kube play: sd-notify integration

Integrate sd-notify policies into `kube play`.  The policies can be
configured for all contianers via the `io.containers.sdnotify`
annotation or for indidivual containers via the
`io.containers.sdnotify/$name` annotation.

The `kube play` process will wait for all containers to be ready by
waiting for the individual `READY=1` messages which are received via
the `pkg/systemd/notifyproxy` proxy mechanism.

Also update the simple "container" sd-notify test as it did not fully
test the expected behavior which became obvious when adding the new
tests.

Signed-off-by: Valentin Rothberg <vrothberg@redhat.com>

13 files changed, 324 insertions, 37 deletions

diff --git a/cmd/podman/kube/play.go b/cmd/podman/kube/play.go
index 4811bcf4b..07c4b59b9 100644
--- a/cmd/podman/kube/play.go
+++ b/cmd/podman/kube/play.go
@@ -182,6 +182,10 @@ func playFlags(cmd *cobra.Command) {
 }
 
 func Play(cmd *cobra.Command, args []string) error {
+	if playOptions.ServiceContainer && !playOptions.StartCLI { // Sanity check to be future proof
+		return fmt.Errorf("--service-container does not work with --start=stop")
+	}
+
 	// TLS verification in c/image is controlled via a `types.OptionalBool`
 	// which allows for distinguishing among set-true, set-false, unspecified
 	// which is important to implement a sane way of dealing with defaults of
diff --git a/libpod/container_validate.go b/libpod/container_validate.go
index e280c60d2..da33f6db7 100644
--- a/libpod/container_validate.go
+++ b/libpod/container_validate.go
@@ -133,5 +133,9 @@ func (c *Container) validate() error {
 	if len(c.config.InitContainerType) > 0 && len(c.config.Pod) < 1 {
 		return fmt.Errorf("init containers must be created in a pod: %w", define.ErrInvalidArg)
 	}
+
+	if c.config.SdNotifyMode == define.SdNotifyModeIgnore && len(c.config.SdNotifySocket) > 0 {
+		return fmt.Errorf("cannot set sd-notify socket %q with sd-notify mode %q", c.config.SdNotifySocket, c.config.SdNotifyMode)
+	}
 	return nil
 }
diff --git a/libpod/define/config.go b/libpod/define/config.go
index 0181bd31c..34c1a675d 100644
--- a/libpod/define/config.go
+++ b/libpod/define/config.go
@@ -81,13 +81,6 @@ const NoLogging = "none"
 // PassthroughLogging is the string conmon expects when specifying to use the passthrough driver
 const PassthroughLogging = "passthrough"
 
-// Strings used for --sdnotify option to podman
-const (
-	SdNotifyModeContainer = "container"
-	SdNotifyModeConmon    = "conmon"
-	SdNotifyModeIgnore    = "ignore"
-)
-
 // DefaultRlimitValue is the value set by default for nofile and nproc
 const RLimitDefaultValue = uint64(1048576)
 
diff --git a/libpod/define/sdnotify.go b/libpod/define/sdnotify.go
new file mode 100644
index 000000000..1d548c764
--- /dev/null
+++ b/libpod/define/sdnotify.go
@@ -0,0 +1,20 @@
+package define
+
+import "fmt"
+
+// Strings used for --sdnotify option to podman
+const (
+	SdNotifyModeContainer = "container"
+	SdNotifyModeConmon    = "conmon"
+	SdNotifyModeIgnore    = "ignore"
+)
+
+// ValidateSdNotifyMode validates the specified mode.
+func ValidateSdNotifyMode(mode string) error {
+	switch mode {
+	case "", SdNotifyModeContainer, SdNotifyModeConmon, SdNotifyModeIgnore:
+		return nil
+	default:
+		return fmt.Errorf("%w: invalid sdnotify value %q: must be %s, %s or %s", ErrInvalidArg, mode, SdNotifyModeContainer, SdNotifyModeConmon, SdNotifyModeIgnore)
+	}
+}
diff --git a/libpod/options.go b/libpod/options.go
index 933c9a1c3..43ed1ff78 100644
--- a/libpod/options.go
+++ b/libpod/options.go
@@ -6,14 +6,12 @@ import (
 	"net"
 	"os"
 	"path/filepath"
-	"strings"
 	"syscall"
 
