After restarting the ToolsDB primary instance, one needs to remember to set read_only = 0; because the database is configured to always start in read_only mode.

We could automate it with a "restart toolsdb" cookbook that does:

servicectl restart mariadb
mysql -e 'SET GLOBAL read_only = 0;'

Though we need to consider if we might want to do some checks before setting read_only = 0. One check could be waiting for the replica lag to return to zero.