# Get started with docker & docker-compose

Installation instructions for Ubuntu Linux from: https://docs.docker.com/engine/install/ubuntu/


## Uninstall old versions
```sh
sudo apt-get remove docker docker-engine docker.io containerd runc
```

## Install Docker & docker-compose-plugin (on Ubuntu)
```sh
sudo apt update
sudo apt install ca-certificates curl gnupg lsb-release
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

sudo apt update
sudo apt install docker-ce docker-ce-cli containerd.io docker-compose-plugin
```


## Usage
Full docs are here: https://docs.docker.com/compose/reference/overview/

Generally the idea of `docker compose` command is simple:
1. First you create a folder for your service, e.g. `home-assistant`
2. Then you then create a `docker-compose.yml` file, which describes the service containers
3. You run `docker compose up -d` and you're done!

Here are the most frequently used commands:


#### Start a container
`-d` starts in a detached mode - which basically mean that it runs it in the background (so you can do other stuff, instead of looking at the logs).
```sh
docker compose up -d
```

### Stop a container
There are 2 options:
```sh
docker compose stop
docker compose down
```
First one (`stop`) onlu stops the containers, whereas the latter (`down`) does some more cleaning (removes the containers, networks, volumes), so I generally recommend `down` if you're tinkering.


### Update a container to use the latest published image
```sh
docker compose pull && docker compose up -d
```
This pulls the latest images as defined in the local `docker-compose.yml` and recreates the containers.