Spring-Boot & Redis Connectivity With Docker/Kubernetes

Introduction

In this article, we will learn on how to establish connectivity with Redis DB using spring-boot & deploying same on Kubernetes cluster.

Pre-Requisites

Editor — IntelliJ Idea/Eclipse

Language — Java 8 or above

Framework — Spring boot

Image Build Tool — Docker

Orchestration — Kubernetes(k8)

Database — Redis

GIT Repo

https://github.com/shethaptech/spring-boot/tree/main/redis-counter-service

Now, lets jump to the design & draw the outline of our implementation.

1. Design

We will design an microservice using spring-boot & jedis client to connect to Redis DB. This application will increment the visitor counter each time visitor visiting our page.

High level design

If you will refer to the above high level design,

→ we will have 2 pods running for “redis-counter-service” & Redis db server each.

→ Both pods are connected & will communicate via ClusterIP type k8s service.

→ We have exposed port 8080 for “redis-counter-service” & 6379 for Redis DB server.

→ “redis-counter-service” will connect to Redis DB using k8s service “reddis-db-svc” on port 6379.

2. Redis DB Server

Let’s install Redis DB using its docker image.

2.1 Pull Redis image from the container registry.

docker pull Redis // this will fetch from docker hub by default

2.2 Make Redis container up using image pulled from docker container registry.

docker run -p 6379:6379 — name redis -d redis

2.3 Verify that Redis DB is up.

docker exec -it redis sh

this command will take you to the Redis container’s bash. It implies that Redis container is up & we are able to connect.

Redis sh shell

Also, you can check logs of the Redis DB container to check if any error during startup or not.

Logs after installing Redis

Since we have Redis DB is up & running, Let’s make our service up.

3. Spring-Boot Service Set-up

3.1 Spring data JPA dependency for Redis

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

3.2 Spring boot java client for Redis

<dependency>
    <groupId>redis.clients</groupId>
    <artifactId>jedis</artifactId>
    <version>3.6.3</version>
</dependency>

3.3 Configuration

redis:
#  host: 127.0.0.1
  host: reddis-db-svc #this should be the k8s service name for Redis
  port: 6379

Please refer to the git repository for the code base.

4. Docker Image Build — Dockerfile

Please refer to the below configuration to build docker image.

docker build -f <<docker file path>> -t <<tag>>

FROM java
ARG ARTIFACT_NAME=redis-counter-service-0.0.1-SNAPSHOT.jar
ENV ARTIFACT_NAME=${ARTIFACT_NAME}
RUN mkdir /app
COPY target/${ARTIFACT_NAME} /app/
CMD java -jar /app/${ARTIFACT_NAME}

5. Container Orchestrations — Kubernetes(k8s)

Here, we will use Kubernetes(k8s) for container orchestrations.

we will create & k8s deployment & service object

Please refer to the git repository for the code base.

→ deploy K8s object using below command.

kubectl apply -f deployment.yaml

kubectl apply -f service.yaml

→ Verify k8s objects are up & available.

kubectl get svc

K8s services

kubectl get pod

K8s deployment

6. Show Time

Once k8s objects are up & running, hit the below URL. Each time you hit the URL, visit counter will increment

http://127.0.0.1:8080/counter/increment

Key takeaways

So, what we have learnt so far,

→ Spring boot service for visitor’s counter

→ Redis DB server using containerization

→ Docker to build an image

→ Kubernetes deployment & service