add "healthy" sdnotify policy

Add a new "healthy" sdnotify policy that instructs Podman to send the
READY message once the container has turned healthy.

Fixes: #6160
Signed-off-by: Valentin Rothberg <[email protected]>

cmd/podman/common/completion.go

@@ -1545,7 +1545,7 @@ func AutocompleteLogLevel(cmd *cobra.Command, args []string, toComplete string)
 // AutocompleteSDNotify - Autocomplete sdnotify options.
 // -> "container", "conmon", "ignore"
 func AutocompleteSDNotify(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
-	types := []string{define.SdNotifyModeContainer, define.SdNotifyModeContainer, define.SdNotifyModeIgnore}
+	types := []string{define.SdNotifyModeConmon, define.SdNotifyModeContainer, define.SdNotifyModeHealthy, define.SdNotifyModeIgnore}
 	return types, cobra.ShellCompDirectiveNoFileComp
 }
 

docs/source/markdown/options/sdnotify.md

@@ -2,13 +2,15 @@
 ####>   podman create, run
 ####> If file is edited, make sure the changes
 ####> are applicable to all of those.
-#### **--sdnotify**=**container** | *conmon* | *ignore*
+#### **--sdnotify**=**container** | *conmon* | *healthy* | *ignore*
 
 Determines how to use the NOTIFY_SOCKET, as passed with systemd and Type=notify.
 
 Default is **container**, which means allow the OCI runtime to proxy the socket into the
 container to receive ready notification. Podman sets the MAINPID to conmon's pid.
 The **conmon** option sets MAINPID to conmon's pid, and sends READY when the container
 has started. The socket is never passed to the runtime or the container.
+The **healthy** option sets MAINPID to conmon's pid, and sends READY when the container
+has turned healthy; requires a healthcheck to be set. The socket is never passed to the runtime or the container.
 The **ignore** option removes NOTIFY_SOCKET from the environment for itself and child processes,
 for the case where some other process above Podman uses NOTIFY_SOCKET and Podman does not use it.

libpod/container_api.go

@@ -113,7 +113,7 @@ func (c *Container) Start(ctx context.Context, recursive bool) (finalErr error)
 	}
 
 	// Start the container
-	return c.start()
+	return c.start(ctx)
 }
 
 // Update updates the given container.

libpod/container_internal.go

@@ -308,7 +308,7 @@ func (c *Container) handleRestartPolicy(ctx context.Context) (_ bool, retErr err
 			return false, err
 		}
 	}
-	if err := c.start(); err != nil {
+	if err := c.start(ctx); err != nil {
 		return false, err
 	}
 	return true, nil
@@ -1198,11 +1198,11 @@ func (c *Container) initAndStart(ctx context.Context) (retErr error) {
 	}
 
 	// Now start the container
-	return c.start()
+	return c.start(ctx)
 }
 
 // Internal, non-locking function to start a container
-func (c *Container) start() error {
+func (c *Container) start(ctx context.Context) error {
 	if c.config.Spec.Process != nil {
 		logrus.Debugf("Starting container %s with command %v", c.ID(), c.config.Spec.Process.Args)
 	}
@@ -1214,9 +1214,11 @@ func (c *Container) start() error {
 
 	c.state.State = define.ContainerStateRunning
 
+	// Unless being ignored, set the MAINPID to conmon.
 	if c.config.SdNotifyMode != define.SdNotifyModeIgnore {
 		payload := fmt.Sprintf("MAINPID=%d", c.state.ConmonPID)
 		if c.config.SdNotifyMode == define.SdNotifyModeConmon {
+			// Also send the READY message for the "conmon" policy.
 			payload += "\n"
 			payload += daemon.SdNotifyReady
 		}
@@ -1241,7 +1243,32 @@ func (c *Container) start() error {
 
 	defer c.newContainerEvent(events.Start)
 
