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https://github.com/mfactory-lab/lagom-on-kube

This tutorial describes how to bootstrap a production-ready Lagom microservices cluster in a Kubernetes environment.
https://github.com/mfactory-lab/lagom-on-kube

ansible aws cassandra docker kubernetes kubernetes-cluster lagom lagom-services lightbend microservice microservice-framework scala service-discovery telegram telegram-api telegram-bot tutorial wolfram-alpha wolfram-alpha-api

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This tutorial describes how to bootstrap a production-ready Lagom microservices cluster in a Kubernetes environment.

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# Lagom on Kube



This *tutorial* describes how to bootstrap a production-ready [Lagom][lagom] microservices cluster in a [Kubernetes][kubernetes] environment.



![alt lagom on kube][tech]



## The Problem



[Lagom][lagom] is a great **java**- and **scala**-based [reactive][reactive] microservices framework. Lagom is free to use in both development and production. However, as detailed later in this doc, deploying lagom requires some extra weight lifting by the end user or using Lightbend's [ConductR][conductr] (which is [free to use up to three nodes](https://www.lightbend.com/platform/enterprise-suite)).



With this tutorial, you can bootstrap a [Kubernetes][kubernetes] cluster hosting [Lagom][lagom] microservices, which is **free-to-use**, however **production-ready**.



The [Lagom framework][lagom] lacks following fuctionality and attributes required for a production-ready microservices framework:



- Service orchestration

- Scalability

- Monitoring

- Resilience

- Load balancing

- Service discovery



Turns out, all of the above can be achieved with [Docker][docker] and [Kubernetes][kubernetes]. (I'm pretty sure it's also possible using [Docker Swarm][docker-swarm] or [Apache Mesos][apache-mesos], but those ways are outside of the scope of this tutorial.)



## The Solution



- **Service orchestration**: we package all of the Lagom services into Docker containers, which are then 'orchestrated' (i.e. deployed, scaled, managed, etc.) through standard Kubernetes tools.



- **Scalability** is provided on two levels

  - Within a Kubernetes cluster, scaling is performed by *Deployments* and *Replication controllers*

  - AWS offers *Auto Scaling group* for further scalability when a Kubernetes cluster hits its limit



- **Monitoring** is provided on two levels as well

  - Heapster (InfluxDB and Grafana) to monitor containers and nodes

  - New Relic to monitor everything at service level



- **Resilience**

  - *Kubernetes Pods* can be configured to track the health status of Docker containers

  - *Deployments* keep number of active containers in line with current load



- **Load balancing** is provided by Kubernetes *services* which select a Pod randomly for each request (more complex load balancing strategies are available using [Ingress][ingress] or an external load balancer, however these methods are outside of the scope of this document)



- [**Service Discovery**][service-discovery] was the *only part* which had to be implemented, not just configured. It is based on the free-to-use Lagom develempent-mode service register and received a number of improvements making it resilient, persistent and compatible with the Kubernetes architecture.



## The Technologies



- [AWS][aws] as a cloud platform

- [kops][kops] to bootstrap Kubernetes on AWS

- [Kubernetes][kubernetes] for service orchestration

- [Ansible][ansible] for configuration management

- [Docker][docker] as a container

- [Lagom][lagom] as a microservices framework

- [Heapster][heapster] for container and node monitoring

- [New Relic][new relic] for application monitoring

- [Cassandra][cassandra] as a persistent storage for service registry



## The Description



The Demo infrastructure is described in [this document][description]



[lagom]: https://www.lagomframework.com/

[reactive]: http://www.reactivemanifesto.org/

[lightbend]: http://www.lightbend.com/platform

[conductr]: https://conductr.lightbend.com/

[lightbend-ra]: http://www.lightbend.com/platform

[docker-swarm]: https://docs.docker.com/engine/swarm/

[apache-mesos]: http://mesos.apache.org/

[service-discovery]: lagomKubeServiceRegister

[aws]: https://console.aws.amazon.com

[kops]: https://github.com/kubernetes/kops/blob/master/docs/aws.md

[kubernetes]: https://kubernetes.io/

[ansible]: https://www.ansible.com/

[docker]: https://www.docker.com/

[heapster]: https://github.com/kubernetes/heapster

[new relic]: https://newrelic.com/

[cassandra]: http://cassandra.apache.org/

[ingress]: https://kubernetes.io/docs/concepts/services-networking/ingress/

[description]: ./docs/service-description.md

[tech]: https://alexanderray.github.io/lagom-on-kube-dev/img/tech_web.svg