fix: add mapping of current POD IP to external IP

[denis-tingaikin]

Signed-off-by: denis-tingajkin denis.tingajkin@xored.com

Motivation

Related to networkservicemesh/sdk#1015

[edwarnicke]

Why are we mapping Pod IP and not Node IP to external IP? The forwarder should be running on the hostnetwork:true Node networking namespace...

[denis-tingaikin]

The forwarder should be running on the hostnetwork:true Node networking namespace...

@edwarnicke yes, you're correct for mechanisms and we already swapping Node IP to external IP for remote mechanisms.
But we also need to swap nsmgr-proxy IP to External IP on NSE registration to make NSE reachable over domains in case of public floating inter-domain scenario.

[edwarnicke]

Ah... so how are we getting an External IP for the nsmgr-proxy Pod?

[denis-tingaikin]

Ah... so how are we getting an External IP for the nsmgr-proxy Pod?

In case of interdomain we are getting it via DNS.
In case of floating interdomain we can store it in floating registry entries in NSE registration: url:${external-ip}:${nsmgr-proxy-port}.

[edwarnicke]

I mean how is the nsmgr-proxy Pod figuring out what its externalIP is for purposes of registering it upstream to the registry.

[denis-tingaikin]

nsmgr-proxy is not need to figuring out what its externalIP, it just can swap one address to another from mapip file.
See at networkservicemesh/sdk#1016 there we added a possible to map IPs on NSE registration.
So this PR just added an entry for swapping the IP in case of registration in floating registry in public clusters.

[edwarnicke]

@denis-tingaikin Is the nsmgr-proxy also running in hostNetwork:true ?

[denis-tingaikin]

@edwarnicke Currently is not, and I think we may try to run in hostNetwork as an alternative to this patch, but I feel this patch direction is more natural and flexible. WDYT?

[edwarnicke]

@denis-tingaikin I'm very much in favor of not running nsmgr-proxy in hostNetwork:true.

I am a bit confused though because this PR seems to go looking for the ExternalIP for the Node, and is using that... which I would expect to be mapped to the Nodes InternalIP... and thus be delivered to hostNetwork:true

What am I misssing?

[denis-tingaikin]

I am a bit confused though because this PR seems to go looking for the ExternalIP for the Node, and is using that... which I would expect to be mapped to the Nodes InternalIP... and thus be delivered to hostNetwork:true

What am I misssing?

With this PR we'll add map current POD IP to External nodeName of the POD where cmd-map-ip-k8s is running.

In this variant nsmgr-proxy will not have a hostNetwork:true and all registrations to upstream floating-registry will have a ExternalIP of the node where nsmgr-proxy is running.

Note: To access to ${externaIP}:${port} we have this line in deployment: https://github.com/networkservicemesh/deployments-k8s/blob/main/apps/nsmgr-proxy/nsmgr-proxy.yaml#L24

So with this patch we'll not need to modify somehow cmd-nsmgr-proxy, but need to add nodeName ref in cmd-ip-map sidecar.

[edwarnicke]

Ah, got it, hostPort :)

[edwarnicke]

Happy to merge this... I wish we didn't need hostPort... but I don't know what other options we have to solve this problem. So if something creative occurs to you, that's good... but otherwise, we can continue with this :)