OpenStack云主机在线动态扩展根目录

2019独角兽企业重金招聘Python工程师标准>>> hot3.png

一、背景

一般云主机的根目录都是在镜像制作时就确定下来了,在启动云主机时,选定的实例类型也会限定云主机的/目录大小。 偶尔可能会出现系统/目录不够用的情况,一般有两种方式来解决这个问题: 第一个是添加磁盘,将相关文件移至新增盘; 第二个是扩展/目录。

二、云主机启动的两种方式

云主机启动时也有两种方式

2.1. 方式一、从卷启动

OpenStack云主机在线动态扩展根目录_第1张图片

这种方式启动的云主机,指定的卷大小必须不小于镜像的根目录大小,比如镜像的/目录大小为50G,此处指定为100G,但是云主机启动之后/目录还是为50G,这样就可以直接将这剩余的50G扩展到/目录下。这样做有个限制,扩展的大小有上限,取决于云主机创建时指定的大小。参考方式二,可以跨过这个限制。

查看分区情况

# lsblk 
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vda             252:0    0  100G  0 disk 
├─vda1          252:1    0    1G  0 part /boot
└─vda2          252:2    0   49G  0 part 
  └─centos-root 253:0    0   49G  0 lvm  /

将剩余空间分区

# fdisk /dev/vda
Command (m for help): n
Partition type:
   p   primary (2 primary, 0 extended, 2 free)
   e   extended
Select (default p): p
Partition number (3,4, default 3): 
First sector (104857600-209715199, default 104857600): 
Using default value 104857600
Last sector, +sectors or +size{K,M,G} (104857600-209715199, default 209715199): 
Using default value 209715199
Partition 3 of type Linux and of size 50 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.
# lsblk 
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vda             252:0    0  100G  0 disk 
├─vda1          252:1    0    1G  0 part /boot
└─vda2          252:2    0   49G  0 part 
  └─centos-root 253:0    0   49G  0 lvm  /
# partprobe
# lsblk    
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vda             252:0    0  100G  0 disk 
├─vda1          252:1    0    1G  0 part /boot
├─vda2          252:2    0   49G  0 part 
│ └─centos-root 253:0    0   49G  0 lvm  /
└─vda3          252:3    0   50G  0 part 

创建PV

# pvcreate /dev/vda3
  Physical volume "/dev/vda3" successfully created.

添加物理卷

# vgscan 
  Reading volume groups from cache.
  Found volume group "centos" using metadata type lvm2
# vgextend centos /dev/vda3
  Volume group "centos" successfully extended

扩展物理卷

# df -h
Filesystem               Size  Used Avail Use% Mounted on
/dev/mapper/centos-root   49G  1.6G   48G   4% /
devtmpfs                 1.9G     0  1.9G   0% /dev
tmpfs                    1.9G     0  1.9G   0% /dev/shm
tmpfs                    1.9G  8.5M  1.9G   1% /run
tmpfs                    1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/vda1               1014M  145M  870M  15% /boot
tmpfs                    379M     0  379M   0% /run/user/0
# lvextend -l +100%FREE /dev/mapper/centos-root
  Size of logical volume centos/root changed from <49.00 GiB (12543 extents) to 98.99 GiB (25342 extents).
  Logical volume centos/root successfully resized.

# lsblk 
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vda             252:0    0  100G  0 disk 
├─vda1          252:1    0    1G  0 part /boot
├─vda2          252:2    0   49G  0 part 
│ └─centos-root 253:0    0   99G  0 lvm  /
└─vda3          252:3    0   50G  0 part 
  └─centos-root 253:0    0   99G  0 lvm  /
# df -h
Filesystem               Size  Used Avail Use% Mounted on
/dev/mapper/centos-root   49G  1.6G   48G   4% /
devtmpfs                 1.9G     0  1.9G   0% /dev
tmpfs                    1.9G     0  1.9G   0% /dev/shm
tmpfs                    1.9G  8.5M  1.9G   1% /run
tmpfs                    1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/vda1               1014M  145M  870M  15% /boot
tmpfs                    379M     0  379M   0% /run/user/0

xfs在线扩容

# xfs_growfs /dev/mapper/centos-root
meta-data=/dev/mapper/centos-root isize=512    agcount=4, agsize=3211008 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0 spinodes=0
data     =                       bsize=4096   blocks=12844032, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal               bsize=4096   blocks=6271, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 12844032 to 25950208

扩展成功,重启云主机后/目录依旧为扩展后大小

# df -h
Filesystem               Size  Used Avail Use% Mounted on
/dev/mapper/centos-root   99G  1.6G   98G   2% /
devtmpfs                 1.9G     0  1.9G   0% /dev
tmpfs                    1.9G     0  1.9G   0% /dev/shm
tmpfs                    1.9G  8.5M  1.9G   1% /run
tmpfs                    1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/vda1               1014M  145M  870M  15% /boot
tmpfs                    379M     0  379M   0% /run/user/0

