CentOS 7 开机自启动ssh服务

2017-12-16     tech linux systemd 2 mins 943 字 

systemctl enable sshd

另外我在某台机器上遇到了一个错误，始终无法启动 ssh，使用 systemctl status sshd.service，内容如下：

sshd.service - OpenSSH server daemon
  Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)
  Active: activating (auto-restart) (Result: exit-code) since Wed 2017-12-27 17:38:43 CST; 9s ago
    Docs: man:sshd(8)
          man:sshd_config(5)
 Process: 6860 ExecStart=/usr/sbin/sshd -D $OPTIONS (code=exited, status=255)
Main PID: 6860 (code=exited, status=255)

Dec 27 17:38:43 adsl-172-10-1-100.dsl.sndg02.sbcglobal.net systemd[1]: Failed to start OpenSSH server daemon.
Dec 27 17:38:43 adsl-172-10-1-100.dsl.sndg02.sbcglobal.net systemd[1]: Unit sshd.service entered failed state.
Dec 27 17:38:43 adsl-172-10-1-100.dsl.sndg02.sbcglobal.net systemd[1]: sshd.service failed.

使用 journalctl -xe 得到了有用的信息：

/var/empty/sshd must be owned by root and not group or world-writable.

发现 /var/empty/sshd 文件的属性为777.改为755即可：

chmod 755 /var/empty/sshd

删除 Docker 容器和镜像

2017-12-10     tech docker 1 mins 298 字

杀死所有正在运行的容器

docker kill $(docker ps -a -q)

删除所有未运行 Docker 容器

docker rm $(docker ps -a -q)

删除所有 Docker 镜像

删除所有未打 tag 的镜像

docker rmi $(docker images -q | awk '/^<none>/ { print $3 }')

删除所有镜像

docker rmi $(docker images -q)

根据格式删除所有镜像

docker rm $(docker ps -qf status=exited)

参考资料

访问容器的方式 —— docker attach/exec

2017-12-09     tech docker 2 mins 1002 字

  1. 进入容器默认运行的session：

    docker attach $pid

     Usage:  docker attach [OPTIONS] CONTAINER
	
 Attach to a running container
	
 Options:
  --detach-keys string   Override the key sequence for detaching a container
  --help                 Print usage
  --no-stdin             Do not attach STDIN
  --sig-proxy            Proxy all received signals to the process (default true)

  2. 进入容器环境并运行新的命令：

    docker exec -it $pid /bin/bash // 对指定的容器执行bash

     docker exec --help
	
 Usage:  docker exec [OPTIONS] CONTAINER COMMAND [ARG...]
	
 Run a command in a running container
	
  -d, --detach         Detached mode: run command in the background
   --detach-keys        Override the key sequence for detaching a container
   --help               Print usage
   -i, --interactive    Keep STDIN open even if not attached
   --privileged         Give extended privileges to the command
   -t, --tty            Allocate a pseudo-TTY
   -u, --user           Username or UID (format: <name|uid>[:<group|gid>])
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