Raspberry Piにdockerをインストールする

# 概要

Raspberry Piを簡易サーバにするためにdockerを入れる。
せっかく入れるので記録しておく。

# docker install

## 参考

* https://www.raspberrypi.org/blog/docker-comes-to-raspberry-pi/

## 手順

以下のコマンドでdockerインストールできる。

```
curl -sSL https://get.docker.com | sh
```

実行結果

```
pi@raspberrypi:~ $ curl -sSL https://get.docker.com | sh
# Executing docker install script, commit: 40b1b76
+ sudo -E sh -c apt-get update -qq >/dev/null
+ sudo -E sh -c apt-get install -y -qq apt-transport-https ca-certificates curl >/dev/null
+ sudo -E sh -c curl -fsSL "https://download.docker.com/linux/raspbian/gpg" | apt-key add -qq - >/dev/null
Warning: apt-key output should not be parsed (stdout is not a terminal)
+ sudo -E sh -c echo "deb [arch=armhf] https://download.docker.com/linux/raspbian stretch edge" > /etc/apt/sources.list.d/docker.list
+ sudo -E sh -c apt-get update -qq >/dev/null
+ sudo -E sh -c apt-get install -y -qq --no-install-recommends docker-ce >/dev/null
+ sudo -E sh -c docker version
Client:
 Version:           18.09.0
 API version:       1.39
 Go version:        go1.10.4
 Git commit:        4d60db4
 Built:             Wed Nov  7 00:57:21 2018
 OS/Arch:           linux/arm
 Experimental:      false

Server: Docker Engine - Community
 Engine:
  Version:          18.09.0
  API version:      1.39 (minimum version 1.12)
  Go version:       go1.10.4
  Git commit:       4d60db4
  Built:            Wed Nov  7 00:17:57 2018
  OS/Arch:          linux/arm
  Experimental:     false
If you would like to use Docker as a non-root user, you should now consider
adding your user to the "docker" group with something like:

  sudo usermod -aG docker pi

Remember that you will have to log out and back in for this to take effect!

WARNING: Adding a user to the "docker" group will grant the ability to run
         containers which can be used to obtain root privileges on the
         docker host.
         Refer to https://docs.docker.com/engine/security/security/#docker-daemon-attack-surface
         for more information.

** DOCKER ENGINE - ENTERPRISE **

If you’re ready for production workloads, Docker Engine - Enterprise also includes:

  * SLA-backed technical support
  * Extended lifecycle maintenance policy for patches and hotfixes
  * Access to certified ecosystem content

** Learn more at https://dockr.ly/engine2 **

ACTIVATE your own engine to Docker Engine - Enterprise using:

  sudo docker engine activate
```

# 動作確認

## バージョン確認

```
pi@raspberrypi:~ $ docker -v
Docker version 18.09.0, build 4d60db4
```

## hello-worldやってみる

```
pi@raspberrypi:~ $ docker pull hello-world
Using default tag: latest
Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Post http://%2Fvar%2Frun%2Fdocker.sock/v1.39/images/create?fromImage=hello-world&tag=latest: dial unix /var/run/docker.sock: connect: permission denied
```

エラーが出たので、以下のサイトを参考に権限付与。
https://techoverflow.net/2017/03/01/solving-docker-permission-denied-while-trying-to-connect-to-the-docker-daemon-socket/

```
pi@raspberrypi:~ $ sudo usermod -a -G docker pi
```

```
pi@raspberrypi:~ $ docker pull hello-world
Using default tag: latest
latest: Pulling from library/hello-world
c1eda109e4da: Pull complete
Digest: sha256:2557e3c07ed1e38f26e389462d03ed943586f744621577a99efb77324b0fe535
Status: Downloaded newer image for hello-world:latest
```

hello-worldイメージ取得成功。

### 取得できたイメージを確認

```
pi@raspberrypi:~ $ docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
hello-world         latest              618e43431df9        8 weeks ago         1.64kB
```

### docker hello world実行

```
pi@raspberrypi:~ $ docker run hello-world

Hello from Docker!
This message shows that your installation appears to be working correctly.

To generate this message, Docker took the following steps:
 1. The Docker client contacted the Docker daemon.
 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
    (arm32v7)
 3. The Docker daemon created a new container from that image which runs the
    executable that produces the output you are currently reading.
 4. The Docker daemon streamed that output to the Docker client, which sent it
    to your terminal.

To try something more ambitious, you can run an Ubuntu container with:
 $ docker run -it ubuntu bash

Share images, automate workflows, and more with a free Docker ID:
 https://hub.docker.com/

For more examples and ideas, visit:
 https://docs.docker.com/get-started/

```

*できた!!!*