Keel: Kubernetes Deployment Automation Engine – A Smarter Way to Manage CI/CD

By Ananta Cloud Engineering Team | September 11, 2025

Modern DevOps practices demand agility, repeatability, and automation, especially in fast-paced microservices architectures deployed on Kubernetes. Enter Keel – an open-source tool that simplifies automated Kubernetes deployment workflows by continuously monitoring your image repositories and applying updates without human intervention.

In this blog, we’ll explore what Keel is, how it works, how to integrate it into your Kubernetes environment, and how you can enforce approval workflows for safer automated deployments. We’ll also share practical examples and best practices from the Ananta Cloud team.

Image Source: Keel

What is Keel?

Keel is an open-source Kubernetes deployment automation engine. It automates rolling updates to your Kubernetes workloads when it detects new Docker image versions. Think of it as a lightweight, GitOps-inspired solution that brings continuous delivery to your Kubernetes clusters without needing complex CI/CD setups.

Keel supports the following update triggers:

• Docker Hub or any container registry updates (e.g., ECR, GCR)

• Helm chart updates

• Git-based triggers

• Manual triggers via CLI or API

Key Features

• Automatic Deployment: Monitors image tags or SHA changes and deploys updated workloads automatically.

• Multi-controller Support: Supports Deployment, DaemonSet, StatefulSet, CronJob, and more.

• Approval Workflows: Optional Slack or webhook-based approval before pushing changes to production.

• Rollbacks: Supports kubectl rollout undo or Helm rollback.

• Security & Audit Logging: Maintains deployment history and approval logs.

How Keel Works

Keel follows a polling mechanism to periodically check for new image versions across registries. Once detected, it evaluates policies and decides whether to:

1. Auto-deploy

2. Request human approval

3. Ignore (based on config)

Keel runs as a controller in your Kubernetes cluster, watching for image updates and applying changes to workloads.

Example: Auto Deploy When New Image Is Pushed

Let’s say you have a Kubernetes deployment using the image anantacloud/api-service:latest. Here's how Keel can automatically update the pod whenever a new latest image is pushed.

Install Keel

kubectl apply -f https://raw.githubusercontent.com/keel-hq/keel/master/deploy/keel.yaml

Annotate Your Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: api-service
  annotations:
    keel.sh/policy: force
spec:
  replicas: 2
  template:
    spec:
      containers:
        - name: api-service
          image: anantacloud/api-service:latest

Keel Auto-triggers the Update

As soon as a new image is pushed with the same latest tag but a different digest (SHA), Keel pulls it and triggers a rolling update.

Integrating Approval Workflows

For production environments, automatic deployment without approval might be risky. Keel supports multiple approval mechanisms:

Slack-Based Approval Flow

Keel can be integrated with Slack to post a message like:

New version of api-service detected (sha256:abc123).
Approve deployment?
[Approve] [Reject]

Admins can approve right from Slack, ensuring human control over production rollouts.

Webhook Approval Flow

If you're using Ananta Cloud’s internal DevOps control panel or another CI tool, Keel can call a webhook for approval requests. The webhook can evaluate conditions (e.g., canary tests passed, QA signed off) and respond accordingly.

Use Case: Multi-Env Strategy at Ananta Cloud

At Ananta Cloud, we’ve implemented Keel in a multi-environment cluster setup:

Environment	Policy	Approval Required?	Integration
Dev	force	❌ No	Auto Deploy
Staging	patch	✅ Yes	Slack
Production	major	✅ Yes	Webhook

• Dev is configured to deploy every minor change.

• Staging waits for Slack approval on patch versions.

• Production only allows major version upgrades with webhook validation.

This workflow drastically reduces lead time while ensuring safe deployments.

Pro Tips from Ananta Cloud Engineers

1. Use SHA tags instead of latest in production.

2. Keep a Helm rollback plan ready in case of regression.

3. Use Keel in conjunction with Prometheus and Alertmanager to monitor post-deploy issues.

4. Apply RBAC rules to restrict who can approve deployments.

Security Considerations

• Ensure only trusted registries are used.

• Configure Keel with appropriate namespace scopes.

• Use SSL and token-based auth for webhooks.

• Audit all deployments with tools like KubeAudit.

Why Choose Keel?

• Simple to install and use

• Works with existing manifests

• Lightweight alternative to full-blown CI/CD tools

• Extensible with plugins and hooks

It’s perfect for teams looking to automate safely without over-engineering their delivery pipelines.

Get Started with Keel on Ananta Cloud

Want to try Keel on your cluster?

➡️ Book a free consultation with the Ananta Cloud DevOps experts.

➡️ Deploy Keel on your cluster with our step-by-step onboarding guide.

➡️ Join our Slack community to discuss Kubernetes, CI/CD, and more.

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