Found boot, space is full, uninstall the previous kernel, clearing space upgrade.
How to upgrade the kernel, please see our article on the blog: https: //www.cnblogs.com/junsec/p/11453049.html
Unload excess kernel, boot cleaning up
1, view the current kernel version
uname -a
2, and the image header to determine system installation
dpkg --list|grep linux-image dpkg --list|grep linux-headers
3, uninstall unwanted header and image
apt-get remove --purge linux-headers-xxxx apt-get remove --purge linux-image-xxx
4, clean up
apt-get autoclean apt-get autoremove
5, update grub, this is the point I stepped pit, no update grub, direct restart, the result is miserable
update-grub2
6, restart it
reboot