Docker镜像、容器等文件目录默认在系统盘，虚拟机分配的系统盘20G容量也太小，研究下系统盘扩容

linux 系统分区 /dev/sda3，创建新系统分区sda4，扩容20G

基本的逻辑卷管理概念

基本的逻辑卷管理概念：
PV（Physical Volume）- 物理卷
物理卷在逻辑卷管理中处于最底层，它可以是实际物理硬盘上的分区，也可以是整个物理硬盘，也可以是raid设备。
VG（Volumne Group）- 卷组
卷组建立在物理卷之上，一个卷组中至少要包括一个物理卷，在卷组建立之后可动态添加物理卷到卷组中。一个逻辑卷管理系统工程中可以只有一个卷组，也可以拥有多个卷组。
LV（Logical Volume）- 逻辑卷
逻辑卷建立在卷组之上，卷组中的未分配空间可以用于建立新的逻辑卷，逻辑卷建立后可以动态地扩展和缩小空间。系统中的多个逻辑卷可以属于同一个卷组，也可以属于不同的多个卷组。

在虚拟机分配20G硬盘

略

系统加盘sda4

[root@node1 ~]# fdisk /dev/sda
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.


Command (m for help): n
Partition type:
   p   primary (3 primary, 0 extended, 1 free)
   e   extended
Select (default e): p
Selected partition 4
First sector (20971520-62914559, default 20971520): 
Using default value 20971520
Last sector, +sectors or +size{K,M,G} (20971520-62914559, default 62914559): 
Using default value 62914559
Partition 4 of type Linux and of size 20 GiB is set

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.

加入sda4

[root@node1 ~]# lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda      8:0    0   30G  0 disk 
├─sda1   8:1    0  300M  0 part /boot
├─sda2   8:2    0    1G  0 part 
├─sda3   8:3    0  8.7G  0 part /
└─sda4   8:4    0   20G  0 part 
sr0     11:0    1 1024M  0 rom  

创建物理卷

[root@node1 ~]# pvcreate /dev/sda4
  Physical volume "/dev/sda4" successfully created.

查看物理卷
[root@node1 ~]# pvs
  PV         VG Fmt  Attr PSize  PFree 
  /dev/sda4     lvm2 ---  20.00g 20.00g


[root@node1 ~]# pvdisplay
  "/dev/sda4" is a new physical volume of "20.00 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sda4
  VG Name               
  PV Size               20.00 GiB
  Allocatable           NO
  PE Size               0   
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               dnbfor-Mftv-L8o5-gdbP-sVdj-H6HY-tHW4J8


[root@node1 ~]# partprobe 

创建卷组

[root@node1 ~]# vgcreate vg0 /dev/sda4
  Volume group "vg0" successfully created

#查看卷组
[root@node1 ~]# vgscan
  Reading volume groups from cache.
  Found volume group "vg0" using metadata type lvm2


[root@node1 ~]# vgextend vg0 /dev/sda6  #增加一个卷组
[root@node1 ~]# pvmove /dev/sda6    //移走PV的数据
[root@node1 ~]# vgreduce vg0 /dev/sda6  //从vg0中删除物理卷

创建逻辑卷（单位:M）

[root@node1 ~]# lvcreate -L 10G -n lv1 vg0
  Logical volume "lv1" created.

[root@node1 /]# lvscan
  ACTIVE            '/dev/vg0/lv1' [10.00 GiB] inherit
[root@node1 ~]# lvdisplay
  --- Logical volume ---
  LV Path                /dev/vg0/lv1
  LV Name                lv1
  VG Name                vg0
  LV UUID                o9Qy20-I08o-GtAK-v0y9-DuY5-QlYl-J63IWc
  LV Write Access        read/write
  LV Creation host, time node1, 2021-03-28 21:40:00 +0800
  LV Status              available
  # open                 0
  LV Size                10.00 GiB
  Current LE             2560
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0

建文件系统（格式化）

[root@node1 ~]# mkfs -t xfs /dev/vg0/lv1
meta-data=/dev/vg0/lv1           isize=512    agcount=4, agsize=655360 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0, sparse=0
data     =                       bsize=4096   blocks=2621440, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal log           bsize=4096   blocks=2560, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0

挂载逻辑卷

[root@node1 ~]# mount /dev/vg0/lv1 /home


[root@node1 ~]# df -h  #扩容前10G
Filesystem           Size  Used Avail Use% Mounted on
/dev/sda3            8.7G  3.3G  5.5G  38% /
/dev/sda1            297M  118M  180M  40% /boot
/dev/mapper/vg0-lv1   10G   33M   10G   1% /home
tmpfs                1.9G     0  1.9G   0% /sys/fs/cgroup

--------------------------------------------------------------------------------
为根分区扩展空间
[root@node1 ~]# lvextend -L +1G /dev/mapper/vg0-lv1
[root@node1 ~]# resize2fs -f /dev/mapper/vg0-lv1 #不生效使用下面

--------------------------------------------------------------------------------
[root@node1 ~]# xfs_growfs /dev/mapper/vg0-lv1 
meta-data=/dev/mapper/vg0-lv1    isize=512    agcount=4, agsize=655360 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0 spinodes=0
data     =                       bsize=4096   blocks=2621440, 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 2621440 to 4507648

