DNS based cross Gslb communication

Makefile

@@ -2,8 +2,7 @@ REPO ?= ytsarev/ohmyglb
 VERSION ?= $$(operator-sdk up local --operator-flags=-v)
 
 .PHONY: up-local
-up-local:
-	kubectl create ns test-gslb
+up-local: create-test-ns
 	kubectl apply -f ./deploy/crds/ohmyglb.absa.oss_gslbs_crd.yaml
 	kubectl apply -f deploy/crds/ohmyglb.absa.oss_v1beta1_gslb_cr.yaml
 	operator-sdk up local --namespace=test-gslb

chart/ohmyglb/templates/operator.yaml

@@ -29,3 +29,5 @@ spec:
                   fieldPath: metadata.name
             - name: OPERATOR_NAME
               value: "ohmyglb"
+            - name: EXT_GSLB_CLUSTERS
+              value: {{ .Values.ohmyglb.extGslbClusters }}

chart/ohmyglb/values.yaml

@@ -9,6 +9,7 @@ ohmyglb:
   image: ytsarev/ohmyglb:v0.2.3
   ingressNamespace: "ohmyglb"
   dnsZone: &dnsZone "example.com"
+  extGslbClusters: "" # comma-separated list of FQDNs pointing to external Gslb enabled clusters to work with
 
 externaldns:
   image: registry.opensource.zalan.do/teapot/external-dns:latest

go.mod

@@ -6,9 +6,9 @@ require (
 	github.com/ghodss/yaml v1.0.1-0.20180820084758-c7ce16629ff4
 	github.com/go-openapi/spec v0.19.0
 	github.com/kubernetes-incubator/external-dns v0.5.17
+	github.com/miekg/dns v1.1.27
 	github.com/operator-framework/operator-sdk v0.12.0
 	github.com/spf13/pflag v1.0.3
-	github.com/txn2/txeh v1.3.0 // indirect
 	k8s.io/api v0.0.0
 	k8s.io/apimachinery v0.0.0
 	k8s.io/client-go v11.0.0+incompatible

