Add support for pids-limit annotation for podman kube play.

This commit adds new annotation called:

io.podman.annotations.pids-limit/$ctrname

This annotation is used to define the PIDsLimit for
a particular pod. It is also automatically defined
when newly added --pids-limit option is used.

Fixes: #24418

Signed-off-by: Jan Kaluza <jkaluza@redhat.com>

docs/source/markdown/podman-kube-play.1.md.in

@@ -55,6 +55,8 @@ by `podman kube play` to create them.
 
 Note: To customize the name of the infra container created during `podman kube play`, use the **io.podman.annotations.infra.name** annotation in the pod definition. This annotation is automatically set when generating a kube yaml from a pod that was created with the `--infra-name` flag set.
 
+Note: Use the **io.podman.annotations.pids-limit/$ctrname** annotation to configure the pod's pids limit.
+
 `Kubernetes PersistentVolumeClaims`
 
 A Kubernetes PersistentVolumeClaim represents a Podman named volume. Only the PersistentVolumeClaim name is required by Podman to create a volume. Kubernetes annotations can be used to make use of the available options for Podman volumes.

libpod/define/annotations.go

@@ -169,6 +169,9 @@ const (
 	// KubeImageAutomountAnnotation
 	KubeImageAutomountAnnotation = "io.podman.annotations.kube.image.volumes.mount"
 
+	// PIDsLimitAnnotation is used to limit the number of PIDs
+	PIDsLimitAnnotation = "io.podman.annotations.pids-limit"
+
 	// TotalAnnotationSizeLimitB is the max length of annotations allowed by Kubernetes.
 	TotalAnnotationSizeLimitB int = 256 * (1 << 10) // 256 kB
 )

pkg/specgen/generate/kube/kube.go

@@ -375,6 +375,20 @@ func ToSpecGen(ctx context.Context, opts *CtrSpecGenOptions) (*specgen.SpecGener
 		s.Annotations[define.InspectAnnotationApparmor] = apparmor
 	}
 
+	if pidslimit, ok := annotations[define.PIDsLimitAnnotation+"/"+opts.Container.Name]; ok {
+		s.Annotations[define.PIDsLimitAnnotation] = pidslimit
+		pidslimitAsInt, err := strconv.ParseInt(pidslimit, 10, 0)
+		if err != nil {
+			return nil, err
+		}
+		if s.ResourceLimits == nil {
+			s.ResourceLimits = &spec.LinuxResources{}
+		}
+		s.ResourceLimits.Pids = &spec.LinuxPids{
+			Limit: pidslimitAsInt,
+		}
+	}
+
 	if label, ok := opts.Annotations[define.InspectAnnotationLabel+"/"+opts.Container.Name]; ok {
 		if label == "nested" {
 			s.ContainerSecurityConfig.LabelNested = &localTrue

pkg/specgenutil/specgen.go

@@ -527,6 +527,10 @@ func FillOutSpecGen(s *specgen.SpecGenerator, c *entities.ContainerCreateOptions
 		s.Annotations[define.UserNsAnnotation] = c.UserNS
 	}
 
+	if c.PIDsLimit != nil {
+		s.Annotations[define.PIDsLimitAnnotation] = strconv.FormatInt(*c.PIDsLimit, 10)
+	}
+
 	if len(c.StorageOpts) > 0 {
 		opts := make(map[string]string, len(c.StorageOpts))
 		for _, opt := range c.StorageOpts {

test/e2e/play_kube_test.go

@@ -6180,4 +6180,18 @@ spec:
 		Expect(execArr[len(execArr)-1]).To(Not(ContainSubstring(arr[len(arr)-1])))
 	})
 
+	It("test pids-limit annotation", func() {
+		ctrAnnotation := "io.podman.annotations.pids-limit/" + defaultCtrName
+		pod := getPod(withAnnotation(ctrAnnotation, "10"), withPodInitCtr(getCtr(withImage(CITEST_IMAGE), withCmd([]string{"printenv", "container"}), withInitCtr(), withName("init-test"))), withCtr(getCtr(withImage(CITEST_IMAGE), withCmd([]string{"top"}))))
+		err := generateKubeYaml("pod", pod, kubeYaml)
+		Expect(err).ToNot(HaveOccurred())
+
+		kube := podmanTest.Podman([]string{"kube", "play", kubeYaml})
+		kube.WaitWithDefaultTimeout()
+		Expect(kube).Should(ExitCleanly())
+
+		exec := podmanTest.PodmanExitCleanly("exec", "testPod-"+defaultCtrName, "cat", "/sys/fs/cgroup/pids.max")
+		Expect(exec.OutputToString()).To(Equal("10"))
+	})
+
 })