最近 Docker 的怪事還真不少…

原本在 CentOS 上的 Docker 跑的好好的，

但今天想跑的時候，卻發現 docker 服務跑不起來：

root@localhost / # 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.

 

用 systemctl status docker.service 查看，

發現有個 error while loading shared libraries: libseccomp.so.2 的錯誤：

root@localhost / # systemctl status docker.service
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; disabled; vendor preset: disabled)
   Active: failed (Result: exit-code) since Tue 2020-09-08 16:20:54 CST; 11s ago
     Docs: http://docs.docker.com
  Process: 4008 ExecStart=/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-path=/usr/libexec/docker/docker-proxy-current --init-path=/usr/libexec/docker/docker-init-current --seccomp-profile=/etc/docker/seccomp.json $OPTIONS $DOCKER_STORAGE_OPTIONS $DOCKER_NETWORK_OPTIONS $ADD_REGISTRY $BLOCK_REGISTRY $INSECURE_REGISTRY $REGISTRIES (code=exited, status=127)
 Main PID: 4008 (code=exited, status=127)

Sep 08 16:20:54 localhost systemd[1]: Starting Docker Application Container Engine...
Sep 08 16:20:54 localhost dockerd-current[4008]: /usr/bin/dockerd-current: error while loading shared libraries: libseccomp.so.2: cannot open shared object file: No such...r directory
Sep 08 16:20:54 localhost systemd[1]: docker.service: main process exited, code=exited, status=127/n/a
Sep 08 16:20:54 localhost systemd[1]: Failed to start Docker Application Container Engine.
Sep 08 16:20:54 localhost systemd[1]: Unit docker.service entered failed state.
Sep 08 16:20:54 localhost systemd[1]: docker.service failed.

 

這個 libseccomp 看起來好像是一個 Linux syscall 的過濾機制，

細節不懂，不過應該是 Docker 有用到的東西，

用 yum 把它裝好後，docker 服務就可以啟動了：

yum install libseccomp
systemctl start docker

 

docker 服務的狀態也是正常的囉：

root@localhost / # 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 Tue 2020-09-08 16:24:06 CST; 5s ago
     Docs: http://docs.docker.com
 Main PID: 6914 (dockerd-current)
   CGroup: /system.slice/docker.service
           ├─6914 /usr/bin/dockerd-current --add-runtime docker-runc=/usr/libexec/docker/docker-runc-current --default-runtime=docker-runc --exec-opt native.cgroupdriver=syste...
           └─6926 /usr/bin/docker-containerd-current -l unix:///var/run/docker/libcontainerd/docker-containerd.sock --metrics-interval=0 --start-timeout 2m --state-dir /var/ru...

Sep 08 16:24:06 localhost dockerd-current[6914]: time="2020-09-08T16:24:06.344848935+08:00" level=warning msg="Docker could not enable SELinux on the host system"
Sep 08 16:24:06 localhost dockerd-current[6914]: time="2020-09-08T16:24:06.401807572+08:00" level=info msg="Graph migration to content-addressability took 0.00 seconds"
Sep 08 16:24:06 localhost dockerd-current[6914]: time="2020-09-08T16:24:06.403124876+08:00" level=info msg="Loading containers: start."
Sep 08 16:24:06 localhost dockerd-current[6914]: time="2020-09-08T16:24:06.541780889+08:00" level=info msg="Firewalld running: false"
Sep 08 16:24:06 localhost dockerd-current[6914]: time="2020-09-08T16:24:06.683700019+08:00" level=info msg="Default bridge (docker0) is assigned with an IP address 172.1...IP address"
Sep 08 16:24:06 localhost dockerd-current[6914]: time="2020-09-08T16:24:06.731530652+08:00" level=info msg="Loading containers: done."
Sep 08 16:24:06 localhost dockerd-current[6914]: time="2020-09-08T16:24:06.762834159+08:00" level=info msg="Daemon has completed initialization"
Sep 08 16:24:06 localhost dockerd-current[6914]: time="2020-09-08T16:24:06.762890537+08:00" level=info msg="Docker daemon" commit="64e9980/1.13.1" graphdriver=overlay2 version=1.13.1
Sep 08 16:24:06 localhost dockerd-current[6914]: time="2020-09-08T16:24:06.773279309+08:00" level=info msg="API listen on /var/run/docker.sock"
Sep 08 16:24:06 localhost systemd[1]: Started Docker Application Container Engine.