Add podman play kube --no-hosts options

This option will setup the containers to not modify their /etc/hosts
file and just use the one from the image.

Fixes: https://github.com/containers/podman/issues/9500

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

cmd/podman/play/kube.go

@@ -78,6 +78,7 @@ func init() {
 	flags.StringVar(&kubeOptions.LogDriver, logDriverFlagName, "", "Logging driver for the container")
 	_ = kubeCmd.RegisterFlagCompletionFunc(logDriverFlagName, common.AutocompleteLogDriver)
 
+	flags.BoolVar(&kubeOptions.NoHosts, "no-hosts", false, "Do not create /etc/hosts within the pod's containers, instead use the version from the image")
 	flags.BoolVarP(&kubeOptions.Quiet, "quiet", "q", false, "Suppress output information when pulling images")
 	flags.BoolVar(&kubeOptions.TLSVerifyCLI, "tls-verify", true, "Require HTTPS and verify certificates when contacting registries")
 	flags.BoolVar(&kubeOptions.StartCLI, "start", true, "Start the pod after creating it")

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

@@ -138,6 +138,10 @@ Valid _mode_ values are:
   Note: Rootlesskit changes the source IP address of incoming packets to a IP address in the container network namespace, usually `10.0.2.100`. If your application requires the real source IP address, e.g. web server logs, use the slirp4netns port handler. The rootlesskit port handler is also used for rootless containers when connected to user-defined networks.
   - **port_handler=slirp4netns**: Use the slirp4netns port forwarding, it is slower than rootlesskit but preserves the correct source IP address. This port handler cannot be used for user-defined networks.
 
+#### **--no-hosts**
+
+Do not create /etc/hosts within the pod's containers, instead use the version from the image
+
 #### **--quiet**, **-q**
 
 Suppress output information when pulling images

pkg/api/handlers/libpod/play.go

@@ -29,6 +29,7 @@ func PlayKube(w http.ResponseWriter, r *http.Request) {
 		Start      bool     `schema:"start"`
 		StaticIPs  []string `schema:"staticIPs"`
 		StaticMACs []string `schema:"staticMACs"`
+		NoHosts    bool     `schema:"noHosts"`
 	}{
 		TLSVerify: true,
 		Start:     true,
@@ -102,6 +103,7 @@ func PlayKube(w http.ResponseWriter, r *http.Request) {
 		Username:   username,
 		Password:   password,
 		Network:    query.Network,
+		NoHosts:    query.NoHosts,
 		Quiet:      true,
 		LogDriver:  query.LogDriver,
 		StaticIPs:  staticIPs,

pkg/bindings/play/play.go

@@ -6,11 +6,10 @@ import (
 	"os"
 	"strconv"
 
-	"github.com/sirupsen/logrus"
-
 	"github.com/containers/podman/v3/pkg/auth"
 	"github.com/containers/podman/v3/pkg/bindings"
 	"github.com/containers/podman/v3/pkg/domain/entities"
+	"github.com/sirupsen/logrus"
 )
 
 func Kube(ctx context.Context, path string, options *KubeOptions) (*entities.PlayKubeReport, error) {

pkg/bindings/play/types.go

@@ -17,6 +17,8 @@ type KubeOptions struct {
 	Password *string
 	// Network - name of the CNI network to connect to.
 	Network *string
+	// NoHosts - do not generate /etc/hosts file in pod's containers
+	NoHosts *bool
 	// Quiet - suppress output when pulling images.
 	Quiet *bool
 	// SignaturePolicy - path to a signature-policy file.

pkg/bindings/play/types_kube_options.go

@@ -93,6 +93,21 @@ func (o *KubeOptions) GetNetwork() string {
 	return *o.Network
 }
 
+// WithNoHosts set field NoHosts to given value
+func (o *KubeOptions) WithNoHosts(value bool) *KubeOptions {
+	o.NoHosts = &value
+	return o
+}
+
+// GetNoHosts returns value of field NoHosts
+func (o *KubeOptions) GetNoHosts() bool {
+	if o.NoHosts == nil {
+		var z bool
+		return z
+	}
+	return *o.NoHosts
+}
+
 // WithQuiet set field Quiet to given value
 func (o *KubeOptions) WithQuiet(value bool) *KubeOptions {
 	o.Quiet = &value

pkg/domain/entities/play.go

@@ -17,6 +17,9 @@ type PlayKubeOptions struct {
 	// Down indicates whether to bring contents of a yaml file "down"
 	// as in stop
 	Down bool
+	// Do not create /etc/hosts within the pod's containers,
+	// instead use the version from the image
+	NoHosts bool
 	// Username for authenticating against the registry.
 	Username string
 	// Password for authenticating against the registry.

pkg/domain/infra/abi/play.go

@@ -181,7 +181,7 @@ func (ic *ContainerEngine) playKubePod(ctx context.Context, podName string, podY
 		}
 	}
 
