podman pod create --uts support

add support for the --uts flag in pod create, allowing users to avoid
issues with default values in containers.conf.

uts follows the same format as other namespace flags:
--uts=private (default), --uts=host, --uts=ns:PATH

resolves #13714

Signed-off-by: Charlie Doern <cdoern@redhat.com>

15 files changed, 165 insertions, 37 deletions

diff --git a/cmd/podman/common/create.go b/cmd/podman/common/create.go
index f05549a8d..c1a744011 100644
--- a/cmd/podman/common/create.go
+++ b/cmd/podman/common/create.go
@@ -544,13 +544,6 @@ func DefineCreateFlags(cmd *cobra.Command, cf *entities.ContainerCreateOptions,
 		)
 		_ = cmd.RegisterFlagCompletionFunc(userFlagName, AutocompleteUserFlag)
 
-		utsFlagName := "uts"
-		createFlags.String(
-			utsFlagName, "",
-			"UTS namespace to use",
-		)
-		_ = cmd.RegisterFlagCompletionFunc(utsFlagName, AutocompleteNamespace)
-
 		mountFlagName := "mount"
 		createFlags.StringArrayVar(
 			&cf.Mount,
@@ -684,6 +677,14 @@ func DefineCreateFlags(cmd *cobra.Command, cf *entities.ContainerCreateOptions,
 		)
 		_ = cmd.RegisterFlagCompletionFunc(usernsFlagName, AutocompleteUserNamespace)
 
+		utsFlagName := "uts"
+		createFlags.StringVar(
+			&cf.UTS,
+			utsFlagName, "",
+			"UTS namespace to use",
+		)
+		_ = cmd.RegisterFlagCompletionFunc(utsFlagName, AutocompleteNamespace)
+
 		cgroupParentFlagName := "cgroup-parent"
 		createFlags.StringVar(
 			&cf.CgroupParent,
diff --git a/cmd/podman/containers/create.go b/cmd/podman/containers/create.go
index 05a59ce7b..7d0f4d9ae 100644
--- a/cmd/podman/containers/create.go
+++ b/cmd/podman/containers/create.go
@@ -224,7 +224,6 @@ func CreateInit(c *cobra.Command, vals entities.ContainerCreateOptions, isInfra
 			return vals, errors.New("--cpu-quota and --cpus cannot be set together")
 		}
 		vals.IPC = c.Flag("ipc").Value.String()
-		vals.UTS = c.Flag("uts").Value.String()
 		vals.PID = c.Flag("pid").Value.String()
 		vals.CgroupNS = c.Flag("cgroupns").Value.String()
 
diff --git a/cmd/podman/pods/create.go b/cmd/podman/pods/create.go
index 45ad2dfd0..aea8a7229 100644
--- a/cmd/podman/pods/create.go
+++ b/cmd/podman/pods/create.go
@@ -277,6 +277,7 @@ func create(cmd *cobra.Command, args []string) error {
 		if err != nil {
 			return err
 		}
+
 		podSpec.Volumes = podSpec.InfraContainerSpec.Volumes
 		podSpec.ImageVolumes = podSpec.InfraContainerSpec.ImageVolumes
 		podSpec.OverlayVolumes = podSpec.InfraContainerSpec.OverlayVolumes
diff --git a/docs/source/markdown/podman-pod-clone.1.md b/docs/source/markdown/podman-pod-clone.1.md
index a18f7dbfe..d90d1efb9 100644
--- a/docs/source/markdown/podman-pod-clone.1.md
+++ b/docs/source/markdown/podman-pod-clone.1.md
@@ -211,6 +211,15 @@ Valid _mode_ values are:
 
   - *nomap*: creates a user namespace where the current rootless user's UID:GID are not mapped into the container. This option is ignored for containers created by the root user.
 
+#### **--uts**=*mode*
+
+Set the UTS namespace mode for the pod. The following values are supported:
+
+- **host**: use the host's UTS namespace inside the pod.
+- **private**: create a new namespace for the pod (default).
+- **ns:[path]**: run the pod in the given existing UTS namespace.
+
+
 #### **--volume**, **-v**[=*[[SOURCE-VOLUME|HOST-DIR:]CONTAINER-DIR[:OPTIONS]]*]
 
 Create a bind mount. If ` -v /HOST-DIR:/CONTAINER-DIR` is specified, Podman
diff --git a/docs/source/markdown/podman-pod-create.1.md b/docs/source/markdown/podman-pod-create.1.md
index 75d2bb611..53d1e3327 100644
--- a/docs/source/markdown/podman-pod-create.1.md
+++ b/docs/source/markdown/podman-pod-create.1.md
@@ -381,6 +381,14 @@ Valid _mode_ values are:
 
   - *nomap*: creates a user namespace where the current rootless user's UID:GID are not mapped into the container. This option is not allowed for containers created by the root user.
 
