Sidecar container pattern in Kubernetes - Mini Project: Build & Apply

Sidecar Container Pattern in Kubernetes

📖 Scenario: You are deploying a web application in Kubernetes. You want to add a sidecar container that helps with logging. The sidecar container will run alongside the main web app container in the same pod.

🎯 Goal: Create a Kubernetes pod manifest with two containers: a main container named webapp running the nginx image, and a sidecar container named log-agent running the busybox image. The sidecar container will simulate log collection by running a simple command.

📋 What You'll Learn

Create a pod manifest with metadata name webapp-pod

Add a container named webapp using the nginx image

Add a sidecar container named log-agent using the busybox image

Configure the sidecar container to run the command sh -c "while true; do echo collecting logs; sleep 5; done"

Output the complete pod manifest YAML

💡 Why This Matters

🌍 Real World

Sidecar containers are used in Kubernetes to add supporting features like logging, monitoring, or proxying without changing the main application container.

💼 Career

Understanding the sidecar pattern is important for DevOps roles working with Kubernetes to build scalable and maintainable applications.

1

Create the basic pod manifest with the main container

Create a Kubernetes pod manifest YAML with apiVersion set to v1, kind set to Pod, and metadata.name set to webapp-pod. Add a single container named webapp using the nginx image under spec.containers.

Kubernetes

apiVersion: v1
kind: Pod
metadata:
  name: webapp-pod
spec:
  containers:
  - name: webapp
    image: nginx
    # Your code here

Need a hint?

Start with the pod basics: apiVersion, kind, metadata, and spec. Then add the containers list with one container named webapp using the nginx image.

2

Add the sidecar container configuration

Add a second container to the spec.containers list. Name this container log-agent and use the busybox image.

Kubernetes

apiVersion: v1
kind: Pod
metadata:
  name: webapp-pod
spec:
  containers:
  - name: webapp
    image: nginx
  # Add the sidecar container named log-agent with busybox image below
  # Your code here

Need a hint?

Remember to add the sidecar container as a second item in the containers list under spec.

3

Configure the sidecar container command

Add the command field to the log-agent container. Set it to run sh -c "while true; do echo collecting logs; sleep 5; done" to simulate continuous log collection.

Kubernetes

apiVersion: v1
kind: Pod
metadata:
  name: webapp-pod
spec:
  containers:
  - name: webapp
    image: nginx
  - name: log-agent
    image: busybox
    # Add the command to run the log collection loop below
    # Your code here

Need a hint?

Use the YAML list syntax for the command field with sh, -c, and the loop string.

4

Output the complete pod manifest

Print the complete pod manifest YAML to display the final configuration with both containers and the sidecar command.

Kubernetes

# Print the pod manifest YAML below
# Your code here

Need a hint?

Just output the full YAML manifest as text. This is the final pod configuration.