[Docker] 도커 학습 - 1. 설치 및 정보 확인

 

 

docker 설치 하기

---

Centos7 환경에서 진행합니다~

 

 

curl 스크립트를 받아와서 sh로 실행합니다.

curl -sSL http://get.docker.com | sh

 

[root@linux-1 ~]# curl -sSL http://get.docker.com | sh
# Executing docker install script, commit: 1b02882d63b9cfc484ad6b0180171c679cfe0                                                               f3a
+ sh -c 'yum install -y -q yum-utils'
+ sh -c 'yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo'
Loaded plugins: fastestmirror
adding repo from: https://download.docker.com/linux/centos/docker-ce.repo
grabbing file https://download.docker.com/linux/centos/docker-ce.repo to /etc/yum.repos.d/docker-ce.repo
repo saved to /etc/yum.repos.d/docker-ce.repo
+ '[' stable '!=' stable ']'
+ sh -c 'yum makecache'
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
epel/x86_64/metalink                                                                                  | 7.8 kB  00:00:00
 * base: mirror.kakao.com
 * epel: ftp.jaist.ac.jp
 * extras: mirror.kakao.com
 * updates: mirror.kakao.com
base                                                                                                  | 3.6 kB  00:00:00
docker-ce-stable                                                                                      | 3.5 kB  00:00:00
extras                                                                                                | 2.9 kB  00:00:00
updates                                                                                               | 2.9 kB  00:00:00
...
Metadata Cache Created
+ '[' -n '' ']'
+ sh -c 'yum install -y -q docker-ce'
warning: /var/cache/yum/x86_64/7/docker-ce-stable/packages/containerd.io-1.2.13-3.1.el7.x86_64.rpm: Header V4 RSA/SHA512 Sign                  ature, key ID 621e9f35: NOKEY
Public key for containerd.io-1.2.13-3.1.el7.x86_64.rpm is not installed
Importing GPG key 0x621E9F35:
 Userid     : "Docker Release (CE rpm) <docker@docker.com>"
 Fingerprint: 060a 61c5 1b55 8a7f 742b 77aa c52f eb6b 621e 9f35
 From       : https://download.docker.com/linux/centos/gpg
setsebool:  SELinux is disabled.
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 your-user

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 구동

systemctl start docker

 

docker 실행 상태 확인

[root@linux-1 ~]# systemctl status docker
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; disabled; vendor preset: disabled)
   Active: active (running) since 토 2020-05-09 08:15:22 KST; 6s ago
     Docs: https://docs.docker.com
 Main PID: 1850 (dockerd)
    Tasks: 8
   Memory: 42.5M
   CGroup: /system.slice/docker.service
           └─1850 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

 5월 09 08:15:21 linux-1 dockerd[1850]: time="2020-05-09T08:15:21.807875060+09:00" level=info msg="scheme \"unix\" not registered, ...ule=grpc
 5월 09 08:15:21 linux-1 dockerd[1850]: time="2020-05-09T08:15:21.807907462+09:00" level=info msg="ccResolverWrapper: sending updat...ule=grpc
 5월 09 08:15:21 linux-1 dockerd[1850]: time="2020-05-09T08:15:21.807939346+09:00" level=info msg="ClientConn switching balancer to...ule=grpc
 5월 09 08:15:21 linux-1 dockerd[1850]: time="2020-05-09T08:15:21.837297940+09:00" level=info msg="Loading containers: start."
 5월 09 08:15:22 linux-1 dockerd[1850]: time="2020-05-09T08:15:22.307886029+09:00" level=info msg="Default bridge (docker0) is assi...address"
 5월 09 08:15:22 linux-1 dockerd[1850]: time="2020-05-09T08:15:22.603792473+09:00" level=info msg="Loading containers: done."
 5월 09 08:15:22 linux-1 dockerd[1850]: time="2020-05-09T08:15:22.620586576+09:00" level=info msg="Docker daemon" commit=afacb8b gr...=19.03.8
 5월 09 08:15:22 linux-1 dockerd[1850]: time="2020-05-09T08:15:22.620708387+09:00" level=info msg="Daemon has completed initialization"
 5월 09 08:15:22 linux-1 systemd[1]: Started Docker Application Container Engine.
 5월 09 08:15:22 linux-1 dockerd[1850]: time="2020-05-09T08:15:22.688243341+09:00" level=info msg="API listen on /var/run/docker.sock"
Hint: Some lines were ellipsized, use -l to show in full.

