134 lines
3.9 KiB
Markdown
134 lines
3.9 KiB
Markdown
# `qemush` - A suckless QEMU wrapper written in shell
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[](https://nogithub.codeberg.page)
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## How does it work
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`qemush` allows to run commands as Unix user `qemu` to manage virtual
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machines and their disks associated.
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## Why
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`qemush` is **daemonless**: no bloaty long running process is needed for
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`qemush` to work.
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`qemush` is **lightweight**: it only consists in a shell script to
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automate repeated tasks and force good practices.
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`qemush` needs **few dependencies**: see section
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[Dependencies](#dependencies) for details.
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`qemush` is **hackable**: you can [write your own launching
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scripts](#writing-a-launching-script) to make it work as intended.
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`qemush` is **easy to setup**: you can make it work in a few steps, see
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section [Installation instructions](#installation-instructions).
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## Good practices?
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Here is a list of good practices forced by `qemush`.
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- **Processes running as user `qemu`**: members of group `qemu` can manage
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the same virtual machines
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- **Modularization**: `qemush` launching scripts are intended to be
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stackable to reuse common `qemu` parameters in all virtual machines
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needing them
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keep track of them
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- **Copy-on-write**: images are formatted using `qcow2` to use less space
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on disk
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- **Process detachment**: you can log out and have your virtual machines
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still running, control them via Unix sockets
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## Dependencies
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All dependencies are common packages for a distribution, you'll be able to
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grab them from your favorite packages sources.
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- `qemu` - this is literally a QEMU wrapper so there's a chance you'll
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need it
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- `bash` - the `qemush` interpreter
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- `coreutils` - used for basic OS operations
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- `sudo` - execute commands as `qemu`
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- `socat` - monitor machines via Unix sockets
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- `pathof` - see [Installation instructions](#installation-instructions)
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- any text editor - used for builtin function to edit launching scripts
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## Installation instructions
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### QEMU user and group
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`qemush` acts as Unix user `qemu` to manage virtual machines. You need to
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create a system user `qemu` that cannot login, with any home directory,
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in an Unix group of the same name. Example:
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```sh
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# Example if the qemu user doesn't exist
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# Make sure /etc/shells contains /bin/nologin
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useradd -r -s /bin/nologin qemu
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```
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For ease of use, you need to grant every user in the `qemu` group via
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`sudo` the right to execute commands as `qemu`. You can find an example
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`sudoers` rule in this repo's `etc/sudoers.d` folder.
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### Via `Makefile` (recommended)
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Just run the following command at the root of this repository to install
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`qemush` (previous step is **mandatory**) :
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```sh
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make
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```
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> And what if I don't want to bindly run this obscure `Makefile` ???
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You'd be right. The next section is the exhaustive list of steps handled
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by the `Makefile` for the installation process.
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### Manual installation (what does the `Makefile` do)
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- Create `disks`, `launchers` and `bin` directories in `~qemu`
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- Copy `qemush` scripts parts from `qemu/bin` in `~qemu/bin` with mode
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`740`
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- Compile C programs from `src` in `~qemu/bin` with mode `740`
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- Copy the default launching scripts to `~qemu/launchers` with mode `740`
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- Copy `bin/qemush` to `/usr/local/bin/qemush` with mode `755`
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## Usage
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### Writing a launching script
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The default text editor used by `qemush` is `nvim`, but it can be
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overriden by the `EDITOR` environment variable.
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Run the following command to start editing a launching script by the name
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of your choice:
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```sh
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qemush edit "$name"
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```
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Example scripts are available in this repo's `qemu/launchers` folder.
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### Launching a virtual machine
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Virtual machines are identified by the name of their launching scripts.
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You can launch any machine with the following command:
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```sh
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qemush start "$name"
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```
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You can also list all available virtual machines by running this command:
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```sh
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qemush ls
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```
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### Other uses
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You can show the full list of possible actions by running this command:
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```sh
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qemush help
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```
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