Use Elasticsearch readiness port

pkg/apis/elasticsearch/v1/fields.go

@@ -4,6 +4,12 @@
 
 package v1
 
+import "github.com/elastic/cloud-on-k8s/v2/pkg/controller/common/version"
+
+// as of 8.2.0 a simplified unauthenticated readiness port is available which takes cluster membership into account
+// see https://www.elastic.co/guide/en/elasticsearch/reference/current/advanced-configuration.html#readiness-tcp-port
+var MinReadinessPortVersion = version.MinFor(8, 2, 0)
+
 const (
 	ClusterName = "cluster.name"
 
@@ -14,6 +20,8 @@ const (
 	DiscoverySeedProviders    = "discovery.seed_providers"     // ES >= 7.X
 	DiscoverySeedHosts        = "discovery.seed_hosts"         // ES >= 7.X
 
+	ReadinessPort = "readiness.port" // ES >= 8.2.0
+
 	NetworkHost        = "network.host"
 	NetworkPublishHost = "network.publish_host"
 	HTTPPublishHost    = "http.publish_host"

pkg/controller/elasticsearch/configmap/configmap.go

@@ -53,11 +53,12 @@ func ReconcileScriptsConfigMap(ctx context.Context, c k8s.Client, es esv1.Elasti
 		types.NamespacedName{Namespace: es.Namespace, Name: esv1.ScriptsConfigMap(es.Name)},
 		k8s.ExtractNamespacedName(&es),
 		map[string]string{
-			nodespec.ReadinessProbeScriptConfigKey: nodespec.ReadinessProbeScript,
-			nodespec.PreStopHookScriptConfigKey:    preStopScript,
-			initcontainer.PrepareFsScriptConfigKey: fsScript,
-			initcontainer.SuspendScriptConfigKey:   initcontainer.SuspendScript,
-			initcontainer.SuspendedHostsFile:       initcontainer.RenderSuspendConfiguration(es),
+			nodespec.ReadinessProbeScriptConfigKey:     nodespec.ReadinessProbeScript,
+			nodespec.ReadinessPortProbeScriptConfigKey: nodespec.ReadinessPortProbeScript,
+			nodespec.PreStopHookScriptConfigKey:        preStopScript,
+			initcontainer.PrepareFsScriptConfigKey:     fsScript,
+			initcontainer.SuspendScriptConfigKey:       initcontainer.SuspendScript,
+			initcontainer.SuspendedHostsFile:           initcontainer.RenderSuspendConfiguration(es),
 		},
 	)
 

pkg/controller/elasticsearch/nodespec/podspec.go

@@ -127,7 +127,7 @@ func BuildPodTemplateSpec(
 		WithResources(DefaultResources).
 		WithTerminationGracePeriod(DefaultTerminationGracePeriodSeconds).
 		WithPorts(defaultContainerPorts).
-		WithReadinessProbe(*NewReadinessProbe()).
+		WithReadinessProbe(*NewReadinessProbe(v)).
 		WithAffinity(DefaultAffinity(es.Name)).
 		WithEnv(DefaultEnvVars(es.Spec.HTTP, headlessServiceName)...).
 		WithVolumes(volumes...).

pkg/controller/elasticsearch/nodespec/podspec_test.go

@@ -362,7 +362,7 @@ func TestBuildPodTemplateSpec(t *testing.T) {
 						DefaultEnvVars(sampleES.Spec.HTTP, HeadlessServiceName(esv1.StatefulSet(sampleES.Name, nodeSet.Name)))...),
 					Resources:      DefaultResources,
 					VolumeMounts:   volumeMounts,
-					ReadinessProbe: NewReadinessProbe(),
+					ReadinessProbe: NewReadinessProbe(ver),
 					Lifecycle: &corev1.Lifecycle{
 						PreStop: NewPreStopHook(),
 					},

pkg/controller/elasticsearch/nodespec/readiness_probe.go

@@ -9,12 +9,30 @@ import (
 
 	corev1 "k8s.io/api/core/v1"
 
