README.md

Docker sample app

About The Project

This is an application for Docker practice

Endpoint	Description
/hello	returns "Hello Stranger"
/hello?name=mhzz	returns "Hello mhzz" (camel case gets cut by spaces)
/author	returns "Mohammad-Hossein Zeynalzadeh"

Running sample application locally

this app is a Spring Boot application built using Maven. You can build a jar file and run it from the command line (it should work just as well with Java 11 or newer):

git clone https://github.com/mh-zeynal/docker-sample.git
cd docker-sample
./mvnw package
java -jar target/*.jar

You can then access the app here: http://localhost:8080/hello

Or you can run it from Maven directly using the Spring Boot Maven plugin. If you do this it will pick up changes that you make in the project immediately (changes to Java source files require a compile as well - most people use an IDE for this):

./mvnw spring-boot:run

NOTE: Windows users should set git config core.autocrlf true to avoid format assertions failing the build (use --global to set that flag globally).

Docker instruction

1. Ensure your docker installed. See here

2. Go to project's root directory

3. Now you have two options
   3.1:

   • Run docker build -t demo .
   • Then run docker run -p 8080:8080 demo

   or

   3.2:

   • Run docker-compose up

4. Visit http://localhost:8080/hello

NOTE: erase "novinrepo:8082/docker/" from both docker-compose.yml and dockerfile

Working with docker-sample App in your IDE

Prerequisites

The following items should be installed in your system:

• Java 17 or newer (full JDK not a JRE).
• git command line tool (https://help.github.com/articles/set-up-git)
• Your preferred IDE
  • Eclipse with the m2e plugin. Note: when m2e is available, there is an m2 icon in Help -> About dialog. If m2e is not there, just follow the install process here: https://www.eclipse.org/m2e/
  • Spring Tools Suite (STS)
  • IntelliJ IDEA
  • VS Code

deploy project on kubernetes(kind)

requirements

• kind local k8s cluster
• kubectl cli tool

build project's image

first and foremost, package the maven project. Run this command at the root of project

mvn clean package

Then, build docker image with command below

docker build . --tag docker_sample:0.0.1

create kind cluster

go to kubernetes directory and run

kind create cluster cluster-config.yml

NOTE: remove novinrepo:8082/docker/ from config file

load image on kind cluster

We load our image on kind cluster as below

kind load docker-image docker_sample:0.0.1

In order to check if image is loaded or not, run this:

docker exec -it kind-control-plane crictl images

the result will be something like this:

execute deployment config

To make a pod out of our project, go to kubernetes directory and run

kubectl apply -f .\deployment-config.yml

access the service from outside of cluster

The port of pod inside of cluster is 8080. At first, get id of pod using

kubectl get pods

now map a local port to cluster's internal port using

kubectl port-forward pod_id 9090:8080

In our case, pod_id is docker-sample-95c4c54f-f9kb6
After port mapping, we can send request to localhost:9090 and use defined routes
enjoy :)