Add --no-hostname option

Fixes: containers#25002

Also add the ability to inspect containers for
UseImageHosts and UseImageHostname.

Finally fixed some bugs in handling of --no-hosts for Pods,
which I descovered.

Signed-off-by: Daniel J Walsh <[email protected]>

Author: rhatdan

cmd/podman/common/netflags.go

@@ -95,6 +95,10 @@ func DefineNetFlags(cmd *cobra.Command) {
 	)
 	_ = cmd.RegisterFlagCompletionFunc(publishFlagName, completion.AutocompleteNone)
 
+	netFlags.Bool(
+		"no-hostname", false, "Do not create /etc/hostname within the container, instead use the version from the image",
+	)
+
 	netFlags.Bool(
 		"no-hosts", podmanConfig.ContainersConfDefaultsRO.Containers.NoHosts,
 		"Do not create /etc/hosts within the container, instead use the version from the image",
@@ -192,6 +196,11 @@ func NetFlagsToNetOptions(opts *entities.NetOptions, flags pflag.FlagSet) (*enti
 		}
 	}
 
+	opts.NoHostname, err = flags.GetBool("no-hostname")
+	if err != nil {
+		return nil, err
+	}
+
 	opts.NoHosts, err = flags.GetBool("no-hosts")
 	if err != nil {
 		return nil, err

cmd/podman/kube/play.go

@@ -98,6 +98,7 @@ func init() {
 func playFlags(cmd *cobra.Command) {
 	flags := cmd.Flags()
 	flags.SetNormalizeFunc(utils.AliasFlags)
+	podmanConfig := registry.PodmanConfig()
 
 	annotationFlagName := "annotation"
 	flags.StringArrayVar(
@@ -139,7 +140,8 @@ func playFlags(cmd *cobra.Command) {
 	)
 	_ = cmd.RegisterFlagCompletionFunc(usernsFlagName, common.AutocompleteUserNamespace)
 
-	flags.BoolVar(&playOptions.NoHosts, "no-hosts", false, "Do not create /etc/hosts within the pod's containers, instead use the version from the image")
+	flags.BoolVar(&playOptions.NoHostname, "no-hostname", false, "Do not create /etc/hostname within the container, instead use the version from the image")
+	flags.BoolVar(&playOptions.NoHosts, "no-hosts", podmanConfig.ContainersConfDefaultsRO.Containers.NoHosts, "Do not create /etc/hosts within the pod's containers, instead use the version from the image")
 	flags.BoolVarP(&playOptions.Quiet, "quiet", "q", false, "Suppress output information when pulling images")
 	flags.BoolVar(&playOptions.TLSVerifyCLI, "tls-verify", true, "Require HTTPS and verify certificates when contacting registries")
 	flags.BoolVar(&playOptions.StartCLI, "start", true, "Start the pod after creating it")

docs/source/markdown/options/no-hostname.md

@@ -1,9 +1,9 @@
 ####> This option file is used in:
-####>   podman build, farm build
+####>   podman build, create, farm build, kube play, pod create, run
 ####> If file is edited, make sure the changes
 ####> are applicable to all of those.
 #### **--no-hostname**
 
-Do not create the _/etc/hostname_ file in the container for RUN instructions.
+Do not create the _/etc/hostname_ file in the containers.
 
-By default, Buildah manages the _/etc/hostname_ file, adding the container's own hostname.  When the **--no-hostname** option is set, the image's _/etc/hostname_ will be preserved unmodified if it exists.
+By default, Podman manages the _/etc/hostname_ file, adding the container's own hostname.  When the **--no-hostname** option is set, the image's _/etc/hostname_ will be preserved unmodified if it exists.

docs/source/markdown/podman-container-inspect.1.md.in

@@ -62,6 +62,10 @@ Valid placeholders for the Go template are listed below:
 | .SizeRw                  | Size of upper (R/W) container layer, in bytes [1]  |
 | .State ...               | Container state info (struct)                      |
 | .StaticDir               | Path to container metadata dir (string)            |
+| .UseImageHostname        | Use /etc/hostname from the image if it exists? (string: true/false)
+|
+| .UseImageHosts           | Use /etc/hosts from the image? (string: true/false)
+|
 
 [1] This format specifier requires the **--size** option
 

docs/source/markdown/podman-create.1.md.in

@@ -268,6 +268,8 @@ If used together with **--pod**, the container does not join the pod's network n
 
 @@option no-healthcheck
 
+@@option no-hostname
+
 @@option no-hosts
 
 This option conflicts with **--add-host**.