+	esv1 "github.com/elastic/cloud-on-k8s/v2/pkg/apis/elasticsearch/v1"
 	"github.com/elastic/cloud-on-k8s/v2/pkg/controller/common/http"
+	"github.com/elastic/cloud-on-k8s/v2/pkg/controller/common/version"
 	"github.com/elastic/cloud-on-k8s/v2/pkg/controller/elasticsearch/label"
 	"github.com/elastic/cloud-on-k8s/v2/pkg/controller/elasticsearch/volume"
 )
 
-func NewReadinessProbe() *corev1.Probe {
+// as of 8.2.0 a simplified unauthenticated readiness port is available which takes cluster membership into account
+// see https://www.elastic.co/guide/en/elasticsearch/reference/current/advanced-configuration.html#readiness-tcp-port
+
+const (
+	ReadinessPortProbeScriptConfigKey = "readiness-port-script.sh"
+	// ReadinessPortProbeScript is the simplified readiness check for ES >= 8.2.0 which supports a dedicated TCP check
+	ReadinessPortProbeScript = `#!/usr/bin/env bash
+nc -z -v -w5 127.0.0.1 8080
+`
+)
+
+func NewReadinessProbe(v version.Version) *corev1.Probe {
+	scriptKey := ReadinessPortProbeScriptConfigKey
+	if v.LE(esv1.MinReadinessPortVersion) {
+		scriptKey = ReadinessProbeScriptConfigKey
+	}
+
 	return &corev1.Probe{
 		FailureThreshold:    3,
 		InitialDelaySeconds: 10,
@@ -23,7 +41,7 @@ func NewReadinessProbe() *corev1.Probe {
 		TimeoutSeconds:      5,
 		ProbeHandler: corev1.ProbeHandler{
 			Exec: &corev1.ExecAction{
-				Command: []string{"bash", "-c", path.Join(volume.ScriptsVolumeMountPath, ReadinessProbeScriptConfigKey)},
+				Command: []string{"bash", "-c", path.Join(volume.ScriptsVolumeMountPath, scriptKey)},
 			},
 		},
 	}

pkg/controller/elasticsearch/settings/merged_config.go

@@ -83,6 +83,10 @@ func baseConfig(clusterName string, ver version.Version, ipFamily corev1.IPFamil
 		cfg[esv1.DiscoverySeedHosts] = []string{}
 	}
 
+	if ver.GTE(esv1.MinReadinessPortVersion) {
+		cfg[esv1.ReadinessPort] = "8080"
+	}
+
 	return &CanonicalConfig{common.MustCanonicalConfig(cfg)}
 }
 

pkg/controller/elasticsearch/settings/merged_config_test.go

@@ -181,6 +181,24 @@ func TestNewMergedESConfig(t *testing.T) {
 				require.Equal(t, 1, len(cfg.HasKeys([]string{esv1.XPackLicenseUploadTypes})))
 			},
 		},
+		{
+			name:     "prior to 8.2.0 we should not enable the readiness.port",
+			version:  "8.1.0",
+			ipFamily: corev1.IPv4Protocol,
+			cfgData:  map[string]interface{}{},
+			assert: func(cfg CanonicalConfig) {
+				require.Equal(t, 0, len(cfg.HasKeys([]string{esv1.ReadinessPort})))
+			},
+		},
+		{
+			name:     "starting 8.2.0 we should enable the readiness.port",
+			version:  "8.2.0",
+			ipFamily: corev1.IPv4Protocol,
+			cfgData:  map[string]interface{}{},
+			assert: func(cfg CanonicalConfig) {
+				require.Equal(t, 1, len(cfg.HasKeys([]string{esv1.ReadinessPort})))
+			},
+		},
 		{
 			name:     "user-provided Elasticsearch config overrides should have precedence over ECK config",
 			version:  "7.6.0",