and force good practices.
|
|
|
|
`qemush` needs **few dependencies**: see section [Dependencies](#dependencies) for details.
|
|
|
|
`qemush` is **hackable**: you can [write your own launching scripts](#writing-a-launching-script) to make it work as intended.
|
|
|
|
`qemush` is **easy to setup**: you can make it work in a few steps, see section [Installation instructions](#installation-instructions).
|
|
|
|
## Good practices?
|
|
|
|
Here is a list of good practices forced by `qemush`.
|
|
|
|
- **Processes running as user `qemu`**: members of group `qemu` can manage the same virtual machines
|
|
- **Modularization**: `qemush` launching scripts are intended to be stackable to reuse common `qemu` parameters in all virtual machines needing them keep track of them
|
|
- **Copy-on-write**: images are formatted using `qcow2` to use less space on disk
|
|
- **Process detachment**: you can log out and have your virtual machines still running, control them via Unix sockets
|
|
|
|
## Is it better than `libvirt` ?
|
|
|
|
No. `qemush` and `libvirt` are for different use cases. `qemush` will allow you to spin up virtual machines really fast and with as little setup as possible, and aims to be nothing more than a QEMU wrapper, while `libvirt` will offer better out-of-the-box experience, with already existing pre-configurations, associated tools like the `virt-manager` GUI and a friendlier process supervision. You should use `qemush` if you care about controlling every aspect of your virtual machines, and are already used to using bare QEMU without an abstraction layer.
|
|
|
|
## Dependencies
|
|
|
|
From version 0.9.0, `qemush` is written in pure POSIX shell! The previous dependency on `bash` was removed in consequence.
|
|
|
|
All dependencies are common packages for a distribution, you'll be able to grab them from your favorite packages sources.
|
|
|
|
- `qemu` - this is literally a QEMU wrapper so there's a chance you'll need it
|
|
- `coreutils` - used for basic OS operations
|
|
- `sudo` - execute commands as `qemu`
|
|
- `socat` - monitor machines via Unix sockets
|
|
|
|
## Installation instructions
|
|
|
|
### QEMU user and group
|
|
|
|
`qemush` acts as Unix user `qemu` to manage virtual machines. You need to create a system user `qemu` that cannot login, with any home directory, in an Unix group of the same name. Example:
|
|
|
|
```sh
|
|
# Example if the qemu user doesn't exist
|
|
# Make sure /etc/shells contains /bin/nologin
|
|
useradd -r -s /bin/nologin qemu
|
|
```
|
|
|
|
For ease of use, you need to grant every user in the `qemu` group via `sudo` the right to execute commands as `qemu`. You can find an example `sudoers` rule in this repo's `etc/sudoers.d` folder.
|
|
|
|
### Via `Makefile` (recommended)
|
|
|
|
Just run the following command at the root of this repository to install `qemush` (previous step is **mandatory**) :
|
|
|
|
```sh
|
|
make
|
|
```
|
|
|
|
> And what if I don't want to bindly run this obscure `Makefile` ???
|
|
|
|
You'd be right. The next section is the exhaustive list of steps handled by the `Makefile` for the installation process.
|
|
|
|
### Manual installation (what does the `Makefile` do)
|
|
|
|
- Create `disks`, `launchers`, `shared`, `sockets/monitors`, `socket/spice` and `bin` directories in `~qemu`
|
|
- Copy `qemush` scripts parts from `qemu/bin` in `~qemu/bin` with mode `740`
|
|
- Compile C programs from `src` in `~qemu/bin` with mode `740`
|
|
- Copy the default launching scripts to `~qemu/launchers` with mode `740` ; this is optional but the one called `kvm` is the reference `qemush` launching script!
|
|
- Copy `bin/qemush` to `/usr/local/bin/qemush` with mode `755`
|
|
|
|
## Usage
|
|
|
|
### Writing a launching script
|
|
|
|
The default text editor used by `qemush` is `vi`, but it can be overriden by the `EDITOR` environment variable.
|
|
|
|
Run the following command to start editing a launching script by the name of your choice:
|
|
|
|
```sh
|
|
qemush edit "$name"
|
|
```
|
|
|
|
Example scripts are available in this repo's `qemu/launchers` folder.
|
|
|
|
### Launching a virtual machine
|
|
|
|
Virtual machines are identified by the name of their launching scripts. You can launch any machine with the following command:
|
|
|
|
```sh
|
|
qemush start "$name"
|
|
```
|
|
|
|
You can also list all available virtual machines by running this command:
|
|
|
|
```sh
|
|
qemush ls
|
|
```
|
|
|
|
### Other uses
|
|
|
|
You can show the full list of possible actions by running this command:
|
|
|
|
```sh
|
|
qemush help
|
|
```
|