play kube: service container

Add the notion of a "service container" to play kube.  A service
container is started before the pods in play kube and is (reverse)
linked to them.  The service container is stopped/removed *after*
all pods it is associated with are stopped/removed.

In other words, a service container tracks the entire life cycle
of a service started via `podman play kube`.  This is required to
enable `play kube` in a systemd unit file.

The service container is only used when the `--service-container`
flag is set on the CLI.  This flag has been marked as hidden as it
is not meant to be used outside the context of `play kube`.  It is
further not supported on the remote client.

The wiring with systemd will be done in a later commit.

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

cmd/podman/play/kube.go

@@ -139,6 +139,15 @@ func init() {
 		flags.StringVar(&kubeOptions.ContextDir, contextDirFlagName, "", "Path to top level of context directory")
 		_ = kubeCmd.RegisterFlagCompletionFunc(contextDirFlagName, completion.AutocompleteDefault)
 
+		// NOTE: The service-container flag is marked as hidden as it
+		// is purely designed for running play-kube in systemd units.
+		// It is not something users should need to know or care about.
+		//
+		// Having a flag rather than an env variable is cleaner.
+		serviceFlagName := "service-container"
+		flags.BoolVar(&kubeOptions.ServiceContainer, serviceFlagName, false, "Starts a service container before all pods")
+		_ = flags.MarkHidden("service-container")
+
 		flags.StringVar(&kubeOptions.SignaturePolicy, "signature-policy", "", "`Pathname` of signature policy file (not usually used)")
 
 		_ = flags.MarkHidden("signature-policy")

libpod/container.go

@@ -211,6 +211,14 @@ type ContainerState struct {
 	// network and an interface names
 	NetInterfaceDescriptions ContainerNetworkDescriptions `json:"networkDescriptions,omitempty"`
 
+	// Service indicates that container is the service container of a
+	// service. A service consists of one or more pods.  The service
+	// container is started before all pods and is stopped when the last
+	// pod stops. The service container allows for tracking and managing
+	// the entire life cycle of service which may be started via
+	// `podman-play-kube`.
+	Service Service
+
 	// containerPlatformState holds platform-specific container state.
 	containerPlatformState
 

libpod/container_config.go

@@ -382,6 +382,9 @@ type ContainerMiscConfig struct {
 	// IsInfra is a bool indicating whether this container is an infra container used for
 	// sharing kernel namespaces in a pod
 	IsInfra bool `json:"pause"`
+	// IsService is a bool indicating whether this container is a service container used for
+	// tracking the life cycle of K8s service.
+	IsService bool `json:"isService"`
 	// SdNotifyMode tells libpod what to do with a NOTIFY_SOCKET if passed
 	SdNotifyMode string `json:"sdnotifyMode,omitempty"`
 	// Systemd tells libpod to setup the container in systemd mode, a value of nil denotes false

libpod/container_inspect.go

@@ -171,6 +171,7 @@ func (c *Container) getContainerInspectData(size bool, driverData *define.Driver
 		Mounts:          inspectMounts,
 		Dependencies:    c.Dependencies(),
 		IsInfra:         c.IsInfra(),
+		IsService:       c.isService(),
 	}
 
 	if c.state.ConfigPath != "" {

libpod/container_validate.go

@@ -1,6 +1,8 @@
 package libpod
 
 import (
+	"fmt"
+
 	"github.com/containers/podman/v4/libpod/define"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/pkg/errors"
@@ -27,6 +29,12 @@ func (c *Container) validate() error {
 		return errors.Wrapf(define.ErrInvalidArg, "must set root filesystem source to either image or rootfs")
 	}
 
+	// A container cannot be marked as an infra and service container at
+	// the same time.
+	if c.IsInfra() && c.isService() {
+		return fmt.Errorf("cannot be infra and service container at the same time: %w", define.ErrInvalidArg)
+	}
+
 	// Cannot make a network namespace if we are joining another container's
 	// network namespace
 	if c.config.CreateNetNS && c.config.NetNsCtr != "" {

libpod/define/container_inspect.go

@@ -683,6 +683,7 @@ type InspectContainerData struct {
 	NetworkSettings *InspectNetworkSettings     `json:"NetworkSettings"`
 	Namespace       string                      `json:"Namespace"`
 	IsInfra         bool                        `json:"IsInfra"`
+	IsService       bool                        `json:"IsService"`
 	Config          *InspectContainerConfig     `json:"Config"`
 	HostConfig      *InspectContainerHostConfig `json:"HostConfig"`
 }

libpod/options.go

@@ -1,6 +1,7 @@
 package libpod
 
 import (
+	"fmt"
 	"net"
 	"os"
 	"path/filepath"
@@ -1477,7 +1478,7 @@ func WithCreateCommand(cmd []string) CtrCreateOption {
 	}
 }
 
