I recreated my AKS cluster because of a failure and the new cluster can not access the azure managed mysql instance. I receive an UnknownHostException for the azure managed mysql instance when my containers start up. The nodes apparently have access to the outside world because it deploys the containers from an external container registry.
EDIT
There is a firewall rule that is open to everything. 0.0.0.0 -> 255.255.255.255
EDIT 2
I have an azure postgresql database also and it is visible.