使用nsenter进入Docker容器
Docker容器运行后,如何进入容器进行操作呢?起初我是用SSH。如果只启动一个容器,用SSH还能应付,只需要将容器的22端口映射到本机的一个端口即可。当我启动了五个容器后,每个容器默认是没有配置SSH Server的,安装配置SSHD,映射容器SSH端口,实在是麻烦。
我发现很多Docker镜像都是没有安装SSHD服务的,难道有其他方法进入Docker容器?
浏览了Docker的文档,我没有找到答案。还是要求助于无所不能的Google,万能的Google告诉我用nsenter吧。
在大多数Linux发行版中,util-linux包中含有nsenter.如果没有,你需要安装它.
cd /tmp curl https://www.kernel.org/pub/linux/utils/util-linux/v2.24/util-linux-2.24.tar.gz \ | tar -zxf- cd util-linux-2.24 ./configure --without-ncurses make nsenter cp nsenter /usr/local/bin
使用shell脚本 docker-enter,将如下代码保存为docker-enter, chomod +x docker-enter
#!/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
关于nsenter更详细的使用方法见这里 https://github.com/jpetazzo/nsenter