-// withIsInfra allows us to dfferentiate between infra containers and regular containers
+// withIsInfra allows us to dfferentiate between infra containers and other containers
 // within the container config
 func withIsInfra() CtrCreateOption {
 	return func(ctr *Container) error {
@@ -1491,6 +1492,20 @@ func withIsInfra() CtrCreateOption {
 	}
 }
 
+// WithIsService allows us to dfferentiate between service containers and other container
+// within the container config
+func WithIsService() CtrCreateOption {
+	return func(ctr *Container) error {
+		if ctr.valid {
+			return define.ErrCtrFinalized
+		}
+
+		ctr.config.IsService = true
+
+		return nil
+	}
+}
+
 // WithCreateWorkingDir tells Podman to create the container's working directory
 // if it does not exist.
 func WithCreateWorkingDir() CtrCreateOption {
@@ -2081,6 +2096,27 @@ func WithInfraContainer() PodCreateOption {
 	}
 }
 
+// WithServiceContainer associates the specified service container ID with the pod.
+func WithServiceContainer(id string) PodCreateOption {
+	return func(pod *Pod) error {
+		if pod.valid {
+			return define.ErrPodFinalized
+		}
+
+		ctr, err := pod.runtime.LookupContainer(id)
+		if err != nil {
+			return fmt.Errorf("looking up service container: %w", err)
+		}
+
+		if err := ctr.addServicePodLocked(pod.ID()); err != nil {
+			return fmt.Errorf("associating service container %s with pod %s: %w", id, pod.ID(), err)
+		}
+
+		pod.config.ServiceContainerID = id
+		return nil
+	}
+}
+
 // WithVolatile sets the volatile flag for the container storage.
 // The option can potentially cause data loss when used on a container that must survive a machine reboot.
 func WithVolatile() CtrCreateOption {

libpod/pod.go

@@ -64,6 +64,13 @@ type PodConfig struct {
 
 	HasInfra bool `json:"hasInfra,omitempty"`
 
+	// ServiceContainerID is the main container of a service.  A service
+	// consists of one or more pods.  The service container is started
+	// before all pods and is stopped when the last pod stops.
+	// The service container allows for tracking and managing the entire
+	// life cycle of service which may be started via `podman-play-kube`.
+	ServiceContainerID string `json:"serviceContainerID,omitempty"`
+
 	// Time pod was created
 	CreatedTime time.Time `json:"created"`
 

libpod/pod_api.go

@@ -75,6 +75,10 @@ func (p *Pod) Start(ctx context.Context) (map[string]error, error) {
 		return nil, define.ErrPodRemoved
 	}
 
+	if err := p.maybeStartServiceContainer(ctx); err != nil {
+		return nil, err
+	}
+
 	// Before "regular" containers start in the pod, all init containers
 	// must have run and exited successfully.
 	if err := p.startInitContainers(ctx); err != nil {
@@ -197,6 +201,11 @@ func (p *Pod) stopWithTimeout(ctx context.Context, cleanup bool, timeout int) (m
 	if len(ctrErrors) > 0 {
 		return ctrErrors, errors.Wrapf(define.ErrPodPartialFail, "error stopping some containers")
 	}
+
+	if err := p.maybeStopServiceContainer(); err != nil {
+		return nil, err
+	}
+
 	return nil, nil
 }
 
@@ -297,6 +306,10 @@ func (p *Pod) Cleanup(ctx context.Context) (map[string]error, error) {
 		return ctrErrors, errors.Wrapf(define.ErrPodPartialFail, "error cleaning up some containers")
 	}
 
+	if err := p.maybeStopServiceContainer(); err != nil {
+		return nil, err
+	}
+
 	return nil, nil
 }
 
@@ -443,6 +456,10 @@ func (p *Pod) Restart(ctx context.Context) (map[string]error, error) {
 		return nil, define.ErrPodRemoved
 	}
 