-	return c.save()
+	if err := c.save(); err != nil {
+		return err
+	}
+
+	if c.config.SdNotifyMode != define.SdNotifyModeHealthy {
+		return nil
+	}
+
+	// Wait for the container to turn healthy before sending the READY
+	// message.  This implies that we need to unlock and re-lock the
+	// container.
+	if !c.batched {
+		c.lock.Unlock()
+		defer c.lock.Lock()
+	}
+
+	if _, err := c.WaitForConditionWithInterval(ctx, DefaultWaitInterval, define.HealthCheckHealthy); err != nil {
+		return err
+	}
+
+	if err := notifyproxy.SendMessage(c.config.SdNotifySocket, daemon.SdNotifyReady); err != nil {
+		logrus.Errorf("Sending READY message after turning healthy: %s", err.Error())
+	} else {
+		logrus.Debugf("Notify sent successfully")
+	}
+	return nil
 }
 
 // Internal, non-locking function to stop container
@@ -1487,7 +1514,7 @@ func (c *Container) restartWithTimeout(ctx context.Context, timeout uint) (retEr
 			return err
 		}
 	}
-	return c.start()
+	return c.start(ctx)
 }
 
 // mountStorage sets up the container's root filesystem

libpod/define/sdnotify.go

@@ -4,17 +4,18 @@ import "fmt"
 
 // Strings used for --sdnotify option to podman
 const (
-	SdNotifyModeContainer = "container"
 	SdNotifyModeConmon    = "conmon"
+	SdNotifyModeContainer = "container"
+	SdNotifyModeHealthy   = "healthy"
 	SdNotifyModeIgnore    = "ignore"
 )
 
 // ValidateSdNotifyMode validates the specified mode.
 func ValidateSdNotifyMode(mode string) error {
 	switch mode {
-	case "", SdNotifyModeContainer, SdNotifyModeConmon, SdNotifyModeIgnore:
+	case "", SdNotifyModeContainer, SdNotifyModeConmon, SdNotifyModeIgnore, SdNotifyModeHealthy:
 		return nil
 	default:
-		return fmt.Errorf("%w: invalid sdnotify value %q: must be %s, %s or %s", ErrInvalidArg, mode, SdNotifyModeContainer, SdNotifyModeConmon, SdNotifyModeIgnore)
+		return fmt.Errorf("%w: invalid sdnotify value %q: must be %s, %s, %s or %s", ErrInvalidArg, mode, SdNotifyModeConmon, SdNotifyModeContainer, SdNotifyModeHealthy, SdNotifyModeIgnore)
 	}
 }

libpod/oci_conmon_attach_common.go

@@ -4,6 +4,7 @@
 package libpod
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"io"
@@ -86,7 +87,7 @@ func (r *ConmonOCIRuntime) Attach(c *Container, params *AttachOptions) error {
 	// If starting was requested, start the container and notify when that's
 	// done.
 	if params.Start {
-		if err := c.start(); err != nil {
+		if err := c.start(context.TODO()); err != nil {
 			return err
 		}
 		params.Started <- true

pkg/specgen/container_validate.go

@@ -14,8 +14,6 @@ var (
 	ErrInvalidSpecConfig = errors.New("invalid configuration")
 	// SystemDValues describes the only values that SystemD can be
 	SystemDValues = []string{"true", "false", "always"}
-	// SdNotifyModeValues describes the only values that SdNotifyMode can be
-	SdNotifyModeValues = []string{define.SdNotifyModeContainer, define.SdNotifyModeConmon, define.SdNotifyModeIgnore}
 	// ImageVolumeModeValues describes the only values that ImageVolumeMode can be
 	ImageVolumeModeValues = []string{"ignore", define.TypeTmpfs, "anonymous"}
 )

pkg/specgen/generate/container_create.go

@@ -601,18 +601,25 @@ func createContainerOptions(rt *libpod.Runtime, s *specgen.SpecGenerator, pod *l
 	}
 	options = append(options, libpod.WithRestartRetries(retries), libpod.WithRestartPolicy(restartPolicy))
 