+#### **--uts**=*mode*
+
+Set the UTS namespace mode for the pod. The following values are supported:
+
+- **host**: use the host's UTS namespace inside the pod.
+- **private**: create a new namespace for the pod (default).
+- **ns:[path]**: run the pod in the given existing UTS namespace.
+
 #### **--volume**, **-v**[=*[[SOURCE-VOLUME|HOST-DIR:]CONTAINER-DIR[:OPTIONS]]*]
 
 Create a bind mount. If you specify, ` -v /HOST-DIR:/CONTAINER-DIR`, Podman
diff --git a/libpod/container.go b/libpod/container.go
index 0619471b4..1e2dad3f3 100644
--- a/libpod/container.go
+++ b/libpod/container.go
@@ -1336,3 +1336,52 @@ func (c *Container) getNetworkStatus() map[string]types.StatusBlock {
 	}
 	return nil
 }
+
+func (c *Container) NamespaceMode(ns spec.LinuxNamespaceType, ctrSpec *spec.Spec) string {
+	switch ns {
+	case spec.UTSNamespace:
+		if c.config.UTSNsCtr != "" {
+			return fmt.Sprintf("container:%s", c.config.UTSNsCtr)
+		}
+	case spec.CgroupNamespace:
+		if c.config.CgroupNsCtr != "" {
+			return fmt.Sprintf("container:%s", c.config.CgroupNsCtr)
+		}
+	case spec.IPCNamespace:
+		if c.config.IPCNsCtr != "" {
+			return fmt.Sprintf("container:%s", c.config.IPCNsCtr)
+		}
+	case spec.PIDNamespace:
+		if c.config.PIDNsCtr != "" {
+			return fmt.Sprintf("container:%s", c.config.PIDNsCtr)
+		}
+	case spec.UserNamespace:
+		if c.config.UserNsCtr != "" {
+			return fmt.Sprintf("container:%s", c.config.UserNsCtr)
+		}
+	case spec.NetworkNamespace:
+		if c.config.NetNsCtr != "" {
+			return fmt.Sprintf("container:%s", c.config.NetNsCtr)
+		}
+	case spec.MountNamespace:
+		if c.config.MountNsCtr != "" {
+			return fmt.Sprintf("container:%s", c.config.MountNsCtr)
+		}
+	}
+
+	if ctrSpec.Linux != nil {
+		// Locate the spec's given namespace.
+		// If there is none, it's namespace=host.
+		// If there is one and it has a path, it's "ns:".
+		// If there is no path, it's default - the empty string.
+		for _, availableNS := range ctrSpec.Linux.Namespaces {
+			if availableNS.Type == ns {
+				if availableNS.Path != "" {
+					return fmt.Sprintf("ns:%s", availableNS.Path)
+				}
+				return "private"
+			}
+		}
+	}
+	return "host"
+}
diff --git a/libpod/container_inspect.go b/libpod/container_inspect.go
index 93240812d..7ccd9fdbf 100644
--- a/libpod/container_inspect.go
+++ b/libpod/container_inspect.go
@@ -794,28 +794,8 @@ func (c *Container) generateInspectContainerHostConfig(ctrSpec *spec.Spec, named
 	hostConfig.PidMode = pidMode
 
 	// UTS namespace mode
-	utsMode := ""
-	if c.config.UTSNsCtr != "" {
-		utsMode = fmt.Sprintf("container:%s", c.config.UTSNsCtr)
-	} else if ctrSpec.Linux != nil {
-		// Locate the spec's UTS namespace.
-		// If there is none, it's uts=host.
-		// If there is one and it has a path, it's "ns:".
-		// If there is no path, it's default - the empty string.
-		for _, ns := range ctrSpec.Linux.Namespaces {
-			if ns.Type == spec.UTSNamespace {
-				if ns.Path != "" {
-					utsMode = fmt.Sprintf("ns:%s", ns.Path)
-				} else {
-					utsMode = "private"
-				}
-				break
-			}
-		}
-		if utsMode == "" {
-			utsMode = "host"
-		}
-	}
+	utsMode := c.NamespaceMode(spec.UTSNamespace, ctrSpec)
+
 	hostConfig.UTSMode = utsMode
 
