Free Tier: Set up Helidon on an Ubuntu Instance

To configure the Ubuntu firewall, follow these steps:

1. Open the navigation menu and click Compute. Under Compute, click Instances.
2. Click the link to the instance you created in the previous step.

   From the Instance Details page look under the Primary VNIC section. Copy the public IP address the system created for you. You use this IP address to connect to your instance.

3. Open a Terminal or Command Prompt window.
4. Change into the directory where you stored the ssh encryption keys you created in part 2.
5. Connect to your instance with this SSH command.

   ssh -i <your-private-key-file> ubuntu@<x.x.x.x>

   Since you identified your public key when you created the instance, this command logs you into your instance. You can now issue sudo commands to install and start your server.

6. Update firewall settings.

   The Ubuntu firewall is disabled by default. However, you must update your iptables configuration to allow HTTP traffic. Run the following commands:

   iptables.

   sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 8080 -j ACCEPT
   sudo netfilter-persistent save

   The commands add a rule to allow HTTP traffic through port 8080 and saves the changes to the iptables configuration files.

1. Run the following commands:

   sudo apt update
   sudo apt -y install openjdk-11-jdk-headless
   java -version

2. Set JAVA_HOME in .bashrc.

   Update the file:

   vi .bashrc

   In the file, append the following text and save the file:

   # set JAVA_HOME
   export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64

3. Activate the preceding command in the current window.

   source ~/.bashrc

Run the following commands:

1. Install Maven.

   sudo apt -y install maven

2. Verify the Maven installation.

   mvn --version

Run the following Maven Archetype which creates a Maven project template to start with. This project uses the Helidon MP Quickstart example from the Helidon website. Run the following commands:

1. Run Helidon Maven install. For example:

   mvn -U archetype:generate -DinteractiveMode=false \
       -DarchetypeGroupId=io.helidon.archetypes \
       -DarchetypeArtifactId=helidon-quickstart-mp \
       -DarchetypeVersion=2.2.1 \
       -DgroupId=io.helidon.examples \
       -DartifactId=helidon-quickstart-mp \
       -Dpackage=io.helidon.examples.quickstart.mp

   The Archetype creates a Maven project under the current directory. Your output is similar to the following:

   [INFO] Project created from Archetype in dir: /home/ubuntu/helidon-quickstart-mp
   [INFO] BUILD SUCCESS

   Note
   
   To install the latest version of Helidon MP, see Helidon MP Quickstart
2. Change to the helidon-quickstart-mp directory.

   cd helidon-quickstart-mp

3. Build the application.

   mvn package

   You get a message of success.

   [INFO] BUILD SUCCESS

4. Run the application.

   java -jar target/helidon-quickstart-mp.jar

You can now test your application.

1. From a new terminal, connect to your Ubuntu instance with your SSH keys, and then in the command line enter:

   curl -X GET http://localhost:8080/greet

   Or, you can connect your browser to the public IP address assigned to your instance: http://<x.x.x.x>:8080/greet

   You see {"message":"Hello World!"} on your instance, or in your browser.

2. Enter a name for the greeting. From the terminal, enter:

   curl -X GET http://localhost:8080/greet/Mike

   Or, from your browser, enter: http://<x.x.x.x>:8080/greet/Mike.

   You see {"message":"Hello Mike!"} on your instance, or in your browser.

3. Update the greeting. From the terminal, enter:

   curl -X PUT -H "Content-Type: application/json" -d '{"greeting" : "Aloha"}' http://localhost:8080/greet/greeting

   The command updates the Hello in the message to Aloha.

4. Test the updated greeting. From the browser, enter: http://<x.x.x.x>:8080/greet/Mike.

   You see {"message":"Aloha Mike!"} on your instance, or in your browser.

5. Enter the following commands in your browser to get health and metrics.

   http://<x.x.x.x>:8080/health
   http://<x.x.x.x>:8080/metrics

   To get metrics in JSON, from the terminal, enter:

   curl -H 'Accept: application/json' -X GET http://localhost:8080/metrics

Congratulations! You have successfully created a Hello World application using the Helidon MicroProfile service, on your Oracle Cloud Infrastructure instance.

References:

For detailed information on this example, see Helidon MP Quickstart