Cloud/Cloud Native

Docker in centos

Jacob_baek 2019. 6. 7. 14:00

CentOS7에서 Docker 설치 및 실행법

CentOS7에서 Docker 설치 및 실행을 하는 방법을 간단히 기술한다.

[root@jenkins centos]# cat /etc/centos-release
CentOS Linux release 7.6.1810 (Core)

위와 같은 환경에서 설치를 진행하였다.

[root@jenkins centos]# yum install docker
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: centos.mirror.moack.net
 * extras: centos.mirror.moack.net
 * updates: centos.mirror.moack.net
Resolving Dependencies
--> Running transaction check
---> Package docker.x86_64 2:1.13.1-96.gitb2f74b2.el7.centos will be installed
--> Processing Dependency: docker-common = 2:1.13.1-96.gitb2f74b2.el7.centos for package: 2:docker-1.13.1-96.gitb2f74b2.el7.centos.x86_64
--> Processing Dependency: docker-client = 2:1.13.1-96.gitb2f74b2.el7.centos for package: 2:docker-1.13.1-96.gitb2f74b2.el7.centos.x86_64

이후 docker 서비스를 재시작해본 결과 아래와 같은 에러가 발생하였다.

[root@jenkins centos]# systemctl start docker
Job for docker.service failed because the control process exited with error code. See "systemctl status docker.service" and "journalctl -xe" for details.

[root@jenkins centos]# tail /var/log/messages
Jun  7 04:52:16 jenkins systemd: Started Docker Storage Setup.
Jun  7 04:52:16 jenkins systemd: Starting Docker Application Container Engine...
Jun  7 04:52:16 jenkins dockerd-current: time="2019-06-07T04:52:16.969455534Z" level=warning msg="could not change group /var/run/docker.sock to docker: group docker not found"
Jun  7 04:52:16 jenkins dockerd-current: time="2019-06-07T04:52:16.971288960Z" level=info msg="libcontainerd: new containerd process, pid: 12655"
Jun  7 04:52:18 jenkins dockerd-current: Error starting daemon: SELinux is not supported with the overlay2 graph driver on this kernel. Either boot into a newer kernel or disable selinux in docker (--selinux-enabled=false)
Jun  7 04:52:18 jenkins systemd: docker.service: main process exited, code=exited, status=1/FAILURE
Jun  7 04:52:18 jenkins systemd: Failed to start Docker Application Container Engine.
Jun  7 04:52:18 jenkins systemd: Unit docker.service entered failed state.
Jun  7 04:52:18 jenkins systemd: docker.service failed.

확인해본 결과 centos에서는 storage driver로 overlay2가 아닌 devicemapper를 사용하도록 해야 하였다. 아래 링크를 참고하기를 권장한다.
https://stackoverflow.com/questions/45461307/selinux-is-not-supported-with-the-overlay-graph-driver

[root@jenkins centos]# cat /etc/sysconfig/docker-storage
#DOCKER_STORAGE_OPTIONS="--storage-driver overlay2 "
DOCKER_STORAGE_OPTIONS="--storage-driver devicemapper "

overlay2의 경우 Ubuntu 의 AUFS를 기반으로 하고 있는데 Red Hat 및 CentOS의 경우 AUFS를 지원하지 않아 devicemapper를 사용하도록 하고 있다. 아래 링크에 좀더 상세히 나와있다. 참고할것을 권장한다.
https://ingeec.tistory.com/77

위와 같이 변경후 서비스 재시작시 정상적으로 재시작되고 동작함을 확인할 수 있다.

[root@jenkins centos]# systemctl restart docker
[root@jenkins centos]# 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 Fri 2019-06-07 04:55:03 UTC; 49min ago
     Docs: http://docs.docker.com
 Main PID: 12714 (dockerd-current)
   CGroup: /system.slice/docker.service
           ├─12714 /usr/bin/dockerd-current --add-runtime docker-runc=/usr/libexec/docker/docker-runc-current --default-runtime=docker-runc --exec-opt native.cgroupdriver=systemd --userland-proxy-p...
           └─12720 /usr/bin/docker-containerd-current -l unix:///var/run/docker/libcontainerd/docker-containerd.sock --metrics-interval=0 --start-timeout 2m --state-dir /var/run/docker/libcontainer...

