Added option to share kernel namespaces in libpod and podman

A pause container is added to the pod if the user opts in. The default pause image and command can be overridden. Pause containers are ignored in ps unless the -a option is present. Pod inspect and pod ps show shared namespaces and pause container. A pause container can't be removed with podman rm, and a pod can be removed if it only has a pause container.

Signed-off-by: haircommander <pehunt@redhat.com>

Closes: #1187
Approved by: mheon

1 files changed, 11 insertions, 0 deletions

diff --git a/libpod/runtime.go b/libpod/runtime.go
index 73f516cd5..7e006b1fc 100644
--- a/libpod/runtime.go
+++ b/libpod/runtime.go
@@ -56,6 +56,11 @@ const (
 	// configuration file. If OverrideConfigPath exists, it will be used in
 	// place of the configuration file pointed to by ConfigPath.
 	OverrideConfigPath = "/etc/containers/libpod.conf"
+
+	// DefaultPauseImage to use for pause container
+	DefaultPauseImage = "k8s.gcr.io/pause:3.1"
+	// DefaultPauseCommand to be run in a pause container
+	DefaultPauseCommand = "/pause"
 )
 
 // A RuntimeOption is a functional option which alters the Runtime created by
@@ -152,6 +157,10 @@ type RuntimeConfig struct {
 	// and all containers and pods will be visible.
 	// The default namespace is "".
 	Namespace string `toml:"namespace,omitempty"`
+	// PauseImage is the image a pod pause container will use to manage namespaces
+	PauseImage string `toml:"pause_image"`
+	// PauseCommand is the command run to start up a pod pause container
+	PauseCommand string `toml:"pause_command"`
 }
 
 var (
@@ -186,6 +195,8 @@ var (
 		NoPivotRoot:   false,
 		CNIConfigDir:  "/etc/cni/net.d/",
 		CNIPluginDir:  []string{"/usr/libexec/cni", "/usr/lib/cni", "/opt/cni/bin"},
+		PauseCommand:  DefaultPauseCommand,
+		PauseImage:    DefaultPauseImage,
 	}
 )