Additionally, after reboot and running unattended-upgrades I saw the following:
2017-05-18 13:01:59,777 INFO Allowed origins are: ['o=Ubuntu,a=yakkety', 'o=Ubuntu,a=yakkety-security'] 2017-05-18 13:01:59,777 WARNING Unclean dpkg state detected, trying to correct 2017-05-18 13:02:20,263 WARNING dpkg --configure -a output: Setting up libdns162:amd64 (1:9.10.3.dfsg.P4-10.1ubuntu1.6) ... ...
So while there isn't a "pop-up window" that unattended-upgrades are running a reboot while they are running is something which can be recovered from.
Additionally, after reboot and running unattended-upgrades I saw the following:
2017-05-18 13:01:59,777 INFO Allowed origins are: ['o=Ubuntu, a=yakkety' , 'o=Ubuntu, a=yakkety- security' ] 3.dfsg. P4-10.1ubuntu1. 6) ...
2017-05-18 13:01:59,777 WARNING Unclean dpkg state detected, trying to correct
2017-05-18 13:02:20,263 WARNING dpkg --configure -a output:
Setting up libdns162:amd64 (1:9.10.
...
So while there isn't a "pop-up window" that unattended-upgrades are running a reboot while they are running is something which can be recovered from.