1. 虚机镜像内安装
centos/rhel： cloud-utils-growpart
debian/ubuntu：cloud-guest-utils
2. /etc/rc.local 内添加：下面的例子是用LVM的
# ROOT_LV=/dev/mapper/klas-root 这个是你的root分区LVM名称，修改后，解开注释
DEV_NUM_PAT=$(dmsetup table $ROOT_LV | awk '{print $4}' | awk -F: '{print $1",\\s+"$2}')
DEV_NAME=$(ls -Al /dev/ | grep -E "$DEV_NUM_PAT" | awk '{print $NF}')
FULL_DEV_NAME=/dev/$DEV_NAME
PART_NUM=$(echo $FULL_DEV_NAME | grep -Eo '[0-9]*')
DISK_DEV_NAME=$(echo $FULL_DEV_NAME | awk -F$PART_NUM '{print $1}')
LANG=en_US.utf-8 growpart $DISK_DEV_NAME $PART_NUM
pvresize $FULL_DEV_NAME
lvextend -l +100%FREE $ROOT_LV
# xfs_growfs / 如果是用XFS，解开这个注释
# resize2fs $ROOT_LV 如果是ext4之类的，解开这个注释