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

@@ -228,6 +228,8 @@ Note: When joining multiple networks use the **--network name:mac=\<mac\>** synt
 
 When no network option is specified and *host* network mode is not configured in the YAML file, a new network stack is created and pods are attached to it making possible pod to pod communication.
 
+@@option no-hostname
+
 @@option no-hosts
 
 This option conflicts with host added in the Kubernetes YAML.

docs/source/markdown/podman-pod-create.1.md.in

@@ -128,6 +128,8 @@ Invalid if using **--dns**, **--dns-option**, or **--dns-search** with **--netwo
 
 @@option network-alias
 
+@@option no-hostname
+
 @@option no-hosts
 
 This option conflicts with **--add-host**.

docs/source/markdown/podman-run.1.md.in

@@ -287,6 +287,8 @@ If used together with **--pod**, the container joins the pod's network namespace
 
 @@option no-healthcheck
 
+@@option no-hostname
+
 @@option no-hosts
 
 This option conflicts with **--add-host**.

libpod/container_config.go

@@ -286,6 +286,9 @@ type ContainerNetworkConfig struct {
 	// DNS options to be set in container resolv.conf
 	// With override options in host resolv if set
 	DNSOption []string `json:"dnsOption,omitempty"`
+	// UseImageHostname indicates that /etc/hostname should not be
+	// bind-mounted inside the container.
+	UseImageHostname bool
 	// UseImageHosts indicates that /etc/hosts should not be
 	// bind-mounted inside the container.
 	// Conflicts with HostAdd.
@@ -472,6 +475,8 @@ type InfraInherit struct {
 	Volumes            []*specgen.NamedVolume   `json:"volumes,omitempty"`
 	ShmSize            *int64                   `json:"shm_size"`
 	ShmSizeSystemd     *int64                   `json:"shm_size_systemd"`
+	UseImageHosts      bool                     `json:"use_image_hosts"`
+	UseImageHostname   bool                     `json:"use_image_hostname"`
 }
 
 // IsDefaultShmSize determines if the user actually set the shm in the parent ctr or if it has been set to the default size

libpod/container_inspect.go

@@ -171,6 +171,8 @@ func (c *Container) getContainerInspectData(size bool, driverData *define.Driver
 		IsService:               c.IsService(),
 		KubeExitCodePropagation: config.KubeExitCodePropagation.String(),
 		LockNumber:              c.lock.ID(),
+		UseImageHosts:           c.config.UseImageHosts,
+		UseImageHostname:        c.config.UseImageHostname,
 	}
 
 	if config.RootfsImageID != "" { // May not be set if the container was created with --rootfs

libpod/container_internal_linux.go

@@ -689,6 +689,10 @@ func setVolumeAtime(mountPoint string, st os.FileInfo) error {
 }
 
 func (c *Container) makePlatformBindMounts() error {
+	if c.config.UseImageHostname {
+		return nil
+	}
+
 	// Make /etc/hostname
 	// This should never change, so no need to recreate if it exists
 	if _, ok := c.state.BindMounts["/etc/hostname"]; !ok {

libpod/define/container_inspect.go

@@ -798,6 +798,8 @@ type InspectContainerData struct {
 	LockNumber              uint32                      `json:"lockNumber"`
 	Config                  *InspectContainerConfig     `json:"Config"`
 	HostConfig              *InspectContainerHostConfig `json:"HostConfig"`
+	UseImageHosts           bool                        `json:"UseImageHosts"`
+	UseImageHostname        bool                        `json:"UseImageHostname"`
 }
 
 // InspectExecSession contains information about a given exec session.