 	"github.com/containers/buildah/pkg/parse"
 	nettypes "github.com/containers/common/libnetwork/types"
 	"github.com/containers/common/pkg/config"
 	"github.com/containers/common/pkg/secrets"
-	cutil "github.com/containers/common/pkg/util"
 	"github.com/containers/image/v5/manifest"
 	"github.com/containers/image/v5/types"
 	"github.com/containers/podman/v4/libpod/define"
@@ -29,12 +27,6 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
-// Runtime Creation Options
-var (
-	// SdNotifyModeValues describes the only values that SdNotifyMode can be
-	SdNotifyModeValues = []string{define.SdNotifyModeContainer, define.SdNotifyModeConmon, define.SdNotifyModeIgnore}
-)
-
 // WithStorageConfig uses the given configuration to set up container storage.
 // If this is not specified, the system default configuration will be used
 // instead.
@@ -631,9 +623,8 @@ func WithSdNotifyMode(mode string) CtrCreateOption {
 			return define.ErrCtrFinalized
 		}
 
-		// verify values
-		if len(mode) > 0 && !cutil.StringInSlice(strings.ToLower(mode), SdNotifyModeValues) {
-			return fmt.Errorf("--sdnotify values must be one of %q: %w", strings.Join(SdNotifyModeValues, ", "), define.ErrInvalidArg)
+		if err := define.ValidateSdNotifyMode(mode); err != nil {
+			return err
 		}
 
 		ctr.config.SdNotifyMode = mode
diff --git a/pkg/domain/infra/abi/play.go b/pkg/domain/infra/abi/play.go
index 3f2fd5f92..faa89cc26 100644
--- a/pkg/domain/infra/abi/play.go
+++ b/pkg/domain/infra/abi/play.go
@@ -27,13 +27,19 @@ import (
 	"github.com/containers/podman/v4/pkg/specgen/generate"
 	"github.com/containers/podman/v4/pkg/specgen/generate/kube"
 	"github.com/containers/podman/v4/pkg/specgenutil"
+	"github.com/containers/podman/v4/pkg/systemd/notifyproxy"
 	"github.com/containers/podman/v4/pkg/util"
+	"github.com/coreos/go-systemd/v22/daemon"
 	"github.com/ghodss/yaml"
 	"github.com/opencontainers/go-digest"
 	"github.com/sirupsen/logrus"
 	yamlv3 "gopkg.in/yaml.v3"
 )
 
+// sdNotifyAnnotation allows for configuring service-global and
+// container-specific sd-notify modes.
+const sdNotifyAnnotation = "io.containers.sdnotify"
+
 // createServiceContainer creates a container that can later on
 // be associated with the pods of a K8s yaml.  It will be started along with
 // the first pod.
@@ -73,7 +79,12 @@ func (ic *ContainerEngine) createServiceContainer(ctx context.Context, name stri
 		return nil, fmt.Errorf("creating runtime spec for service container: %w", err)
 	}
 	opts = append(opts, libpod.WithIsService())
-	opts = append(opts, libpod.WithSdNotifyMode(define.SdNotifyModeConmon))
+
+	// Set the sd-notify mode to "ignore".  Podman is responsible for
+	// sending the notify messages when all containers are ready.
+	// The mode for individual containers or entire pods can be configured
+	// via the `sdNotifyAnnotation` annotation in the K8s YAML.
+	opts = append(opts, libpod.WithSdNotifyMode(define.SdNotifyModeIgnore))
 
 	// Create a new libpod container based on the spec.
 	ctr, err := ic.Libpod.NewContainer(ctx, runtimeSpec, spec, false, opts...)
@@ -96,6 +107,10 @@ func k8sName(content []byte, suffix string) string {
 }
 
 func (ic *ContainerEngine) PlayKube(ctx context.Context, body io.Reader, options entities.PlayKubeOptions) (_ *entities.PlayKubeReport, finalErr error) {
+	if options.ServiceContainer && options.Start == types.OptionalBoolFalse { // Sanity check to be future proof
+		return nil, fmt.Errorf("running a service container requires starting the pod(s)")
+	}
+
 	report := &entities.PlayKubeReport{}
 	validKinds := 0
 
