Book Image

Hands-On Docker for Microservices with Python

By : Jaime Buelta
Book Image

Hands-On Docker for Microservices with Python

By: Jaime Buelta

Overview of this book

Microservices architecture helps create complex systems with multiple, interconnected services that can be maintained by independent teams working in parallel. This book guides you on how to develop these complex systems with the help of containers. You’ll start by learning to design an efficient strategy for migrating a legacy monolithic system to microservices. You’ll build a RESTful microservice with Python and learn how to encapsulate the code for the services into a container using Docker. While developing the services, you’ll understand how to use tools such as GitHub and Travis CI to ensure continuous delivery (CD) and continuous integration (CI). As the systems become complex and grow in size, you’ll be introduced to Kubernetes and explore how to orchestrate a system of containers while managing multiple services. Next, you’ll configure Kubernetes clusters for production-ready environments and secure them for reliable deployments. In the concluding chapters, you’ll learn how to detect and debug critical problems with the help of logs and metrics. Finally, you’ll discover a variety of strategies for working with multiple teams dealing with different microservices for effective collaboration. By the end of this book, you’ll be able to build production-grade microservices as well as orchestrate a complex system of services using containers.
Table of Contents (19 chapters)
Free Chapter
1
Section 1: Introduction to Microservices
3
Section 2: Designing and Operating a Single Service – Creating a Docker Container
7
Section 3:Working with Multiple Services – Operating the System through Kubernetes
13
Section 4: Production-Ready System – Making It Work in Real-Life Environments

Making a Kubernetes cluster change through GitHub

Your local Kubernetes cluster, through Flux, will update to reflect changes in the Git repo. Any change in Git will be propagated to the cluster after a few minutes.

Let's see this with a test updating the number of pods in the frontend deployment:

  1. Change the Chapter08/example/frontend/deployment.yaml file in your forked repo as described here:
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: frontend
labels:
app: frontend
namespace: example
spec:
replicas: 2

This changes the number of replicas from 4 to 2.

  1. Commit the change into the master branch and push into the GitHub repo.
  2. Monitor the cluster with the following command:
$ kubectl get pods -n example -w

You will see how the number of frontend pods will decrease after a few minutes. You can speed it up by manually syncing Flux.

  1. Revert the change...