如何nsenter,docker-enter给已经启动的docker容器挂载文件？

脚本如下：

#!/bin/bash
set -ex

useage(){
    echo "useage:"
    echo "  dockermnt.sh CONTAINER HOSTPATH CONTPATH"
}

if [ $# -ne 3 ];then
    useage
    exit
fi

CONTAINER=$1
HOSTPATH=$2
CONTPATH=$3

REALPATH=$(readlink --canonicalize "$HOSTPATH")
FILESYS=$(df -P "$REALPATH" | tail -n 1 | awk '{print $6}')

while read -r DEV MOUNT JUNK
do [ "$MOUNT" = "$FILESYS" ] && break
done </proc/mounts
[ "$MOUNT" = "$FILESYS" ] # Sanity check!

while read -r 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))

docker-enter "$CONTAINER" sh -c \
	     "[ -b $DEV ] || mknod --mode 0600 $DEV b $DEVDEC"
docker-enter "$CONTAINER" mkdir /tmpmnt
docker-enter "$CONTAINER" mount "$DEV" /tmpmnt
docker-enter "$CONTAINER" mkdir -p "$CONTPATH"
docker-enter "$CONTAINER" mount -o bind "/tmpmnt/$SUBROOT/$SUBPATH" "$CONTPATH"
docker-enter "$CONTAINER" umount /tmpmnt
docker-enter "$CONTAINER" rmdir /tmpmnt

使用方法：

dockermnt.sh CONTAINER HOSTPATH CONTPATH