libpod/define/pod_inspect.go

@@ -118,6 +118,9 @@ type InspectPodInfraConfig struct {
 	// DNSOption is a set of DNS options that will be used by the infra
 	// container's resolv.conf and shared with the remainder of the pod.
 	DNSOption []string
+	// NoManageHostname indicates that the pod will not manage /etc/hostname
+	// and instead each container will handle their own.
+	NoManageHostname bool
 	// NoManageHosts indicates that the pod will not manage /etc/hosts and
 	// instead each container will handle their own.
 	NoManageHosts bool

libpod/options.go

@@ -1389,6 +1389,19 @@ func WithUseImageResolvConf() CtrCreateOption {
 	}
 }
 
+// WithUseImageHostname tells the container not to bind-mount /etc/hostname in.
+func WithUseImageHostname() CtrCreateOption {
+	return func(ctr *Container) error {
+		if ctr.valid {
+			return define.ErrCtrFinalized
+		}
+
+		ctr.config.UseImageHostname = true
+
+		return nil
+	}
+}
+
 // WithUseImageHosts tells the container not to bind-mount /etc/hosts in.
 // This conflicts with WithHosts().
 func WithUseImageHosts() CtrCreateOption {

libpod/pod_api.go

@@ -677,6 +677,7 @@ func (p *Pod) Inspect() (*define.InspectPodData, error) {
 		infraConfig.HostNetwork = p.NetworkMode() == "host"
 		infraConfig.StaticIP = infra.config.ContainerNetworkConfig.StaticIP
 		infraConfig.NoManageResolvConf = infra.config.UseImageResolvConf
+		infraConfig.NoManageHostname = infra.config.UseImageHostname
 		infraConfig.NoManageHosts = infra.config.UseImageHosts
 		infraConfig.CPUPeriod = p.CPUPeriod()
 		infraConfig.CPUQuota = p.CPUQuota()

pkg/api/handlers/libpod/kube.go

@@ -109,6 +109,7 @@ func KubePlay(w http.ResponseWriter, r *http.Request) {
 		LogDriver        string            `schema:"logDriver"`
 		LogOptions       []string          `schema:"logOptions"`
 		Network          []string          `schema:"network"`
+		NoHostname       bool              `schema:"noHostname"`
 		NoHosts          bool              `schema:"noHosts"`
 		NoTrunc          bool              `schema:"noTrunc"`
 		Replace          bool              `schema:"replace"`
@@ -182,6 +183,7 @@ func KubePlay(w http.ResponseWriter, r *http.Request) {
 		LogDriver:          logDriver,
 		LogOptions:         query.LogOptions,
 		Networks:           query.Network,
+		NoHostname:         query.NoHostname,
 		NoHosts:            query.NoHosts,
 		Password:           password,
 		PublishPorts:       query.PublishPorts,

pkg/bindings/kube/types.go

@@ -20,6 +20,8 @@ type PlayOptions struct {
 	Password *string
 	// Network - name of the networks to connect to.
 	Network *[]string
+	// NoHostname - do not generate /etc/hostname file in pod's containers
+	NoHostname *bool
 	// NoHosts - do not generate /etc/hosts file in pod's containers
 	NoHosts *bool
 	// Quiet - suppress output when pulling images.

pkg/bindings/kube/types_play_options.go

@@ -27,6 +27,9 @@ type PlayKubeOptions struct {
 	ExitCodePropagation string
 	// Replace indicates whether to delete and recreate a yaml file
 	Replace bool
+	// Do not create /etc/hostname within the pod's containers,
+	// instead use the version from the image
+	NoHostname bool
 	// Do not create /etc/hosts within the pod's containers,
 	// instead use the version from the image
 	NoHosts bool

pkg/domain/entities/play.go

@@ -367,6 +367,7 @@ func ToPodSpecGen(s specgen.PodSpecGenerator, p *PodCreateOptions) (*specgen.Pod
 		s.DNSSearch = p.Net.DNSSearch
 		s.DNSOption = p.Net.DNSOptions
 		s.NoManageHosts = p.Net.NoHosts
+		s.NoManageHostname = p.Net.NoHostname
 		s.HostAdd = p.Net.AddHosts
 		s.HostsFile = p.Net.HostsFile
 	}