+	if err := p.maybeStartServiceContainer(ctx); err != nil {
+		return nil, err
+	}
+
 	allCtrs, err := p.runtime.state.PodContainers(p)
 	if err != nil {
 		return nil, err
@@ -530,6 +547,11 @@ func (p *Pod) Kill(ctx context.Context, signal uint) (map[string]error, error) {
 	if len(ctrErrors) > 0 {
 		return ctrErrors, errors.Wrapf(define.ErrPodPartialFail, "error killing some containers")
 	}
+
+	if err := p.maybeStopServiceContainer(); err != nil {
+		return nil, err
+	}
+
 	return nil, nil
 }
 

libpod/runtime_img.go

@@ -40,7 +40,7 @@ func (r *Runtime) RemoveContainersForImageCallback(ctx context.Context) libimage
 			if ctr.config.IsInfra {
 				pod, err := r.state.Pod(ctr.config.Pod)
 				if err != nil {
-					return errors.Wrapf(err, "container %s is in pod %s, but pod cannot be retrieved", ctr.ID(), pod.ID())
+					return errors.Wrapf(err, "container %s is in pod %s, but pod cannot be retrieved", ctr.ID(), ctr.config.Pod)
 				}
 				if err := r.removePod(ctx, pod, true, true, timeout); err != nil {
 					return errors.Wrapf(err, "removing image %s: container %s using image could not be removed", imageID, ctr.ID())

libpod/runtime_pod_linux.go

@@ -380,6 +380,10 @@ func (r *Runtime) removePod(ctx context.Context, p *Pod, removeCtrs, force bool,
 		}
 	}
 
+	if err := p.maybeRemoveServiceContainer(); err != nil {
+		return err
+	}
+
 	// Remove pod from state
 	if err := r.state.RemovePod(p); err != nil {
 		if removalErr != nil {

libpod/service.go

@@ -0,0 +1,213 @@
+package libpod
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/containers/podman/v4/libpod/define"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+)
+
+// A service consists of one or more pods.  The service container is started
+// before all pods and is stopped when the last pod stops. The service
+// container allows for tracking and managing the entire life cycle of service
+// which may be started via `podman-play-kube`.
+type Service struct {
+	// Pods running as part of the service.
+	Pods []string `json:"servicePods"`
+}
+
+// Indicates whether the pod is associated with a service container.
+// The pod is expected to be updated and locked.
+func (p *Pod) hasServiceContainer() bool {
+	return p.config.ServiceContainerID != ""
+}
+
+// Returns the pod's service container.
+// The pod is expected to be updated and locked.
+func (p *Pod) serviceContainer() (*Container, error) {
+	id := p.config.ServiceContainerID
+	if id == "" {
+		return nil, errors.Wrap(define.ErrNoSuchCtr, "pod has no service container")
+	}
+	return p.runtime.state.Container(id)
+}
+
+// ServiceContainer returns the service container.
+func (p *Pod) ServiceContainer() (*Container, error) {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+	if err := p.updatePod(); err != nil {
+		return nil, err
+	}
+	return p.serviceContainer()
+}
+
+func (c *Container) addServicePodLocked(id string) error {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	if err := c.syncContainer(); err != nil {
+		return err
+	}
+	c.state.Service.Pods = append(c.state.Service.Pods, id)
+	return c.save()
+}
+
+func (c *Container) isService() bool {
+	return c.config.IsService
+}
+
+// canStopServiceContainer returns true if all pods of the service are stopped.
+// Note that the method acquires the container lock.
+func (c *Container) canStopServiceContainerLocked() (bool, error) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	if err := c.syncContainer(); err != nil {
+		return false, err
+	}
+
+	if !c.isService() {
+		return false, fmt.Errorf("internal error: checking service: container %s is not a service container", c.ID())
+	}
+
+	for _, id := range c.state.Service.Pods {
+		pod, err := c.runtime.LookupPod(id)
+		if err != nil {
+			if errors.Is(err, define.ErrNoSuchPod) {
+				continue
+			}
+			return false, err
+		}
+
