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Install Docker & Docker Compose With Ubuntu

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Install Docker

Prerequsites

Install packages to allow apt to use a repository over HTTPS:

sudo apt-get install apt-transport-https ca-certificates curl software-properties-common

Setup Docker Repository

Add Docker’s official GPG key:

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

After that add the Docker repository on your Ubuntu system which contains Docker packages including its dependencies

 sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"

Install Docker on Ubuntu

Update the apt package index.

 sudo apt-get update

Install the latest version of Docker CE, or go to the next step to install a specific version:

 sudo apt-get install -y docker-ce

Verify that Docker CE is installed correctly by running the hello-world image.

 sudo docker container run hello-world

Install Docker Compose

Run this command to download the latest version of Docker Compose

sudo curl -L "https://github.com/docker/compose/releases/download/1.23.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

Apply executable permissions to the binary:

 sudo chmod +x /usr/local/bin/docker-compose

免 sudo 用 docker 指令

因為使用的是 sudo 來安裝 docker，因此在普通用戶的狀況，使用 docker 的指令會導致

docker ps -a

# Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.39/containers/json?all=1: dial unix /var/run/docker.sock: connect: permission denied

可以看到最後一行 var/run/docker.sock: connect: permission denied 因此來看一下這個檔案的權限狀況

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ls -al /var/run/
srw-rw----  1 root docker    0 Jan 20 14:59 docker.sock

可以看到

  • user 權限 rw-
  • group 權限 rw-
  • other 權限: —
  • 擁有人: root
  • 組別“ docker

所以希望有權限，要嗎是 root 或是在 docker 這個組別裡面，先查一下目前有沒有這個組別

entire group list

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cut -d: -f1 /etc/group | sort

發現沒有 docker 這個組別，那就自己新增一個

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sudo groupadd docker

將自己加入 docker group

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sudo gpasswd -a ${USER} docker
# 或是 sudo usermod -G docker -a ${USER}

usemod -G 改寫用戶的組之後 如果用戶同時屬於多個組 那麼最終只會屬於一個組 而 gpasswd -a 則是將一個用戶加入到另一個組 同時不改變用戶原來的組

重啟 docker

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sudo service docker restart

切換當前 group，或重開新的 session

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newgrp - docker

接著就可以試著用普通用戶來執行，成功!

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docker ps -a

參考文件:

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