Add option to merge kubeconfig when cluster is created (#196)

* pkg/utils/exec: Simplify command invocation and set default PATH variable

Signed-off-by: Din Music <[email protected]>

* kubeconfig: Merge kubeconfig instead of overriding it

Signed-off-by: Din Music <[email protected]>

* pkg: Rename copyKubeconfig to mergeKubeconfig

Signed-off-by: Din Music <[email protected]>

* embed/presets: Set mergeKubeconfig to true for getting-started guide

Signed-off-by: Din Music <[email protected]>

* docs: Replace copyKubeconfig with mergeKubeconfig

Signed-off-by: Din Music <[email protected]>

* scripts: Use mergeKubeconfig in test scripts

Signed-off-by: Din Music <[email protected]>

* pkg/cluster/managers: Rewrite final kubeconfig

Replace default occurences of context/cluster/user in kubeconfig
with a cluster name.

Signed-off-by: Din Music <[email protected]>

---------

Signed-off-by: Din Music <[email protected]>

docs/examples/full-example.md

@@ -163,7 +163,7 @@ kubernetes:
   networkPlugin: calico
   dnsMode: coredns # (36)!
   other:
-    copyKubeconfig: false
+    mergeKubeconfig: true
 
 #
 # The 'addons' section contains the configuration of the applications that

docs/getting-started/getting-started.md

@@ -245,20 +245,29 @@ cluster:
 7.  A static IP address set for this particular instance.
     If the `ip` property is omitted, the node requests a DHCP lease during creation.
 
-8.  In this example, the amount of RAM allocated to the worker node instance is set to 4 GiB, which overwrites the default value of 8 GiB.
+8.  In this example, the amount of RAM allocated to the worker node instance is set to 4 GiB,
+    which overwrites the default value of 8 GiB.
 
 ### Step 3.4 - Kubernetes properties
 
 The final section of the cluster configuration contains the Kubernetes properties,
-such as the version and network plugin.
+such as the Kubernetes version and network plugin.
 
+In addition, you can deploy the Kubernetes cluster either using `kubespray` (default) or `k3s`.
 
 ```yaml title="kubitect.yaml"
 kubernetes:
+  manager: kubespray
   version: v1.28.6
   networkPlugin: calico
+  other:
+    mergeKubeconfig: true # (1)
 ```
 
+1.  Kubeconfig can be automatically merged into `~/.kube/config` when a cluster is
+    created by setting property [mergeKubeconfig](../../user-guide/configuration/kubernetes/#merge-kubeconfig)
+    to `true` in the cluster's configuration file.
+
 ## Step 4 - Create the cluster
 
 Below is the final configuration for our Kubernetes cluster:
@@ -305,6 +314,8 @@ Below is the final configuration for our Kubernetes cluster:
     kubernetes:
       version: v1.28.6
       networkPlugin: calico
+      other:
+        mergeKubeconfig: true
     ```
 
 To create the cluster, **apply the configuration** file to Kubitect:
@@ -347,20 +358,24 @@ kubitect list clusters
 
 ## Step 5 - Test the cluster
 
-Once you have successfully installed a Kubernetes cluster, the Kubeconfig file can be found in the cluster's directory.
-However, you will most likely want to **export the Kubeconfig** to a separate file:
-
+Finally, to confirm that the cluster is ready, you can list its nodes using the `kubectl` command:
 
 ```sh
-kubitect export kubeconfig --cluster k8s-cluster > kubeconfig.yaml
+kubectl --context k8s-cluster get nodes
 ```
 
-This will create a file named `kubeconfig.yaml` in your current directory.
-Finally, to confirm that the cluster is ready, you can list its nodes using the `kubectl` command:
+??? question "Where do I find kubeconfig? <i class="click-tip"></i>"
 
-```sh
-kubectl get nodes --kubeconfig kubeconfig.yaml
-```
+    Once the Kubernetes cluster is deployed, the Kubeconfig file can be found in the cluster's directory.
+
+    You can easily export the Kubeconfig into a separate file using the following command, which creates a file named `kubeconfig.yaml` in your current directory.
+
+    ```sh
+    kubitect export kubeconfig --cluster k8s-cluster > kubeconfig.yaml
+    ```
+
+    Kubeconfig can be also automatically merged into existing `~/.kube/config`
+    when a cluster is created by setting property [mergeKubeconfig](../../user-guide/configuration/kubernetes/#merge-kubeconfig) to `true` in the cluster's configuration file.
 
