CAST AI Webhooks & Events

Overview

CAST AI emits events for node lifecycle changes, autoscaler decisions, and security findings. Configure webhook endpoints or use the audit log API to track all cluster operations. Integrates with Slack, PagerDuty, and custom HTTP endpoints.

Prerequisites

• CAST AI cluster connected and active
• HTTPS endpoint for receiving webhooks (or Slack webhook URL)
• API key with Full Access

Instructions

Step 1: Configure Notification Channels in Console

Navigate to console.cast.ai > your cluster > Notifications. Available channels:

• Slack: Webhook URL integration
• Email: Per-user notifications
• PagerDuty: Incident escalation
• Custom webhook: Any HTTPS endpoint

Step 2: Query Audit Log via API

# Get recent cluster operations
curl -s -H "X-API-Key: ${CASTAI_API_KEY}" \
  "https://api.cast.ai/v1/kubernetes/clusters/${CASTAI_CLUSTER_ID}/audit-log?limit=20" \
  | jq '.items[] | {
    time: .createdAt,
    action: .action,
    initiator: .initiatedBy,
    details: .details
  }'

Step 3: Build a Custom Notification Handler

// castai-webhook-handler.ts
import express from "express";

const app = express();
app.use(express.json());

interface CastAIEvent {
  eventType: string;
  clusterId: string;
  clusterName: string;
  timestamp: string;
  data: {
    nodeName?: string;
    instanceType?: string;
    lifecycle?: string;
    action?: string;
    savingsImpact?: number;
  };
}

app.post("/castai/events", async (req, res) => {
  const event: CastAIEvent = req.body;

  switch (event.eventType) {
    case "node.added":
      console.log(
        `Node added: ${event.data.nodeName} (${event.data.instanceType}, ${event.data.lifecycle})`
      );
      await notifySlack(
        `New ${event.data.lifecycle} node: ${event.data.instanceType}`
      );
      break;

    case "node.removed":
      console.log(`Node removed: ${event.data.nodeName}`);
      break;

    case "node.spot_interrupted":
      console.log(`Spot interruption: ${event.data.nodeName}`);
      await notifyPagerDuty("Spot instance interrupted", event);
      break;

    case "savings.threshold":
      console.log(`Savings threshold crossed: ${event.data.savingsImpact}%`);
      break;

    default:
      console.log(`Unhandled event: ${event.eventType}`);
  }

  res.status(200).json({ received: true });
});

async function notifySlack(message: string): Promise<void> {
  await fetch(process.env.SLACK_WEBHOOK_URL!, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({
      text: `:kubernetes: CAST AI: ${message}`,
    }),
  });
}

app.listen(3000, () => console.log("CAST AI webhook handler on :3000"));

Step 4: Kubernetes-Native Event Monitoring

# Watch CAST AI events in the cluster
kubectl get events -n castai-agent --watch \
  --field-selector=source=castai

# Or use a CronJob to post daily summaries

apiVersion: batch/v1
kind: CronJob
metadata:
  name: castai-daily-summary
spec:
  schedule: "0 9 * * *"
  jobTemplate:
    spec:
      template:
        spec:
          containers:
            - name: summary
              image: curlimages/curl
              command:
                - sh
                - -c
                - |
                  SAVINGS=$(curl -s -H "X-API-Key: ${CASTAI_API_KEY}" \
                    "https://api.cast.ai/v1/kubernetes/clusters/${CLUSTER_ID}/savings")
                  curl -X POST ${SLACK_WEBHOOK_URL} \
                    -H "Content-Type: application/json" \
                    -d "{\"text\": \"Daily CAST AI savings: $(echo $SAVINGS | jq -r '.monthlySavings') USD/month\"}"
          restartPolicy: Never

Error Handling

Issue	Cause	Solution
Webhook not firing	Wrong URL in console	Verify endpoint is reachable
Slack message empty	Payload format changed	Check current event schema
Duplicate events	No idempotency	Track event IDs in your handler
Events delayed	Queue backlog	Monitor CAST AI status page

Resources

• CAST AI Notifications
• CAST AI API Reference

Next Steps

For performance optimization, see castai-performance-tuning.