+		status, err := pod.GetPodStatus()
+		if err != nil {
+			return false, err
+		}
+
+		// We can only stop the service if all pods are done.
+		switch status {
+		case define.PodStateStopped, define.PodStateExited, define.PodStateErrored:
+			continue
+		default:
+			return false, nil
+		}
+	}
+
+	return true, nil
+}
+
+// Checks whether the service container can be stopped and does so.
+func (p *Pod) maybeStopServiceContainer() error {
+	if !p.hasServiceContainer() {
+		return nil
+	}
+
+	serviceCtr, err := p.serviceContainer()
+	if err != nil {
+		return fmt.Errorf("getting pod's service container: %w", err)
+	}
+	// Checking whether the service can be stopped must be done in
+	// the runtime's work queue to resolve ABBA dead locks in the
+	// pod->container->servicePods hierarchy.
+	p.runtime.queueWork(func() {
+		logrus.Debugf("Pod %s has a service %s: checking if it can be stopped", p.ID(), serviceCtr.ID())
+		canStop, err := serviceCtr.canStopServiceContainerLocked()
+		if err != nil {
+			logrus.Errorf("Checking whether service of container %s can be stopped: %v", serviceCtr.ID(), err)
+			return
+		}
+		if !canStop {
+			return
+		}
+		logrus.Debugf("Stopping service container %s", serviceCtr.ID())
+		if err := serviceCtr.Stop(); err != nil {
+			logrus.Errorf("Stopping service container %s: %v", serviceCtr.ID(), err)
+		}
+	})
+	return nil
+}
+
+// Starts the pod's service container if it's not already running.
+func (p *Pod) maybeStartServiceContainer(ctx context.Context) error {
+	if !p.hasServiceContainer() {
+		return nil
+	}
+
+	serviceCtr, err := p.serviceContainer()
+	if err != nil {
+		return fmt.Errorf("getting pod's service container: %w", err)
+	}
+
+	serviceCtr.lock.Lock()
+	defer serviceCtr.lock.Unlock()
+
+	if err := serviceCtr.syncContainer(); err != nil {
+		return err
+	}
+
+	if serviceCtr.state.State == define.ContainerStateRunning {
+		return nil
+	}
+
+	// Restart will reinit among other things.
+	return serviceCtr.restartWithTimeout(ctx, 0)
+}
+
+// canRemoveServiceContainer returns true if all pods of the service are removed.
+// Note that the method acquires the container lock.
+func (c *Container) canRemoveServiceContainerLocked() (bool, error) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	if err := c.syncContainer(); err != nil {
+		return false, err
+	}
+
+	if !c.isService() {
+		return false, fmt.Errorf("internal error: checking service: container %s is not a service container", c.ID())
+	}
+
+	for _, id := range c.state.Service.Pods {
+		if _, err := c.runtime.LookupPod(id); err != nil {
+			if errors.Is(err, define.ErrNoSuchPod) {
+				continue
+			}
+			return false, err
+		}
+		return false, nil
+	}
+
+	return true, nil
+}
+
+// Checks whether the service container can be removed and does so.
+func (p *Pod) maybeRemoveServiceContainer() error {
+	if !p.hasServiceContainer() {
+		return nil
+	}
+
+	serviceCtr, err := p.serviceContainer()
+	if err != nil {
+		return fmt.Errorf("getting pod's service container: %w", err)
+	}
+	// Checking whether the service can be stopped must be done in
+	// the runtime's work queue to resolve ABBA dead locks in the
+	// pod->container->servicePods hierarchy.
+	p.runtime.queueWork(func() {
+		logrus.Debugf("Pod %s has a service %s: checking if it can be removed", p.ID(), serviceCtr.ID())
+		canRemove, err := serviceCtr.canRemoveServiceContainerLocked()
+		if err != nil {
+			logrus.Errorf("Checking whether service of container %s can be removed: %v", serviceCtr.ID(), err)
+			return
+		}
+		if !canRemove {
+			return
+		}
+		timeout := uint(0)
+		logrus.Debugf("Removing service container %s", serviceCtr.ID())
+		if err := p.runtime.RemoveContainer(context.Background(), serviceCtr, true, false, &timeout); err != nil {
+			logrus.Errorf("Removing service container %s: %v", serviceCtr.ID(), err)
+		}
+	})
+	return nil
+}

