docker容器跑起来默认占用/var/lib目录的空间，我知道的有两种解决办法，欢迎大家补充。
一是迁移工作目录，二是扩根。
反正都是要挂盘，我直接扩根了，省点事。
一、扩容
查看磁盘空间
df -h
lsblk
fdisk -l系统盘真的很小，全靠外挂数据盘
lsblk这样看得更清晰些
我有一块500G的盘，分个249G出来扩根吧！！！
磁盘分区
fdisk /dev/sdb[root@123123 ~]# fdisk /dev/sdb
Welcome to fdisk (util-linux 2.23.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0xcffa3732.
Command (m for help): m #打印帮助文档
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition
g create a new empty GPT partition table
G create an IRIX (SGI) partition table
l list known partition types
m print this menu
n add a new partition #n表示创建1个新分区
o create a new empty DOS partition table
p print the partition table
q quit without saving changes
s create a new empty Sun disklabel
t change a partition's system id
u change display/entry units
v verify the partition table
w write table to disk and exit #w表示保存并退出
x extra functionality (experts only)
Command (m for help): n #输入 n,我们开始新建一个分区
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): p #输入 p,我们将分区创建为主分区
Partition number (1-4, default 1): 1 #输入1，我们将分区定义为第1个分区，即sdb1
First sector (2048-1048575999, default 2048): #好像是开始字节数
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-1048575999, default 1048575999): 249.9G
#新分区的大小，要规范输入
Value out of range.
Last sector, +sectors or +size{K,M,G} (2048-1048575999, default 1048575999): +249G
Partition 1 of type Linux and of size 249 GiB is set
Command (m for help): t #输入t,我们来改变一下分区的类型
Selected partition 1
Hex code (type L to list all codes): 8e #输入8e,8e就是LVM
Changed type of partition 'Linux' to 'Linux LVM'
Command (m for help): w #保存并退出
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@nanhavezhi~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 64G 0 disk
├─sda1 8:1 0 1G 0 part /boot
└─sda2 8:2 0 63G 0 part
├─rootvg-lvroot 253:0 0 26G 0 lvm /
├─rootvg-lvswap 253:1 0 10G 0 lvm [SWAP]
├─rootvg-lvvar 253:2 0 16G 0 lvm /var
├─rootvg-lvopt 253:3 0 10G 0 lvm /opt
└─rootvg-lvhome 253:4 0 1G 0 lvm /home
sdb 8:16 0 500G 0 disk
└─sdb1 8:17 0 249G 0 part
sr0 11:0 1 1024M 0 rom格式化sdb1
mkfs.xfs /dev/sdb1
查看卷组信息
找到根分区的卷组信息
lvdisplay
开始扩容
[root@123123~]# pvcreate /dev/sdb1 #创建pv
WARNING: xfs signature detected on /dev/sdb1 at offset 0. Wipe it? [y/n]: y
Wiping xfs signature on /dev/sdb1.
Physical volume "/dev/sdb1" successfully created.
[root@123123 ~]# vgextend rootvg /dev/sdb1
#将/dev/sdb1卷加入根目录所在的卷组名rootvg，rootvg就是查看卷组信息时看到的vg的名字（这一步俗称 扩容 vg ）
Volume group "rootvg" successfully extended
[root@123123~]# vgdisplay
--- Volume group ---
VG Name rootvg
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 7
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 5
Open LV 5
Max PV 0
Cur PV 2
Act PV 2
VG Size 311.99 GiB
PE Size 4.00 MiB
Total PE 79870
Alloc PE / Size 16127 / <63.00 GiB
Free PE / Size 63743 / <249.00 GiB ##关注这个可用Free PE
VG UUID bCPgVl-rpYe-lqlT-ooCs-gA3j-E2AP-wENic3
[root@123123 ~]# lvextend -l +63743 /dev/rootvg/lvroot
#把可用空间全部加给根分区，2559就是上面的Free PE值，/dev/cl/root就是上面查看卷组信息的LV Path值（扩容LV）
Size of logical volume rootvg/lvroot changed from 26.00 GiB (6656 extents) to <275.00 GiB (70399 extents).
Logical volume rootvg/lvroot successfully resized.
