Deploy Cassandra Cluster on Kubernetes with K8ssandra

Happy devSecOps

(λx.x)eranga

Published in

Effectz.AI

4 min readNov 18, 2021

Background

In this post I’m gonna discuss about deploying Cassandra cluster on Kubernetes with using K8ssandra. All the deployments which related to this post available in gitlab. Please clone the repo and continue the post.

About K8ssandra

K8ssandra is an open-source production-ready distribution of Apache Cassandra for Kubernetes. It uses Kubernetes Operator to manage Cassandra clusters in Kubernetes. Additionally it includes packages/tools for automation of Cassandra operational tasks such as repairs, backups, and monitoring. Following are the main packages/tools includes in K8ssandra. K8ssandra assembles these tools and delivered as a collection of Helm charts. That is the main difference between other Kubernetes Cassandra Operators(Cass-Operator, CassKop) and K8ssandra.

Cass-Operator — The Kubernetes Operator to manage Cassandra database cluster on Kubernetes. It’s at the heart of K8ssandra.
Cassandra Reaper — Automatic Cassandra repair management tool.
Cassandra Medusa— Cassandra Backup and restore tool that works with different storage options.
Prometheus —Tool for collecting and visualizing metrics in the cloud-native container world.
Grafana — Data/matrix visualization tool which capable for making dashboards on top of Prometheus & Graphite.
Metric Collector — Built on collectd, it can work with Prometheus and Grafana or other systems.
Traefik — Ingress management/Proxy for containers and Kubernetes.
Stargate — Open-source data gateway providing common API interfaces for backend databases(e.g Cassandra).

Setup Kubernets Cluster

I have installed K8ssandra in local environment with K3d based Kubernetes cluster(K3d run Kubernetes cluster on Docker). K8ssandra currently support till Kubernets v1.21.1. So I have installed Kubernetes cluster below to this version(v1.20.12). Following is the way to setup the Kubernetes cluster with K3d.

Deploy K8ssandra

Following is the configuration file to deploy single node Cassandra cluster with K8ssandra. This configuration need to inject when deploying the Helm chart.

The deployment of K8ssandra can be done with Helm chart as below. Then Helm chart will install all the above mentioned tools as Kubernetes pods and expose the Kubernetes services for them.

Connect to Cassandra

First we need to find the K8ssandra superuser username and password in order to access Cassandra utilities and do things like generate a Stargate access token.

K8ssandra expose Cassandra APIs to outside via k8ssandra-dc1-stargate-service. Basically the service exposes 8080/TCP: GraphQL interface, 8081/TCP: REST authorization service, 8082/TCP: REST interface, 9042/TCP: CQL service. Following is the way to connect to Cassandra with nodetool and cqlsh.

Connect to Prometheus

K8ssandra expose Prometheus APIs via k8ssandra-kube-prometheus-prometheus service. It export 9090/TCP port. We can port forward this port to the outside the cluster and connect to the Prometheus web.

Connect to Grafana

K8ssandra expose Grafana APIs via k8ssandra-grafana service. It export 80/TCP port. We can port forward this port to the outside the cluster and connect to the Grafana web dashboards. admin/admin123 are the username/password of Grafana dashboard. These admin credentials are defined in the k8ssandra.yaml config file.

Connect to Reaper

K8ssandra expose Reaper APIs via k8ssandra-reaper-reaper-service. It export 8080/TCP port. We can port forward this port to the outside the cluster and connect to the Reaper web.