Spring boot and Consul in Kubernetes

Apr 15, 18

Synopsis

In this post, I will walk through an example to demonstrate the usage of Spring boot and Consul in the Kubernetes environment

To keep things simple, I will not make use of TLS and tokens for communication between Consul Agent and Server.

The logical view for this setup is quite simple and can be tested both in Minikube and Kubernetes on the Cloud.

Code example for this blog is available here. https://github.com/hariinfo/service-c

Logical view

------- POD 1 --------------------    ------- POD 2 ----------------------
                                 |   |   Consul server 0 (Leader)         |
                                 |    ------------------------------------
                                 |    --------- POD 3 --------------------  
Spring Boot App -> Consul Agent  | ->|   Consul server 1                  |
(container 1)      (container 2) |    ------------------------------------
                                 |    -------- POD 4 ---------------------       
                                 |   |   Consul server 2                  |
----------------------------------    ------------------------------------

Deploy microservice and consul agent

kubectl create -f deploy.yaml

Create consul configmap

kubectl create -f consul-config.yaml

Create consul service

kubectl create -f consul-server-service.yaml

Create consul deployment

kubectl create -f consul-server-deploy.yaml

Validate Consul Agent and Server Logs

Validate the logs to ensure consul server and client have joined successfully through the gossip protocol

kubectl logs consul-0
kubectl logs consul-1
kubectl logs consul-2

Accessing the web UI

kubectl port-forward consul-0 8500:8500

Visit http://127.0.0.1:8500 in your web browser.

Test your application

From the consul UI, create a simple key value pair Key=config/consulAppSample/servicec Value=Hello World!!!

Now access the Spring boot URL, In minikube setup you may retrieve the service url as follows

minikube service service-c --url

Visit [http:///getKV](http:///getKV) in your web browser. You should now see the KV value that you entered from Consul UI

Cleanup and Purge command

kubectl delete deployment,service service-c
kubectl delete statefulset, service consul
kubectl delete config consul-config