#以上只是完成了卷的扩容，文件系统还没扩容，执行最后一步：
[root@123123~]# xfs_growfs /dev/rootvg/lvroot
meta-data=/dev/mapper/rootvg-lvroot isize=512 agcount=4, agsize=1703936 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=6815744, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=3328, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 6815744 to 72088576二、重大失误
到这一步我出现了，严重的错误。
这台机器是我申请来了，不是我自己装的，/var/是独立挂载出来的，不是在/根下的，扩根没啥用。
看了看缩容的文档，找到一个老哥写的
https://blog.51cto.com/u_15070093/2812023 用 lvreduce 可以缩容，收回来的空间可以重新划分，我现在的需求是把/var扩容，正好在一个vg里面，把收回来的空间扩容给/var就好了。
三、缩容
[root@123123~]# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
lvhome rootvg -wi-ao---- 1.00g
lvopt rootvg -wi-ao---- 10.00g
lvroot rootvg -wi-ao---- <273.00g
lvswap rootvg -wi-ao---- <10.00g
lvvar rootvg -wi-ao---- 18.00g
[root@123123 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 32G 0 32G 0% /dev
tmpfs 32G 0 32G 0% /dev/shm
tmpfs 32G 12M 32G 1% /run
tmpfs 32G 0 32G 0% /sys/fs/cgroup
/dev/mapper/rootvg-lvroot 275G 14G 262G 5% /
/dev/sda1 1014M 172M 843M 17% /boot
/dev/mapper/rootvg-lvopt 10G 33M 10G 1% /opt
/dev/mapper/rootvg-lvhome 1014M 37M 978M 4% /home
/dev/mapper/rootvg-lvvar 18G 2.6G 16G 15% /var
tmpfs 6.3G 12K 6.3G 1% /run/user/42
tmpfs 6.3G 0 6.3G 0% /run/user/1000
[root@123123~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 64G 0 disk
├─sda1 8:1 0 1G 0 part /boot
└─sda2 8:2 0 63G 0 part
├─rootvg-lvroot 253:0 0 273G 0 lvm /
├─rootvg-lvswap 253:1 0 10G 0 lvm [SWAP]
├─rootvg-lvvar 253:2 0 18G 0 lvm /var
├─rootvg-lvopt 253:3 0 10G 0 lvm /opt
└─rootvg-lvhome 253:4 0 1G 0 lvm /home
sdb 8:16 0 500G 0 disk
├─sdb1 8:17 0 249G 0 part
│ ├─rootvg-lvroot 253:0 0 273G 0 lvm /
│ └─rootvg-lvvar 253:2 0 18G 0 lvm /var
└─sdb2 8:18 0 251G 0 part
sr0 11:0 1 1024M 0 rom
#以上是磁盘调整前的状况
[root@123123 ~]# lvreduce -L 240G /dev/rootvg/lv
#这条命令的意思是给它剩240g，我一开始弄错了！！
/dev/rootvg/lvhome /dev/rootvg/lvopt /dev/rootvg/lvroot /dev/rootvg/lvswap /dev/rootvg/lvvar
[root@123123 ~]# lvreduce -L 240G /dev/rootvg/lvroot
WARNING: Reducing active and open logical volume to 240.00 GiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce rootvg/lvroot? [y/n]: y
Size of logical volume rootvg/lvroot changed from <273.00 GiB (69887 extents) to 240.00 GiB (61440 extents).
Logical volume rootvg/lvroot successfully resized.
[root@123123123 ~]# vgdisplay
--- Volume group ---
VG Name rootvg
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 11
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 5
Open LV 5
Max PV 0
Cur PV 2
Act PV 2
VG Size 311.99 GiB
PE Size 4.00 MiB
Total PE 79870
Alloc PE / Size 71423 / <279.00 GiB
Free PE / Size 8447 / <33.00 GiB #记住这个 Free PE值
VG UUID bCPgVl-rpYe-lqlT-ooCs-gA3j-E2AP-wENic3
[root@123123 ~]# lvextend -l +8447 /dev/rootvg/lvvar
Size of logical volume rootvg/lvvar changed from 18.00 GiB (4608 extents) to <51.00 GiB (13055 extents).