pkg/domain/entities/play.go

@@ -54,6 +54,8 @@ type PlayKubeOptions struct {
 	LogOptions []string
 	// Start - don't start the pod if false
 	Start types.OptionalBool
+	// ServiceContainer - creates a service container that is started before and is stopped after all pods.
+	ServiceContainer bool
 	// Userns - define the user namespace to use.
 	Userns string
 }

pkg/domain/infra/abi/play.go

@@ -28,12 +28,54 @@ import (
 	"github.com/containers/podman/v4/pkg/specgenutil"
 	"github.com/containers/podman/v4/pkg/util"
 	"github.com/ghodss/yaml"
+	"github.com/opencontainers/go-digest"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 	yamlv2 "gopkg.in/yaml.v2"
 )
 
-func (ic *ContainerEngine) PlayKube(ctx context.Context, body io.Reader, options entities.PlayKubeOptions) (*entities.PlayKubeReport, error) {
+// 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.
+func (ic *ContainerEngine) createServiceContainer(ctx context.Context, name string) (*libpod.Container, error) {
+	// Similar to infra containers, a service container is using the pause image.
+	image, err := generate.PullOrBuildInfraImage(ic.Libpod, "")
+	if err != nil {
+		return nil, fmt.Errorf("image for service container: %w", err)
+	}
+
+	ctrOpts := entities.ContainerCreateOptions{
+		// Inherited from infra containers
+		ImageVolume:      "bind",
+		IsInfra:          false,
+		MemorySwappiness: -1,
+		// No need to spin up slirp etc.
+		Net: &entities.NetOptions{Network: specgen.Namespace{NSMode: specgen.NoNetwork}},
+	}
+
+	// Create and fill out the runtime spec.
+	s := specgen.NewSpecGenerator(image, false)
+	if err := specgenutil.FillOutSpecGen(s, &ctrOpts, []string{}); err != nil {
+		return nil, fmt.Errorf("completing spec for service container: %w", err)
+	}
+	s.Name = name
+
+	runtimeSpec, spec, opts, err := generate.MakeContainer(ctx, ic.Libpod, s, false, nil)
+	if err != nil {
+		return nil, fmt.Errorf("creating runtime spec for service container: %w", err)
+	}
+	opts = append(opts, libpod.WithIsService())
+
+	// Create a new libpod container based on the spec.
+	ctr, err := ic.Libpod.NewContainer(ctx, runtimeSpec, spec, false, opts...)
+	if err != nil {
+		return nil, fmt.Errorf("creating service container: %w", err)
+	}
+
+	return ctr, nil
+}
+
+func (ic *ContainerEngine) PlayKube(ctx context.Context, body io.Reader, options entities.PlayKubeOptions) (_ *entities.PlayKubeReport, finalErr error) {
 	report := &entities.PlayKubeReport{}
 	validKinds := 0
 
@@ -67,6 +109,30 @@ func (ic *ContainerEngine) PlayKube(ctx context.Context, body io.Reader, options
 			return nil, errors.Wrap(err, "unable to read kube YAML")
 		}
 
+		// TODO: create constants for the various "kinds" of yaml files.
+		var serviceContainer *libpod.Container
+		if options.ServiceContainer && (kind == "Pod" || kind == "Deployment") {
+			// The name of the service container is the first 12
+			// characters of the yaml file's hash followed by the
+			// '-service' suffix to guarantee a predictable and
+			// discoverable name.
+			hash := digest.FromBytes(content).Encoded()
+			ctr, err := ic.createServiceContainer(ctx, hash[0:12]+"-service")
+			if err != nil {
+				return nil, err
+			}
+			serviceContainer = ctr
+			// Make sure to remove the container in case something goes wrong below.
+			defer func() {
+				if finalErr == nil {
+					return
+				}
+				if err := ic.Libpod.RemoveContainer(ctx, ctr, true, false, nil); err != nil {
+					logrus.Errorf("Cleaning up service container after failure: %v", err)
+				}
+			}()
+		}
+
 		switch kind {
 		case "Pod":
 			var podYAML v1.Pod
@@ -90,7 +156,7 @@ func (ic *ContainerEngine) PlayKube(ctx context.Context, body io.Reader, options
 				podYAML.Annotations[name] = val
 			}
 
-			r, err := ic.playKubePod(ctx, podTemplateSpec.ObjectMeta.Name, &podTemplateSpec, options, &ipIndex, podYAML.Annotations, configMaps)
+			r, err := ic.playKubePod(ctx, podTemplateSpec.ObjectMeta.Name, &podTemplateSpec, options, &ipIndex, podYAML.Annotations, configMaps, serviceContainer)
 			if err != nil {
 				return nil, err
 			}
@@ -104,7 +170,7 @@ func (ic *ContainerEngine) PlayKube(ctx context.Context, body io.Reader, options
 				return nil, errors.Wrap(err, "unable to read YAML as Kube Deployment")
 			}
 
-			r, err := ic.playKubeDeployment(ctx, &deploymentYAML, options, &ipIndex, configMaps)
+			r, err := ic.playKubeDeployment(ctx, &deploymentYAML, options, &ipIndex, configMaps, serviceContainer)
 			if err != nil {
 				return nil, err
 			}
@@ -148,7 +214,7 @@ func (ic *ContainerEngine) PlayKube(ctx context.Context, body io.Reader, options
 	return report, nil
 }
 
