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>

1 files changed, 22 insertions, 0 deletions

diff --git a/libpod/pod_api.go b/libpod/pod_api.go
index 73b28822b..eede896a9 100644
--- a/libpod/pod_api.go
+++ b/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
 }