📝 Docker Deep Dive - Notes
==========================

Date: April 23, 2021

## Play With Docker

A handy way to try weird things in docker is using
[play-with-docker](https://play-with-docker.com). You get a four hour session for
free, after four hours everything will be deleted, but you can start a new
session.

### Installing Docker on Linux

Installing on Ubuntu.

``` bash
wget -qO- https://get.docker.com/ | sh
```

### Running Docker commands without sudo

In order to run docker commands without using sudo you need to add docker to
your group.

``` bash
sudo usermod -aG docker ubuntu
```

## Architecture and Theory

**Container** - Isolated area of an OS with resource usage limits applied.

Namespaces and Control Groups are hard, which is why containers were unusable
by mortals before docker.

## Namespaces

_Isolation_

Each container looks and feels like a regular OS. It has its own eth0, users,
kernel. These are completely isolated from every other container running on
the system.

Namespaces are analogous to what Hypervisors do on hardware.

* Process ID (pid)
* Network (net)
* Filesystem/mount (mnt)
* Inter-proc comms (ipc)
* UTS (uts)
* User (usr)

## Control Groups

_Resource usage limits_