pkg/domain/entities/pods.go

@@ -40,6 +40,7 @@ type NetFlags struct {
 	MacAddr      string   `json:"mac-address,omitempty"`
 	Publish      []string `json:"publish,omitempty"`
 	IP           string   `json:"ip,omitempty"`
+	NoHostname   bool     `json:"no-hostname,omitempty"`
 	NoHosts      bool     `json:"no-hosts,omitempty"`
 	Network      string   `json:"network,omitempty"`
 	NetworkAlias []string `json:"network-alias,omitempty"`
@@ -57,6 +58,7 @@ type NetOptions struct {
 	DNSServers         []net.IP                           `json:"dns_server,omitempty"`
 	HostsFile          string                             `json:"hosts_file,omitempty"`
 	Network            specgen.Namespace                  `json:"netns,omitempty"`
+	NoHostname         bool                               `json:"no_manage_hostname,omitempty"`
 	NoHosts            bool                               `json:"no_manage_hosts,omitempty"`
 	PublishPorts       []types.PortMapping                `json:"portmappings,omitempty"`
 	// NetworkOptions are additional options for each network

pkg/domain/entities/types.go

@@ -625,7 +625,7 @@ func (ic *ContainerEngine) playKubePod(ctx context.Context, podName string, podY
 
 	podOpt := entities.PodCreateOptions{
 		Infra:      true,
-		Net:        &entities.NetOptions{NoHosts: options.NoHosts},
+		Net:        &entities.NetOptions{NoHosts: options.NoHosts, NoHostname: options.NoHostname},
 		ExitPolicy: string(config.PodExitPolicyStop),
 	}
 	podOpt, err = kube.ToPodOpt(ctx, podName, podOpt, options.PublishAllPorts, podYAML)

pkg/domain/infra/abi/play.go

@@ -65,7 +65,7 @@ func (ic *ContainerEngine) PlayKube(ctx context.Context, body io.Reader, opts en
 	if opts.Annotations != nil {
 		options.WithAnnotations(opts.Annotations)
 	}
-	options.WithNoHosts(opts.NoHosts).WithUserns(opts.Userns)
+	options.WithNoHostname(opts.NoHostname).WithNoHosts(opts.NoHosts).WithUserns(opts.Userns)
 	if s := opts.SkipTLSVerify; s != types.OptionalBoolUndefined {
 		options.WithSkipTLSVerify(s == types.OptionalBoolTrue)
 	}

pkg/domain/infra/tunnel/kube.go

@@ -495,6 +495,8 @@ func ConfigToSpec(rt *libpod.Runtime, specg *specgen.SpecGenerator, containerID
 	specg.Networks = conf.Networks
 	specg.ShmSize = &conf.ShmSize
 	specg.ShmSizeSystemd = &conf.ShmSizeSystemd
+	specg.UseImageHostname = &conf.UseImageHostname
+	specg.UseImageHosts = &conf.UseImageHosts
 
 	mapSecurityConfig(conf, specg)
 

pkg/specgen/generate/container.go

@@ -42,7 +42,7 @@ import (
 )
 
 func ToPodOpt(ctx context.Context, podName string, p entities.PodCreateOptions, publishAllPorts bool, podYAML *v1.PodTemplateSpec) (entities.PodCreateOptions, error) {
-	p.Net = &entities.NetOptions{NoHosts: p.Net.NoHosts}
+	p.Net = &entities.NetOptions{NoHosts: p.Net.NoHosts, NoHostname: p.Net.NoHostname}
 
 	p.Name = podName
 	p.Labels = podYAML.ObjectMeta.Labels

pkg/specgen/generate/kube/kube.go

@@ -366,6 +366,9 @@ func namespaceOptions(s *specgen.SpecGenerator, rt *libpod.Runtime, pod *libpod.
 	} else if len(s.HostAdd) > 0 {
 		toReturn = append(toReturn, libpod.WithHosts(s.HostAdd))
 	}
+	if s.UseImageHostname != nil && *s.UseImageHostname {
+		toReturn = append(toReturn, libpod.WithUseImageHostname())
+	}
 	if len(s.DNSSearch) > 0 {
 		toReturn = append(toReturn, libpod.WithDNSSearch(s.DNSSearch))
 	}