-func (ic *ContainerEngine) playKubeDeployment(ctx context.Context, deploymentYAML *v1apps.Deployment, options entities.PlayKubeOptions, ipIndex *int, configMaps []v1.ConfigMap) (*entities.PlayKubeReport, error) {
+func (ic *ContainerEngine) playKubeDeployment(ctx context.Context, deploymentYAML *v1apps.Deployment, options entities.PlayKubeOptions, ipIndex *int, configMaps []v1.ConfigMap, serviceContainer *libpod.Container) (*entities.PlayKubeReport, error) {
 	var (
 		deploymentName string
 		podSpec        v1.PodTemplateSpec
@@ -170,7 +236,7 @@ func (ic *ContainerEngine) playKubeDeployment(ctx context.Context, deploymentYAM
 	// create "replicas" number of pods
 	for i = 0; i < numReplicas; i++ {
 		podName := fmt.Sprintf("%s-pod-%d", deploymentName, i)
-		podReport, err := ic.playKubePod(ctx, podName, &podSpec, options, ipIndex, deploymentYAML.Annotations, configMaps)
+		podReport, err := ic.playKubePod(ctx, podName, &podSpec, options, ipIndex, deploymentYAML.Annotations, configMaps, serviceContainer)
 		if err != nil {
 			return nil, errors.Wrapf(err, "error encountered while bringing up pod %s", podName)
 		}
@@ -179,7 +245,7 @@ func (ic *ContainerEngine) playKubeDeployment(ctx context.Context, deploymentYAM
 	return &report, nil
 }
 
-func (ic *ContainerEngine) playKubePod(ctx context.Context, podName string, podYAML *v1.PodTemplateSpec, options entities.PlayKubeOptions, ipIndex *int, annotations map[string]string, configMaps []v1.ConfigMap) (*entities.PlayKubeReport, error) {
+func (ic *ContainerEngine) playKubePod(ctx context.Context, podName string, podYAML *v1.PodTemplateSpec, options entities.PlayKubeOptions, ipIndex *int, annotations map[string]string, configMaps []v1.ConfigMap, serviceContainer *libpod.Container) (*entities.PlayKubeReport, error) {
 	var (
 		writer      io.Writer
 		playKubePod entities.PlayKubePod
@@ -374,6 +440,10 @@ func (ic *ContainerEngine) playKubePod(ctx context.Context, podName string, podY
 		}
 	}
 
+	if serviceContainer != nil {
+		podSpec.PodSpecGen.ServiceContainerID = serviceContainer.ID()
+	}
+
 	// Create the Pod
 	pod, err := generate.MakePod(&podSpec, ic.Libpod)
 	if err != nil {

pkg/specgen/generate/pause_image.go

@@ -0,0 +1,89 @@
+package generate
+
+import (
+	"context"
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	buildahDefine "github.com/containers/buildah/define"
+	"github.com/containers/common/pkg/config"
+	"github.com/containers/podman/v4/libpod"
+	"github.com/containers/podman/v4/libpod/define"
+)
+
+// PullOrBuildInfraImage pulls down the specified image or the one set in
+// containers.conf.  If none is set, it builds a local pause image.
+func PullOrBuildInfraImage(rt *libpod.Runtime, imageName string) (string, error) {
+	rtConfig, err := rt.GetConfigNoCopy()
+	if err != nil {
+		return "", err
+	}
+
+	if imageName == "" {
+		imageName = rtConfig.Engine.InfraImage
+	}
+
+	if imageName != "" {
+		_, err := rt.LibimageRuntime().Pull(context.Background(), imageName, config.PullPolicyMissing, nil)
+		if err != nil {
+			return "", err
+		}
+		return imageName, nil
+	}
+
+	name, err := buildPauseImage(rt, rtConfig)
+	if err != nil {
+		return "", fmt.Errorf("building local pause image: %w", err)
+	}
+	return name, nil
+}
+
+func buildPauseImage(rt *libpod.Runtime, rtConfig *config.Config) (string, error) {
+	version, err := define.GetVersion()
+	if err != nil {
+		return "", err
+	}
+	imageName := fmt.Sprintf("localhost/podman-pause:%s-%d", version.Version, version.Built)
+
+	// First check if the image has already been built.
+	if _, _, err := rt.LibimageRuntime().LookupImage(imageName, nil); err == nil {
+		return imageName, nil
+	}
+
+	// Also look into the path as some distributions install catatonit in
+	// /usr/bin.
+	catatonitPath, err := rtConfig.FindHelperBinary("catatonit", true)
+	if err != nil {
+		return "", fmt.Errorf("finding pause binary: %w", err)
+	}
+
+	buildContent := fmt.Sprintf(`FROM scratch
+COPY %s /catatonit
+ENTRYPOINT ["/catatonit", "-P"]`, catatonitPath)
+
+	tmpF, err := ioutil.TempFile("", "pause.containerfile")
+	if err != nil {
+		return "", err
+	}
+	if _, err := tmpF.WriteString(buildContent); err != nil {
+		return "", err
+	}
+	if err := tmpF.Close(); err != nil {
+		return "", err
+	}
+	defer os.Remove(tmpF.Name())
+
+	buildOptions := buildahDefine.BuildOptions{
+		CommonBuildOpts: &buildahDefine.CommonBuildOptions{},
+		Output:          imageName,
+		Quiet:           true,
+		IgnoreFile:      "/dev/null", // makes sure to not read a local .ignorefile (see #13529)
+		IIDFile:         "/dev/null", // prevents Buildah from writing the ID on stdout
+	}
+	if _, _, err := rt.Build(context.Background(), buildOptions, tmpF.Name()); err != nil {
+		return "", err
+	}
+
+	return imageName, nil
+}

