kube play: set service container as main PID when possible

pkg/domain/infra/abi/play.go

@@ -314,14 +314,37 @@ func (ic *ContainerEngine) PlayKube(ctx context.Context, body io.Reader, options
 		return nil, fmt.Errorf("YAML document does not contain any supported kube kind")
 	}
 
+	// If we started containers along with a service container, we are
+	// running inside a systemd unit and need to set the main PID.
 	if options.ServiceContainer && ranContainers {
-		message := fmt.Sprintf("MAINPID=%d\n%s", os.Getpid(), daemon.SdNotifyReady)
-		if err := notifyproxy.SendMessage("", message); err != nil {
-			return nil, err
-		}
+		switch len(notifyProxies) {
+		case 0: // Optimization for containers/podman/issues/17345
+			// No container needs sdnotify, so we can mark the
+			// service container's conmon as the main PID and
+			// return early.
+			data, err := serviceContainer.Inspect(false)
+			if err != nil {
+				return nil, err
+			}
+			message := fmt.Sprintf("MAINPID=%d\n%s", data.State.ConmonPid, daemon.SdNotifyReady)
+			if err := notifyproxy.SendMessage("", message); err != nil {
+				return nil, err
+			}
+		default:
+			// At least one container has a custom sdnotify policy,
+			// so we need to let the sdnotify proxies run for the
+			// lifetime of the service container.  That means, we
+			// need to wait for the service container to stop.
+			// Podman will hence be marked as the main PID.  That
+			// comes at the cost of keeping Podman running.
+			message := fmt.Sprintf("MAINPID=%d\n%s", os.Getpid(), daemon.SdNotifyReady)
+			if err := notifyproxy.SendMessage("", message); err != nil {
+				return nil, err
+			}
 
-		if _, err := serviceContainer.Wait(ctx); err != nil {
-			return nil, fmt.Errorf("waiting for service container: %w", err)
+			if _, err := serviceContainer.Wait(ctx); err != nil {
+				return nil, fmt.Errorf("waiting for service container: %w", err)
+			}
 		}
 	}
 

test/system/250-systemd.bats

@@ -399,7 +399,7 @@ EOF
 
     # Make sure that Podman is the service's MainPID
     run systemctl show --property=MainPID --value $service_name
-    is "$(</proc/$output/comm)" "podman" "podman is the service mainPID"
+    is "$(</proc/$output/comm)" "conmon" "podman is the service mainPID"
 
     # The name of the service container is predictable: the first 12 characters
     # of the hash of the YAML file followed by the "-service" suffix
@@ -433,12 +433,13 @@ EOF
     run_podman pod kill test_pod
     for i in {0..20}; do
         run systemctl is-active $service_name
-        if [[ $output == "inactive" ]]; then
+        if [[ $output == "failed" ]]; then
             break
         fi
         sleep 0.5
     done
-    is "$output" "inactive" "systemd service transitioned to 'inactive' state: $service_name"
+    # The service is marked as failed as the service container exits non-zero.
+    is "$output" "failed" "systemd service transitioned to 'inactive' state: $service_name"
 
     # Now stop and start the service again.
     systemctl stop $service_name

test/system/252-quadlet.bats

@@ -420,7 +420,8 @@ EOF
     run_podman container inspect  --format "{{.State.Status}}" test_pod-test
     is "$output" "running" "container should be started by systemd and hence be running"
 
-    service_cleanup $QUADLET_SERVICE_NAME inactive
+    # The service is marked as failed as the service container exits non-zero.
+    service_cleanup $QUADLET_SERVICE_NAME failed
     run_podman rmi $(pause_image)
 }
 

test/system/260-sdnotify.bats

@@ -218,8 +218,14 @@ EOF
     _start_socat
     wait_for_file $_SOCAT_LOG
 
-    # Will run until all containers have stopped.
     run_podman play kube --service-container=true --log-driver journald $yaml_source
+
+    # The service container is the main PID since no container has a custom
+    # sdnotify policy.
+    run_podman container inspect $service_container --format "{{.State.ConmonPid}}"
+    main_pid="$output"
+
+    # Will run until all containers have stopped.
     run_podman container wait $service_container test_pod-test
 
     # Make sure the containers have the correct policy.
@@ -233,7 +239,7 @@ ignore"
     echo "$output"
 
     # The "with policies" test below checks the MAINPID.
-    is "$output" "MAINPID=.*
+    is "$output" "MAINPID=$main_pid
 READY=1" "sdnotify sent MAINPID and READY"
 
     _stop_socat