k8s status should return immediately if the api server is down (#154)

* k8s status: fail fast if we cannot determine kube-apiserver endpoints for our cluster

* k8s status: tweak fail fast errors

We want status to fail fast if:
- not bootstrapped
- kube-apiserver is unreachable
- no cluster endpoints are known

src/k8s/api/v1/errors.go

@@ -21,5 +21,8 @@ var ErrTimeout = errors.New("context deadline exceeded")
 // ErrConnectionFailed indicates that a connection to the k8sd daemon could not be established.
 var ErrConnectionFailed = errors.New("dial unix")
 
+// ErrAPIServerFailed indicates that kube-apiserver endpoint(s) could not be determined.
+var ErrAPIServerFailed = errors.New("failed to get kube-apiserver endpoints")
+
 // ErrUnknown indicates that the server returns an unknown error.
 var ErrUnknown = errors.New("unknown error")

src/k8s/cmd/k8s/errors/errors.go

@@ -9,9 +9,11 @@ import (
 )
 
 var genericErrorMsgs = map[error]string{
-	v1.ErrNotBootstrapped: fmt.Sprintln("The cluster has not been initialized yet. Please call:\n\n    sudo k8s bootstrap"),
-	v1.ErrConnectionFailed: "Unable to connect to the cluster. Verify that that the services are running:\n\n sudo snap services k8s\n\n" +
+	v1.ErrNotBootstrapped: "The cluster has not been initialized yet. Please call:\n\n sudo k8s bootstrap",
+	v1.ErrConnectionFailed: "Unable to connect to the cluster. Verify k8s services are running:\n\n sudo snap services k8s\n\n" +
 		"and see logs for more details:\n\n sudo journalctl -n 300 -u snap.k8s.k8sd\n\n",
+	v1.ErrAPIServerFailed: "Unable to get Kubernetes API server endpoints. Verify k8s services are running:\n\n sudo snap services k8s\n\n" +
+		"and see logs for more details:\n\n sudo journalctl -n 300 -u snap.k8s.kube-apiserver\n\n",
 	v1.ErrTimeout: "Command timed out. See logs for more details:\n\n" +
 		" sudo journalctl -n 300 -u snap.k8s.k8sd\n\n" +
 		"You may increase the timeout with `--timeout 3m`.",

src/k8s/cmd/k8s/k8s_status.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"time"
 
+	v1 "github.com/canonical/k8s/api/v1"
 	"github.com/canonical/k8s/cmd/k8s/errors"
 	"github.com/canonical/k8s/cmd/k8s/formatter"
 	"github.com/spf13/cobra"
@@ -27,6 +28,17 @@ func newStatusCmd() *cobra.Command {
 		RunE: func(cmd *cobra.Command, args []string) (err error) {
 			defer errors.Transform(&err, nil)
 
+			// fail fast if we're not bootstrapped
+			if !k8sdClient.IsBootstrapped(cmd.Context()) {
+				return v1.ErrNotBootstrapped
+			}
+			// fail fast if we're not explicitly waiting and we can't get kube-apiserver endpoints
+			if !statusCmdOpts.waitReady {
+				if ready := k8sdClient.IsKubernetesAPIServerReady(cmd.Context()); !ready {
+					return fmt.Errorf("failed to get kube-apiserver endpoints; cluster status is unavailable")
+				}
+			}
+
 			const minTimeout = 3 * time.Second
 			if statusCmdOpts.timeout < minTimeout {
 				cmd.PrintErrf("Timeout %v is less than minimum of %v. Using the minimum %v instead.\n", statusCmdOpts.timeout, minTimeout, minTimeout)

src/k8s/pkg/k8s/client/cluster.go

@@ -9,6 +9,7 @@ import (
 	apiv1 "github.com/canonical/k8s/api/v1"
 	"github.com/canonical/k8s/pkg/config"
 	"github.com/canonical/k8s/pkg/utils/control"
+	"github.com/canonical/k8s/pkg/utils/k8s"
 	"github.com/canonical/lxd/lxd/util"
 	"github.com/canonical/lxd/shared/api"
 )
@@ -84,3 +85,16 @@ func (c *k8sdClient) KubeConfig(ctx context.Context) (string, error) {
 	}
 	return response.KubeConfig, nil
 }
+
+// IsKubernetesAPIServerReady checks if kube-apiserver is reachable.
+func (c *k8sdClient) IsKubernetesAPIServerReady(ctx context.Context) bool {
+	kc, err := k8s.NewClient(c.opts.Snap)
+	if err != nil {
+		return false
+	}
+	_, err = kc.GetKubeAPIServerEndpoints(ctx)
+	if err != nil {
+		return false
+	}
+	return err == nil
+}

src/k8s/pkg/k8s/client/interface.go

@@ -12,6 +12,8 @@ import (
 type Client interface {
 	// Bootstrap initializes a new cluster member using the provided bootstrap configuration.
 	Bootstrap(ctx context.Context, bootstrapConfig apiv1.BootstrapConfig) (apiv1.ClusterMember, error)
+	// IsKubernetesAPIServerReady checks if kube-apiserver is reachable.
+	IsKubernetesAPIServerReady(ctx context.Context) bool
 	// IsBootstrapped checks whether the current node is already bootstrapped.
 	IsBootstrapped(ctx context.Context) bool
 	// CleanupNode performs cleanup operations for a specific node in the cluster.