DNS resolver doesn't use target address in SRV record

[d-uzlov]

Expected Behavior

NSM should connect successfully when you setup DNS like this:

registry.nsm-system.my.cluster2. 86400 IN SRV 10 0 30002 some.real.domain.
some.real.domain. IN A 1.2.3.4

NSM should connect to 1.2.3.4:30002, resolved via some.real.domain.

Current Behavior

NSM can't resolve address:

failed to look up a host using a local resolver for a registry.nsm-system.my.cluster2

For NSM to work I have to use the same A/AAAA record name as for SRV:

registry.nsm-system.my.cluster2. 86400 IN SRV 10 0 30002 can.be.whatever.
registry.nsm-system.my.cluster2. IN A 1.2.3.4

Failure Information (for bugs)

NSM uses only port from SRV record.

When you try to connect to netsvcname@my.cluster2, NSM resolves SRV for registry.nsm-system.my.cluster2, and then IP for registry.nsm-system.my.cluster2, regardless of value in records[0].Target

sdk/pkg/registry/common/dnsresolve/common.go

Lines 81 to 90 in 97bacd7

	_, records, err := r.LookupSRV(ctx, "", "", serviceDomain)
	if err != nil {
	return nil, errors.Wrapf(err, "failed to resolve a SRV query for a %s", serviceDomain)
	}
	if len(records) == 0 {
	return nil, errors.New("resolver.LookupSERV return empty result")
	}
	port = strconv.Itoa(int(records[0].Port))
	ips, err := r.LookupIPAddr(ctx, serviceDomain)