+	healthCheckSet := false
 	if s.ContainerHealthCheckConfig.HealthConfig != nil {
 		options = append(options, libpod.WithHealthCheck(s.ContainerHealthCheckConfig.HealthConfig))
 		logrus.Debugf("New container has a health check")
+		healthCheckSet = true
 	}
 	if s.ContainerHealthCheckConfig.StartupHealthConfig != nil {
 		options = append(options, libpod.WithStartupHealthcheck(s.ContainerHealthCheckConfig.StartupHealthConfig))
+		healthCheckSet = true
 	}
 
 	if s.ContainerHealthCheckConfig.HealthCheckOnFailureAction != define.HealthCheckOnFailureActionNone {
 		options = append(options, libpod.WithHealthCheckOnFailureAction(s.ContainerHealthCheckConfig.HealthCheckOnFailureAction))
 	}
 
+	if s.SdNotifyMode == define.SdNotifyModeHealthy && !healthCheckSet {
+		return nil, fmt.Errorf("%w: sdnotify policy %q requires a healthcheck to be set", define.ErrInvalidArg, s.SdNotifyMode)
+	}
+
 	if len(s.Secrets) != 0 {
 		manager, err := rt.SecretsManager()
 		if err != nil {

test/system/260-sdnotify.bats

@@ -184,6 +184,65 @@ READY=1"
     _stop_socat
 }
 
+# These tests can fail in dev. environment because of SELinux.
+# quick fix: chcon -t container_runtime_exec_t ./bin/podman
+@test "sdnotify : healthy" {
+    export NOTIFY_SOCKET=$PODMAN_TMPDIR/container.sock
+    _start_socat
+
+    wait_file="$PODMAN_TMPDIR/$(random_string).wait_for_me"
+    run_podman 125 create --sdnotify=healthy $IMAGE
+    is "$output" "Error: invalid argument: sdnotify policy \"healthy\" requires a healthcheck to be set"
+
+    # Create a container with a simple `/bin/true` healthcheck that we need to
+    # run manually.
+    ctr=$(random_string)
+    run_podman create --name $ctr     \
+            --health-cmd=/bin/true    \
+            --health-retries=1        \
+            --health-interval=disable \
+            --sdnotify=healthy        \
+            $IMAGE sleep infinity
+
+    # Start the container in the background which will block until the
+    # container turned healthy.  After that, create the wait_file which
+    # indicates that start has returned.
+    (timeout --foreground -v --kill=5 20 $PODMAN start $ctr && touch $wait_file) &
+
+    run_podman wait --condition=running $ctr
+
+    # Make sure that the MAINPID is set but without the READY message.
+    run_podman container inspect $ctr --format "{{.State.ConmonPid}}"
+    mainPID="$output"
+    # With container, READY=1 isn't necessarily the last message received;
+    # just look for it anywhere in received messages
+    run cat $_SOCAT_LOG
+    # The 'echo's help us debug failed runs
+    echo "socat log:"
+    echo "$output"
+
+    is "$output" "MAINPID=$mainPID" "Container is not healthy yet, so we only know the main PID"
+
+    # Now run the healthcheck and look for the READY message.
+    run_podman healthcheck run $ctr
+    is "$output" "" "output from 'podman healthcheck run'"
+
+    # Wait for start to return.  At that point the READY message must have been
+    # sent.
+    wait_for_file $wait_file
+    run cat $_SOCAT_LOG
+    echo "socat log:"
+    echo "$output"
+    is "$output" "MAINPID=$mainPID
+READY=1"
+
+    run_podman container inspect  --format "{{.State.Status}}" $ctr
+    is "$output" "running" "make sure container is still running"
+
+    run_podman rm -f -t0 $ctr
+    _stop_socat
+}
+
 @test "sdnotify : play kube - no policies" {
     # Create the YAMl file
     yaml_source="$PODMAN_TMPDIR/test.yaml"