 :clap: Congratulations, you have completed the *getting started* quide.
 

docs/getting-started/quick-start.md

@@ -36,21 +36,12 @@ kubitect apply --config cluster.yaml
 
 That's it! The cluster, named `k8s-cluster`, should be up and running in approximately 10 minutes.
 
-### Step 2 - Export kubeconfig
-
-After successfully installing the Kubernetes cluster, a Kubeconfig file will be created within the cluster's directory.
-To export the Kubeconfig to a custom file, use the following command:
-
-```sh
-kubitect export kubeconfig --cluster k8s-cluster > kubeconfig.yaml
-```
-
-### Step 3 - Test the cluster
+### Step 2 - Test the cluster
 
 To test that the cluster is up and running, display all cluster nodes using the exported Kubeconfig and the kubectl command:
 
 ```sh
-kubectl get nodes --kubeconfig kubeconfig.yaml
+kubectl --context k8s-cluster get nodes
 ```
 
 :clap: Congratulations, you have successfully deployed a Kubernetes cluster using Kubitect!

docs/user-guide/configuration/kubernetes.md

@@ -91,19 +91,19 @@ kubernetes:
   dnsMode: coredns
 ```
 
-### Copy kubeconfig
+### Merge kubeconfig
 
-:material-tag-arrow-up-outline: [v2.0.0][tag 2.0.0]
+:material-tag-arrow-up-outline: [v3.4.0][tag 3.4.0]
  
 :octicons-file-symlink-file-24: Default: `false`
 
-Kubitect offers the option to automatically copy the Kubeconfig file to the `~/.kube/config` path.
-By default, this feature is disabled to prevent overwriting an existing file.
+Kubitect offers an option to merge the resulting Kubeconfig file with the config on path `~/.kube/config`.
+This means that whenever a new cluster is created, it can be selected by context which equals the cluster name.
 
