标签：docker动态绑定卷组 docker绑定目录 docker绑定 docker volumes
之前介绍过docker高级应用之动态扩展容器空间大小（地址：http://dl528888.blog.51cto.com/2382721/1606170），本次介绍如何动态的绑定卷组。
为什么使用卷组呢，比如想把物理机里的目录给予容器共享，或者把物理机的一个目录作为共享目录，做日志搜集等等功能。
默认docker添加卷组是在启动容器的使用使用-v参数
-v, --volume=[] Bind mount a volume (e.g., from the host: -v /host:/container, from docker: -v /container)
举例
物理机目录/data/software想挂载到容器的/tmp/software里
其中/data/software内容是
15:21:14 # ll /data/software/ total 19692 -rw-r--r-- 1 root root 1940 Nov 10 20:42 CentOS-Base-6.repo -rwxr-xr-x 1 root root 12752168 Nov 10 14:15 etcd -rwxr-xr-x 1 root root 7400424 Nov 10 14:15 etcdctl drwxr-xr-x 21 1000 1000 4096 Oct 29 02:06 systemd-217
启动docker的命令是
docker run -d -p 22 --name="test" -v /data/software:/tmp/software docker.ops-chukong.com:5000/centos6-http:new /usr/bin/supervisord
下面是做绑定测试
root@docker-test2:/tmp 15:29:23 # docker run -d -p 22 --name="test" -v /data/software:/tmp/software docker.ops-chukong.com:5000/centos6-http:new /usr/bin/supervisord a21506d7b36e04e091008f4a326ac17c94e3d855e3aadb52992d7ba95f45cbbf root@docker-test2:/tmp 15:31:15 # docker-enter test sh -c "ls -l /tmp/software" total 19692 -rw-r--r-- 1 root root 1940 Nov 10 20:42 CentOS-Base-6.repo -rwxr-xr-x 1 root root 12752168 Nov 10 14:15 etcd -rwxr-xr-x 1 root root 7400424 Nov 10 14:15 etcdctl drwxr-xr-x 21 1000 1000 4096 Oct 29 02:06 systemd-217 root@docker-test2:/tmp 15:31:21 # docker-enter test sh -c "mount" rootfs on / type rootfs (rw) /dev/mapper/docker-8:17-37748738-a21506d7b36e04e091008f4a326ac17c94e3d855e3aadb52992d7ba95f45cbbf on / type ext4 (rw,relatime,discard,stripe=16,data=ordered) proc on /proc type proc (rw,nosuid,nodev,noexec,relatime) sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime) shm on /dev/shm type tmpfs (rw,nosuid,nodev,noexec,relatime,size=65536k) /dev/sdb1 on /.dockerinit type ext4 (rw,relatime,data=ordered) /dev/sda3 on /etc/resolv.conf type ext4 (rw,relatime,data=ordered) /dev/sdb1 on /etc/hostname type ext4 (rw,relatime,data=ordered) /dev/sdb1 on /etc/hosts type ext4 (rw,relatime,data=ordered) /dev/sda3 on /tmp/software type ext4 (rw,relatime,data=ordered) /dev/sdb1 on /.dockerenv type ext4 (rw,relatime,data=ordered) devpts on /dev/tty1 type devpts (rw,relatime,gid=5,mode=620,ptmxmode=000) devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620,ptmxmode=666) devpts on /dev/ptmx type devpts (rw,relatime,gid=5,mode=620,ptmxmode=666) root@docker-test2:/tmp 15:31:28 # docker-enter test sh -c "df -h" Filesystem Size Used Avail Use% Mounted on rootfs 9.8G 470M 8.8G 5% / /dev/mapper/docker-8:17-37748738-a21506d7b36e04e091008f4a326ac17c94e3d855e3aadb52992d7ba95f45cbbf 9.8G 470M 8.8G 5% / shm 64M 0 64M 0% /dev/shm /dev/sdb1 1.8T 22G 1.7T 2% /.dockerinit /dev/sda3 518G 457G 35G 93% /etc/resolv.conf /dev/sdb1 1.8T 22G 1.7T 2% /etc/hostname /dev/sdb1 1.8T 22G 1.7T 2% /etc/hosts /dev/sda3 518G 457G 35G 93% /tmp/software /dev/sdb1 1.8T 22G 1.7T 2% /.dockerenv