go.sum

@@ -390,6 +390,8 @@ github.com/mesos/mesos-go v0.0.9/go.mod h1:kPYCMQ9gsOXVAle1OsoY4I1+9kPu8GHkf88aV
 github.com/mholt/caddy v0.0.0-20180213163048-2de495001514/go.mod h1:Wb1PlT4DAYSqOEd03MsqkdkXnTxA8v9pKjdpxbqM1kY=
 github.com/miekg/dns v0.0.0-20160614162101-5d001d020961/go.mod h1:W1PPwlIAgtquWBMBEV9nkV9Cazfe8ScdGz/Lj7v3Nrg=
 github.com/miekg/dns v1.0.8/go.mod h1:W1PPwlIAgtquWBMBEV9nkV9Cazfe8ScdGz/Lj7v3Nrg=
+github.com/miekg/dns v1.1.27 h1:aEH/kqUzUxGJ/UHcEKdJY+ugH6WEzsEBBSPa8zuy1aM=
+github.com/miekg/dns v1.1.27/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7xM=
 github.com/mindprince/gonvml v0.0.0-20171110221305-fee913ce8fb2/go.mod h1:2eu9pRWp8mo84xCg6KswZ+USQHjwgRhNp06sozOdsTY=
 github.com/mistifyio/go-zfs v0.0.0-20151009155749-1b4ae6fb4e77/go.mod h1:8AuVvqP/mXw1px98n46wfvcGfQ4ci2FwoAjKYxuo3Z4=
 github.com/mitchellh/copystructure v1.0.0/go.mod h1:SNtv71yrdKgLRyLFxmLdkAbkKEFWgYaq1OVrnRcwhnw=
@@ -515,6 +517,7 @@ github.com/satori/go.uuid v1.2.0/go.mod h1:dA0hQrYB0VpLJoorglMZABFdXlWrHn1NEOzdh
 github.com/sclevine/spec v1.0.0/go.mod h1:W4J29eT/Kzv7/b9IWLB055Z+qvVC9vt0Arko24q7p+U=
 github.com/sclevine/spec v1.2.0/go.mod h1:W4J29eT/Kzv7/b9IWLB055Z+qvVC9vt0Arko24q7p+U=
 github.com/seccomp/libseccomp-golang v0.0.0-20150813023252-1b506fc7c24e/go.mod h1:GbW5+tmTXfcxTToHLXlScSlAvWlF4P2Ca7zGrPiEpWo=
+github.com/sergi/go-diff v1.0.0 h1:Kpca3qRNrduNnOQeazBd0ysaKrUJiIuISHxogkT9RPQ=
 github.com/sergi/go-diff v1.0.0/go.mod h1:0CfEIISq7TuYL3j771MWULgwwjU+GofnZX9QAmXWZgo=
 github.com/shurcooL/sanitized_anchor_name v0.0.0-20151028001915-10ef21a441db/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
 github.com/sigma/go-inotify v0.0.0-20181102212354-c87b6cf5033d/go.mod h1:stlh9OsqBQSdwxTxX73mu41BBtRbIpZLQ7flcAoxAfo=
@@ -561,15 +564,14 @@ github.com/stretchr/testify v0.0.0-20151208002404-e3a8ff8ce365/go.mod h1:a8OnRci
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/syndtr/gocapability v0.0.0-20160928074757-e7cb7fa329f4/go.mod h1:hkRG7XYTFWNJGYcbNJQlaLq0fg1yr4J4t/NcTQtrfww=
 github.com/technosophos/moniker v0.0.0-20180509230615-a5dbd03a2245/go.mod h1:O1c8HleITsZqzNZDjSNzirUGsMT0oGu9LhHKoJrqO+A=
 github.com/tmc/grpc-websocket-proxy v0.0.0-20170815181823-89b8d40f7ca8/go.mod h1:ncp9v5uamzpCO7NfCPTXjqaC+bZgJeR0sMTm6dMHP7U=
 github.com/tmc/grpc-websocket-proxy v0.0.0-20171017195756-830351dc03c6/go.mod h1:ncp9v5uamzpCO7NfCPTXjqaC+bZgJeR0sMTm6dMHP7U=
 github.com/tmc/grpc-websocket-proxy v0.0.0-20190109142713-0ad062ec5ee5/go.mod h1:ncp9v5uamzpCO7NfCPTXjqaC+bZgJeR0sMTm6dMHP7U=
 github.com/transip/gotransip v5.8.2+incompatible/go.mod h1:uacMoJVmrfOcscM4Bi5NVg708b7c6rz2oDTWqa7i2Ic=
-github.com/txn2/txeh v1.3.0 h1:vnbv63htVMZCaQgLqVBxKvj2+HHHFUzNW7I183zjg3E=
-github.com/txn2/txeh v1.3.0/go.mod h1:O7M6gUTPeMF+vsa4c4Ipx3JDkOYrruB1Wry8QRsMcw8=
 github.com/ugorji/go v1.1.1/go.mod h1:hnLbHMwcvSihnDhEfx2/BzKp2xb0Y+ErdfYcrs9tkJQ=
 github.com/ugorji/go v1.1.2/go.mod h1:hnLbHMwcvSihnDhEfx2/BzKp2xb0Y+ErdfYcrs9tkJQ=
 github.com/ugorji/go v1.1.4/go.mod h1:uQMGLiO92mf5W77hV/PUCpI3pbzQx3CRekS0kk+RGrc=
@@ -612,6 +614,8 @@ golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACk
 golang.org/x/crypto v0.0.0-20190404164418-38d8ce5564a5/go.mod h1:WFFai1msRO1wXaEeE5yQxYXgSfI8pQAWXbQop6sCtWE=
 golang.org/x/crypto v0.0.0-20190621222207-cc06ce4a13d4 h1:ydJNl0ENAG67pFbB+9tfhiL2pYqLhfoaZFw/cjLhY4A=
 golang.org/x/crypto v0.0.0-20190621222207-cc06ce4a13d4/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550 h1:ObdrDkeb4kJdCP557AjRjq69pTHfNouLtWZG7j9rPN8=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190125153040-c74c464bbbf2/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190312203227-4b39c73a6495/go.mod h1:ZjyILWgesfNpC6sMxTJOJm9Kp84zZh5NQWvqDGG3Qr8=