Jun 07 04:55:02 jenkins dockerd-current[12714]: time="2019-06-07T04:55:02.912942012Z" level=info msg="devmapper: Successfully created filesystem xfs on device docker-253:1-16818109-base"
Jun 07 04:55:02 jenkins dockerd-current[12714]: time="2019-06-07T04:55:02.992695613Z" level=info msg="Graph migration to content-addressability took 0.00 seconds"
Jun 07 04:55:02 jenkins dockerd-current[12714]: time="2019-06-07T04:55:02.993717359Z" level=info msg="Loading containers: start."
Jun 07 04:55:03 jenkins dockerd-current[12714]: time="2019-06-07T04:55:03.045208871Z" level=info msg="Firewalld running: false"
Jun 07 04:55:03 jenkins dockerd-current[12714]: time="2019-06-07T04:55:03.121608858Z" level=info msg="Default bridge (docker0) is assigned with an IP address 172.17.0.0/16. Daemon opti...d IP address"Jun 07 04:55:03 jenkins dockerd-current[12714]: time="2019-06-07T04:55:03.161344874Z" level=info msg="Loading containers: done."
Jun 07 04:55:03 jenkins dockerd-current[12714]: time="2019-06-07T04:55:03.173893692Z" level=info msg="Daemon has completed initialization"
Jun 07 04:55:03 jenkins dockerd-current[12714]: time="2019-06-07T04:55:03.173941585Z" level=info msg="Docker daemon" commit="b2f74b2/1.13.1" graphdriver=devicemapper version=1.13.1
Jun 07 04:55:03 jenkins dockerd-current[12714]: time="2019-06-07T04:55:03.185151400Z" level=info msg="API listen on /var/run/docker.sock"
Jun 07 04:55:03 jenkins systemd[1]: Started Docker Application Container Engine.
Hint: Some lines were ellipsized, use -l to show in full.

CentOS8에서 Docker 사용

아래 링크에 자세히 나와있다.
참고로 yum 이 아닌 dnf로 repo 추가부터 설치를 진행한다.

dnf config-manager

문제상황과 해결법

만약 아래와 같은 문제를 겪고 있다면 CentOS의 환경을 다시한번 확인해보자.

[root@docker centos]# docker run -d -p 8080:8080 -p 50000:50000 --name jenkinsci jenkins/jenkins:lts
6f7fcdd5de26015e953715f156e54e1a712d584d84c8013b5ccd190430e97070
/usr/bin/docker-current: Error response from daemon: oci runtime error: container_linux.go:235: starting container process caused "process_linux.go:258: applying cgroup configuration for process caused \"Cannot set property TasksAccounting, or unknown property.\"".

위와 같은 문제를 겪고 있었을때의 환경은 아래와 같이 노후된 버전이었다.

[root@docker centos]# cat /etc/redhat-release && uname -msr
CentOS Linux release 7.3.1611 (Core) 
Linux 3.10.0-514.26.2.el7.x86_64 x86_64

하여 아래와 같이 update를 수행한후 다시 확인해본 결과 정상적으로 동작하였다.

[root@docker centos]# cat /etc/redhat-release && uname -msr
CentOS Linux release 7.6.1810 (Core) 
Linux 3.10.0-957.12.2.el7.x86_64 x86_64
[root@docker centos]# docker --version
Docker version 1.13.1, build b2f74b2/1.13.1
[root@docker centos]# docker run -d -p 8080:8080 -p 50000:50000 --name jenkinsci jenkins/jenkins:lts
020b678690429e05d737db0a5e68f1289edd0387c2053461e1f644a61649a754

Ubuntu 에서의 설치 및 사용법

만약 Ubuntu 16.04를 기반으로 설치를 진행하고자 할 경우 아래 링크를 참고하자. 아래링크에 잘설명이 되어있어 따로 기술하지는 않는다.

http://iamartin-gh.herokuapp.com/ubuntu-16-04-docker-install/

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