2023-06-25 20:18:31 +00:00
|
|
|
---
|
|
|
|
|
title: "LXD: Containers for Human Beings"
|
|
|
|
|
subtitle: "Docker's great and all, but I prefer the workflow of interacting with VMs"
|
|
|
|
|
date: 2023-06-14T10:50:41-04:00
|
|
|
|
|
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
|
|
|
|
|
|
|
|
|
|
## 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:**
|
2023-07-18 17:21:24 +00:00
|
|
|
|
|
|
|
|
## 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
|
|
|
|
|
|
|
|
|
|
> See Drew DeVault's blog post [_In praise of qemu_](https://earl.run/rmBs) for a great use of VMs
|
|
|
|
|
|
|
|
|
|
### 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`
|