pkg/specgen/generate/pod_create.go

@@ -2,13 +2,8 @@ package generate
 
 import (
 	"context"
-	"fmt"
-	"io/ioutil"
 	"net"
-	"os"
 
-	buildahDefine "github.com/containers/buildah/define"
-	"github.com/containers/common/pkg/config"
 	"github.com/containers/podman/v4/libpod"
 	"github.com/containers/podman/v4/libpod/define"
 	"github.com/containers/podman/v4/pkg/domain/entities"
@@ -17,98 +12,18 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
-func buildPauseImage(rt *libpod.Runtime, rtConfig *config.Config) (string, error) {
-	version, err := define.GetVersion()
-	if err != nil {
-		return "", err
-	}
-	imageName := fmt.Sprintf("localhost/podman-pause:%s-%d", version.Version, version.Built)
-
-	// First check if the image has already been built.
-	if _, _, err := rt.LibimageRuntime().LookupImage(imageName, nil); err == nil {
-		return imageName, nil
-	}
-
-	// Also look into the path as some distributions install catatonit in
-	// /usr/bin.
-	catatonitPath, err := rtConfig.FindHelperBinary("catatonit", true)
-	if err != nil {
-		return "", fmt.Errorf("finding pause binary: %w", err)
-	}
-
-	buildContent := fmt.Sprintf(`FROM scratch
-COPY %s /catatonit
-ENTRYPOINT ["/catatonit", "-P"]`, catatonitPath)
-
-	tmpF, err := ioutil.TempFile("", "pause.containerfile")
-	if err != nil {
-		return "", err
-	}
-	if _, err := tmpF.WriteString(buildContent); err != nil {
-		return "", err
-	}
-	if err := tmpF.Close(); err != nil {
-		return "", err
-	}
-	defer os.Remove(tmpF.Name())
-
-	buildOptions := buildahDefine.BuildOptions{
-		CommonBuildOpts: &buildahDefine.CommonBuildOptions{},
-		Output:          imageName,
-		Quiet:           true,
-		IgnoreFile:      "/dev/null", // makes sure to not read a local .ignorefile (see #13529)
-		IIDFile:         "/dev/null", // prevents Buildah from writing the ID on stdout
-	}
-	if _, _, err := rt.Build(context.Background(), buildOptions, tmpF.Name()); err != nil {
-		return "", err
-	}
-
-	return imageName, nil
-}
-
-func pullOrBuildInfraImage(p *entities.PodSpec, rt *libpod.Runtime) error {
-	if p.PodSpecGen.NoInfra {
-		return nil
-	}
-
-	rtConfig, err := rt.GetConfigNoCopy()
-	if err != nil {
-		return err
-	}
-
-	// NOTE: we need pull down the infra image if it was explicitly set by
-	// the user (or containers.conf) to the non-default one.
-	imageName := p.PodSpecGen.InfraImage
-	if imageName == "" {
-		imageName = rtConfig.Engine.InfraImage
-	}
-
-	if imageName != "" {
-		_, err := rt.LibimageRuntime().Pull(context.Background(), imageName, config.PullPolicyMissing, nil)
-		if err != nil {
-			return err
-		}
-	} else {
-		name, err := buildPauseImage(rt, rtConfig)
-		if err != nil {
-			return fmt.Errorf("building local pause image: %w", err)
-		}
-		imageName = name
-	}
-
-	p.PodSpecGen.InfraImage = imageName
-	p.PodSpecGen.InfraContainerSpec.RawImageName = imageName
-
-	return nil
-}
-
 func MakePod(p *entities.PodSpec, rt *libpod.Runtime) (*libpod.Pod, error) {
 	if err := p.PodSpecGen.Validate(); err != nil {
 		return nil, err
 	}
 
