containers.conf: add pod_exit_policy

Add a new `pod_exit_policy` field to the containers.conf's engine table.
A pod's exit policy determines the behaviour when the last container of
a pod exits.

Required-in: containers/podman/pull/13859
Signed-off-by: Valentin Rothberg <[email protected]>

docs/containers.conf.5.md

@@ -549,6 +549,15 @@ pod consumes one lock. The default number available is 2048. If this is
 changed, a lock renumbering must be performed, using the
 `podman system renumber` command.
 
+**pod_exit_policy**="continue"
+
+Set the exit policy of the pod when the last container exits. Supported policies are:
+
+| Exit Policy | Description |
+| ------------------ | --------------------------------------------------------------------------- |
+| *continue* | The pod continues running when the last container exits. Used by default. |
+| *stop* | The pod is stopped when the last container exits. Used in `play kube`. |
+
 **pull_policy**="always"|"missing"|"never"
 
 Pull image before running or creating a container. The default is **missing**.

pkg/config/config.go

@@ -349,6 +349,9 @@ type EngineConfig struct {
  // OCIRuntimes are the set of configured OCI runtimes (default is runc).
  OCIRuntimes map[string][]string `toml:"runtimes,omitempty"`
 
+ // PodExitPolicy determines the behaviour when the last container of a pod exits.
+ PodExitPolicy PodExitPolicy `toml:"pod_exit_policy,omitempty"`
+
  // PullPolicy determines whether to pull image before creating or running a container
  // default is "missing"
  PullPolicy string `toml:"pull_policy,omitempty"`

pkg/config/config_test.go

@@ -362,6 +362,7 @@ image_copy_tmp_dir="storage"`
  }
  gomega.Expect(config.Engine.EventsLogFilePath).To(gomega.BeEquivalentTo(config.Engine.TmpDir + "/events/events.log"))
  gomega.Expect(uint64(config.Engine.EventsLogFileMaxSize)).To(gomega.Equal(DefaultEventsLogSizeMax))
+ gomega.Expect(config.Engine.PodExitPolicy).To(gomega.Equal(PodExitPolicyContinue))
  })
 
  It("should success with valid user file path", func() {
@@ -402,6 +403,7 @@ image_copy_tmp_dir="storage"`
  gomega.Expect(err).To(gomega.BeNil())
  gomega.Expect(path).To(gomega.BeEquivalentTo("/tmp/foobar"))
  gomega.Expect(uint64(config.Engine.EventsLogFileMaxSize)).To(gomega.Equal(uint64(500)))
+ gomega.Expect(config.Engine.PodExitPolicy).To(gomega.BeEquivalentTo(PodExitPolicyStop))
  })
 
  It("should fail with invalid value", func() {

pkg/config/containers.conf

@@ -506,6 +506,9 @@ default_sysctls = [
 #
 #num_locks = 2048
 
+# Set the exit policy of the pod when the last container exits.
+#pod_exit_policy = "continue"
+
 # Whether to pull new image before running a container
 #
 #pull_policy = "missing"

pkg/config/default.go

@@ -388,6 +388,8 @@ func defaultConfigFromMemory() (*EngineConfig, error) {
  c.MachineEnabled = false
  c.ChownCopiedFiles = true
 
+ c.PodExitPolicy = defaultPodExitPolicy
+
  return c, nil
 }
 

pkg/config/pod_exit_policy.go

@@ -0,0 +1,36 @@
+package config
+
+import "fmt"
+
+// PodExitPolicies includes the supported pod exit policies.
+var PodExitPolicies = []string{string(PodExitPolicyContinue), string(PodExitPolicyStop)}
+
+// PodExitPolicy determines a pod's exit and stop behaviour.
+type PodExitPolicy string
+
+const (
+ // PodExitPolicyContinue instructs the pod to continue running when the
+ // last container has exited.
+ PodExitPolicyContinue PodExitPolicy = "continue"
+ // PodExitPolicyStop instructs the pod to stop when the last container
+ // has exited.
+ PodExitPolicyStop = "stop"
+ // PodExitPolicyUnsupported implies an internal error.
+ // Negative for backwards compat.
+ PodExitPolicyUnsupported = "invalid"
+
+ defaultPodExitPolicy = PodExitPolicyContinue
+)
+
+// ParsePodExitPolicy parses the specified policy and returns an error if it is
+// invalid.
+func ParsePodExitPolicy(policy string) (PodExitPolicy, error) {
+ switch policy {
+ case "", string(PodExitPolicyContinue):
+ return PodExitPolicyContinue, nil
+ case string(PodExitPolicyStop):
+ return PodExitPolicyStop, nil
+ default:
+ return PodExitPolicyUnsupported, fmt.Errorf("invalid pod exit policy: %q", policy)
+ }
+}

pkg/config/pod_exit_policy_test.go

@@ -0,0 +1,33 @@
+package config
+
+import (
+ "testing"
+
+ "github.com/stretchr/testify/require"
+)
+
+func TestParsePodExitPolicy(t *testing.T) {
+ tests := []struct {
+ input string
+ expected PodExitPolicy
+ mustFail bool
+ }{
+ {"", PodExitPolicyContinue, false},
+ {"continue", PodExitPolicyContinue, false},
+ {"stop", PodExitPolicyStop, false},
+ {"-", PodExitPolicyUnsupported, true},
+ {" stop", PodExitPolicyUnsupported, true},
+ {"continue ", PodExitPolicyUnsupported, true},
+ {"invalid", PodExitPolicyUnsupported, true},
+ }
+
+ for _, test := range tests {
+ parsed, err := ParsePodExitPolicy(test.input)
+ require.Equal(t, test.expected, parsed, "%v", test)
+ if test.mustFail {
+ require.Error(t, err, "%v", test)
+ } else {
+ require.NoError(t, err, "%v", test)
+ }
+ }
+}

pkg/config/testdata/containers_override.conf

@@ -11,6 +11,7 @@ image_default_format="v2s2"
 image_copy_tmp_dir="/tmp/foobar"
 events_logfile_path = "/tmp/events.log"
 events_logfile_max_size="500"
+pod_exit_policy="stop"
 
 [secrets]
 driver = "pass"