Docker学习之外部容器管理工具nsenter

在这里使用的OS是ubuntu16:04，所以不需要安装nsenter。

#运行一个容器
# docker run -itd ubuntu:16.04 /bin/bash
# docker ps
a5bb8d87ceff        ubuntu:16.04        "/bin/bash"              14 minutes ago      Up 9 minutes                                 goofy_bartik
#
#为了连接到容器，需要找到容器的第一个进程(这里容器的第一个进程是/bin/bash)的PID
# PID=$(docker inspect --format "{{ .State.Pid }}" a5bb8d87ceff)
# nsenter --target $PID --mount --uts --ipc --net --pid
mesg: ttyname failed: No such file or directory
root@a5bb8d87ceff:/


或者下载.bashrc_docker脚本
# wget -P ~ https://github.com/yeasy/docker_practice/raw/master/_local/.bashrc_docker
# echo "[ -f ~/.bashrc_docker ] && . ~/.bashrc_docker" >> ~/.bashrc;source ~/.bashrc
# docker inspect --format '{{.State.Pid}}' a5bb8d87ceff
# docker inspect --format '{{ .NetworkSettings.IPAddress }}' a5bb8d87ceff
#查看容器第一个进程的pid
# echo $(docker-pid a5bb8d87ceff)
#进入容器
# docker-enter a5bb8d87ceff pwd

.bashrc_docker内容如下：

# Some useful commands to use docker.
# Author: yeasy@github
# Created:2014-09-25

#.bashrc_docker定义了docker-pid和docker-ip两个命令，为了方便查看pid和ip信息。
alias docker-pid="sudo docker inspect --format '{{.State.Pid}}'"
alias docker-ip="sudo docker inspect --format '{{ .NetworkSettings.IPAddress }}'"

#the implementation refs from https://github.com/jpetazzo/nsenter/blob/master/docker-enter
function docker-enter() {
    #if [ -e $(dirname "$0")/nsenter ]; then
    #Change for centos bash running
    if [ -e $(dirname '$0')/nsenter ]; then
        # with boot2docker, nsenter is not in the PATH but it is in the same folder
        NSENTER=$(dirname "$0")/nsenter
    else
        # if nsenter has already been installed with path notified, here will be clarified
        NSENTER=$(which nsenter)
        #NSENTER=nsenter
    fi
    [ -z "$NSENTER" ] && echo "WARN Cannot find nsenter" && return

    if [ -z "$1" ]; then
        echo "Usage: `basename "$0"` CONTAINER [COMMAND [ARG]...]"
        echo ""
        echo "Enters the Docker CONTAINER and executes the specified COMMAND."
        echo "If COMMAND is not specified, runs an interactive shell in CONTAINER."
    else
        PID=$(sudo docker inspect --format "{{.State.Pid}}" "$1")
        if [ -z "$PID" ]; then
            echo "WARN Cannot find the given container"
            return
        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.
            #sudo $NSENTER "$OPTS" su - root
            sudo $NSENTER --target $PID --mount --uts --ipc --net --pid su - root
        else
            # Use env to clear all host environment variables.
            sudo $NSENTER --target $PID --mount --uts --ipc --net --pid env -i $@
        fi
    fi
}