[Feature]: Per-interface DNS entries

[travisbcotton]

Describe the feature

It's common to have multiple interfaces per node
The current behavior is to return the first interface as the IP for the record

coresmd/plugin/coredns/handler.go

Lines 162 to 185 in b334b09

	for _, zone := range p.zones {
	if strings.HasSuffix(name, zone.Name) {
	for _, ei := range p.cache.EthernetInterfaces {
	if comp, ok := p.cache.Components[ei.ComponentID]; ok && comp.Type == "Node" {
	xnameHost := comp.ID
	xnameFQDN := xnameHost + "." + zone.Name
	// Expand node pattern
	nidFQDN := ""
	if zone.NodePattern != "" {
	// nid{04d} pattern: e.g., nid0001.cluster.local
	nidHost := expandPattern(zone.NodePattern, comp.NID, comp.ID)
	nidFQDN = nidHost + "." + zone.Name
	}
	if name == nidFQDN || name == xnameFQDN {
	for _, ipEntry := range ei.IPAddresses {
	if ip := net.ParseIP(ipEntry.IPAddress); ip != nil && ip.To4() != nil {
	return ip
	}
	}
	}
	}
	}
	}

I would like to be able to store multiple interfaces in SMD and have DNS entries per interface
Something like

nid001 192.168.0.1
nid001-hsn1 10.100.0.1
nid001-hsn2 10.100.0.2

Why do you want this feature?

This would be nice to be able to use DNS for multiple interfaces to separate HSN traffic from management traffic

Alternatives you've considered

I considered doing...

Additional context

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[synackd]

This seems like useful functionality.

I would like to be able to store multiple interfaces in SMD and have DNS entries per interface Something like

nid001 192.168.0.1
nid001-hsn1 10.100.0.1
nid001-hsn2 10.100.0.2

Something like this can likely be already be achieved in the Corefile via the hosts plugin being placed after the coresmd plugin. Is that sufficient or are patternistic name generation or SMD name prepopulation required for this feature?

[travisbcotton]

Could probably use this as a workaround. But longer term I would like to be able to use the EthernetInterfaces feature of SMD and store multiple interfaces per component and then leverage that in coredns.

[alexlovelltroy]

How would you want to control fqdn and/or reverse lookups?

1. nid001.hsn.cluster.name could resolve RR to each.
2. nid001-if1.hsn.cluster.name and nid001-if2.hsn.cluster.name
3. nid001-hsn1.cluster.name and nid001-hsn2.cluster.name

Should we also consider nid001.nmn.cluster.name or nid001-nmn1.cluster.name?

[travisbcotton]

For the immediate use case it would be nid001-hsn1.cluster.name and nid001-hsn2.cluster.name, with potentially up to 4 HSN interfaces.
I don't anticipate multiple NMN interfaces so nid001.nmn.cluster.name should be fine.

[synackd]

SMD also has a name field per-interface that could be leveraged, though it applies per-interface and not per-ip, for potential interface name customization.