 	// User namespace mode
diff --git a/libpod/define/pod_inspect.go b/libpod/define/pod_inspect.go
index 935e0f5f9..2afef48c4 100644
--- a/libpod/define/pod_inspect.go
+++ b/libpod/define/pod_inspect.go
@@ -122,6 +122,8 @@ type InspectPodInfraConfig struct {
 	PidNS string `json:"pid_ns,omitempty"`
 	// UserNS is the usernamespace that all the containers in the pod will join.
 	UserNS string `json:"userns,omitempty"`
+	// UtsNS is the uts namespace that all containers in the pod will join
+	UtsNS string `json:"uts_ns,omitempty"`
 }
 
 // InspectPodContainerInfo contains information on a container in a pod.
diff --git a/libpod/pod_api.go b/libpod/pod_api.go
index f06e62007..29dc22890 100644
--- a/libpod/pod_api.go
+++ b/libpod/pod_api.go
@@ -676,6 +676,7 @@ func (p *Pod) Inspect() (*define.InspectPodData, error) {
 		infraConfig.CPUSetCPUs = p.ResourceLim().CPU.Cpus
 		infraConfig.PidNS = p.NamespaceMode(specs.PIDNamespace)
 		infraConfig.UserNS = p.NamespaceMode(specs.UserNamespace)
+		infraConfig.UtsNS = p.NamespaceMode(specs.UTSNamespace)
 		namedVolumes, mounts := infra.SortUserVolumes(infra.config.Spec)
 		inspectMounts, err = infra.GetMounts(namedVolumes, infra.config.ImageVolumes, mounts)
 		infraSecurity = infra.GetSecurityOptions()
diff --git a/pkg/specgen/container_validate.go b/pkg/specgen/container_validate.go
index 5616a4511..e09757d1d 100644
--- a/pkg/specgen/container_validate.go
+++ b/pkg/specgen/container_validate.go
@@ -59,6 +59,7 @@ func (s *SpecGenerator) Validate() error {
 		if s.ContainerBasicConfig.UtsNS.IsPod() {
 			return errors.Wrap(ErrInvalidSpecConfig, "cannot set hostname when joining the pod UTS namespace")
 		}
+
 		return errors.Wrap(ErrInvalidSpecConfig, "cannot set hostname when running in the host UTS namespace")
 	}
 	// systemd values must be true, false, or always
diff --git a/pkg/specgen/generate/container_create.go b/pkg/specgen/generate/container_create.go
index 6b2e90b22..f31e46090 100644
--- a/pkg/specgen/generate/container_create.go
+++ b/pkg/specgen/generate/container_create.go
@@ -133,6 +133,12 @@ func MakeContainer(ctx context.Context, rt *libpod.Runtime, s *specgen.SpecGener
 
 		options = append(options, libpod.WithRootFSFromImage(newImage.ID(), resolvedImageName, s.RawImageName))
 	}
+
+	_, err = rt.LookupPod(s.Hostname)
+	if len(s.Hostname) > 0 && !s.UtsNS.IsPrivate() && err == nil {
+		// ok, we are incorrectly setting the pod as the hostname, lets undo that before validation
+		s.Hostname = ""
+	}
 	if err := s.Validate(); err != nil {
 		return nil, nil, nil, errors.Wrap(err, "invalid config provided")
 	}
diff --git a/pkg/specgen/generate/namespaces.go b/pkg/specgen/generate/namespaces.go
index 4224d16ce..a3719d58e 100644
--- a/pkg/specgen/generate/namespaces.go
+++ b/pkg/specgen/generate/namespaces.go
@@ -176,7 +176,14 @@ func namespaceOptions(s *specgen.SpecGenerator, rt *libpod.Runtime, pod *libpod.
 		if pod == nil || infraCtr == nil {
 			return nil, errNoInfra
 		}
-		toReturn = append(toReturn, libpod.WithUTSNSFrom(infraCtr))
+		if pod.NamespaceMode(spec.UTSNamespace) == host {
+			// adding infra as a nsCtr is not what we want to do when uts == host
+			// this leads the new ctr to try to add an ns path which is should not in this mode
+			logrus.Debug("pod has host uts, not adding infra as a nsCtr")
+			s.UtsNS = specgen.Namespace{NSMode: specgen.Host}
+		} else {
+			toReturn = append(toReturn, libpod.WithUTSNSFrom(infraCtr))
+		}
 	case specgen.FromContainer:
 		utsCtr, err := rt.LookupContainer(s.UtsNS.Value)
 		if err != nil {
diff --git a/pkg/specgen/generate/pod_create.go b/pkg/specgen/generate/pod_create.go
index 4ac8a0aa2..59936c7a8 100644
--- a/pkg/specgen/generate/pod_create.go
+++ b/pkg/specgen/generate/pod_create.go
@@ -60,6 +60,7 @@ func MakePod(p *entities.PodSpec, rt *libpod.Runtime) (*libpod.Pod, error) {
 		if err != nil {
 			return nil, err
 		}
+
 		spec.Pod = pod.ID()
 		opts = append(opts, rt.WithPod(pod))
 		spec.CgroupParent = pod.CgroupParent()
diff --git a/test/e2e/pod_clone_test.go b/test/e2e/pod_clone_test.go
index b90bf10da..0a1d2358c 100644
--- a/test/e2e/pod_clone_test.go
+++ b/test/e2e/pod_clone_test.go
@@ -11,9 +11,10 @@ import (
 
