fix: specify containerd-base-dir when bootstrapping k8s

(cherry picked from commit 63173e9)

internal/providers/k8s.go

@@ -138,8 +138,19 @@ func (k *K8s) install() error {
 // init ensures that K8s is installed, minimally configured, and ready.
 func (k *K8s) init() error {
 	if k.needsBootstrap() {
-		cmd := system.NewCommand("k8s", []string{"bootstrap"})
-		_, err := k.system.RunWithRetries(cmd, (5 * time.Minute))
+		// Write a K8s bootstrap config file to change the default containerd-base-path,
+		// avoiding conflicts on machines where containerd is already present. This mostly
+		// occurs on Github Actions runners.
+		filepath := path.Join(k.system.User().HomeDir, ".cache", "concierge", "k8s-bootstrap.yaml")
+		err := k.system.WriteHomeDirFile(filepath, []byte(
+			"containerd-base-dir: /run/containerd-k8s-snap\n",
+		))
+		if err != nil {
+			return fmt.Errorf("failed to write K8s bootstrap confile file: %w", err)
+		}
+
+		cmd := system.NewCommand("k8s", []string{"bootstrap", "--file", filepath})
+		_, err = k.system.RunWithRetries(cmd, (5 * time.Minute))
 		if err != nil {
 			return err
 		}

internal/providers/k8s_test.go

@@ -75,7 +75,7 @@ func TestK8sPrepareCommands(t *testing.T) {
 	expectedCommands := []string{
 		fmt.Sprintf("snap install k8s --channel %s", defaultK8sChannel),
 		"snap install kubectl --channel stable",
-		"k8s bootstrap",
+		"k8s bootstrap --file /tmp/.cache/concierge/k8s-bootstrap.yaml",
 		"k8s status --wait-ready",
 		"k8s set load-balancer.l2-mode=true",
 		"k8s status",
@@ -88,6 +88,7 @@ func TestK8sPrepareCommands(t *testing.T) {
 
 	expectedFiles := map[string]string{
 		".kube/config": "",
+		"/tmp/.cache/concierge/k8s-bootstrap.yaml": "containerd-base-dir: /run/containerd-k8s-snap\n",
 	}
 
 	system := system.NewMockSystem()