Set the listen address to the predictable IP for mdns

Have mDNS listen and use the predictable IP for apps expecting replies
from mDNS to be from the same address that was used for the request.

Jira: OSPRH-15638

Author: beagles

pkg/designatemdns/statefulset.go

@@ -26,7 +26,6 @@ import (
 	appsv1 "k8s.io/api/apps/v1"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/apimachinery/pkg/util/intstr"
 )
 
 // StatefulSet func
@@ -63,25 +62,27 @@ func StatefulSet(
 		ReadOnly:  true,
 	})
 
+	// Ideally we would use the connection probe but the mdns service does
+	// not listen on a cluster allocated IP
 	livenessProbe := &corev1.Probe{
 		// TODO might need tuning
 		TimeoutSeconds:      15,
 		PeriodSeconds:       13,
 		InitialDelaySeconds: 15,
 	}
-	readinessProbe := &corev1.Probe{
+	startupProbe := &corev1.Probe{
 		// TODO might need tuning
 		TimeoutSeconds:      15,
 		PeriodSeconds:       13,
 		InitialDelaySeconds: 10,
 	}
 
-	livenessProbe.TCPSocket = &corev1.TCPSocketAction{
-		Port: intstr.IntOrString{Type: intstr.Int, IntVal: int32(5354)},
-	}
-	readinessProbe.TCPSocket = &corev1.TCPSocketAction{
-		Port: intstr.IntOrString{Type: intstr.Int, IntVal: int32(5354)},
+	livenessProbe.Exec = &corev1.ExecAction{
+		Command: []string{
+			"/usr/bin/pgrep", "-r", "DRST", "-f", "designate.mdns",
+		},
 	}
+	startupProbe.Exec = livenessProbe.Exec
 
 	envVars := map[string]env.Setter{}
 	envVars["KOLLA_CONFIG_STRATEGY"] = env.SetValue("COPY_ALWAYS")
@@ -119,11 +120,11 @@ func StatefulSet(
 							SecurityContext: &corev1.SecurityContext{
 								RunAsUser: &rootUser,
 							},
-							Env:            env.MergeEnvs([]corev1.EnvVar{}, envVars),
-							VolumeMounts:   volumeMounts,
-							Resources:      instance.Spec.Resources,
-							ReadinessProbe: readinessProbe,
-							LivenessProbe:  livenessProbe,
+							Env:           env.MergeEnvs([]corev1.EnvVar{}, envVars),
+							VolumeMounts:  volumeMounts,
+							Resources:     instance.Spec.Resources,
+							StartupProbe:  startupProbe,
+							LivenessProbe: livenessProbe,
 						},
 					},
 				},

templates/common/setipalias.py

@@ -7,35 +7,35 @@
 
 mapping_prefix =  os.environ.get("MAP_PREFIX")
 if not len(mapping_prefix):
-    print(f"{sys.argv[0]} requires MAP_PREFIX to be set in environment variables")
+    print(f"{sys.argv[0]} requires MAP_PREFIX to be set in environment variables", file=sys.stderr)
     sys.exit(1)
 
-print(f"Using {mapping_prefix} as the map prefix")
+print(f"Using {mapping_prefix} as the map prefix", file=sys.stderr)
 
 nodefile = ""
 podname = os.environ.get("POD_NAME").strip()
 if not len(podname):
-    print(f"{sys.argv[0]} requires POD_NAME in environment variables")
+    print(f"{sys.argv[0]} requires POD_NAME in environment variables", file=sys.stderr)
     sys.exit(1)
 
-print(f"Pod name is {podname}")
+print(f"Pod name is {podname}", file=sys.stderr)
 namepieces = podname.split('-')
 pod_index = namepieces[-1]
 nodefile = f"{mapping_prefix}{pod_index}"
 
 interface_name = os.environ.get("NAD_NAME", "designate").strip()
 
-print(f"working with address file {nodefile}")
+print(f"working with address file {nodefile}", file=sys.stderr)
 filename = os.path.join('/var/lib/predictableips', nodefile)
 if not os.path.exists(filename):
-    print(f"Required alias address file {filename} does not exist")
+    print(f"Required alias address file {filename} does not exist", file=sys.stderr)
     sys.exit(1)
 
 ip = IPRoute()
 designateinterface = ip.link_lookup(ifname=interface_name)
 
 if not len(designateinterface):
-    print(f"{interface_name} attachment not present")
+    print(f"{interface_name} attachment not present", file=sys.stderr)
     sys.exit(1)
 
 
@@ -44,7 +44,9 @@
 ipfile.close()
 
 if ipaddr:
-    print(f"Setting {ipaddr} on {interface_name}")
+    print(f"Setting {ipaddr} on {interface_name}", file=sys.stderr)
+    # output the ipaddr to stdout so that the container-scripts/setipalias.sh can read it
+    print(f"{ipaddr}")
     # Get our current addresses so we can avoid trying to set the
     # same address again.
     version = ipaddress.ip_address(ipaddr).version
@@ -57,6 +59,6 @@
             mask_value = 128
         ip.addr('add', index = designateinterface[0], address=ipaddr, mask=mask_value)
 else:
-    print('No IP address found')
+    print('No IP address found', file=sys.stderr)
 
 ip.close()

templates/designatemdns/bin/setipalias.sh

@@ -18,5 +18,9 @@ set -ex
 # expect that the common.sh is in the same dir as the calling script
 #
 SCRIPTPATH="$( cd "$(dirname "$0")" >/dev/null 2>&1 ; pwd -P )"
+SVC_CFG_MERGED=/var/lib/config-data/merged/designate.conf
 
-/usr/local/bin/container-scripts/setipalias.py
+IPADDR=$(/usr/local/bin/container-scripts/setipalias.py)
+if [ $? -eq 0 ] && [ -n "$IPADDR" ]; then
+    crudini --set $SVC_CFG_MERGED 'service:mdns' 'listen' "${IPADDR}:5354"
+fi