-	podOpt := entities.PodCreateOptions{Infra: true, Net: &entities.NetOptions{StaticIP: &net.IP{}, StaticMAC: &net.HardwareAddr{}}}
+	podOpt := entities.PodCreateOptions{Infra: true, Net: &entities.NetOptions{StaticIP: &net.IP{}, StaticMAC: &net.HardwareAddr{}, NoHosts: options.NoHosts}}
 	podOpt, err = kube.ToPodOpt(ctx, podName, podOpt, podYAML)
 	if err != nil {
 		return nil, err

pkg/domain/infra/tunnel/play.go

@@ -13,7 +13,7 @@ func (ic *ContainerEngine) PlayKube(ctx context.Context, path string, opts entit
 	options.WithCertDir(opts.CertDir).WithQuiet(opts.Quiet).WithSignaturePolicy(opts.SignaturePolicy).WithConfigMaps(opts.ConfigMaps)
 	options.WithLogDriver(opts.LogDriver).WithNetwork(opts.Network).WithSeccompProfileRoot(opts.SeccompProfileRoot)
 	options.WithStaticIPs(opts.StaticIPs).WithStaticMACs(opts.StaticMACs)
-
+	options.WithNoHosts(opts.NoHosts)
 	if s := opts.SkipTLSVerify; s != types.OptionalBoolUndefined {
 		options.WithSkipTLSVerify(s == types.OptionalBoolTrue)
 	}

pkg/specgen/generate/kube/kube.go

@@ -26,8 +26,8 @@ import (
 )
 
 func ToPodOpt(ctx context.Context, podName string, p entities.PodCreateOptions, podYAML *v1.PodTemplateSpec) (entities.PodCreateOptions, error) {
-	//	p := specgen.NewPodSpecGenerator()
-	p.Net = &entities.NetOptions{}
+	p.Net = &entities.NetOptions{NoHosts: p.Net.NoHosts}
+
 	p.Name = podName
 	p.Labels = podYAML.ObjectMeta.Labels
 	// Kube pods must share {ipc, net, uts} by default
@@ -47,6 +47,9 @@ func ToPodOpt(ctx context.Context, podName string, p entities.PodCreateOptions,
 		p.Net.Network = specgen.Namespace{NSMode: "host"}
 	}
 	if podYAML.Spec.HostAliases != nil {
+		if p.Net.NoHosts {
+			return p, errors.New("HostAliases in yaml file will not work with --no-hosts")
+		}
 		hosts := make([]string, 0, len(podYAML.Spec.HostAliases))
 		for _, hostAlias := range podYAML.Spec.HostAliases {
 			for _, host := range hostAlias.Hostnames {

test/e2e/play_kube_test.go

@@ -1137,6 +1137,49 @@ var _ = Describe("Podman play kube", func() {
 		Expect(infraContainerImage).To(Equal(config.DefaultInfraImage))
 	})
 
+	It("podman play kube --no-host", func() {
+		err := writeYaml(checkInfraImagePodYaml, kubeYaml)
+		Expect(err).To(BeNil())
+
+		kube := podmanTest.Podman([]string{"play", "kube", "--no-hosts", kubeYaml})
+		kube.WaitWithDefaultTimeout()
+		Expect(kube).Should(Exit(0))
+
+		podInspect := podmanTest.Podman([]string{"pod", "inspect", "check-infra-image"})
+		podInspect.WaitWithDefaultTimeout()
+		Expect(podInspect).Should(Exit(0))
+
+		data := podInspect.InspectPodToJSON()
+		for _, ctr := range data.Containers {
+			if strings.HasSuffix(ctr.Name, "-infra") {
+				continue
+			}
+			exec := podmanTest.Podman([]string{"exec", ctr.ID, "cat", "/etc/hosts"})
+			exec.WaitWithDefaultTimeout()
+			Expect(exec).Should(Exit(0))
+			Expect(exec.OutputToString()).To(Not(ContainSubstring("check-infra-image")))
+		}
+	})
+
+	It("podman play kube test HostAliases with --no-hosts", func() {
+		pod := getPod(withHostAliases("192.168.1.2", []string{
+			"test1.podman.io",
+			"test2.podman.io",
+		}),
+			withHostAliases("192.168.1.3", []string{
+				"test3.podman.io",
+				"test4.podman.io",
+			}),
+		)
+		err := generateKubeYaml("pod", pod, kubeYaml)
+		Expect(err).To(BeNil())
+
+		kube := podmanTest.Podman([]string{"play", "kube", "--no-hosts", kubeYaml})
+		kube.WaitWithDefaultTimeout()
+		Expect(kube).Should(Exit(125))
+		Expect(kube.ErrorToString()).To(ContainSubstring("HostAliases in yaml file will not work with --no-hosts"))
+	})
+
 	It("podman play kube should use customized infra_image", func() {
 		conffile := filepath.Join(podmanTest.TempDir, "container.conf")