一、安装

用hg为关键词搜索，得出以下结果：

 

$ docker search hg
NAME                              DESCRIPTION                                     STARS     OFFICIAL   AUTOMATED
hgomez/gatling                                                                    1                    [OK]
v7soft/hgdns                                                                      0                    [OK]
hg8496/gridvis-service                                                            0                    [OK]
hgomez/di-centos6-myjenkins-lts                                                   0                    [OK]
jrandall/hgi-project                                                              0                    [OK]
hgomez/di-centos6-myartifactory                                                   0                    [OK]
hgomez/di-centos6-myjenkins                                                       0                    [OK]
hgomez/di-centos6-mynexus                                                         0                    [OK]
hgomez/di-centos6-myarchiva                                                       0                    [OK]
hg8496/piwigo                                                                     0                    [OK]
hg8496/apache                                                                     0                    [OK]
hgomez/di-centos6-mygitblit                                                       0                    [OK]
hgomez/di-centos6-mygitbucket                                                     0                    [OK]
jyotisingh/ubuntu-hg                                                              0                    
hg8496/dokuwiki                                                                   0                    [OK]
hg8496/owncloud                                                                   0                    [OK]
misshie/ucsc-blat-hg19                                                            0                    [OK]
ussie/hg-exec                     adds mercurial to ubuntu:14.04.                 0                    
misshie/ucsc-blat-hg38                                                            0                    [OK]
hg8496/gridvis-pc                                                                 0                    [OK]
           Test. Automated builds for this repo are b...   0                    [OK]
hg8496/rsync                                                                      0                    [OK]
secondbit/hgbundler                                                               0                    
uotbw/hgamer3d                    Docker image for hgamer3d, see www.hgamer3...   0                    
hgomez/di-centos6-base                                                            0                    [OK]

 

将其pull下来，在漫长的等待中我也在思考着如何启动它。

主页上提供了它的Dockerfile，通过它我们就可以了解这个image是如果构造的。先来说说什么是Dockerfile。

二、Dockerfile

它是用户创建自定义镜像的文件。它通常分为四部分：基础镜像信息，维护者信息，镜像操作指令和容器启动时的指令。

 

#基础系统信息，基于ubuntu 14.04构建的
FROM ubuntu:14.04
MAINTAINER Alex McLain <alex@alexmclain.com>
RUN apt-get -qq update
#安装apache、hg、php5
RUN apt-get -y install apache2 apache2-utils curl mercurial php5 php5-cli php5-mcrypt
# TODO: Remove
#是的，vim确实很大，不安装为好
RUN apt-get -y install vim
RUN echo "colorscheme delek" > ~/.vimrc
# Configure hgweb
ADD hg/add.php /etc/default/hgweb/hg/
ADD hg/hgweb.config /etc/default/hgweb/hg/
ADD hg/hgweb.cgi /etc/default/hgweb/hg/
ADD hg/hgusers /etc/default/hgweb/hg/
# Configure Apache
ADD apache/hg.conf /etc/default/hgweb/apache/
RUN rm /etc/apache2/sites-enabled/*
RUN a2enmod rewrite && a2enmod cgi
ADD load-default-scripts /bin/
RUN chmod u+x /bin/load-default-scripts
#创建一个挂载点，本机或其他容器可以将其挂载。启动时用-v参数进行挂载
VOLUME /var/hg
VOLUME /etc/apache2/sites-available
#暴露的端口号，启动时要通过-p参数指定
EXPOSE 80
#启动时执行的命令
CMD load-default-scripts && service apache2 start && /bin/bash

三、启动

 

有了上述的背景，我们知道启动时要做两件事：指定端口号、挂载本地目录。

比如还是使用端口号80，那么只需用 -p 80:80即可。

比如本机目录hg-repos用来做hg repo的放置目录，只需 -v /home/linc/hg-repos:/var/hg/repos 挂载即可。

另外，我们还要将其启动在后台（Daemonized），加上-d参数。

完整启动命令如下：

 

docker run -idt -p 80:80 -v /home/linc/hg-repos:/var/hg/repos amclain/hgweb

四、与后台容器交互

 

1.attach方法

docker 自带attach命令，但此命令的不方便之处在于，多个窗口（同时attach此容器）会同步显示操作，并且当一个窗口exit时，所有窗口都会退出，后台运行的容器也停止了。

 

$ docker ps
CONTAINER ID        IMAGE                           COMMAND                CREATED             STATUS              PORTS                  NAMES
b22cc1880b7a        amclain/hgweb:latest            "/bin/sh -c 'load-de   3 hours ago         Up 3 hours          0.0.0.0:80->80/tcp     high_almeida  

$ docker attach b22cc1880b7a
root@b22cc1880b7a:/# 

2.nsenter

 

此工具需要从源码安装：

 

$ 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 && sudo cp nsenter /usr/local/bin

直接用nsenter命令交互很繁琐，然后有人写了配置文件放到bashrc中，就可以方便的使用了。

 

 

#docker
export DOCKER_HOST=tcp://localhost:4243
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 "$0")/nsenter ]; then
        # with boot2docker, nsenter is not in the PATH but it is in the same folder
        NSENTER=$(dirname "$0")/nsenter
    else
        NSENTER=nsenter
    fi
    [ -z "$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
}

其中有两个alias和一个function，使用docker-enter会很容易于容器交互并没有attach中的副作用。如下：

 

 

$ docker ps
CONTAINER ID        IMAGE                           COMMAND                CREATED             STATUS              PORTS                  NAMES
beb178cd9335        amclain/hgweb:latest            "/bin/sh -c 'load-de   11 seconds ago      Up 10 seconds       0.0.0.0:80->80/tcp     stoic_yonath          

$ docker-enter beb178cd9335
root@beb178cd9335:~# ls
root@beb178cd9335:~# pwd
/root

五、快速启动hg-server

 

咱也写个alias放子bashrc中，如下：

 

alias docker-load-hg-server="sudo docker run -idt -p 80:80 -v /home/linc/hg-repos:/var/hg/repos amclain/hgweb"

启动它：

 

 

$ docker-load-hg-server 
[sudo] password for linc: 
beb178cd933502970fd12d9a4babecef5475a52d85a207066c665b4a620c5a62