How Kubernetes Automates and Manages Your Docker Containers

Saravanan Gnanaguru — Mon, 21 Apr 2025 13:06:10 +0000

Blog Description: Learn how we can use Kubernetes to automate the deployment, scaling, and management of Docker containers. Discover how it simplifies container orchestration and enhances application reliability.

Introduction

In today’s microservices-driven world, Docker revolutionized how we build and package applications. But managing containers at scale? That’s where Kubernetes steps in. Kubernetes is an open-source container orchestration platform that automates the deployment, scaling, and management of containerized applications — especially those created with Docker.

As part creating the Demo I've used UpCloud - A Leading European Cloud Provider.

Why UpCloud Good for Containers and Kubernetes?

UpCloud is a high-performance cloud provider known for:

⚡ Ultra-fast MaxIOPS storage
🌍 Global data centers
🧩 Easy Kubernetes-ready infrastructure (via manual setup or Terraform)
💰 Cost-effective pricing for scalable clusters

Whether you're starting locally with Minikube or going full-scale with K8s on cloud VMs, UpCloud gives you the flexibility and performance edge.

What is Docker?

Docker is a tool that packages your code, libraries, and dependencies into a container—an isolated, lightweight executable. Containers solve the “it works on my machine” problem, ensuring consistent environments across dev, test, and production.
But what happens when you have hundreds or thousands of these containers?

What Is Kubernetes?

Kubernetes (aka K8s) is an open-source container orchestration engine developed by Google. It manages clusters of Docker containers, offering automation, monitoring, and self-healing capabilities out of the box.

How Kubernetes helps to Orchestrate Docker Containers

Let’s break down the Orchestration functionality of Kubernetes brings:

1. Automated Deployment and Rollbacks

Define your desired container state in YAML files.
Kubernetes ensures the cluster matches this state.
Supports rolling updates and easy rollbacks if something goes wrong.

2. Self-Healing Mechanisms

Failed containers? Kubernetes replaces them automatically.
Restarts containers if they crash.
Removes non-responsive containers from the network.

3. Load Balancing and Service Discovery

Automatically distributes network traffic across containers.
Built-in DNS service allows containers to find each other by name.

4. Horizontal Scaling

Scale container instances up/down based on CPU/memory usage.
Manual or automatic scaling using the Horizontal Pod Autoscaler.

5. Resource Optimization

Efficient bin-packing ensures optimal use of compute resources.
Limits and requests help avoid resource hogging.

Core Components of Kubernetes

Category	Component	Definition
Control Plane	kube-apiserver	Handles all REST requests and serves as the front-end of the Kubernetes control plane.
	etcd	Stores all Kubernetes cluster data in a distributed, consistent key-value store.
	kube-scheduler	Assigns pods to nodes based on defined scheduling rules and resource availability.
	kube-controller-manager	Runs controllers to monitor and maintain the desired cluster state.
	cloud-controller-manager	Manages cloud-specific control loops like load balancers, volumes, and node management.
Node Components	kubelet	Ensures that containers in pods are running as defined in their PodSpecs.
	kube-proxy	Maintains network rules for pod-to-pod and pod-to-service communication.
	Container Runtime	Executes and manages containers on the node (e.g., containerd, CRI-O).
Workload Object	Pod	The smallest deployable unit that can run a container or set of containers in Kubernetes.
Networking Object	Service	Exposes a stable network endpoint for accessing a group of pods.
Cluster Resource	Cluster	A set of nodes and control plane components that together run containerized workloads.

Real-World Example of Kubernetes Implementation

Imagine you have a web app built with Node.js in a Docker container:

You define a Deployment that runs 3 replicas.
Kubernetes ensures 3 instances are always running.
If one crashes, it spins up a new one instantly.
A Service ensures traffic is routed to available instances.
Want to scale to 10 instances? Just change the replica count.

Demo of Deploying a Docker image in Kubernetes

We will see the step by step approach to deploy an application Docker image in kubernetes using minikube

Create a Server in UpCloud

System Requirement for Minikube is 2 Core CPU, so we have created an UpCloud server with 2 Core CPU and 4 GB RAM in Singapore Region.

👉 Start with UpCloud and deploy your next app with confidence.

You can also get started with UpCloud by following the documentation here

Logged into UpCloud server and proceeded the further steps

Steps to Deploy Application in Kubernetes

Step 1: Install Minikube and Dependencies

1.1 Install Docker (Required for Minikube)

Please Follow Docker Installation Steps in official documentation to install Docker.

Docker Official Documentation

1.2 Install Kubectl (Kubernetes CLI)

Please Follow Installation Steps to install Kubectl here - Official Installation Docs

curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
chmod +x kubectl
sudo mv kubectl /usr/local/bin/
kubectl version --client

1.3 Install Minikube

Please Follow Installation Steps to install Minikube here - Installation Docs

List of commands to install Minikube

curl -Lo minikube https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64
chmod +x minikube
sudo mv minikube /usr/local/bin/
minikube version

Step 2: Start Minikube Cluster

minikube start --driver=docker 
# or
minikube start --driver=docker --force

Step 3: Deploy a Simple Application

3.1 Create a Deployment

kubectl create deployment my-app --image=nginx

3.2 Expose the Deployment

kubectl expose deployment my-app --type=NodePort --port=80

3.3 Get Service Details

kubectl get svc my-app

3.4 Access the Application

minikube service my-app --url

Step 4: Scale the Application

kubectl scale deployment my-app --replicas=3
kubectl get pods -o wide

Step 5: Clean Up Resources

kubectl delete svc my-app
kubectl delete deployment my-app
minikube stop
minikube delete

(Alternative Method) Using `deployment.yaml` File

Create a deployment.yaml file, which deploys a nginx server and creates a service for access it.

Here’s a simple Kubernetes deployment.yaml file that deploys an nginx container and exposes it using a NodePort service.

We are deploying the yaml in minikube cluster, to access the service via your browser using minikube.

📄 `nginx-deployment.yaml`

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
        - name: nginx
          image: nginx:latest
          ports:
            - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  type: NodePort
  selector:
    app: nginx
  ports:
    - port: 80
      targetPort: 80
      nodePort: 30080

🧪 Steps to Deploy and Access NGINX

Apply the YAML file:

kubectl apply -f nginx-deployment.yaml

Check pod and service status:

kubectl get pods
kubectl get svc nginx-service

Access NGINX in browser (if using Minikube):

minikube service nginx-service --url

This will return a URL like: http://192.168.49.2:30080 — open this in your browser.

Conclusion

As part of this blog, you have learnt the following aspects,

What is Docker and Kubernetes
Basics understanding of various components of Kubernetes and it's advantages
how to deploy Docker image using Kubernetes using kubectl in-line command and Kubernetes yaml deployment.

In the next blog - we will see how to scale the application and we will get into internals of application scaling in Kubernetes.

Call to Action

Ready to scale your Docker containers with ease? Dive deeper into Kubernetes, or start building your own K8s-powered apps today!

Shout out to UpCloud for their developer-friendly cloud platform.

If you're trying out Kubernetes or deploying applications for testing or learning — check out UpCloud Developer Plans.

Use the personalized promo code cloudenginelabs to get $50 in free credits with an extended 30-day trial period.

👉 Start with UpCloud and deploy your next app with confidence.

You can also get started with UpCloud by following the documentation here

DEV Community: UpCloud