6782b7fb42
*add option for resolving headless Services without external IPs in k8s_external Signed-off-by: Tomas Kohout <tomas.kohout1995@gmail.com>
103 lines
2.7 KiB
Go
103 lines
2.7 KiB
Go
package kubernetes
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import (
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"net"
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"strings"
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"github.com/miekg/dns"
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)
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func isDefaultNS(name, zone string) bool {
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return strings.Index(name, defaultNSName) == 0 && strings.Index(name, zone) == len(defaultNSName)
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}
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// nsAddrs returns the A or AAAA records for the CoreDNS service in the cluster. If the service cannot be found,
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// it returns a record for the local address of the machine we're running on.
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func (k *Kubernetes) nsAddrs(external, headless bool, zone string) []dns.RR {
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var (
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svcNames []string
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svcIPs []net.IP
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foundEndpoint bool
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)
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// Find the CoreDNS Endpoints
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for _, localIP := range k.localIPs {
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endpoints := k.APIConn.EpIndexReverse(localIP.String())
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// Collect IPs for all Services of the Endpoints
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for _, endpoint := range endpoints {
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foundEndpoint = true
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svcs := k.APIConn.SvcIndex(endpoint.Index)
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for _, svc := range svcs {
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if external {
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svcName := strings.Join([]string{svc.Name, svc.Namespace, zone}, ".")
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if headless && svc.Headless() {
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for _, s := range endpoint.Subsets {
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for _, a := range s.Addresses {
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svcNames = append(svcNames, endpointHostname(a, k.endpointNameMode)+"."+svcName)
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svcIPs = append(svcIPs, net.ParseIP(a.IP))
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}
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}
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} else {
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for _, exIP := range svc.ExternalIPs {
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svcNames = append(svcNames, svcName)
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svcIPs = append(svcIPs, net.ParseIP(exIP))
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}
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}
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continue
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}
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svcName := strings.Join([]string{svc.Name, svc.Namespace, Svc, zone}, ".")
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if svc.Headless() {
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// For a headless service, use the endpoints IPs
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for _, s := range endpoint.Subsets {
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for _, a := range s.Addresses {
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svcNames = append(svcNames, endpointHostname(a, k.endpointNameMode)+"."+svcName)
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svcIPs = append(svcIPs, net.ParseIP(a.IP))
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}
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}
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} else {
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for _, clusterIP := range svc.ClusterIPs {
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svcNames = append(svcNames, svcName)
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svcIPs = append(svcIPs, net.ParseIP(clusterIP))
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}
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}
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}
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}
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}
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// If no CoreDNS endpoints were found, use the localIPs directly
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if !foundEndpoint {
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svcIPs = make([]net.IP, len(k.localIPs))
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svcNames = make([]string, len(k.localIPs))
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for i, localIP := range k.localIPs {
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svcNames[i] = defaultNSName + zone
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svcIPs[i] = localIP
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}
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}
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// Create an RR slice of collected IPs
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rrs := make([]dns.RR, len(svcIPs))
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for i, ip := range svcIPs {
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if ip.To4() == nil {
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rr := new(dns.AAAA)
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rr.Hdr.Class = dns.ClassINET
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rr.Hdr.Rrtype = dns.TypeAAAA
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rr.Hdr.Name = svcNames[i]
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rr.AAAA = ip
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rrs[i] = rr
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continue
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}
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rr := new(dns.A)
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rr.Hdr.Class = dns.ClassINET
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rr.Hdr.Rrtype = dns.TypeA
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rr.Hdr.Name = svcNames[i]
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rr.A = ip
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rrs[i] = rr
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}
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return rrs
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}
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const defaultNSName = "ns.dns."
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