@@ -121,6 +136,8 @@ func (ic *ContainerEngine) PlayKube(ctx context.Context, body io.Reader, options
 
 	var configMaps []v1.ConfigMap
 
+	ranContainers := false
+	var serviceContainer *libpod.Container
 	// create pod on each document if it is a pod or deployment
 	// any other kube kind will be skipped
 	for _, document := range documentList {
@@ -130,8 +147,7 @@ func (ic *ContainerEngine) PlayKube(ctx context.Context, body io.Reader, options
 		}
 
 		// TODO: create constants for the various "kinds" of yaml files.
-		var serviceContainer *libpod.Container
-		if options.ServiceContainer && (kind == "Pod" || kind == "Deployment") {
+		if options.ServiceContainer && serviceContainer == nil && (kind == "Pod" || kind == "Deployment") {
 			ctr, err := ic.createServiceContainer(ctx, k8sName(content, "service"), options)
 			if err != nil {
 				return nil, err
@@ -178,6 +194,7 @@ func (ic *ContainerEngine) PlayKube(ctx context.Context, body io.Reader, options
 
 			report.Pods = append(report.Pods, r.Pods...)
 			validKinds++
+			ranContainers = true
 		case "Deployment":
 			var deploymentYAML v1apps.Deployment
 
@@ -192,6 +209,7 @@ func (ic *ContainerEngine) PlayKube(ctx context.Context, body io.Reader, options
 
 			report.Pods = append(report.Pods, r.Pods...)
 			validKinds++
+			ranContainers = true
 		case "PersistentVolumeClaim":
 			var pvcYAML v1.PersistentVolumeClaim
 
@@ -239,6 +257,20 @@ 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 options.ServiceContainer && ranContainers {
+		// We can consider the service to be up and running now.
+		// Send the sd-notify messages pointing systemd to the
+		// service container.
+		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
+		}
+	}
+
 	return report, nil
 }
 
@@ -280,6 +312,11 @@ func (ic *ContainerEngine) playKubePod(ctx context.Context, podName string, podY
 		report      entities.PlayKubeReport
 	)
 
+	mainSdNotifyMode, err := getSdNotifyMode(annotations, "")
+	if err != nil {
+		return nil, err
+	}
+
 	// Create the secret manager before hand
 	secretsManager, err := ic.Libpod.SecretsManager()
 	if err != nil {
@@ -562,6 +599,9 @@ func (ic *ContainerEngine) playKubePod(ctx context.Context, podName string, podY
 
 		initContainers = append(initContainers, ctr)
 	}
+
+	var sdNotifyProxies []*notifyproxy.NotifyProxy // containers' sd-notify proxies
+
 	for _, container := range podYAML.Spec.Containers {
 		// Error out if the same name is used for more than one container
 		if _, ok := ctrNames[container.Name]; ok {
@@ -606,7 +646,31 @@ func (ic *ContainerEngine) playKubePod(ctx context.Context, podName string, podY
 		if err != nil {
 			return nil, err
 		}
-		opts = append(opts, libpod.WithSdNotifyMode(define.SdNotifyModeIgnore))
+
+		sdNotifyMode := mainSdNotifyMode
+		ctrNotifyMode, err := getSdNotifyMode(annotations, container.Name)
+		if err != nil {
+			return nil, err
+		}
+		if ctrNotifyMode != "" {
+			sdNotifyMode = ctrNotifyMode
+		}
+		if sdNotifyMode == "" { // Default to "ignore"
+			sdNotifyMode = define.SdNotifyModeIgnore
+		}
+
+		opts = append(opts, libpod.WithSdNotifyMode(sdNotifyMode))
+
+		// Create a notify proxy for the container.
+		if sdNotifyMode != "" && sdNotifyMode != define.SdNotifyModeIgnore {
+			proxy, err := notifyproxy.New("")
+			if err != nil {
+				return nil, err
+			}
+			sdNotifyProxies = append(sdNotifyProxies, proxy)
+			opts = append(opts, libpod.WithSdNotifySocket(proxy.SocketPath()))
+		}
+
 		ctr, err := generate.ExecuteCreate(ctx, ic.Libpod, rtSpec, spec, false, opts...)
 		if err != nil {
 			return nil, err
@@ -624,6 +688,13 @@ func (ic *ContainerEngine) playKubePod(ctx context.Context, podName string, podY
 			playKubePod.ContainerErrors = append(playKubePod.ContainerErrors, fmt.Errorf("error starting container %s: %w", id, err).Error())
 			fmt.Println(playKubePod.ContainerErrors)
 		}
+
+		// Wait for each proxy to receive a READY message.
+		for _, proxy := range sdNotifyProxies {
+			if err := proxy.WaitAndClose(); err != nil {
+				return nil, err
+			}
+		}
 	}
 
