Allow the node name to be set directly

CHANGELOG.md

@@ -4,6 +4,9 @@ Notable changes between versions.
 
 ## Latest
 
+* Allow the node name to be set directly
+  * Add `-node` flag to set the Kubernetes node name
+  * Default to using the `HOSTNAME` environment variable
 * Add Slack threading and reactions ([#7](https://github.com/poseidon/scuttle/pull/7))
   * Add `-channel-id` flag to set a channel
   * Add `-token` flag to set a Slack token

README.md

@@ -67,7 +67,7 @@ systemd:
           --env KUBECONFIG=/var/lib/kubelet/kubeconfig \
           -v /var/lib/kubelet:/var/lib/kubelet:ro,z \
           --stop-timeout=60 \
-          quay.io/poseidon/scuttle:261fc0f \
+          quay.io/poseidon/scuttle:v0.1.0 \
           -platform=aws
         ExecStop=/usr/bin/podman stop scuttle
         TimeoutStopSec=180
@@ -91,13 +91,14 @@ Configure via flags.
 
 | flag        | description  | default      |
 |-------------|--------------|--------------|
+| -node       | Kubernetes node name | $HOSTNAME |
 | -platform   | Platform to poll for termination notices | none |
-| -channel-id | Slack Channel ID       | ""   |
-| -token      | Slack Bot Token        | ""   |
-| -webhook    | Slack Webhook URL      | ""   |
 | -uncordon   | Uncordon node on start | true |
 | -drain      | Drain node on stop     | true |
 | -delete     | Delete node on stop    | true |
+| -channel-id | Slack Channel ID       | ""   |
+| -token      | Slack Bot Token        | ""   |
+| -webhook    | Slack Webhook URL      | ""   |
 | -log-level  | Logger level | info |
 | -version    | Show version | NA   |
 | -help       | Show help    | NA   |
@@ -177,9 +178,10 @@ INFO[0004] scuttle: stopping...                          hostname=ip-10-0-35-141
 INFO[0004] scuttle: cordoning node                       hostname=ip-10-0-35-141
 INFO[0004] drainer: cordoning node                       node=ip-10-0-35-141
 INFO[0004] scuttle: draining node                        hostname=ip-10-0-35-141
-WARN[0005] WARNING: ignoring DaemonSet-managed Pods: kube-system/cilium-gpdk8, kube-system/kube-proxy-cvwx5, monitoring/promtail-k9slg
-INFO[0005] evicting pod default/redacted
+INFO[0026] drainer: evicting pod                         node=ip-10-0-35-141 pod=redacted
+INFO[0027] drainer: evicting pod                         node=ip-10-0-35-141 pod=redacted
 ...
-INFO[0009] scuttle: deleting node                        hostname=ip-10-0-35-141
+INFO[0027] drainer: drained node                         node=ip-10-0-35-141
+INFO[0027] scuttle: deleting node                        hostname=ip-10-0-35-141
 INFO[0009] done
 ```

cmd/scuttle/main.go

@@ -28,6 +28,7 @@ var (
 
 func main() {
 	flags := struct {
+		nodeName string
 		channel  string
 		token    string
 		webhook  string
@@ -40,6 +41,7 @@ func main() {
 		help     bool
 	}{}
 
+	flag.StringVar(&flags.nodeName, "node", "", "Kubernetes node name (defaults to $HOSTNAME)")
 	flag.StringVar(&flags.platform, "platform", "none", "Set platform (none, aws, azure) to poll termination notices")
 	flag.BoolVar(&flags.uncordon, "uncordon", true, "Enabling uncordoning node on start")
 	flag.BoolVar(&flags.drain, "drain", true, "Enabling draining node on stop")
@@ -91,22 +93,24 @@ func main() {
 		stop()
 	}()
 
-	// Termination watcher
+	// termination watcher
 	scuttle, err := sctl.New(&sctl.Config{
 		Logger:         log,
-		Channel:        flags.channel,
-		Token:          flags.token,
-		Webhook:        flags.webhook,
+		NodeName:       flags.nodeName,
 		Platform:       flags.platform,
 		ShouldUncordon: flags.uncordon,
 		ShouldDrain:    flags.drain,
 		ShouldDelete:   flags.delete,
+		// Slack
+		Channel: flags.channel,
+		Token:   flags.token,
+		Webhook: flags.webhook,
 	})
 	if err != nil {
 		log.Fatalf("main: scuttle New error: %v", err)
 	}
 
-	// watch for spot termination notice
+	// watch for termination
 	log.Infof("main: starting scuttle")
 	err = scuttle.Run(ctx)
 	if err != nil {

internal/scuttle.go

@@ -29,13 +29,15 @@ const (
 // Config configures a Scuttle
 type Config struct {
 	Logger         *logrus.Logger
-	Channel        string
-	Token          string
-	Webhook        string
+	NodeName       string
 	Platform       string
 	ShouldUncordon bool
 	ShouldDrain    bool
 	ShouldDelete   bool
+	// Slack
+	Channel string
+	Token   string
+	Webhook string
 }
 
 // Scuttle watches for termination notices and performs Kubelet teardown actions.
@@ -55,8 +57,11 @@ func New(config *Config) (*Scuttle, error) {
 		return nil, fmt.Errorf("scuttle: logger must be non-nil")
 	}
 
-	// Use HOSTNAME to identify Kubelet node
-	hostname := os.Getenv("HOSTNAME")
+	hostname := config.NodeName
+	if hostname == "" {
+		// fallback to HOSTNAME to identify Kubelet node
+		hostname = os.Getenv("HOSTNAME")
+	}
 
 	// Kubernetes client from kubeconfig or service account (in-cluster)
 	kubeconfigPath := os.Getenv("KUBECONFIG")
@@ -65,20 +70,22 @@ func New(config *Config) (*Scuttle, error) {
 		return nil, fmt.Errorf("scuttle: error creating Kubernetes client: %v", err)
 	}
 
-	w := &Scuttle{
+	// initialize Slack client if token is set
+	var slackClient *slack.Client
+	if config.Token != "" {
+		slackClient = slack.New(config.Token)
+	}
+
+	return &Scuttle{
 		hostname: hostname,
 		config:   config,
 		log:      config.Logger,
 		client: &http.Client{
 			Timeout: 2 * time.Second,
 		},
 		kubeClient: kubeClient,
-	}
-	if config.Token != "" {
-		w.slack = slack.New(config.Token)
-	}
-
-	return w, nil
+		slack:      slackClient,
+	}, nil
 }
 
 // Run runs the spot termination watch loop.

internal/slack.go

@@ -71,7 +71,6 @@ func (w *Scuttle) notifySlack(action Notification, node string, thread string) s
 		}
 
 		opts := []slack.MsgOption{
-			//slack.MsgOptionText(text, true),
 			slack.MsgOptionAttachments(attachment),
 		}
 		if thread != "" {