I ran into an odd situation where installing a package via
apt-get caused running (production!) instances of mysqld to restart on some 16.04 Linux servers.
sudo apt-get install -y iotop on four servers. On three of the servers the installation failed stating
[ERROR] unknown variable 'rpl_semi_sync_slave_enabled=1'. This variable was only set on these three servers. At this point the mysql service we were running shut down!
The fourth server did not have an identical mysql configuration. Notably, the variable
rpl_semi_sync_slave_enabled was not present. Apt was able to install
iotop but interestingly our mysql service did not restart or shut down.
So it seems that some packages, on failing to install, will kill running processes that seem tangential to the installation! This has me very wary about installing further packages on our production servers running processes that we don't like to restart whenever. How can I know whether a package install will restart these processes and why is it happening in the first place?