 	playKubePod.ID = pod.ID()
diff --git a/pkg/domain/infra/abi/play_utils.go b/pkg/domain/infra/abi/play_utils.go
new file mode 100644
index 000000000..482a158e6
--- /dev/null
+++ b/pkg/domain/infra/abi/play_utils.go
@@ -0,0 +1,16 @@
+package abi
+
+import "github.com/containers/podman/v4/libpod/define"
+
+// getSdNotifyMode returns the `sdNotifyAnnotation/$name` for the specified
+// name. If name is empty, it'll only look for `sdNotifyAnnotation`.
+func getSdNotifyMode(annotations map[string]string, name string) (string, error) {
+	var mode string
+	switch len(name) {
+	case 0:
+		mode = annotations[sdNotifyAnnotation]
+	default:
+		mode = annotations[sdNotifyAnnotation+"/"+name]
+	}
+	return mode, define.ValidateSdNotifyMode(mode)
+}
diff --git a/pkg/domain/infra/abi/play_utils_test.go b/pkg/domain/infra/abi/play_utils_test.go
new file mode 100644
index 000000000..80a9fe543
--- /dev/null
+++ b/pkg/domain/infra/abi/play_utils_test.go
@@ -0,0 +1,38 @@
+package abi
+
+import (
+	"testing"
+
+	"github.com/containers/podman/v4/libpod/define"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGetSdNotifyMode(t *testing.T) {
+	tests := []struct {
+		key, value, name, result string
+		mustError                bool
+	}{
+		{sdNotifyAnnotation, define.SdNotifyModeConmon, "", define.SdNotifyModeConmon, false},
+		{sdNotifyAnnotation + "/container-a", define.SdNotifyModeContainer, "container-a", define.SdNotifyModeContainer, false},
+		{sdNotifyAnnotation + "/container-b", define.SdNotifyModeIgnore, "container-b", define.SdNotifyModeIgnore, false},
+		{sdNotifyAnnotation + "/container-c", "", "container-c", "", false},
+		{sdNotifyAnnotation + "-/wrong-key", "xxx", "wrong-key", "", false},
+		{sdNotifyAnnotation + "/container-error", "invalid", "container-error", "", true},
+	}
+
+	annotations := make(map[string]string)
+	// Populate the annotations
+	for _, test := range tests {
+		annotations[test.key] = test.value
+	}
+	// Run the tests
+	for _, test := range tests {
+		result, err := getSdNotifyMode(annotations, test.name)
+		if test.mustError {
+			require.Error(t, err, "%v", test)
+			continue
+		}
+		require.NoError(t, err, "%v", test)
+		require.Equal(t, test.result, result, "%v", test)
+	}
+}
diff --git a/pkg/specgen/container_validate.go b/pkg/specgen/container_validate.go
index 63d94b6b3..064245602 100644
--- a/pkg/specgen/container_validate.go
+++ b/pkg/specgen/container_validate.go
@@ -67,9 +67,9 @@ func (s *SpecGenerator) Validate() error {
 	if len(s.ContainerBasicConfig.Systemd) > 0 && !util.StringInSlice(strings.ToLower(s.ContainerBasicConfig.Systemd), SystemDValues) {
 		return fmt.Errorf("--systemd values must be one of %q: %w", strings.Join(SystemDValues, ", "), ErrInvalidSpecConfig)
 	}
-	// sdnotify values must be container, conmon, or ignore
-	if len(s.ContainerBasicConfig.SdNotifyMode) > 0 && !util.StringInSlice(strings.ToLower(s.ContainerBasicConfig.SdNotifyMode), SdNotifyModeValues) {
-		return fmt.Errorf("--sdnotify values must be one of %q: %w", strings.Join(SdNotifyModeValues, ", "), ErrInvalidSpecConfig)
+
+	if err := define.ValidateSdNotifyMode(s.ContainerBasicConfig.SdNotifyMode); err != nil {
+		return err
 	}
 
