hal

Table of Contents

• Overview
• Key features
• Demonstration
• Building hal
• Downloading a snapshot
• Deploying a component using hal
  • 1. Scaffold the Spring Boot applications
  • 2. Deploy the Component
  • 3. Connect to the REST services
• Additional documentation

Overview

Hal is a CLI tool for developers to simplify the deployment of applications such as Spring Boot on OpenShift and Kubernetes using Dekorate and Halkyon Component Operator. Made with ❤️ by the Halkyon team.

Key features

hal is part of the Halkyon project which aims to simplify the deployment of modern micro-services applications on Kubernetes. We encourage you to take a look to the documentation of Halkyon in order to understand better the context of hal. hal is a tool capable of communicating with the cluster doing the following tasks

• Scaffold Spring Boot applications
• Deploy Microservices applications as Components
• Switch the DeploymentMode of the component from Dev to Build mode
• Compose & link microservices

Demonstration

To see hal in action where it will compose 2 Spring Boot Applications as microservices with a Database

Building hal

• git clone this project outside of your $GOPATH (since it uses go modules) or set GO111MODULE=on on your environment
• Build: cd hal;make with Go 1.11+ (currently only 1.12 is tested)
• Run: ./hal, this will display the inline help
• Enjoy!

Downloading a snapshot

• Go to https://circleci.com/gh/halkyonio/hal/tree/master and select the build number you are interested in (presumably, one that succeeded! 😁)
• Select the Artifacts tab and navigate the hierarchy to find the artifact you are interested in.

Deploying a component using hal

After installing hal, the following steps allows to create and deploy a project to a cluster. Note: this assumes that you are connected to a Halkyon-enabled OpenShift/Kubernetes cluster.

1. Scaffold the Spring Boot applications

• Create a development folder on your laptop mkdir haldemo && cd haldemo

• Create a new scaffolded component (note that it might make more sense to do this interactively):

hal component create \
    -r spring-boot \
    -i 2.1.6.RELEASE \
    -g me.example \
    -a hello-world \
    -v 1.0.0-SNAPSHOT \
    -p me.example.demo \
    -s true \
    -x true \
    -o 8080 \
    hello-world

2. Deploy the Component

A component represents a micro-service, i.e. part of an application to be deployed. The Component custom resource provides a simpler to fathom abstraction over what's actually required at the Kubernetes level to deploy and optionally expose the micro-service outside of the cluster. In fact, when a component is deployed to a Halkyon-enabled cluster, the Halkyon operator will create these OpenShift/Kubernetes resources such as Deployment, Service, PersistentVolumeClaim, Ingress or Route on OpenShift if the component is exposed.

• Compile and generate the halkyon descriptors files of the application using the following command:

  mvn package -f hello-world

• Push the hello-world component to the remote cluster you're connected to:

  hal component push -c hello-world

• Check if the component has been correctly installed:

  
  kubectl get components

NAME RUNTIME VERSION AGE MODE STATUS MESSAGE REVISION hello-world spring-boot 2.1.6.RELEASE 7m17s dev Ready Ready 6aadfc1a982fcd68

### 3. Connect to the REST services

If you deploy on OpenShift, get the route address of the microservice using this command: 

oc get routes/hello-world --template={{.spec.host}}

If you deploy on a plain Kubernetes, you can use this command:

kubectl get ingress/hello-world

Copy/paste the address displayed within the terminal in a browser and say Hello world 😉

## Additional documentation

Additional documentation can be found below:
- [CLI Reference](https://github.com/halkyonio/hal/blob/master/cli-reference.adoc)