k8s-playground

Kubernetes Playground

This project contains a Vagrantfile and associated Ansible playbook to provisioning a 3 nodes Kubernetes cluster using VirtualBox and Ubuntu 18.04.

Attention

Ansible playbook is not idempotent, so if you run it twice error happens.

Prerequisites

You need the following installed to use this playground:

• Vagrant, tested with version 2.2.14
• VirtualBox, tested with Version 6.1
• Internet access, this playground pulls Vagrant boxes from the Internet as well as installs Ubuntu application packages from the Internet.

Bringing Up The cluster

To bring up the cluster, clone this repository to a working directory.

git clone https://github.com/i-sevostyanov/k8s-playground.git

Change into the working directory and vagrant up

cd k8s-playground/vagrant
vagrant up

After the vagrant up is complete, you can connect to management machine and wait few minutes until all pods not started. You can check the status by running the following commands:

vagrant ssh management
kubectl get pods -o wide -A

Everything is okay?

To check that the consumer and producer are working correctly you need to connect to the management machine and execute the following command:

kubectl exec -i -t kafka-0 -- kafka-console-consumer --bootstrap-server localhost:9092 --topic output --from-beginning

If the screen displays dates in RFC format with an interval of 5 seconds (by default), then everything works correctly:

2021-01-01T08:49:26Z
2021-01-01T08:49:31Z
2021-01-01T08:49:36Z
2021-01-01T08:49:41Z
2021-01-01T08:49:46Z
2021-01-01T08:49:51Z

Monitoring

Grafana

To access the grafana dashboards, you need to do port forwarding as follows:

vagrant ssh management
kubectl port-forward `kubectl get pods -l app=grafana -n monitoring -o name` --address 0.0.0.0 3000:3000 -n monitoring &

After you can access grafana by going to the following address: http://192.168.50.13:3000. In addition to Kubernetes dashboards, you will find a dashboard with consumer and producer metrics, as well as a Kafka dashboard.

Prometheus

Same for Prometheus:

vagrant ssh management
kubectl port-forward prometheus-k8s-0 --address 0.0.0.0 9090:9090 -n monitoring &

Prometheus web interface will be available at http://192.168.50.13:9090.

What can be improved

• Idempotent Ansible Playbooks
• Linting for Ansible Playbooks (ansible-lint)
• Split Ansible Playbooks into roles and tasks
• Testing for Ansible Playbooks (Molecule)
• Parametrize kubernetes manifests with helm or kustomize
• Collect metrics from JMX