 	//
diff --git a/pkg/specgen/generate/container_create.go b/pkg/specgen/generate/container_create.go
index f4c67e534..e9cec2873 100644
--- a/pkg/specgen/generate/container_create.go
+++ b/pkg/specgen/generate/container_create.go
@@ -353,9 +353,11 @@ func createContainerOptions(rt *libpod.Runtime, s *specgen.SpecGenerator, pod *l
 	}
 	if len(s.SdNotifyMode) > 0 {
 		options = append(options, libpod.WithSdNotifyMode(s.SdNotifyMode))
-	}
-	if notify, ok := os.LookupEnv("NOTIFY_SOCKET"); ok {
-		options = append(options, libpod.WithSdNotifySocket(notify))
+		if s.SdNotifyMode != define.SdNotifyModeIgnore {
+			if notify, ok := os.LookupEnv("NOTIFY_SOCKET"); ok {
+				options = append(options, libpod.WithSdNotifySocket(notify))
+			}
+		}
 	}
 
 	if pod != nil {
diff --git a/pkg/systemd/notifyproxy/notifyproxy.go b/pkg/systemd/notifyproxy/notifyproxy.go
index b9f5737f7..9e6eb4cf0 100644
--- a/pkg/systemd/notifyproxy/notifyproxy.go
+++ b/pkg/systemd/notifyproxy/notifyproxy.go
@@ -12,7 +12,15 @@ import (
 )
 
 // SendMessage sends the specified message to the specified socket.
+// No message is sent if no socketPath is provided and the NOTIFY_SOCKET
+// variable is not set either.
 func SendMessage(socketPath string, message string) error {
+	if socketPath == "" {
+		socketPath, _ = os.LookupEnv("NOTIFY_SOCKET")
+		if socketPath == "" {
+			return nil
+		}
+	}
 	socketAddr := &net.UnixAddr{
 		Name: socketPath,
 		Net:  "unixgram",
diff --git a/test/system/260-sdnotify.bats b/test/system/260-sdnotify.bats
index fe442f57d..6c3ef7f3f 100644
--- a/test/system/260-sdnotify.bats
+++ b/test/system/260-sdnotify.bats
@@ -92,7 +92,7 @@ function _assert_mainpid_is_conmon() {
     cid="$output"
 
     run_podman container inspect $cid --format "{{.Config.SdNotifyMode}} {{.Config.SdNotifySocket}}"
-    is "$output" "ignore $NOTIFY_SOCKET"
+    is "$output" "ignore " "NOTIFY_SOCKET is not set with 'ignore' mode"
 
     run_podman 1 start --attach $cid
     is "$output" "" "\$NOTIFY_SOCKET in container"
@@ -122,6 +122,7 @@ function _assert_mainpid_is_conmon() {
     is "$output" "READY" "\$NOTIFY_SOCKET in container"
 
     # The 'echo's help us debug failed runs
+    wait_for_file $_SOCAT_LOG
     run cat $_SOCAT_LOG
     echo "socat log:"
     echo "$output"
@@ -141,7 +142,7 @@ READY=1" "sdnotify sent MAINPID and READY"
 # These tests can fail in dev. environment because of SELinux.
 # quick fix: chcon -t container_runtime_exec_t ./bin/podman
 @test "sdnotify : container" {
-    skip_if_aarch64 "FIXME: #15074 - fails on aarch64 non-remote"
+    skip_if_aarch64 "FIXME: #15277 sdnotify doesn't work on aarch64"
     # Sigh... we need to pull a humongous image because it has systemd-notify.
     # (IMPORTANT: fedora:32 and above silently removed systemd-notify; this
     # caused CI to hang. That's why we explicitly require fedora:31)
@@ -156,7 +157,7 @@ READY=1" "sdnotify sent MAINPID and READY"
     _start_socat
 
