chainsaw-kube: A Java repository from brunojensen

[ WARNING ] This is a small project that I've created to try some libraries and frameworks for study purposes, don't use it in production without review and configure everything properly.

Why chainsaw? Nothing special, was a github suggestion. =)

Here you'll find:

Spring-boot application with spring-cloud-config-client, actuator, google jib (docker img creator), oauth2 client.
Quarkus application (need improvements)
Spring cloud config server.
Helm chart for the applications
Keycloak installed with helm charts

What I'm planning to add

Add Prometheus for monitoring
GraphQL as Backend For Frontend (BFF)
ArchUnit to keep architecture consistent
Migrate to Helm 3
Support for openshift
Keycloak cluster
Upgrade to OpenJDK 11

Follow the recipe and should work, otherwise drop an issue:

openJDK 8
Maven
VirtualBox
Minikube / Kind

motivation: basic kubernetes env. to run applications locally

Minikube installation: https://kubernetes.io/docs/tasks/tools/install-minikube/

Kind installation: https://kind.sigs.k8s.io/docs/user/quick-start/

** Additional steps for Minikube:
```
# start a new kubernetes cluster with minikube
minikube start --cpus 2 --memory 8192

# first steps
kubectl config use minikube

# config to use internal docker environment
eval $(minikube docker-env)
```
Helm charts V3+:

motivation: easy to deploy containers and stateful services into kubernetes and also have a good catalog of ready-to-use charts and configurations.

installation: https://helm.sh/docs/intro/install/
Keycloak operator

motivation: provides a great management interface, openID support and it has a great development and support community
1. Install Operator Lifecycle Manager (OLM), a tool to help manage the Operators running on your cluster.
```
$ curl -sL https://github.com/operator-framework/operator-lifecycle-manager/releases/download/0.14.1/install.sh | bash -s 0.13.0
```
1. Install the operator by running the following command:What happens when I execute this command?
```
$ kubectl create -f https://operatorhub.io/install/keycloak-operator.yaml
```
1. This Operator will be installed in the "my-keycloak-operator" namespace and will be usable from this namespace only.
After install, watch your operator come up using next command.
```
$ kubectl get csv -n my-keycloak-operator
```
1. Create a Keycloak instance:
** You can download and customize the keycloak.yaml as you need.
```
kubectl apply -f https://raw.githubusercontent.com/keycloak/keycloak-operator/master/deploy/examples/keycloak/keycloak.yaml
```
To use it, checkout the custom resource definitions (CRDs) introduced by this operator to start using it.

IMPORTANT:

There's some step to configure on keycloak:
1. From the "Realm Setting" > "Keys" click on the public key button and copy the public key to be used on the chainsaw-config-server as is configured on this Github repo: https://github.com/brunojensen/chainsaw-kube-config
2. Create a new client called "bank-platform" with "Client Protocol"="openid connect".
Optionally, we could also install keycloak-gatekeeper to work as a side-car to app pod and provide authentication out-of-shelf
Service discovery comes off-the-shelf with kubernetes

motivation: kubernetes provides a way to identify services and balance the request between the multiple instances of the application.
Monitoring with spring actuator and kubernetes liveness/readness probe

motivation: as a quick solution to monitor the health of the application and configure the environment to restore in case of failure
Spring-boot Services

motivation: spring-boot provides an easy-to-go template generation for microservices. One good alternative was to use the quarkus project, but I didn't want to go that far and the requirements of this code challenge is to use spring. But to create the docker image I decide to use a google container tool called jib.
```
# pre-defined bash script to run maven and helm to package and install the application on the local environment
chmod +x app.sh && ./app.sh install
```

Postgres operator

how to install via helm

helm install postgres-operator ./charts/postgres-operator

how to create a postgres instance

kubectl create -f k8s-config/postgres-manifest/minimal-postgres-manifest.yaml

Obs.: change to the service type to NodePort

how to get host/port/user/password

export HOST_PORT=$(minikube service acid-minimal-cluster --url | sed 's,.*/,,')
export PGHOST=$(echo $HOST_PORT | cut -d: -f 1)
export PGPORT=$(echo $HOST_PORT | cut -d: -f 2)
export PGPASSWORD=$(kubectl get secret postgres.acid-minimal-cluster.credentials -o 'jsonpath={.data.password}' | base64 -d)'

Application evaluation

# requires "jq" -> https://stedolan.github.io/jq/download/
# use this script to run tests on the APIs.
./app.sh

kubectl tips:

https://kubernetes.io/docs/reference/kubectl/overview/

brunojensen/chainsaw-kube