pkg/specgen/generate/namespaces.go

@@ -272,6 +272,9 @@ func MapSpec(p *specgen.PodSpecGenerator) (*specgen.SpecGenerator, error) {
 	if p.NoManageHosts {
 		spec.UseImageHosts = &p.NoManageHosts
 	}
+	if p.NoManageHostname {
+		spec.UseImageHostname = &p.NoManageHostname
+	}
 
 	if len(p.InfraConmonPidFile) > 0 {
 		spec.ConmonPidFile = p.InfraConmonPidFile

pkg/specgen/generate/pod_create.go

@@ -159,6 +159,10 @@ type PodNetworkConfig struct {
 	// Conflicts with NoInfra=true.
 	// Optional.
 	DNSOption []string `json:"dns_option,omitempty"`
+	// NoManageHostname indicates that /etc/hostname should not be managed
+	//  by the pod. Instead, each container will create a separate
+	// /etc/hostname as they would if not in a pod.
+	NoManageHostname bool `json:"no_manage_hostname,omitempty"`
 	// NoManageHosts indicates that /etc/hosts should not be managed by the
 	// pod. Instead, each container will create a separate /etc/hosts as
 	// they would if not in a pod.

pkg/specgen/podspecgen.go

@@ -534,6 +534,10 @@ type ContainerNetworkConfig struct {
 	// Conflicts with UseImageResolvConf.
 	// Optional.
 	DNSOptions []string `json:"dns_option,omitempty"`
+	// UseImageHostname indicates that /etc/hostname should not be managed by
+	// Podman, and instead sourced from the image.
+	// Optional.
+	UseImageHostname *bool `json:"use_image_hostname,omitempty"`
 	// UseImageHosts indicates that /etc/hosts should not be managed by
 	// Podman, and instead sourced from the image.
 	// Conflicts with HostAdd.

pkg/specgen/specgen.go

@@ -593,6 +593,7 @@ func FillOutSpecGen(s *specgen.SpecGenerator, c *entities.ContainerCreateOptions
 		s.DNSSearch = c.Net.DNSSearch
 		s.DNSOptions = c.Net.DNSOptions
 		s.NetworkOptions = c.Net.NetworkOptions
+		s.UseImageHostname = &c.Net.NoHostname
 		s.UseImageHosts = &c.Net.NoHosts
 	}
 	if len(s.HostUsers) == 0 || len(c.HostUsers) != 0 {

pkg/specgenutil/specgen.go

@@ -2384,6 +2384,34 @@ var _ = Describe("Podman kube play", func() {
 		Expect(label).To(ContainSubstring("unconfined_u:system_r:spc_t:s0"))
 	})
 
+	It("--no-hostname", func() {
+		err := writeYaml(checkInfraImagePodYaml, kubeYaml)
+		Expect(err).ToNot(HaveOccurred())
+
+		kube := podmanTest.Podman([]string{"kube", "play", "--no-hostname", kubeYaml})
+		kube.WaitWithDefaultTimeout()
+		Expect(kube).Should(ExitCleanly())
+
+		alpineHostname := podmanTest.Podman([]string{"run", "--rm", "--no-hostname", ALPINE, "cat", "/etc/hostname"})
+		alpineHostname.WaitWithDefaultTimeout()
+		Expect(alpineHostname).Should(ExitCleanly())
+
+		podInspect := podmanTest.Podman([]string{"pod", "inspect", "check-infra-image"})
+		podInspect.WaitWithDefaultTimeout()
+		Expect(podInspect).Should(ExitCleanly())
+
+		data := podInspect.InspectPodToJSON()
+		for _, ctr := range data.Containers {
+			if strings.HasSuffix(ctr.Name, "-infra") {
+				continue
+			}
+			exec := podmanTest.Podman([]string{"exec", ctr.ID, "cat", "/etc/hostname"})
+			exec.WaitWithDefaultTimeout()
+			Expect(exec).Should(ExitCleanly())
+			Expect(exec.OutputToString()).To(Equal(alpineHostname.OutputToString()))
+		}
+	})
+
 	It("--no-host", func() {
 		err := writeYaml(checkInfraImagePodYaml, kubeYaml)
 		Expect(err).ToNot(HaveOccurred())