@@ -623,6 +627,7 @@ golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvx
 golang.org/x/lint v0.0.0-20190301231843-5614ed5bae6f/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
 golang.org/x/lint v0.0.0-20190313153728-d0100b6bd8b3/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
 golang.org/x/mobile v0.0.0-20190312151609-d3739f865fa6/go.mod h1:z+o9i4GpDbdi3rU15maQ/Ox0txvL9dWGYEHz965HBQE=
+golang.org/x/mod v0.1.1-0.20191105210325-c90efee705ee/go.mod h1:QqPTAvyqsEbceGzBzNggFXnrqF1CaUcvgkdR5Ot7KZg=
 golang.org/x/net v0.0.0-20170114055629-f2499483f923/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180611182652-db08ff08e862/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
@@ -645,6 +650,8 @@ golang.org/x/net v0.0.0-20190522155817-f3200d17e092/go.mod h1:HSz+uSET+XFnRR8LxR
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20190812203447-cdfb69ac37fc h1:gkKoSkUmnU6bpS/VhkuO27bzQeSA51uaEfbOW5dNb68=
 golang.org/x/net v0.0.0-20190812203447-cdfb69ac37fc/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20190923162816-aa69164e4478 h1:l5EDrHhldLYb3ZRHDUhXF7Om7MvYXnkV9/iQNo1lX6g=
+golang.org/x/net v0.0.0-20190923162816-aa69164e4478/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20181105165119-ca4130e427c7/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20190130055435-99b60b757ec1/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
@@ -656,6 +663,7 @@ golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190227155943-e225da77a7e6/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58 h1:8gQV6CLnAEikrhgkHFbMAEhagSSnXWGV915qUMm9mrU=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20170830134202-bb24a47a89ea/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
@@ -678,6 +686,8 @@ golang.org/x/sys v0.0.0-20190422165155-953cdadca894/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20190508220229-2d0786266e9c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190515120540-06a5c4944438 h1:khxRGsvPk4n2y8I/mLLjp7e5dMTJmH75wvqS6nMwUtY=
 golang.org/x/sys v0.0.0-20190515120540-06a5c4944438/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe h1:6fAMxZRR6sl1Uq8U61gxU+kPTs2tR8uOySCbBP7BN/M=
+golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.0.0-20160726164857-2910a502d2bf/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.1-0.20180807135948-17ff2d5776d2/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
@@ -713,8 +723,12 @@ golang.org/x/tools v0.0.0-20190621195816-6e04913cbbac/go.mod h1:/rFqwRUd4F7ZHNgw
 golang.org/x/tools v0.0.0-20190624180213-70d37148ca0c/go.mod h1:/rFqwRUd4F7ZHNgwSSTFct+R/Kf4OFW1sUzUTQQTgfc=
 golang.org/x/tools v0.0.0-20191018212557-ed542cd5b28a h1:UuQ+70Pi/ZdWHuP4v457pkXeOynTdgd/4enxeIO/98k=
 golang.org/x/tools v0.0.0-20191018212557-ed542cd5b28a/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.0.0-20191216052735-49a3e744a425 h1:VvQyQJN0tSuecqgcIxMWnnfG5kSmgy9KZR9sW3W5QeA=
+golang.org/x/tools v0.0.0-20191216052735-49a3e744a425/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7 h1:9zdDQZ7Thm29KFXgAX/+yaf3eVbP7djjWp/dXAppNCc=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898 h1:/atklqdjdhuosWIl6AIbOeHJjicWYPqR9bpxqxYG2pA=
+golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gomodules.xyz/jsonpatch/v2 v2.0.1 h1:xyiBuvkD2g5n7cYzx6u2sxQvsAy4QJsZFCzGVdzOXZ0=
 gomodules.xyz/jsonpatch/v2 v2.0.1/go.mod h1:IhYNNY4jnS53ZnfE4PAmpKtDpTCj1JFXc+3mwe7XcUU=
 gonum.org/v1/gonum v0.0.0-20190331200053-3d26580ed485/go.mod h1:2ltnJ7xHfj0zHS40VVPYEAAMTa3ZGguvHGBSJeRWqE0=

