这里我们介绍docker的nsenter命令安装和使用。在大多数Linux发行版中,util-linux包中含有nsenter.
nsenter - run program with namespaces of other processes
【安装】
源码安装
$ wget https://www.kernel.org/pub/linux/utils/util-linux/v2.24/util-linux-2.24.tar.gz; tar xzvf util-linux-2.24.tar.gz $ cd util-linux-2.24 $ ./configure --without-ncurses && make nsenter $ sudo cp nsenter /usr/local/bin
yum安装
[root@localhost tmp]# yum install util-linux Loaded plugins: fastestmirror, refresh-packagekit, security Loading mirror speeds from cached hostfile * base: mirrors.zju.edu.cn * epel: ftp.riken.jp * extras: mirrors.163.com * updates: mirrors.163.com Setting up Install Process Package util-linux-ng-2.17.2-12.18.el6.x86_64 already installed and latest version Nothing to do
【nsenter连接容器】
为了连接到容器,你还需要找到容器的第一个进程的 PID,可以通过下面的命令获取。
PID=$(docker inspect --format "{{ .State.Pid }}" <container>)
通过这个 PID,就可以连接到这个容器:
$ nsenter --target $PID --mount --uts --ipc --net --pid
可运行脚本
#!/bin/sh if [ -e $(dirname "$0")/nsenter ]; then # with boot2docker, nsenter is not in the PATH but it is in the same folder NSENTER=$(dirname "$0")/nsenter else NSENTER=nsenter fi if [ -z "$1" ]; then echo "Usage: `basename "$0"` CONTAINER [COMMAND [ARG]...]" echo "" echo "Enters the Docker CONTAINER and executes the specified COMMAND." echo "If COMMAND is not specified, runs an interactive shell in CONTAINER." else PID=$(docker inspect --format "{{.State.Pid}}" "$1") if [ -z "$PID" ]; then exit 1 fi shift OPTS="--target $PID --mount --uts --ipc --net --pid --" if [ -z "$1" ]; then # No command given. # Use su to clear all host environment variables except for TERM, # initialize the environment variables HOME, SHELL, USER, LOGNAME, PATH, # and start a login shell. "$NSENTER" $OPTS su - root else # Use env to clear all host environment variables. "$NSENTER" $OPTS env --ignore-environment -- "$@" fi fi
运行 docker-enter <container id> ,这样就进入到指定的容器中。
更简单的,建议大家下载 .bashrc_docker,并将内容放到 .bashrc 中。
$ wget -P ~ https://github.com/yeasy/docker_practice/raw/master/_local/.bashrc_docker; $ echo "[ -f ~/.bashrc_docker ] && . ~/.bashrc_docker" >> ~/.bashrc; source ~/.bashrc
这个文件中定义了很多方便使用 Docker 的命令,例如 docker-pid 可以获取某个容器的 PID;而 docker-enter 可以进入容器或直接在容器内执行命令。
$ echo $(docker-pid <container>) $ docker-enter <container> ls
【参考】
http://www.tuicool.com/articles/eYnUBrR
http://yeasy.gitbooks.io/docker_practice/content/container/enter.html