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minikube
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add host.minikube.internal to coredns

pull/11404/head
Predrag Rogic 2021-05-13 18:28:16 +01:00
parent 78618d04fc
commit 3ddb4e30b3
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2 changed files with 43 additions and 0 deletions
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21
pkg/minikube/node/start.go
View File

@ -21,6 +21,7 @@ import (
"net"
"os"
"os/exec"
"path"
"strconv"
"strings"
"sync"
@ -60,6 +61,7 @@ import (
"k8s.io/minikube/pkg/minikube/proxy"
"k8s.io/minikube/pkg/minikube/reason"
"k8s.io/minikube/pkg/minikube/style"
"k8s.io/minikube/pkg/minikube/vmpath"
"k8s.io/minikube/pkg/util"
"k8s.io/minikube/pkg/util/retry"
)
@ -131,6 +133,10 @@ func Start(starter Starter, apiServer bool) (*kubeconfig.Settings, error) {
if err := kapi.ScaleDeployment(starter.Cfg.Name, meta.NamespaceSystem, kconst.CoreDNSDeploymentName, 1); err != nil {
klog.Errorf("Unable to scale down deployment %q in namespace %q to 1 replica: %v", kconst.CoreDNSDeploymentName, meta.NamespaceSystem, err)
}
// inject {"host.minikube.internal": hostIP} record into CoreDNS
if err := updateCoreDNS(starter.Runner, "host.minikube.internal", hostIP.String(), *starter.Cfg); err != nil {
klog.Errorf("Unable to inject {%q: %s} record into CoreDNS: %v", "host.minikube.internal", hostIP.String(), err)
}
} else {
bs, err = cluster.Bootstrapper(starter.MachineAPI, viper.GetString(cmdcfg.Bootstrapper), *starter.Cfg, starter.Runner)
if err != nil {
@ -669,3 +675,18 @@ func prepareNone() {
exit.Message(reason.HostHomeChown, "Failed to change permissions for {{.minikube_dir_path}}: {{.error}}", out.V{"minikube_dir_path": localpath.MiniPath(), "error": err})
}
}
// updateCoreDNS adds host name and IP record to the DNS by updating CoreDNS's ConfigMap.
// ref: https://coredns.io/plugins/hosts/
func updateCoreDNS(runner command.Runner, name, ip string, cc config.ClusterConfig) error {
kubectl := kapi.KubectlBinaryPath(cc.KubernetesConfig.KubernetesVersion)
kubecfg := path.Join(vmpath.GuestPersistentDir, "kubeconfig")
cur := fmt.Sprintf("sudo %s --kubeconfig=%s -n kube-system get configmap coredns -o yaml", kubectl, kubecfg)
sed := fmt.Sprintf("sed '/^ forward . \\/etc\\/resolv.conf.*/i \\ hosts {\\n %s %s\\n fallthrough\\n }'", ip, name)
new := fmt.Sprintf("sudo %s --kubeconfig=%s replace -f -", kubectl, kubecfg)
_, err := runner.RunCmd(exec.Command("/bin/bash", "-c", fmt.Sprintf("%s | %s | %s", cur, sed, new)))
if err == nil {
klog.Infof("{%q: %s} record injected into CoreDNS", name, ip)
}
return err
}

22
test/integration/multinode_test.go
View File

@ -464,6 +464,7 @@ func validateDeployAppToMultiNode(ctx context.Context, t *testing.T, profile str
t.Errorf("Pod %s could not resolve 'kubernetes.io': %v", name, err)
}
}
// verify both Pods could resolve "kubernetes.default"
// this one is also checked by k8s e2e node conformance tests:
// https://github.com/kubernetes/kubernetes/blob/f137c4777095b3972e2dd71a01365d47be459389/test/e2e_node/environment/conformance.go#L125-L179
@ -473,6 +474,7 @@ func validateDeployAppToMultiNode(ctx context.Context, t *testing.T, profile str
t.Errorf("Pod %s could not resolve 'kubernetes.default': %v", name, err)
}
}
// verify both pods could resolve to a local service.
for _, name := range podNames {
_, err = Run(t, exec.CommandContext(ctx, Target(), "kubectl", "-p", profile, "--", "exec", name, "--", "nslookup", "kubernetes.default.svc.cluster.local"))
@ -480,4 +482,24 @@ func validateDeployAppToMultiNode(ctx context.Context, t *testing.T, profile str
t.Errorf("Pod %s could not resolve local service (kubernetes.default.svc.cluster.local): %v", name, err)
}
}
// verify both pods could resolve "host.minikube.internal"
for _, name := range podNames {
// get node's default gateway via 'ip' - eg: "default via 192.168.49.1 dev eth0" => "192.168.49.1"
out, err := Run(t, exec.CommandContext(ctx, Target(), "ssh", "-p", profile, "ip -4 route show default | cut -d' ' -f3"))
if err != nil {
t.Errorf("Error getting default gateway for pod %s: %v", name, err)
} else {
dgw := strings.TrimSpace(out.Stdout.String())
out, err = Run(t, exec.CommandContext(ctx, Target(), "kubectl", "-p", profile, "--", "exec", name, "--", "sh", "-c", "nslookup host.minikube.internal | awk 'NR==5' | cut -d' ' -f3"))
if err != nil {
t.Errorf("Pod %s could not resolve 'host.minikube.internal': %v", name, err)
} else {
hip := strings.TrimSpace(out.Stdout.String())
if hip != dgw {
t.Errorf("Pod %s resolved 'host.minikube.internal' to %q different from host's IP (%s)", name, hip, dgw)
}
}
}
}
}