Sunday, May 10, 2020

Run a Spring Boot application on OCI Compute Instance

In this article, we will see how to deploy a spring boot application in Oracle cloud compute instance.

Creating a new Spring Boot app and running it locally

We will create a spring boot app and test locally. can be used to start. Or there is a sample Hello World project I have created can be referred

package myexpjava.demo; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.ResponseBody; @Controllerpublic class DemoController { @GetMapping("/hello") @ResponseBody public String sayHello() { return "Hello World !!!"; } } ./gradlew bootRun This command will run the application and we can test the same in any browser in the url http://localhost:8080/hello/ It should print Hello World !!! in browser

Creating an OCI compute instance and deploy the app.

We will try to deploy this app directly to a single OCI compute instance and we will run it. 
For this example, we have used the standard Oracle-Linux-7.8 image.
To create a compute instance in OCI console, we need to navigate compute and create instance. To access the instance we need ssh keys, to genarte the same please refer 

Once the compute is ready. We need to install Java, as our Spring Boot App requires a java environment to run.
1. ssh to compute instance
ssh -i ~/.ssh/oci_compute opc@<public ip> of the compute instance>
2. Install java in the compute instance, for this example jre is enough.
sudo yum install jre-12.x86_64
3. Configure the firewall to open port 8080, as our app will run in 8080
sudo firewall-cmd --zone=public --permanent --add-port=8080/tcp
sudo firewall-cmd --reload
Make a directory where we will copy our spring app
mkdir spring-app/

4. Network configuration to allow Internet traffic to our compute instance.
     a) We need an internet gateway configured in the VCN where the compute instance belongs
     b) Route table entry to allow the traffic through the internet gateway

    c) Security Ingress rule needs to be added to allow traffic. 

5. Copy our Spring Boot app from laptop to compute instance and run.
./gradlew clean build This will build and create the spring-web-rest-demo-1.0.jar in ./build/libs
To copy the same to our compute instance
scp -i ~/.ssh/oci_compute build/libs/spring-web-rest-demo-1.0.jar opc@<public ip>:spring-app/
Now ssh to the compute and run the app
ssh -i ~/.ssh/oci_compute opc@<public ip> of the compute instance>
java -jar spring-app/spring-web-rest-demo-1.0.jar

Our spring app should run in port 8080. If all the configs are correct 
we should able to see Hello World !!! in the browser, by trying compute's 
http://<public ip>:8080/hello
If you don't see please revisit step 3 and 4