     run_podman run -d --sdnotify=container $_FEDORA \
-               sh -c 'printenv NOTIFY_SOCKET;echo READY;systemd-notify --ready;while ! test -f /stop;do sleep 0.1;done'
+               sh -c 'printenv NOTIFY_SOCKET; echo READY; while ! test -f /stop;do sleep 0.1;done;systemd-notify --ready'
     cid="$output"
     wait_for_ready $cid
 
@@ -166,6 +167,8 @@ READY=1" "sdnotify sent MAINPID and READY"
     run_podman logs $cid
     is "${lines[0]}" "/run/notify/notify.sock" "NOTIFY_SOCKET is passed to container"
 
+    run_podman container inspect $cid --format "{{.State.ConmonPid}}"
+    mainPID="$output"
     # With container, READY=1 isn't necessarily the last message received;
     # just look for it anywhere in received messages
     run cat $_SOCAT_LOG
@@ -173,19 +176,25 @@ READY=1" "sdnotify sent MAINPID and READY"
     echo "socat log:"
     echo "$output"
 
-    is "$output" ".*READY=1" "received READY=1 through notify socket"
-
-    _assert_mainpid_is_conmon "$output"
+    is "$output" "MAINPID=$mainPID" "Container is not ready yet, so we only know the main PID"
 
     # Done. Stop container, clean up.
     run_podman exec $cid touch /stop
     run_podman wait $cid
+
+    wait_for_file $_SOCAT_LOG
+    run cat $_SOCAT_LOG
+    echo "socat log:"
+    echo "$output"
+    is "$output" "MAINPID=$mainPID
+READY=1"
+
     run_podman rm $cid
     run_podman rmi $_FEDORA
     _stop_socat
 }
 
-@test "sdnotify : play kube" {
+@test "sdnotify : play kube - no policies" {
     # Create the YAMl file
     yaml_source="$PODMAN_TMPDIR/test.yaml"
     cat >$yaml_source <<EOF
@@ -214,8 +223,15 @@ EOF
     _start_socat
 
     run_podman play kube --service-container=true $yaml_source
+
+    # Make sure the containers have the correct policy.
+    run_podman container inspect test_pod-test $service_container --format "{{.Config.SdNotifyMode}}"
+    is "$output" "ignore
+ignore"
+
     run_podman container inspect $service_container --format "{{.State.ConmonPid}}"
     mainPID="$output"
+    wait_for_file $_SOCAT_LOG
     # The 'echo's help us debug failed runs
     run cat $_SOCAT_LOG
     echo "socat log:"
@@ -228,9 +244,116 @@ READY=1" "sdnotify sent MAINPID and READY"
 
     # Clean up pod and pause image
     run_podman play kube --down $PODMAN_TMPDIR/test.yaml
-    run_podman version --format "{{.Server.Version}}-{{.Server.Built}}"
-    podman rmi -f localhost/podman-pause:$output
+    run_podman rmi $(pause_image)
 }
 