可以看到挂载完成，并且容器里的/tmp/software与/data/software里内容一致
但上面只是在创建并启动容器的时候可以挂载卷组，如果允许中的如何挂载呢？
具体知识可以参考http://jpetazzo.github.io/2015/01/13/docker-mount-dynamic-volumes/
下面是修改的脚本
内容为
#!/bin/bash
#This script is dynamic mount docker volumens
#Author Deng Lei
if [ -z $1 ] || [ -z $2 ] || [ -z $3 ]; then
echo "Usage: container_name physics_volumes container_volumes"
echo "Example: I want mount physics /tmp/test to container /src in test"
echo "The command is: bash `basename $0` test /tmp/test /src "
exit 1
fi
which nsenter &>>/dev/null
if [ $? -ne 0 ];then
echo "plsease install nsenser,command is:yum install util-linux"
exit 1
fi
set -e
CONTAINER=$1
HOSTPATH=$2
CONTPATH=$3
if [ ! -d $HOSTPATH ];then
echo "physics $HOSTPATH is not exist!"
exit 1
fi
REALPATH=$(readlink --canonicalize $HOSTPATH)
FILESYS=$(df -P $REALPATH | tail -n 1 | awk ‘{print $6}‘)
while read DEV MOUNT JUNK
do
[ $MOUNT = $FILESYS ] && [ $DEV != "rootfs" ] && break
done </proc/mounts
[ $MOUNT = $FILESYS ] # Sanity check!
while read A B C SUBROOT MOUNT JUNK
do [ $MOUNT = $FILESYS ] && break
done < /proc/self/mountinfo
[ $MOUNT = $FILESYS ] # Moar sanity check!
SUBPATH=$(echo $REALPATH | sed s,^$FILESYS,,)
DEVDEC=$(printf "%d %d" $(stat --format "0x%t 0x%T" $DEV))
PID=$(docker inspect --format "{{.State.Pid}}" "$CONTAINER")
run_command="nsenter --target $PID --mount --uts --ipc --net --pid -- sh -c"
if [ `$run_command "mount|grep $CONTPATH|wc -l"` -ne 0 ];then
echo "container $CONTAINER mount dir $CONTPATH is mounting!"
exit 1
fi
$run_command "[ -b $DEV ] ||mknod --mode 0600 $DEV b $DEVDEC"
$run_command "mkdir /tmpmnt"
$run_command "mount $DEV /tmpmnt"
$run_command "mkdir -p $CONTPATH"
$run_command "mount -o bind /tmpmnt/$SUBROOT/$SUBPATH $CONTPATH"
$run_command "umount /tmpmnt"
$run_command "rmdir /tmpmnt"
check_result=`$run_command "mount|grep $CONTPATH|wc -l"`
if [ $check_result -ne 0 ];then
echo "dymainc mount physics $HOSTPATH on $CONTAINER $CONTPATH is success!"
else
echo "dymaninc mount physics $HOSTPATH on $CONTAINER $CONTPATH is fail!"
fi然后在给已经存在的test容器里新挂载一个卷组，把本地的/data/docker-dir挂载到/tmp/docker-dir
当前物理机/data/docker-dir里内容是
root@docker-test2:/tmp 15:37:17 # ll /data/docker-dir/ total 4 -rw-r--r-- 1 root root 0 Feb 11 09:31 a -rw-r--r-- 1 root root 2 Feb 11 09:31 b
挂载的方法是
15:38:28 # sh dynamic_mount_docker_volume.sh Usage: container_name physics_volumes container_volumes Example: I want mount physics /tmp/test to container /src in test The command is: bash dynamic_mount_docker_volume.sh test /tmp/test /src
第一个参数是容器名，第二个参数的物理机的目录，第三个参数是挂载到容器里的目录
进行挂载
root@docker-test2:/tmp 15:36:14 # sh dynamic_mount_docker_volume.sh test /data/docker-dir/ /tmp/docker-dir dymainc mount physics /data/docker-dir/ on test /tmp/docker-dir is success!
