mjhjmtu

I've got unattended upgrades configured on my system. Every so often emails come in that a reboot is required. Yesterday after I rebooted my system to complete an upgrade, only to find that mysql-server had been removed from my system. /etc/init.d/mysql did still exist, but the mysqld and mysqld_secure executables were nowhere to be found. I've had this before with a different package.

How can I figure out why this happened, and how to prevent this in the future?

The first email that said I needed to reboot:

Unattended upgrade returned: True

Warning: A reboot is required to complete this upgrade.

Packages that were upgraded:
 dnsmasq dnsmasq-base linux-compiler-gcc-4.9-x86 linux-headers-amd64 
 linux-image-amd64 linux-libc-dev 
Packages with upgradable origin but kept back:
 python-reportbug reportbug 

Unattended-upgrades log:
Initial blacklisted packages: 
Initial whitelisted packages: 
Starting unattended upgrades script
Allowed origins are: ['origin=Debian,codename=jessie,label=Debian-Security']
Packages that will be upgraded: dnsmasq dnsmasq-base linux-compiler-gcc-4.9-x86 linux-headers-amd64 linux-image-amd64 linux-libc-dev
Writing dpkg log to '/var/log/unattended-upgrades/unattended-upgrades-dpkg.log'
All upgrades installed