+@test "sdnotify : play kube - with policies" {
+    skip_if_aarch64 "FIXME: #15277 sdnotify doesn't work on aarch64"
+
+    # Sigh... we need to pull a humongous image because it has systemd-notify.
+    # (IMPORTANT: fedora:32 and above silently removed systemd-notify; this
+    # caused CI to hang. That's why we explicitly require fedora:31)
+    # FIXME: is there a smaller image we could use?
+    local _FEDORA="$PODMAN_TEST_IMAGE_REGISTRY/$PODMAN_TEST_IMAGE_USER/fedora:31"
+    # Pull that image. Retry in case of flakes.
+    run_podman pull $_FEDORA || \
+        run_podman pull $_FEDORA || \
+        run_podman pull $_FEDORA
+
+    # Create the YAMl file
+    yaml_source="$PODMAN_TMPDIR/test.yaml"
+    cat >$yaml_source <<EOF
+apiVersion: v1
+kind: Pod
+metadata:
+  labels:
+    app: test
+  name: test_pod
+  annotations:
+    io.containers.sdnotify:   "container"
+    io.containers.sdnotify/b: "conmon"
+spec:
+  containers:
+  - command:
+    - /bin/sh
+    - -c
+    - 'printenv NOTIFY_SOCKET; echo READY; while ! test -f /stop;do sleep 0.1;done;systemd-notify --ready'
+    image: $_FEDORA
+    name: a
+  - command:
+    - /bin/sh
+    - -c
+    - 'echo READY; top'
+    image: $IMAGE
+    name: b
+EOF
+    container_a="test_pod-a"
+    container_b="test_pod-b"
+
+    # The name of the service container is predictable: the first 12 characters
+    # of the hash of the YAML file followed by the "-service" suffix
+    yaml_sha=$(sha256sum $yaml_source)
+    service_container="${yaml_sha:0:12}-service"
+
+    export NOTIFY_SOCKET=$PODMAN_TMPDIR/conmon.sock
+    _start_socat
+
+    # Run `play kube` in the background as it will wait for all containers to
+    # send the READY=1 message.
+    timeout --foreground -v --kill=10 60 \
+        $PODMAN play kube --service-container=true $yaml_source &>/dev/null &
+
+    # Wait for both containers to be running
+    for i in $(seq 1 20); do
+        run_podman "?" container wait $container_a $container_b --condition="running"
+        if [[ $status == 0 ]]; then
+            break
+        fi
+        sleep 0.5
+        # Just for debugging
+        run_podman ps -a
+    done
+    if [[ $status != 0 ]]; then
+        die "container $container_a and/or $container_b did not start"
+    fi
+
+    # Make sure the containers have the correct policy
+    run_podman container inspect $container_a $container_b $service_container --format "{{.Config.SdNotifyMode}}"
+    is "$output" "container
+conmon
+ignore"
+
+    is "$(< $_SOCAT_LOG)" "" "nothing received on socket"
+
+    # Make sure the container received a "proxy" socket and is not using the
+    # one of `kube play`
+    run_podman container inspect $container_a --format "{{.Config.SdNotifySocket}}"
+    assert "$output" != $NOTIFY_SOCKET
+
+    run_podman logs $container_a
+    is "${lines[0]}" "/run/notify/notify.sock" "NOTIFY_SOCKET is passed to container"
+
+    # Instruct the container to send the READY
+    run_podman exec $container_a /bin/touch /stop
+
+    run_podman container inspect $service_container --format "{{.State.ConmonPid}}"
+    main_pid="$output"
+
+    run_podman container wait $container_a
+    wait_for_file $_SOCAT_LOG
+    # The 'echo's help us debug failed runs
+    run cat $_SOCAT_LOG
+    echo "socat log:"
+    echo "$output"
+
+    is "$output" "MAINPID=$main_pid
+READY=1" "sdnotify sent MAINPID and READY"
+
+    _stop_socat
+
+    # Clean up pod and pause image
+    run_podman play kube --down $yaml_source
+    run_podman rmi $_FEDORA $(pause_image)
+}
 
 # vim: filetype=sh
diff --git a/test/system/helpers.bash b/test/system/helpers.bash
index b821175bb..5ff3fae6d 100644
--- a/test/system/helpers.bash
+++ b/test/system/helpers.bash
@@ -342,6 +342,23 @@ function wait_for_port() {
     die "Timed out waiting for $host:$port"
 }
 
+###################
+#  wait_for_file  #  Returns once file is available on host
+###################
+function wait_for_file() {
+    local file=$1                       # The path to the file
+    local _timeout=${2:-5}              # Optional; default 5 seconds
+
+    # Wait
+    while [ $_timeout -gt 0 ]; do
+        test -e $file && return
+        sleep 1
+        _timeout=$(( $_timeout - 1 ))
+    done
+
+    die "Timed out waiting for $file"
+}
+
 # END   podman helpers
 ###############################################################################
 # BEGIN miscellaneous tools