[CRD] Allow monitoring of an alias port in VirtualServer and TransportServer

[tkam8]

Title

Allow monitoring of an alias port in VirtualServer and TransportServer

Description

As an app owner, I want to be able to monitor an alias port that is different from the port that is used to serve traffic. I am using calico BGP (clusterIP mode) integration so will LB directly to pods.

Actual Problem

Today I cannot specify an aliasPort (a.k.a. targetPort) in the CRDs that makes the monitor target a different port to determine the health of a pool member.

Solution Proposed

In the TransportServer CRD and VirtualServer CRD monitor block, add a parameter like targetPort to define the monitored port.

• In BIG-IP TMUI, this translates to "Alias Service Port" on BIG-IP pool.
• In AS3, this translates to "targetPort" in the Monitor class.

Alternatives

the only alternative is to use AS3 configmaps, but today we cannot use both configmaps and CRDs so will be high impact.

[trinaths]

Created [CONTCNTR-3376] for internal tracking.