pkg/controller/gslb/dnsupdate.go

@@ -4,9 +4,12 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"os"
+	"strings"
 
 	ohmyglbv1beta1 "github.com/AbsaOSS/ohmyglb/pkg/apis/ohmyglb/v1beta1"
 	externaldns "github.com/kubernetes-incubator/external-dns/endpoint"
+	"github.com/miekg/dns"
 	v1beta1 "k8s.io/api/extensions/v1beta1"
 	"k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -40,6 +43,44 @@ func (r *ReconcileGslb) getGslbIngressIPs(gslb *ohmyglbv1beta1.Gslb) ([]string,
 	return gslbIngressIPs, nil
 }
 
+func getExternalTargets(host string) ([]string, error) {
+
+	extGslbClustersVar := os.Getenv("EXT_GSLB_CLUSTERS")
+
+	if extGslbClustersVar == "" {
+		log.Info("No other Gslb enabled clusters are defined in the configuration...Working standalone")
+		return nil, nil
+	}
+
+	extGslbClusters := strings.Split(extGslbClustersVar, ",")
+
+	var targets []string
+
+	for _, cluster := range extGslbClusters {
+		log.Info(fmt.Sprintf("Adding external Gslb targets from %s cluster...", cluster))
+		g := new(dns.Msg)
+		host = fmt.Sprintf("localtargets.%s.", host) //Convert to true FQDN with dot at the endOtherwise dns lib freaks out
+		g.SetQuestion(host, dns.TypeA)
+		ns := fmt.Sprintf("%s:53", cluster)
+		a, err := dns.Exchange(g, ns)
+		if err != nil {
+			return nil, err
+		}
+		var clusterTargets []string
+
+		for _, A := range a.Answer {
+			IP := strings.Split(A.String(), "\t")[4]
+			clusterTargets = append(clusterTargets, IP)
+		}
+		if len(clusterTargets) > 0 {
+			targets = append(targets, clusterTargets...)
+			log.Info(fmt.Sprintf("Added external %s Gslb targets from %s cluster", clusterTargets, cluster))
+		}
+	}
+
+	return targets, nil
+}
+
 func (r *ReconcileGslb) gslbDNSEndpoint(gslb *ohmyglbv1beta1.Gslb) (*externaldns.DNSEndpoint, error) {
 	var gslbHosts []*externaldns.Endpoint
 
@@ -48,18 +89,44 @@ func (r *ReconcileGslb) gslbDNSEndpoint(gslb *ohmyglbv1beta1.Gslb) (*externaldns
 		return nil, err
 	}
 
-	targets, err := r.getGslbIngressIPs(gslb)
+	localTargets, err := r.getGslbIngressIPs(gslb)
 	if err != nil {
 		return nil, err
 	}
 
 	for host, health := range serviceHealth {
+		var finalTargets []string
+
 		if health == "Healthy" {
+			finalTargets = append(finalTargets, localTargets...)
+			localTargetsHost := fmt.Sprintf("localtargets.%s", host)
+			dnsRecord := &externaldns.Endpoint{
+				DNSName:    localTargetsHost,
+				RecordTTL:  30,
+				RecordType: "A",
+				Targets:    localTargets,
+			}
+			gslbHosts = append(gslbHosts, dnsRecord)
+		}
+
+		// Check if host is alive on external Gslb
+		externalTargets, err := getExternalTargets(host)
+		if err != nil {
+			return nil, err
+		}
+		if len(externalTargets) > 0 {
+			switch gslb.Spec.Strategy {
+			case "roundRobin":
+				finalTargets = append(finalTargets, externalTargets...)
+			}
+		}
+
+		if len(finalTargets) > 0 {
 			dnsRecord := &externaldns.Endpoint{
 				DNSName:    host,
 				RecordTTL:  30,
 				RecordType: "A",
-				Targets:    targets,
+				Targets:    finalTargets,
 			}
 			gslbHosts = append(gslbHosts, dnsRecord)
 		}

pkg/controller/gslb/gslb_controller_test.go

@@ -3,6 +3,7 @@ package gslb
 import (
 	"context"
 	"io/ioutil"
+	"os"
 	"reflect"
 	"testing"
 
@@ -25,6 +26,10 @@ import (
 var crSampleYaml = "../../../deploy/crds/ohmyglb.absa.oss_v1beta1_gslb_cr.yaml"
 
 func TestGslbController(t *testing.T) {
+	err := os.Setenv("DNS_ZONE", "example.com")
+	if err != nil {
+		t.Fatalf("Can't setup env var: (%v)", err)
+	}
 	gslbYaml, err := ioutil.ReadFile(crSampleYaml)
 	if err != nil {
 		t.Fatalf("Can't open example CR file: %s", crSampleYaml)
@@ -205,11 +210,17 @@ func TestGslbController(t *testing.T) {
 
 		got := dnsEndpoint.Spec.Endpoints
 
-		want := []*externaldns.Endpoint{{
-			DNSName:    "app3.cloud.example.com",
-			RecordTTL:  30,
-			RecordType: "A",
-			Targets:    externaldns.Targets{"10.0.0.1"}},
+		want := []*externaldns.Endpoint{
+			{
+				DNSName:    "localtargets.app3.cloud.example.com",
+				RecordTTL:  30,
+				RecordType: "A",
+				Targets:    externaldns.Targets{"10.0.0.1"}},
+			{
+				DNSName:    "app3.cloud.example.com",
+				RecordTTL:  30,
+				RecordType: "A",
+				Targets:    externaldns.Targets{"10.0.0.1"}},
 		}
 
 		prettyGot := prettyPrint(got)