Allow fixing the p2p IP

[PierreBesson]

Automatic node port discovery was introduced in #28, however in some cases the operator will not want / be able to open a large range of ports (30000-32767) on their Kubernetes nodes.

An option should be added to fix the attributed nodePort, however in this case it might be impossible to support more than 1 replica for the statefulset as fixing the port will result in a port conflict for the second replica.

Similarly, it should be possible to deploy a node which uses a fixed p2p IP by using loadBalancerIP for LoadBalancer services using a pre-reserved IP at the Cloud Provider (eg. for GCP).
However in this case, the p2p service would no longer be of type NodePort but instead of type LoadBalancer.

[dblane-digicatapult]

When using type LoadBalancer our implementation would vary depending on the cloudProvider being used when we query a service to get the external address which is either an FQDN or an IP, which we then need to advertise when using --public-addr

AWS example:

status:
  loadBalancer:
    ingress:
    - hostname: some-loadbalancer-hostname.eu-west-1.elb.amazonaws.com

Where as GCP will return:

status:
    loadBalancer:
      ingress:
      - ip: 111.111.111.111

This complicates how we then advertise, do we want to detect the address's format and then setup our multiaddr format based on if its an IP or FQDN? The current kubectl image we are using for the init container that queries these services has no dig or hosts command so reducing an FQDN to either a single or an array of IPs is challenging.

Also currently our naming is very specific to NodePort node.perNodeServices.createP2pNodePortService Do we want to change something more generically named for the p2p service? E.G.

  perNodeServices:
    createApiService: true
    createP2pService: true
    p2pServiceType: LoadBalancer  # Must be type ClusterIP, NodePort or LoadBalancer
    setPublicAddressToExternal:
      enabled: true
      ipRetrievalServiceUrl: https://ifconfig.io/ip

[dblane-digicatapult]

@PierreBesson Any comments on above suggestions?

[PierreBesson]

For me the renaming you propose withcreateP2pService and p2pServiceType make sense. As for supporting FQDN instead of IPs for --public-addr, I didn't even know this was possible but I would be fine to add this feature if it is strictly additive to regular IP-based public address.
That would mean maybe setting up a different init-container for doing FQDN resolution when the option is enabled.

[PierreBesson]

Fixing the p2p ports is now possible with chart v2.0 using the node.perNodeServices.relayP2pService.port and node.perNodeServices.paraP2pService.port properties. However fixing the public IP with the Service loadBalancerIP still needs to be implemented.