--------------------------------------------------------------------------------
[root@node1 ~]# df -h  #扩容后18G
Filesystem           Size  Used Avail Use% Mounted on
/dev/sda3            8.7G  3.3G  5.5G  38% /
devtmpfs             1.9G     0  1.9G   0% /dev
tmpfs                1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/sda1            297M  118M  180M  40% /boot
/dev/mapper/vg0-lv1   18G   33M   18G   1% /home

完

修改docker默认目录（终极大招）

修改docker默认目录到/home/docker下
Docker镜像、容器等文件目录迁移
https://blog.csdn.net/halikes23/article/details/87269997

[root@node1 ~]# systemctl stop docker

[root@node1 ~]# mkdir /home/docker

[root@node1 ~]# cp -R /var/lib/docker/* /home/docker/


[root@node1 ~]# cat /etc/docker/daemon.json
{
  "registry-mirrors": ["https://17tjx23n.mirror.aliyuncs.com"],
  "exec-opts": ["native.cgroupdriver=systemd"],
  "graph": "/home/docker"  #添加新目录
}
[root@node1 ~]# systemctl daemon-reload  && systemctl start docker

[root@node1 ~]# ln -s /usr/libexec/docker/docker-runc-current docker-runc

删除原有文件
[root@node1 ~]# rm -rf /var/lib/docker

虽然没有用删除操作，但是看到/var/lib/docker目录已经不存在了，镜像与容器显示在了新的目录/home/docker中

[root@node1 ~]# df -Th
Filesystem          Type      Size  Used Avail Use% Mounted on
/dev/sda3           xfs       8.7G  2.7G  6.1G  31% /
devtmpfs            devtmpfs  1.4G     0  1.4G   0% /dev
tmpfs               tmpfs     1.4G     0  1.4G   0% /dev/shm
tmpfs               tmpfs     1.4G  9.3M  1.4G   1% /run
tmpfs               tmpfs     1.4G     0  1.4G   0% /sys/fs/cgroup
/dev/sda1           xfs       297M  118M  180M  40% /boot
/dev/mapper/vg0-lv1 xfs        20G  831M   20G   5% /home
tmpfs               tmpfs     1.4G   12K  1.4G   1% /var/lib/kubelet/pods/9bb01287-42bd-4d81-9e24-4fd1b2953df1/volumes/kubernetes.io~secret/default-token-2l58c
tmpfs               tmpfs     1.4G   12K  1.4G   1% /var/lib/kubelet/pods/dcbaf00d-64f2-4c41-8d94-78e919a84db3/volumes/kubernetes.io~secret/flannel-token-k794f
tmpfs               tmpfs     1.4G   12K  1.4G   1% /var/lib/kubelet/pods/9e616d2b-6328-4edf-bf03-8666fb094871/volumes/kubernetes.io~secret/kube-proxy-token-78wp7
tmpfs               tmpfs     284M     0  284M   0% /run/user/0
overlay             overlay    20G  831M   20G   5% /home/docker/overlay2/136ee7e8387889f29b5d8b348d6efbad849d8c961fa65eb3d0777a002daac01b/merged
overlay             overlay    20G  831M   20G   5% /home/docker/overlay2/0ae46f788b0344c898b2b05c00ad644e5abc2d5629048b76393bf53e93bc5173/merged
overlay             overlay    20G  831M   20G   5% /home/docker/overlay2/c9fdd6a853ebb74d6aa5d6a7116b57ba4152c9ae6fcd50c1e5c75198961a49ba/merged
shm                 tmpfs      64M     0   64M   0% /home/docker/containers/3f778588c1026b13831ca20b83ebb2049660ed2d275ad869cace012b1322bea8/mounts/shm
shm                 tmpfs      64M     0   64M   0% /home/docker/containers/334ed06000ed551253d46f7fb93fe96ff3fbd7a1beddc9f6dbbf83228dce6b1b/mounts/shm
shm                 tmpfs      64M     0   64M   0% /home/docker/containers/b8644ce2df31395ca9d985cf1c27ed000ee0aff164d0b9bad33738d261e47094/mounts/shm
overlay             overlay    20G  831M   20G   5% /home/docker/overlay2/a4723f525ef18097008ca12f6dad08c40a93a240c4fbf3c278333a70ca14634f/merged
overlay             overlay    20G  831M   20G   5% /home/docker/overlay2/4fa16c90c3201c2766dd99b2aa0153f9d7827e57869e1d07b307ab24afa0e7c3/merged
overlay             overlay    20G  831M   20G   5% /home/docker/overlay2/746c68cd3386c7f246439bc7cfb1a1f13171b83b8596d6e907c7147bcf88d159/merged

参考资料

Linux虚拟机 sda分区扩容
https://blog.csdn.net/liuweijin_hot/article/details/105082645

centos7 -lvm卷组
http://t.zoukankan.com/jjp816-p-8917027.html

逻辑卷的使用
https://blog.51cto.com/9480860/1700288

linux如何使用umount命令强制卸载文件系统
https://blog.csdn.net/qq_19175749/article/details/51154529

Docker镜像、容器等文件目录迁移
https://blog.csdn.net/halikes23/article/details/87269997