---
title: "LXD: Containers for Human Beings"
subtitle: "Docker's great and all, but I prefer the workflow of interacting with VMs"
date: 2023-08-11T16:30:00-04:00
categories:
  - Technology
tags:
  - Sysadmin
  - Containers
  - VMs
  - Docker
  - LXD
draft: true
rss_only: false
cover: ./cover.png
---

This is a blog post version of a talk I presented at both Ubuntu Summit 2022 and
SouthEast LinuxFest 2023. The first was not recorded, but the second was and is
on [SELF's PeerTube instance.][selfpeertube] I apologise for the terrible, but
there's unfortunately nothing I can do about that.

[selfpeertube]: https://peertube.linuxrocks.online/w/hjiTPHVwGz4hy9n3cUL1mq?start=1m

{{< adm type="warn" >}}

**Note:** Canonical has decided to [pull LXD out][lxd] from under the Linux
Containers entity and instead continue development under the Canonical brand.
The majority of the LXD creators and developers have congregated around
[Incus.][inc] I'll be keeping a close eye on the project and intend to migrate
as soon as there's an installable release.

[lxd]: https://linuxcontainers.org/lxd/
[inc]: https://linuxcontainers.org/incus/

{{< /adm >}}

## The benefits of VMs and containers

- **Isolation:** we don't want an attacker to get into our webserver and be able
  to gain access to our email server
- **Flexibility:** <abbr title="Virtual Machines">VMs</abbr> and containers only
  use the resources they've been given
- **Portability:** once set up and configured, VMs and containers can mostly be
  treated as black boxes; as long as the surrounding environment is similar to
  the previous in terms of communication, they can just be picked up and dropped
  on bare metal servers as necessary.
- **Density:**
- **Cleanliness:**

## Virtual machines

```goat
 .---------------------------------.
|  .-------.  .-------.  .-------. |
| | Guest  | | Guest  | | Guest  | |
| | OS     | | OS     | | OS     | |
| .---+---'  .---+---'  .---+---'  |
|  .--+----.  .--+----.  .--+----. |
| | Guest  | | Guest  | | Guest  | |
| | Kernel | | Kernel | | Kernel | |
| .---+---'  .---+---'  .---+---'  |
|  .--+----------+----------+----. |
| |          Hypervisor          | |
| .--------------+--------------'  |
|  .-------------+---------------. |
| |          Host Kernel         | |
| .-----------------------------'  |
.---------------------------------'
```

## Containers

```goat
       Application containers                 System containers
 .---------------------------------.   .------------------------------.
|  .-------.  .-------.  .-------. |  |  .------.  .------.  .------. |
| | App 01 | | App 02 | | App 03 | |  | | Guest | | Guest | | Guest | |
| '---+---'  '---+---'  '---+---'  |  | | OS    | | OS    | | OS    | |
|  .--+----------+----------+----. |  | '---+--'  '---+--'  '---+--'  |
| |          Hypervisor          | |  |  .--+---------+---------+---. |
| '--------------+--------------'  |  | |         Host Kernel       | |
|  .-------------+---------------. |  | '--------------------------'  |
| |          Host Kernel         | |  '------------------------------'
| '-----------------------------'  |
'---------------------------------'
```

## When to use which

### Virtual machines

- Virtualising esoteric hardware
- Virtualising non-Linux operating systems (Windows, macOS)
- Completely isolating processes from one another with a decades-old, battle-tested technique

{{< adm type="note" >}}
See Drew DeVault's blog post [_In praise of qemu_](https://earl.run/rmBs) for a great use of VMs
{{< /adm >}}

### Application containers

- Microservices
- Extremely reproducible builds
  - (NixOS.org would likely be a better fit though)
- Dead-set on using cloud platforms with extreme scaling capabilities (AWS, GCP, etc.)
- When the app you want to run is _only_ distributed as a Docker container and
  the maintainers adamantly refuse to support any other deployment method
  - (Docker does run in LXD 😉)

### System containers

- Anything not listed above 👍

## Crash course to LXD

1. Install snap following [Canonical's tutorial](https://earl.run/ZvUK)
   - LXD is natively packaged for Arch and Alpine, but configuration can be a massive headache.
2. `sudo snap install lxd`
3. `lxd init`
4. `lxc image copy images:debian/11 local: --alias deb-11`
5. `lxc launch deb-11 container-name`
6. `lxc shell container-name`