// INSTRUCTION: Please remove all comments that start INSTRUCTION prior to commit. Most comments should be removed, although not the copyright. // INSTRUCTION: The copyright statement must appear at the top of the file // // Copyright (c) 2018 IBM Corporation and others. // Licensed under Creative Commons Attribution-NoDerivatives // 4.0 International (CC BY-ND 4.0) // https://creativecommons.org/licenses/by-nd/4.0/ // // Contributors: // IBM Corporation // :projectid: caching-microservices-hazelcast :page-layout: guide :page-duration: 25 minutes :page-releasedate: 2019-02-15 :page-description: Explore how to use caching in microservices within Kubernetes environment. :page-tags: ['Hazelcast', 'Caching', 'microservices', 'Kubernetes', 'Containers','Spring Boot' , 'Minikube'] :page-permalink: /guides/{projectid} :page-related-guides: ['docker', 'kubernetes-intro'] :common-includes: https://raw.githubusercontent.com/OpenLiberty/guides-common/master :source-highlighter: prettify :page-seo-title: Caching in microservices with Hazelcast Tutorial :page-seo-description: How to use Hazelcast with microservices = Caching Microservices with Hazelcast in Kubernetes

[.hidden] NOTE: This repository contains the guide documentation source. To view the guide in published form, view it on the https://openliberty.io/guides/{projectid}.html[Open Liberty website].

Use Hazelcast Caching in Open Liberty and Spring Boot based Microservices and deploy to Kubernetes

:minikube-ip: 192.168.99.100 :kube: Kubernetes :hashtag: # :win: WINDOWS :mac: MAC :linux: LINUX :hazelcast: Hazelcast

// ================================================================================================= // What you'll learn // =================================================================================================

== What you'll learn

You will learn how to use Hazelcast distributed caching with Spring Boot, bundle with openliberty and deploy to a local {kube} cluster. You will then create a Kubernetes Service which load balance between containers and verify that you can share data between Microservices.

The microservice you will deploy is called hazelcast-caching. The hazelcast-caching microservice simply helps you put a data and read it back. As Kubernetes Service will send the request to different pod each time you initiate the request, the data will be served by shared hazelcast cluster between hazelcast-caching pods.

You will use a local single-node {kube} cluster. However, you can deploy this application on any kubernetes distributions such as IBM Cloud Private.

== What is {hazelcast}? Hazelcast is an open source In-Memory Data Grid (IMDG). It provides elastically scalable distributed In-Memory computing, widely recognized as the fastest and most scalable approach to application performance.

Hazelcast is designed to scale up to hundreds and thousands of members. Simply add new members and they will automatically discover the cluster and will linearly increase both memory and processing capacity

== Why Spring Boot? Spring Boot makes it easy to create stand-alone, production-grade Spring based Applications that you can "just run". To learn more about Spring Boot. http://spring.io/projects/spring-boot

// ================================================================================================= // Prerequisites // =================================================================================================

include::{common-includes}/kube-prereq.adoc[]

// ================================================================================================= // Getting Started // =================================================================================================

include::{common-includes}/gitclone.adoc[]

// no "try what you'll build" section in this guide since it would be too long due to all setup the user will have to do.

// ================================================================================================= // Staring and preparing your cluster for deployment // =================================================================================================

include::{common-includes}/kube-start.adoc[]

// ================================================================================================= // Use Hazelcast Caching in Spring Boot Application // =================================================================================================

== Use Hazelcast Caching in Spring Boot Application

The microservice in the start directory has in-process cache which is not accessible between microservices.

Firstly, you need to configure Hazelcast to be used in Spring Boot Application. replace Application.java with the following java class.

[source, java]

include::finish/src/main/java/io/openliberty/guides/hazelcast/Application.java[tags=**;]

This configuration will tell Spring Boot what kind of configuration is needed when each hazelcast member is started.

Now it is time to use Hazelcast in the hazelcast-caching microservice. if you check the source code of CommandController.java, you would notice that ConcurrentHashMap is used for backing key value store. In order to make this cache distributed, replace CommandController.java with Hazelcast version.

[source, java]

include::finish/src/main/java/io/openliberty/guides/hazelcast/CommandController.java[tags=**;]

You would notice that getting hazelcast member is Autowired by Spring Boot and made available to the CommandController and there is no change in /put and /get endpoints.

// ================================================================================================= // Building and containerizing the microservices // =================================================================================================

== Building and containerizing microservice

The first step of deploying to {kube} is to build your microservices and containerize them with Docker.

The starting Java project, which you can find in the start directory, is a spring boot based microservice. It is called hazelcast-caching which has two simple endpoints, /put and /get. This guide uses boost-maven-plugin to bundle spring boot app and openliberty together and build docker image for the deployment. Boost plugin does not require you to create your own Dockerfile but instead opionated docker image.

If you wanna learn more about boost maven plugin, you can visit the project website. https://github.com/OpenLiberty/boost/tree/master/boost-maven

If you want to create your own Dockerfile then you can always use dockerfile-maven plugin. please refer to https://openliberty.io/guides/kubernetes-intro.html#starting-and-preparing-your-cluster-for-deployment

To build hazelcast-caching microservice, run the following command in the start folder. This will build the docker image and push it to docker registry provided by minikube

[role='command']

mvn package

Execute following command to see available docker images

[role='command']

docker images

Verify that the hazelcast-caching:latest is listed among them, for example:

[system]#{win} | {mac}#

[source, role="no_copy"]

REPOSITORY TAG IMAGE ID CREATED SIZE hazelcast-caching latest ee0fb6a53f68 11 seconds ago 595MB