Gain insights into Docker, its impact on development, and why it's essential. Learn about creating, deploying, and running applications with containers to enhance your software and career.

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docker-hello

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By now, you've probably heard the buzz around Docker. It's fundamentally changed the development process and been adopted by software teams of all sizes, and for good reason: Docker makes it considerably easier to create, deploy, and run applications with the use of containers.

Docker is here to stay, and is becoming one of the most in-demand technologies on the market. Mastering it now will help you produce better software, level up your career, and stand out from the crowd. Get started today.

Docker for Developers

In this chapter, we saw some tools (the `--restart-mode` switch, the *docker stats* command) that help keep your containers running and keep an eye on them. This is good for starters. However, if you rely on containers and/or have high workloads, using such tools and automating their use will become tedious.

Imagine coding calls to create or update containers, and to remove them when necessary. How will you update your containers when you publish new versions? Since running containers is cheap, you may want to perform rolling updates so that your application isn't down during updates. In a rolling update, a new container is started with the newest image, and once it is ready, users are routed to it, then the old container is removed. Imagine coding this; it's going to be tedious.

Now factor in the possibility that several Docker hosts may need to run your containers either for large workloads, scaling out, or simply good reliability. In such cases, you will need to set up a reverse proxy and have it route users to the appropriate containers. You really don't want to maintain script files that do this.

Good news; you don't need to worry about that. Those problems are solved by orchestration tools. When such needs arise, it will be time to use an orchestration tool like Docker Swarm or Kubernetes.

Kubernetes or Docker Swarm receive your orders and apply them. You create a cluster of servers (a single server is fine also), then you feed your Kubernetes or Docker Swarm with a file that states which containers you want, how to expose them to the outside world, and how many containers should be run for each image. Your orchestrator will make sure that happens.

Here is an example Kubernetes file:



We've been using the term 'orchestration' throughout the course. In this lesson, you'll learn what orchestration tools are and when to use them.

Orchestration Basics

Before Getting Started

Why Docker?

Get Docker up and Running

Basic Concepts

Use Docker Images

Create Docker Images

Publish Docker Images

Forget SDK Installs

Docker with Common Development Profiles

More About Running Containers

Orchestration Basics