-	if err := pullOrBuildInfraImage(p, rt); err != nil {
+	if !p.PodSpecGen.NoInfra {
-		return nil, err
+		imageName, err := PullOrBuildInfraImage(rt, p.PodSpecGen.InfraImage)
+		if err != nil {
+			return nil, err
+		}
+		p.PodSpecGen.InfraImage = imageName
+		p.PodSpecGen.InfraContainerSpec.RawImageName = imageName
 	}
 
 	if !p.PodSpecGen.NoInfra && p.PodSpecGen.InfraContainerSpec != nil {
@@ -180,6 +95,11 @@ func createPodOptions(p *specgen.PodSpecGenerator) ([]libpod.PodCreateOption, er
 			options = append(options, libpod.WithPodUser())
 		}
 	}
+
+	if len(p.ServiceContainerID) > 0 {
+		options = append(options, libpod.WithServiceContainer(p.ServiceContainerID))
+	}
+
 	if len(p.CgroupParent) > 0 {
 		options = append(options, libpod.WithPodCgroupParent(p.CgroupParent))
 	}

pkg/specgen/podspecgen.go

@@ -204,6 +204,9 @@ type PodSpecGenerator struct {
 	PodStorageConfig
 	PodSecurityConfig
 	InfraContainerSpec *SpecGenerator `json:"-"`
+
+	// The ID of the pod's service container.
+	ServiceContainerID string `json:"serviceContainerID,omitempty"`
 }
 
 type PodResourceConfig struct {

test/system/200-pod.bats

@@ -408,19 +408,6 @@ EOF
     run_podman pod rm test
 }
 
-# Wait for the pod (1st arg) to transition into the state (2nd arg)
-function _ensure_pod_state() {
-    for i in {0..5}; do
-        run_podman pod inspect $1 --format "{{.State}}"
-        if [[ $output == "$2" ]]; then
-            break
-        fi
-        sleep 0.5
-    done
-
-    is "$output" "$2" "unexpected pod state"
-}
-
 @test "pod exit policies" {
     # Test setting exit policies
     run_podman pod create

test/system/700-play.bats

@@ -100,6 +100,61 @@ RELABEL="system_u:object_r:container_file_t:s0"
     run_podman pod rm -t 0 -f test_pod
 }
 
+@test "podman play --service-container" {
+    skip_if_remote "service containers only work locally"
+
+    TESTDIR=$PODMAN_TMPDIR/testdir
+    mkdir -p $TESTDIR
+
+yaml="
+apiVersion: v1
+kind: Pod
+metadata:
+  labels:
+    app: test
+  name: test_pod
+spec:
+  containers:
+  - command:
+    - top
+    image: $IMAGE
+    name: test
+    resources: {}
+"
+
+    echo "$yaml" > $PODMAN_TMPDIR/test.yaml
+    run_podman play kube --service-container=true $PODMAN_TMPDIR/test.yaml
+
+    # Make sure that the service container exists and runs.
+    run_podman container inspect "352a88685060-service" --format "{{.State.Running}}"
+    is "$output" "true"
+
+    # Stop the *main* container and make sure that
+    #  1) The pod transitions to Exited
+    #  2) The service container is stopped
+    #  #) The service container is marked as an service container
+    run_podman stop test_pod-test
+    _ensure_pod_state test_pod Exited
+    run_podman container inspect "352a88685060-service" --format "{{.State.Running}}"
+    is "$output" "false"
+    run_podman container inspect "352a88685060-service" --format "{{.IsService}}"
+    is "$output" "true"
+
+    # Restart the pod, make sure the service is running again
+    run_podman pod restart test_pod
+    run_podman container inspect "352a88685060-service" --format "{{.State.Running}}"
+    is "$output" "true"
+
+    # Kill the pod and make sure the service is not running
+    run_podman pod kill test_pod
+    run_podman container inspect "352a88685060-service" --format "{{.State.Running}}"
+    is "$output" "false"
+
+    # Remove the pod and make sure the service is removed along with it
+    run_podman pod rm test_pod
+    run_podman 1 container exists "352a88685060-service"
+}
+
 @test "podman play --network" {
     TESTDIR=$PODMAN_TMPDIR/testdir
     mkdir -p $TESTDIR

test/system/helpers.bash

@@ -392,6 +392,19 @@ function pause_image() {
     echo "localhost/podman-pause:$output"
 }
 
+# Wait for the pod (1st arg) to transition into the state (2nd arg)
+function _ensure_pod_state() {
+    for i in {0..5}; do
+        run_podman pod inspect $1 --format "{{.State}}"
+        if [[ $output == "$2" ]]; then
+            break
+        fi
+        sleep 0.5
+    done
+
+    is "$output" "$2" "unexpected pod state"
+}
+
 ###########################
 #  _add_label_if_missing  #  make sure skip messages include rootless/remote
 ###########################