可以看到成功的挂载了
下面做一下测试
15:37:28 # docker-enter test sh -c "ls -l /tmp/docker-dir" total 4 -rw-r--r-- 1 root root 0 Feb 11 09:31 a -rw-r--r-- 1 root root 2 Feb 11 09:31 b root@docker-test2:/tmp 15:38:18 # docker-enter test sh -c "mount" rootfs on / type rootfs (rw) /dev/mapper/docker-8:17-37748738-a21506d7b36e04e091008f4a326ac17c94e3d855e3aadb52992d7ba95f45cbbf on / type ext4 (rw,relatime,discard,stripe=16,data=ordered) proc on /proc type proc (rw,nosuid,nodev,noexec,relatime) sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime) shm on /dev/shm type tmpfs (rw,nosuid,nodev,noexec,relatime,size=65536k) /dev/sdb1 on /.dockerinit type ext4 (rw,relatime,data=ordered) /dev/sda3 on /etc/resolv.conf type ext4 (rw,relatime,data=ordered) /dev/sdb1 on /etc/hostname type ext4 (rw,relatime,data=ordered) /dev/sdb1 on /etc/hosts type ext4 (rw,relatime,data=ordered) /dev/sda3 on /tmp/software type ext4 (rw,relatime,data=ordered) /dev/sdb1 on /.dockerenv type ext4 (rw,relatime,data=ordered) devpts on /dev/tty1 type devpts (rw,relatime,gid=5,mode=620,ptmxmode=000) devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620,ptmxmode=666) devpts on /dev/ptmx type devpts (rw,relatime,gid=5,mode=620,ptmxmode=666) /dev/sda3 on /tmp/docker-dir type ext4 (rw,relatime,data=ordered) root@docker-test2:/tmp 15:38:24 # docker-enter test sh -c "df -h" Filesystem Size Used Avail Use% Mounted on rootfs 9.8G 470M 8.8G 5% / /dev/mapper/docker-8:17-37748738-a21506d7b36e04e091008f4a326ac17c94e3d855e3aadb52992d7ba95f45cbbf 9.8G 470M 8.8G 5% / shm 64M 0 64M 0% /dev/shm /dev/sdb1 1.8T 22G 1.7T 2% /.dockerinit /dev/sda3 518G 457G 35G 93% /etc/resolv.conf /dev/sdb1 1.8T 22G 1.7T 2% /etc/hostname /dev/sdb1 1.8T 22G 1.7T 2% /etc/hosts /dev/sda3 518G 457G 35G 93% /tmp/software /dev/sdb1 1.8T 22G 1.7T 2% /.dockerenv /dev/sda3 518G 457G 35G 93% /tmp/docker-dir
可以看到已经动态的挂在上了，并且挂在后目录里的内容一致
如果挂载的时候，第一个参数，容器不存在会报以下错误
16:23:27 # sh dynamic_mount_docker_volume.sh test123 /data/docker-dir/ /src Error: No such image or container: test123
如果挂载的时候，第二个参数，物理机的被挂载的目录不存在，会报错
root@docker-test2:/tmp 15:39:18 # sh dynamic_mount_docker_volume.sh test /tmp/sfsdfdf1 /src physics /tmp/sfsdfdf1 is not exist!
如果挂载的时候，第三个参数，容器的挂载的目录已经被挂载了，会报错
15:44:25 # sh dynamic_mount_docker_volume.sh test /data/software/ /src container test mount dir /src is mounting!
上面就是介绍如何动态的绑定卷组，只是一种方法，不太建议使用，有问题请留言。
本文出自 “吟—技术交流” 博客，请务必保留此出处http://dl528888.blog.51cto.com/2382721/1613764
标签：docker动态绑定卷组 docker绑定目录 docker绑定 docker volumes
原文地址：http://dl528888.blog.51cto.com/2382721/1613764
