Support Cloudflare Load Balancers

[adyanth]

Support adding the created Tunnels to existing/new Cloudflare Load Balancers, therefore reducing the manual step of doing it and recording it on the CR.

Requested by #1 (comment)

[christidis]

I am currently using 4 tunnels (each with size of 2 but this doesn't really matter) all sinked in the same Cloudflare Load Balancer. This is the suggested design for a really HA and Fault tolerant setup from Cloudflare's side.
cf-operator-tunnel-01
cf-operator-tunnel-02
cf-operator-tunnel-03
cf-operator-tunnel-04

It would be nice to be able to define more than one tunnels in each tunnelRef definition or provide a regex to match them all with a single manifest or something similar.

The current configuration is the following:

tunnelRef:
  kind: ClusterTunnel # Or Tunnel
  name: cf-operator-tunnel-01
  disableDNSUpdates: true

which means that I need to deduplicate all the TunnelBinding CRDs for each tunnel. Am I correct?

I added my comment here because having more than one tunnels is common when using a CF LB. But if you think I need to file a separate suggestion for this one, I can do that! Thanks.

[adyanth]

The way it is implemented currently is using a role/roleBinding strategy which does not reliably lend itself to having multiple tunnelRefs being used. Providing a regex would also have similar problems because of the way each tunnelBinding discovers a tunnel to configure.
Each tunnelBinding has labels of it's tunnel on it, so that when configuring, we can enumerate all the relevant tunnelBindings.

Implementing this would need a different way of looking up connected tunnelBindings for a given tunnel (effectively making a many to many lookup), which is not directly possible as of now. An idea would be to store all the linked tunnelBindings in the tunnel's status, but it needs to be tested out.