feat: add hostPathVolume (docker) (#3277)

README.md

@@ -470,6 +470,13 @@ You can now override the context portForward default address configuration by se
         memory: 100Mi
       # Enable TTY
       tty: true
+      hostPathVolume:
+      - name: docker-socket
+        # Mount the Docker socket into the shell pod
+        mountPath: /var/run/docker.sock
+        # The path on the host to mount
+        hostPath: /var/run/docker.sock
+        readOnly: true
   ```
 
 ---
@@ -518,6 +525,21 @@ k9s:
   portForwardAddress: localhost
 ```
 
+### Customizing the Shell Pod
+You can also customize the shell pod by adding a `hostPathVolume` to your shell pod. This allows you to mount a local directory or file into the shell pod. For example, if you want to mount the Docker socket into the shell pod, you can do so as follows:
+```yaml
+k9s:
+  shellPod:
+    hostPathVolume:
+    - name: docker-socket
+      # Mount the Docker socket into the shell pod
+      mountPath: /var/run/docker.sock
+      # The path on the host to mount
+      hostPath: /var/run/docker.sock
+      readOnly: true
+```
+This will mount the Docker socket into the shell pod at `/var/run/docker.sock` and make it read-only. You can also mount any other directory or file in a similar way.
+
 ---
 
 ## Command Aliases

internal/config/shell_pod.go

@@ -23,6 +23,14 @@ type ShellPod struct {
 	ImagePullSecrets []v1.LocalObjectReference `json:"imagePullSecrets,omitempty" yaml:"imagePullSecrets,omitempty"`
 	ImagePullPolicy  v1.PullPolicy             `json:"imagePullPolicy,omitempty" yaml:"imagePullPolicy,omitempty"`
 	TTY              bool                      `json:"tty,omitempty" yaml:"tty,omitempty"`
+	HostPathVolume   []hostPathVolume          `json:"hostPathVolume,omitempty" yaml:"hostPathVolume,omitempty"`
+}
+
+type hostPathVolume struct {
+	Name      string `json:"name" yaml:"name"`
+	MountPath string `json:"mountPath" yaml:"mountPath"`
+	HostPath  string `json:"hostPath" yaml:"hostPath"`
+	ReadOnly  bool   `json:"readOnly,omitempty" yaml:"readOnly,omitempty"`
 }
 
 // NewShellPod returns a new instance.

internal/view/exec.go

@@ -477,13 +477,39 @@ func k9sShellPod(node string, cfg *config.ShellPod) *v1.Pod {
 			Privileged: &priv,
 		},
 	}
+	v := []v1.Volume{
+		{
+			Name: "root-vol",
+			VolumeSource: v1.VolumeSource{
+				HostPath: &v1.HostPathVolumeSource{
+					Path: "/",
+				},
+			},
+		},
+	}
 	if len(cfg.Command) != 0 {
 		c.Command = cfg.Command
 	}
 	if len(cfg.Args) > 0 {
 		c.Args = cfg.Args
 	}
-
+	if len(cfg.HostPathVolume) > 0 {
+		for _, h := range cfg.HostPathVolume {
+			c.VolumeMounts = append(c.VolumeMounts, v1.VolumeMount{
+				Name:      h.Name,
+				MountPath: h.MountPath,
+				ReadOnly:  h.ReadOnly,
+			})
+			v = append(v, v1.Volume{
+				Name: h.Name,
+				VolumeSource: v1.VolumeSource{
+					HostPath: &v1.HostPathVolumeSource{
+						Path: h.HostPath,
+					},
+				},
+			})
+		}
+	}
 	return &v1.Pod{
 		ObjectMeta: metav1.ObjectMeta{
 			Name:      k9sShellPodName(),
@@ -497,17 +523,8 @@ func k9sShellPod(node string, cfg *config.ShellPod) *v1.Pod {
 			HostNetwork:                   true,
 			ImagePullSecrets:              cfg.ImagePullSecrets,
 			TerminationGracePeriodSeconds: &grace,
-			Volumes: []v1.Volume{
-				{
-					Name: "root-vol",
-					VolumeSource: v1.VolumeSource{
-						HostPath: &v1.HostPathVolumeSource{
-							Path: "/",
-						},
-					},
-				},
-			},
-			Containers: []v1.Container{c},
+			Volumes:                       v,
+			Containers:                    []v1.Container{c},
 			Tolerations: []v1.Toleration{
 				{
 					Operator: v1.TolerationOperator("Exists"),