由于主分区大小只有8g，pip安装依赖时提示空间不足，考虑对主分区进行扩容。
本来看了 https://askubuntu.com/a/937351 ，用growpart扩容/dev/sda5即可，但是出现The filesystem is already 9906432 (4k) blocks long. Nothing to do!这种提示。
看到Ubuntu ext4 partition is not being extended or resized as expected with growpart or resize2fs，如果fdisk -l看到主分区和扩展分区有重合（漏截图了），需要先用growpart扩容/dev/sda2，再扩容/dev/sda5 ，最后用resize2fs修改/dev/sda5 才可以。（似乎是因为/dev/sda2是/dev/sda5的父分区）
命令是：
growpart /dev/sda 2
growpart /dev/sda 5
resize2fs /dev/sda5如果没有growpart，先安装：
sudo apt-get install cloud-utils 过程：可以看到/大小变大了
~# growpart /dev/sda 2
CHANGED: partition=2 start=1052670 old: size=15722498 end=16775168 new: size=62215137 end=63267807
root@mininet-vm:~# growpart /dev/sda 5
CHANGED: partition=5 start=1052672 old: size=15722496 end=16775168 new: size=62215135 end=63267807
root@mininet-vm:~# resize2fs /dev/sda5
resize2fs 1.45.5 (07-Jan-2020)
Filesystem at /dev/sda5 is mounted on /; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 4
The filesystem on /dev/sda5 is now 7776891 (4k) blocks long.
root@mininet-vm:~# df -h
Filesystem Size Used Avail Use% Mounted on
udev 3.9G 0 3.9G 0% /dev
tmpfs 797M 696K 796M 1% /run
/dev/sda5 30G 4.6G 24G 17% /
tmpfs 3.9G 0 3.9G 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 3.9G 0 3.9G 0% /sys/fs/cgroup
/dev/sda1 511M 4.0K 511M 1% /boot/efi
/dev/sdb1 11G 48M 9.5G 1% /work
tmpfs 797M 0 797M 0% /run/user/1000
# fdisk -l
Disk /dev/sda: 30.17 GiB, 32393134080 bytes, 63267840 sectors
Disk model: HARDDISK
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x54b142dc
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 1050623 1048576 512M b W95 FAT32
/dev/sda2 1052670 63267806 62215137 29.7G 5 Extended
/dev/sda5 1052672 63267806 62215135 29.7G 83 Linux另外的手动扩容方法容易出问题，比如https://hellogitlab.com/OS/Centos/X_VirtualBox_enhance_hdds#查看当前lvm信息