 ```yaml
 kubernetes:
   other:
-    copyKubeconfig: true
+    mergeKubeconfig: true
 ```
 
 ### Auto renew control plane certificates

docs/user-guide/reference/configuration.md

@@ -779,13 +779,12 @@ Each configuration property is documented with 5 columns: Property name, descrip
       </td>
     </tr>
     <tr>
-      <td><code>kubernetes.other.copyKubeconfig</code></td>
+      <td><code>kubernetes.other.mergeKubeconfig</code></td>
       <td>boolean</td>
       <td>false</td>
       <td></td>
       <td>
-        When this property is set to true, the kubeconfig of a new cluster is copied to the <code>~/.kube/config</code>.
-        Please note that setting this property to true may cause the existing file at the destination to be overwritten.
+        When this property is set to true, the kubeconfig of a new cluster is merged to the config on path <code>~/.kube/config</code>.
       </td>
     </tr>
     <tr>

embed/ansible/kubitect/finalize.yaml

@@ -25,22 +25,6 @@
         path: "{{ config_dir }}/admin.conf"
         mode: 0600
 
-    - name: Copy Kubeconfig
-      block:
-        - name: Make sure ~/.kube directory exists
-          file:
-            path: "~/.kube"
-            state: directory
-
-        - name: Copy kubeconfig file to a ~/.kube dirctory
-          copy:
-            src: "{{ config_dir }}/admin.conf"
-            dest: "~/.kube/config"
-            mode: 0600
-      when:
-        - config.kubernetes.other.copyKubeconfig is defined
-        - config.kubernetes.other.copyKubeconfig == true
-
 - name: Install addons
   hosts: localhost
   gather_facts: false

embed/presets/getting-started.yaml

@@ -37,3 +37,5 @@ cluster:
 kubernetes:
   version: v1.28.6
   networkPlugin: calico
+  other:
+    mergeKubeconfig: true

pkg/cluster/managers/common.go

@@ -2,11 +2,15 @@ package managers
 
 import (
 	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
 
 	"github.com/MusicDin/kubitect/pkg/cluster/event"
 	"github.com/MusicDin/kubitect/pkg/models/config"
 	"github.com/MusicDin/kubitect/pkg/models/infra"
 	"github.com/MusicDin/kubitect/pkg/tools/ansible"
+	"github.com/MusicDin/kubitect/pkg/utils/exec"
 )
 
 type common struct {
@@ -34,6 +38,52 @@ func (e common) SshPKey() string {
 	return e.SshPrivateKeyPath
 }
 
+// mergeKubeconfig merges cluster kubeconfig with config default
+// config in user directory (~/.kube/config). Note that if kubectl
+// is not present locally, the command will fail.
+func (e common) mergeKubeconfig() error {
+	// Get directory of the current user.
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return err
+	}
+
+	defConfigPath := filepath.Join(home, ".kube", "config")
+	clsConfigPath := filepath.Join(e.ConfigDir, "admin.conf")
+
+	exec := exec.NewLocalClient()
+	exec.SetEnv("KUBECONFIG", fmt.Sprintf("%s:%s", clsConfigPath, defConfigPath))
+
+	config, err := exec.Output("kubectl", "config", "view", "--raw")
+	if err != nil {
+		return err
+	}
+
+	return os.WriteFile(defConfigPath, config, 0600)
+}
+
+// rewriteKubeconfig reads the kubeconfig file and replaces occurrences of map
+// keys with corresponding map values.
+func (e *common) rewriteKubeconfig(replaces map[string]string) error {
+	kubeconfigPath := filepath.Join(e.ConfigDir, "admin.conf")
+	kubeconfig, err := os.ReadFile(kubeconfigPath)
+	if err != nil {
+		return err
+	}
+
+	s := []string{}
+	for k, v := range replaces {
+		if k == "" || v == "" {
+			return fmt.Errorf("cannot rewrite config with empty values")
+		}
+		s = append(s, k, v)
+	}
+
+	replacer := strings.NewReplacer(s...)
+	new := replacer.Replace(string(kubeconfig))
+	return os.WriteFile(kubeconfigPath, []byte(new), 0600)
+}
+
 // extractRemovedNodes returns removed node instances extracted from the event changes.
 func extractRemovedNodes(events []event.Event) ([]config.Instance, error) {
 	var nodes []config.Instance

pkg/cluster/managers/k3s.go

