Binary package “bootmail” in ubuntu kinetic

automatically email one or more admins when a system reboots

 bootmail is a handy utility that will automatically send an email
 to a configurable list of email addresses each time the system boots.
 This is perhaps useful for unattended servers that should not reboot often.
 It appends a configurable list of log files to the email body.
 If you install the suggested packages, it will also cryptographically
 sign the email messages.