 

docker 정보 확인

---

docker server client 버전 확인

[root@linux-1 ~]# docker version
Client: Docker Engine - Community
 Version:           19.03.8
 API version:       1.40
 Go version:        go1.12.17
 Git commit:        afacb8b
 Built:             Wed Mar 11 01:27:04 2020
 OS/Arch:           linux/amd64
 Experimental:      false

Server: Docker Engine - Community
 Engine:
  Version:          19.03.8
  API version:      1.40 (minimum version 1.12)
  Go version:       go1.12.17
  Git commit:       afacb8b
  Built:            Wed Mar 11 01:25:42 2020
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.2.13
  GitCommit:        7ad184331fa3e55e52b890ea95e65ba581ae3429
 runc:
  Version:          1.0.0-rc10
  GitCommit:        dc9208a3303feef5b3839f4323d9beb36df0a9dd
 docker-init:
  Version:          0.18.0
  GitCommit:        fec3683

 

docker 상세 정보 확인

당연한 소리지만 실행 중인 컨테이너 없고, 이미지도 없다.

[root@linux-1 ~]# docker info
Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 0

 

docker Root directory

[root@linux-1 docker]# pwd
/var/lib/docker
[root@linux-1 docker]# ls -al
합계 4
drwx--x--x  14 root root  182  5월  9 08:15 .
drwxr-xr-x. 30 root root 4096  5월  9 08:15 ..
drwx------   2 root root   24  5월  9 08:15 builder
drwx--x--x   4 root root   92  5월  9 08:15 buildkit
drwx------   2 root root    6  5월  9 08:15 containers
drwx------   3 root root   22  5월  9 08:15 image
drwxr-x---   3 root root   19  5월  9 08:15 network
drwx------   3 root root   15  5월  9 08:15 overlay2
drwx------   4 root root   32  5월  9 08:15 plugins
drwx------   2 root root    6  5월  9 08:15 runtimes
drwx------   2 root root    6  5월  9 08:15 swarm
drwx------   2 root root    6  5월  9 08:15 tmp
drwx------   2 root root    6  5월  9 08:15 trust
drwx------   2 root root   25  5월  9 08:15 volumes

 

 

사용자 계정 추가 및 docker 권한 할당

---

다음은 docker.sock파일에 대해 잠깐 살펴보겠습니다.

docker.sock 파일은 docker api의 주요한 entry point로서 docker daemon이 listening 하고 있는 UNIX 소켓입니다.

docker client는 기본적으로 이 socket을 사용하여 도커 명령어를 실행합니다.

docker 명령어를 입력하면 docker CLI가 명령어를 소켓을 통해 docker 데몬에 전달을 하는 방식입니다.

 

docker.sock의 위치는 아래와 같습니다.

[root@linux-1 run]# ls -al /var/run/docker.sock
srw-rw---- 1 root docker 0  5월  9 08:15 /var/run/docker.sock

 

docker.sock 그룹 권한이 docker 그룹이네요.

그럼, 만약 root가 아닌 사용자 계정으로 docker 명령어를 수행하고 싶으시면 docker 그룹에 추가하면 되겠죠?

한 번 진행해보겠습니다.

 

test 계정이 속해있는 그룹 확인 후 docker 명령어 실행 ->  "permission denied"

[test@linux-1 run]$ id test
uid=1000(test) gid=1000(test) groups=1000(test)
[test@linux-1 run]$ docker  version
Client: Docker Engine - Community
 Version:           19.03.8
 API version:       1.40
 Go version:        go1.12.17
 Git commit:        afacb8b
 Built:             Wed Mar 11 01:27:04 2020
 OS/Arch:           linux/amd64
 Experimental:      false
Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.40/version: dial unix /var/run/docker.sock: connect: permission denied

 

test 계정을 docker 그룹에 포함시키고 다시 docker 명령어 실행 -> "성공"

[root@linux-1 run]# usermod -aG docker test
[root@linux-1 run]# su test
[test@linux-1 run]$ docker version
Client: Docker Engine - Community
 Version:           19.03.8
 API version:       1.40
 Go version:        go1.12.17
 Git commit:        afacb8b
 Built:             Wed Mar 11 01:27:04 2020
 OS/Arch:           linux/amd64
 Experimental:      false

Server: Docker Engine - Community
 Engine:
  Version:          19.03.8
  API version:      1.40 (minimum version 1.12)
  Go version:       go1.12.17
  Git commit:       afacb8b
  Built:            Wed Mar 11 01:25:42 2020
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.2.13
  GitCommit:        7ad184331fa3e55e52b890ea95e65ba581ae3429
 runc:
  Version:          1.0.0-rc10
  GitCommit:        dc9208a3303feef5b3839f4323d9beb36df0a9dd
 docker-init:
  Version:          0.18.0
  GitCommit:        fec3683
[test@linux-1 run]$ id test
uid=1000(test) gid=1000(test) groups=1000(test),991(docker)

 

오늘은 docker 설치하는 방법과 계정 권한 추가 방법에 대해 간단히 알아보았습니다.

다음 시간에는 이미지를 다운 및 컨터이너를 띄어보도록 하겠습니다.

감사합니다~