2.2. 方式二、从镜像启动

OpenStack云主机在线动态扩展根目录_第2张图片

直接从镜像启动,不创建卷,云主机启动后/目录的大小为镜像中默认大小,这样就得新增一块盘,直接将这块盘扩展到/目录即可

# lsblk 
NAME            MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vda             252:0    0  50G  0 disk 
├─vda1          252:1    0   1G  0 part /boot
└─vda2          252:2    0  49G  0 part 
  └─centos-root 253:0    0  49G  0 lvm  /
# lsblk 
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vda             252:0    0   50G  0 disk 
├─vda1          252:1    0    1G  0 part /boot
└─vda2          252:2    0   49G  0 part 
  └─centos-root 253:0    0   49G  0 lvm  /
vdb             252:16   0  100G  0 disk 
# fdisk /dev/vdb
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 0x5ee47290.

Command (m for help): n
Partition type:
   p   primary (0 primary, 0 extended, 4 free)
   e   extended
Select (default p): p
Partition number (1-4, default 1): 
First sector (2048-209715199, default 2048): 
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-209715199, default 209715199): 
Using default value 209715199
Partition 1 of type Linux and of size 100 GiB is set

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

Calling ioctl() to re-read partition table.
Syncing disks.
# lsblk          
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vda             252:0    0   50G  0 disk 
├─vda1          252:1    0    1G  0 part /boot
└─vda2          252:2    0   49G  0 part 
  └─centos-root 253:0    0   49G  0 lvm  /
vdb             252:16   0  100G  0 disk 
└─vdb1          252:17   0  100G  0 part 
# df -h
Filesystem               Size  Used Avail Use% Mounted on
/dev/mapper/centos-root   49G  1.6G   48G   4% /
devtmpfs                 1.9G     0  1.9G   0% /dev
tmpfs                    1.9G     0  1.9G   0% /dev/shm
tmpfs                    1.9G  8.5M  1.9G   1% /run
tmpfs                    1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/vda1               1014M  145M  870M  15% /boot
tmpfs                    379M     0  379M   0% /run/user/0
# pvcreate /dev/vdb1
  Physical volume "/dev/vdb1" successfully created.
# vgscan 
  Reading volume groups from cache.
  Found volume group "centos" using metadata type lvm2
# df -h
Filesystem               Size  Used Avail Use% Mounted on
/dev/mapper/centos-root   49G  1.6G   48G   4% /
devtmpfs                 1.9G     0  1.9G   0% /dev
tmpfs                    1.9G     0  1.9G   0% /dev/shm
tmpfs                    1.9G  8.5M  1.9G   1% /run
tmpfs                    1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/vda1               1014M  145M  870M  15% /boot
tmpfs                    379M     0  379M   0% /run/user/0
# vgextend VolGroup /dev/vdb1
  Volume group "VolGroup" not found
  Cannot process volume group VolGroup
# vgextend centos /dev/vdb1  
  Volume group "centos" successfully extended
# lvextend -l +100%FREE /dev/mapper/centos-root
  Size of logical volume centos/root changed from <49.00 GiB (12543 extents) to 148.99 GiB (38142 extents).
  Logical volume centos/root successfully resized.
# xfs_growfs /dev/mapper/centos-root
meta-data=/dev/mapper/centos-root isize=512    agcount=4, agsize=3211008 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0 spinodes=0
data     =                       bsize=4096   blocks=12844032, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal               bsize=4096   blocks=6271, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 12844032 to 39057408
# df -h
Filesystem               Size  Used Avail Use% Mounted on
/dev/mapper/centos-root  149G  1.6G  148G   2% /
devtmpfs                 1.9G     0  1.9G   0% /dev
tmpfs                    1.9G     0  1.9G   0% /dev/shm
tmpfs                    1.9G  8.5M  1.9G   1% /run
tmpfs                    1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/vda1               1014M  145M  870M  15% /boot
tmpfs                    379M     0  379M   0% /run/user/0
# lsblk 
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vda             252:0    0   50G  0 disk 
├─vda1          252:1    0    1G  0 part /boot
└─vda2          252:2    0   49G  0 part 
  └─centos-root 253:0    0  149G  0 lvm  /
vdb             252:16   0  100G  0 disk 
└─vdb1          252:17   0  100G  0 part 
  └─centos-root 253:0    0  149G  0 lvm  /

转载于:https://my.oschina.net/xiaozhublog/blog/3053248

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