@@ -13,6 +13,7 @@ import (
 	"github.com/MusicDin/kubitect/pkg/tools/ansible"
 	"github.com/MusicDin/kubitect/pkg/tools/git"
 	"github.com/MusicDin/kubitect/pkg/tools/virtualenv"
+	"github.com/MusicDin/kubitect/pkg/ui"
 	"github.com/MusicDin/kubitect/pkg/utils/exec"
 )
 
@@ -117,7 +118,27 @@ func (e *k3s) Create() error {
 		return err
 	}
 
-	return e.Finalize()
+	err = e.Finalize()
+	if err != nil {
+		return err
+	}
+
+	// Rewrite kubeconfig before merging to prevent accidental
+	// overwrite of an existing configuration.
+	err = e.rewriteKubeconfig()
+	if err != nil {
+		return err
+	}
+
+	if e.Config.Kubernetes.Other.MergeKubeconfig {
+		err := e.mergeKubeconfig()
+		if err != nil {
+			// Just warn about failure, since deployment has succeeded.
+			ui.Print(ui.WARN, "Failed to merge kubeconfig:", err)
+		}
+	}
+
+	return nil
 }
 
 // Upgrades upgrades a Kubernetes cluster by calling appropriate k3s
@@ -184,17 +205,17 @@ func (e *k3s) ScaleDown(events event.Events) error {
 	for _, n := range rmNodes {
 		name := fmt.Sprintf("%s-%s-%s", e.ClusterName, n.GetTypeName(), n.GetID())
 
-		err = ssh.Run(exec.NewCommand("kubectl", "cordon", name))
+		err = ssh.Run("kubectl", "cordon", name)
 		if err != nil {
 			return fmt.Errorf("cordon node %q: %v", name, err)
 		}
 
-		err = ssh.Run(exec.NewCommand("kubectl", "drain", name, "--ignore-daemonsets", "--force"))
+		err = ssh.Run("kubectl", "drain", name, "--ignore-daemonsets", "--force")
 		if err != nil {
 			return fmt.Errorf("drain node %q: %v", name, err)
 		}
 
-		err = ssh.Run(exec.NewCommand("kubectl", "delete", "node", name))
+		err = ssh.Run("kubectl", "delete", "node", name)
 		if err != nil {
 			return fmt.Errorf("delete node %q: %v", name, err)
 		}
@@ -203,3 +224,13 @@ func (e *k3s) ScaleDown(events event.Events) error {
 	// No need for further cleanup. This instance will be removed.
 	return nil
 }
+
+// rewriteKubeconfig replaces "default" context/cluster/user in kubeconfig
+// with a cluster name.
+func (e *k3s) rewriteKubeconfig() error {
+	replaces := map[string]string{
+		"default": e.ClusterName,
+	}
+
+	return e.common.rewriteKubeconfig(replaces)
+}

pkg/cluster/managers/kubespray.go

@@ -13,6 +13,7 @@ import (
 	"github.com/MusicDin/kubitect/pkg/tools/ansible"
 	"github.com/MusicDin/kubitect/pkg/tools/git"
 	"github.com/MusicDin/kubitect/pkg/tools/virtualenv"
+	"github.com/MusicDin/kubitect/pkg/ui"
 	"gopkg.in/yaml.v3"
 )
 
@@ -102,7 +103,27 @@ func (e *kubespray) Create() error {
 		return err
 	}
 
-	return e.Finalize()
+	err = e.Finalize()
+	if err != nil {
+		return err
+	}
+
+	// Rewrite kubeconfig before merging to prevent accidental
+	// overwrite of an existing configuration.
+	err = e.rewriteKubeconfig()
+	if err != nil {
+		return err
+	}
+
+	if e.Config.Kubernetes.Other.MergeKubeconfig {
+		err := e.mergeKubeconfig()
+		if err != nil {
+			// Just warn about failure, since deployment has succeeded.
+			ui.Print(ui.WARN, "Failed to merge kubeconfig:", err)
+		}
+	}
+
+	return nil
 }
 
 // Upgrades upgrades a Kubernetes cluster by calling appropriate Kubespray
@@ -113,7 +134,14 @@ func (e *kubespray) Upgrade() error {
 		return err
 	}
 
-	return e.Finalize()
+	err = e.Finalize()
+	if err != nil {
+		return err
+	}
+
+	// Rewrite kubeconfig on upgrade, because it is re-fetched
+	// from the server.
+	return e.rewriteKubeconfig()
 }
 
 // ScaleUp adds new nodes to the cluster.
@@ -207,3 +235,15 @@ func (e *kubespray) generateGroupVars() error {
 
 	return nil
 }
+
+// rewriteKubeconfig replaces context/cluster/user in kubeconfig with the
+// cluster name.
+func (e *kubespray) rewriteKubeconfig() error {
+	replaces := map[string]string{
+		"[email protected]": e.ClusterName,
+		"kubernetes-admin":               e.ClusterName,
+		"cluster.local":                  e.ClusterName,
+	}
+
+	return e.common.rewriteKubeconfig(replaces)
+}