 var _ = Describe("Podman pod clone", func() {
 	var (
-		tempdir    string
-		err        error
-		podmanTest *PodmanTestIntegration
+		tempdir     string
+		err         error
+		podmanTest  *PodmanTestIntegration
+		hostname, _ = os.Hostname()
 	)
 
 	BeforeEach(func() {
@@ -155,4 +156,39 @@ var _ = Describe("Podman pod clone", func() {
 		Expect(strings[0]).Should(ContainSubstring("size=10240k"))
 	})
 
+	It("podman pod create --uts test", func() {
+		SkipIfRemote("hostname for the custom NS test is not as expected on the remote client")
+
+		session := podmanTest.Podman([]string{"pod", "create"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+
+		session = podmanTest.Podman([]string{"pod", "clone", "--uts", "host", session.OutputToString()})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+
+		session = podmanTest.Podman([]string{"run", "-it", "--pod", session.OutputToString(), ALPINE, "printenv", "HOSTNAME"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		Expect(session.OutputToString()).To(ContainSubstring(hostname))
+
+		podName := "utsPod"
+		ns := "ns:/proc/self/ns/"
+
+		session = podmanTest.Podman([]string{"pod", "create"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+
+		// just share uts with a custom path
+		podCreate := podmanTest.Podman([]string{"pod", "clone", "--uts", ns, "--name", podName, session.OutputToString()})
+		podCreate.WaitWithDefaultTimeout()
+		Expect(podCreate).Should(Exit(0))
+
+		podInspect := podmanTest.Podman([]string{"pod", "inspect", podName})
+		podInspect.WaitWithDefaultTimeout()
+		Expect(podInspect).Should(Exit(0))
+		podJSON := podInspect.InspectPodToJSON()
+		Expect(podJSON.InfraConfig).To(HaveField("UtsNS", ns))
+	})
+
 })
diff --git a/test/e2e/pod_create_test.go b/test/e2e/pod_create_test.go
index e463862f5..4effc98ca 100644
--- a/test/e2e/pod_create_test.go
+++ b/test/e2e/pod_create_test.go
@@ -23,9 +23,10 @@ import (
 
 var _ = Describe("Podman pod create", func() {
 	var (
-		tempdir    string
-		err        error
-		podmanTest *PodmanTestIntegration
+		tempdir     string
+		err         error
+		podmanTest  *PodmanTestIntegration
+		hostname, _ = os.Hostname()
 	)
 
 	BeforeEach(func() {
@@ -1136,4 +1137,30 @@ ENTRYPOINT ["sleep","99999"]
 		Expect(run).ShouldNot(Exit(0))
 	})
 
+	It("podman pod create --uts test", func() {
+		session := podmanTest.Podman([]string{"pod", "create", "--uts", "host"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+
+		session = podmanTest.Podman([]string{"run", "-it", "--pod", session.OutputToString(), ALPINE, "printenv", "HOSTNAME"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		if !IsRemote() { // remote hostname will not match os.Hostname()
+			Expect(session.OutputToString()).To(ContainSubstring(hostname))
+		}
+
+		podName := "utsPod"
+		ns := "ns:/proc/self/ns/"
+
+		// just share uts with a custom path
+		podCreate := podmanTest.Podman([]string{"pod", "create", "--uts", ns, "--name", podName, "--share", "uts"})
+		podCreate.WaitWithDefaultTimeout()
+		Expect(podCreate).Should(Exit(0))
+
+		podInspect := podmanTest.Podman([]string{"pod", "inspect", podName})
+		podInspect.WaitWithDefaultTimeout()
+		Expect(podInspect).Should(Exit(0))
+		podJSON := podInspect.InspectPodToJSON()
+		Expect(podJSON.InfraConfig).To(HaveField("UtsNS", ns))
+	})
 })