Logical volume rootvg/lvvar successfully resized.
[root@123123 ~]# xfs_growfs /dev/rootvg/lvvar #这次只扩容了33g
meta-data=/dev/mapper/rootvg-lvvar isize=512 agcount=5, agsize=1048576 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=4718592, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 4718592 to 13368320
[root@e7tops ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 32G 0 32G 0% /dev
tmpfs 32G 0 32G 0% /dev/shm
tmpfs 32G 12M 32G 1% /run
tmpfs 32G 0 32G 0% /sys/fs/cgroup
/dev/mapper/rootvg-lvroot 275G 14G 262G 5% /
/dev/sda1 1014M 172M 843M 17% /boot
/dev/mapper/rootvg-lvopt 10G 33M 10G 1% /opt
/dev/mapper/rootvg-lvhome 1014M 37M 978M 4% /home
/dev/mapper/rootvg-lvvar 51G 2.6G 49G 5% /var
tmpfs 6.3G 12K 6.3G 1% /run/user/42
tmpfs 6.3G 0 6.3G 0% /run/user/1000
[root@123123 ~]# lvreduce -L 100G /dev/rootvg/lvroot
WARNING: Reducing active and open logical volume to 100.00 GiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce rootvg/lvroot? [y/n]: y
Size of logical volume rootvg/lvroot changed from 240.00 GiB (61440 extents) to 100.00 GiB (25600 extents).
Logical volume rootvg/lvroot successfully resized.
[root@123123 ~]# vgdisplay
--- Volume group ---
VG Name rootvg
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 13
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 5
Open LV 5
Max PV 0
Cur PV 2
Act PV 2
VG Size 311.99 GiB
PE Size 4.00 MiB
Total PE 79870
Alloc PE / Size 44030 / 171.99 GiB
Free PE / Size 35840 / 140.00 GiB
VG UUID bCPgVl-rpYe-lqlT-ooCs-gA3j-E2AP-wENic3
[root@123123 ~]# lvextend -l +35840 /dev/rootvg/lvvar
Size of logical volume rootvg/lvvar changed from <51.00 GiB (13055 extents) to <191.00 GiB (48895 extents).
Logical volume rootvg/lvvar successfully resized.
[root@213213 ~]# xfs_growfs /dev/rootvg/lvvar
meta-data=/dev/mapper/rootvg-lvvar isize=512 agcount=13, agsize=1048576 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=13368320, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 13368320 to 50068480
经过我的一番操作，磁盘空间调整后是这样的
[root@123123 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 32G 0 32G 0% /dev
tmpfs 32G 0 32G 0% /dev/shm
tmpfs 32G 12M 32G 1% /run
tmpfs 32G 0 32G 0% /sys/fs/cgroup
/dev/mapper/rootvg-lvroot 275G 14G 262G 5% /
/dev/sda1 1014M 172M 843M 17% /boot
/dev/mapper/rootvg-lvopt 10G 33M 10G 1% /opt
/dev/mapper/rootvg-lvhome 1014M 37M 978M 4% /home
/dev/mapper/rootvg-lvvar 261G 2.6G 259G 1% /var
tmpfs 6.3G 12K 6.3G 1% /run/user/42
tmpfs 6.3G 0 6.3G 0% /run/user/1000
[root@123123 ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 64G 0 disk
├─sda1 8:1 0 1G 0 part /boot
└─sda2 8:2 0 63G 0 part
├─rootvg-lvroot 253:0 0 42G 0 lvm /
├─rootvg-lvswap 253:1 0 10G 0 lvm [SWAP]
├─rootvg-lvvar 253:2 0 249G 0 lvm /var
├─rootvg-lvopt 253:3 0 10G 0 lvm /opt
└─rootvg-lvhome 253:4 0 1G 0 lvm /home
sdb 8:16 0 500G 0 disk
├─sdb1 8:17 0 249G 0 part
│ ├─rootvg-lvroot 253:0 0 42G 0 lvm /
│ └─rootvg-lvvar 253:2 0 249G 0 lvm /var
└─sdb2 8:18 0 251G 0 part
sr0 11:0 1 1024M 0 rom
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