Chef vs Docker. Understand the Difference

With the growth in DevOps adoption, configuration management and containerization are being used by a lot in many organizations. Configuration management is all about automating infrastructure using code and containerization is the modern way of virtualization which packages software and its dependencies inside standardized units. 

Now there are multiple tools out there for configuration management and containerization. In this blog, I will talk about two very popular tools, Chef (configuration management) and Docker (containerization) and their differences. Both are used in infrastructure automation, but the way of achieving the automation is very different. 

Let me briefly explain to you about these two DevOps tools.

What is Chef?

Chef is a very popular open-source configuration management tool developed by Adam Jacob at OpsCode in 2009. It is written in Ruby programming language. It is widely used to automate multiple IT tasks such as deployment and management of infrastructure. With configuration management tools like Chef, you can automate a lot of repetitive and manual tasks to save a lot of time for the administrators from such mundane tasks.

Chef uses recipe and cookbook to write all the configurations for deploying and managing the infrastructure. In Chef, recipe is used to define all the attributes (resources) need to manage the infrastructure and Cookbook is basically a collection of recipes. The cookbooks and available in the chef server and the recipes in cookbooks are deployed on every node after the ‘chef run’ command to update the infrastructure state. It has a command-line utility called Knife, where you need to run all the chef command.

Chef has a client-server architecture. This architecture has 3 tier which consists of chef workstation, chef-server and chef-client. The chef workstation is the location where all the cookbooks in chef are developed. The chef server is a single unit where all the configurations (cookbooks, API, policy, data store, etc.) are uploaded after development. Chef nodes are the machines that need to be managed. You need to install chef-client on all the nodes to communicate with the chef server.        

It follows a pull-based deployment model for configuration management. This means that the chef-client present on the chef node will pull configurations from the chef server and update the configuration of the nodes accordingly. You need not run any command on the chef server to apply the configuration on the nodes.

Chef advantages and features:

• Uses easy to learn Ruby language to create DSL for writing the configurations
• Easy integration with the majority of cloud providers such as AWS, Azure, GCP
• Configures thousands of machines (nodes) in a few minutes
• Uses pull-based configuration management model
• Helps you deploy the software faster through IT automation
• Well suited for developers for writing recipes in the cookbook

What is Docker?

Docker is one of the most popular DevOps tools used for containerization. Docker helps you to build, ship and run your applications anywhere. Docker packages your application with all the necessary dependencies and libraries inside a container and these containers can run the application on any platform seamlessly. In today’s IT world, a lot of time, developers and QA engineers get into arguments on the working of the application. The developer says it works on my system, but the QA engineer says it doesn’t work on his/her system. This is because the configuration of their systems is different. Docker was introduced to solve such problems with ease.

In comparison to a virtual machine, a docker container is much lighter. Virtual machines have their own (guest) operating system on top of the host operating system, whereas in Docker, the containers share the same HostOS, and that is why the size of containers is much lesser than virtual machines. Virtual machine blocks all the RAM assigned to it whether it is completely getting utilized or not, but container do not block RAM, they utilize RAM as needed to run the application. 

In DockerHub, you can find thousands of readily available docker images that you can use for running your application. It is basically GitHub of docker images. You can also upload your own docker images over DockerHub and share them with your team. They can pull the image on their system, which you uploaded on DockerHub and start developing the application on that image.

To run Docker, you need to install the docker engine on the host machine. Docker has a client-server architecture where server s docker daemon and client is the command-line interface. Docker uses REST APIs for communication between the server (docker daemon) and client (CLI).

Docker advantages and features:

• Provides consistent and isolated environments for running the application
• Alpine docker images take very less storage space
• Can run on all the operating systems and cloud providers with ease
• It is very fast to deploy and helps in rapid development
• Docker images on DockerHub are free to use, so it is cost-effective
• It can easily scale up and down containers as per the requirement
• The docker containers are secure to use as each container has its own resources for networking

Chef vs Docker: Key Differences

1. Configuration Management vs Containerization

The major difference between the two is the purpose for which these tools were created.

Chef is a configuration management tool that is used to manage and automate the IT infrastructure. It is based on the concept of infrastructure as code where you apply changes to your infrastructure using code. Here you play around with the configuration files and write scripts to execute the commands automatically.

Docker is a containerization tool. It was introduced to run the application packaged with its dependencies and libraries on the host operating system itself in a single unit. This makes the containers lightweight and the deployments are faster. Here you configure dockerfile with all the commands that needs to be executed in a sequence. 

2. Installation

The installation of Chef is complex as compared to docker installation. In Chef, you need to install Chef Automate and Chef Infra Server on the master machine. After that, you need to install the chef workstation, which provides the development kit for configuration management.

To install Docker, you just need to setup the docker engine depending on your operating system type. That’s all, you can start using docker after installing docker engine. 

3. Deployment

In chef, all the automated deployments happen through codified application definitions. The definitions contain all the instructions, configurations, dependencies required for the deployment. These definitions need to be present in the cookbooks.

In Docker, all the deployments happen through the dockerfile, which is present in the application repository. The deployments in docker are faster as all the dependencies are already packaged with the application’s container.

4. Learning Curve

Chef is complex than Docker. Writing recipes for configuration management on larger infrastructure can get complex. Whereas learning docker is very straightforward and creating dockerfile for larger infrastructure is easier using docker compose and docker swarm.

5. Community

Between Chef and Docker, I would say the community of Docker is comparatively stronger. If you check the GitHub repository of both the tools, Chef has 120 branches, 3425 tags, 404 watch, 6.4K star, 2.5K forks so far. Whereas Docker GitHub has multiple projects which comprise 100+ branches, 600+ tags, 1000+ watch, 60K+ star, 16K+ forks. But recently, both the tools have seen explosive growth in terms of their community activities.

Which One to Choose?

The working of these tools is for different purposes, so for only configuration management, you need to use Chef and for containerization, you need to use Docker. 

But, one can ask, can chef and docker be used together? The answer is ‘Absolutely’! 

The bigger organizations who are leveraging DevOps tools the most are using Chef and Docker together. All the popular configuration management tools like chef, puppet, ansible etc. have easy integration with docker. Using Chef cookbooks and recipes, you can easily deploy docker containers on your servers.

Here is a table which shows the differences between Chef and Docker briefly.

Final Thoughts

Both Chef and Docker are among the most popular DevOps tools in the industry. If you are starting to use DevOps in your organization for IT automation, then I would suggest starting with one tool at a time, depending on the requirement. Chef for configuration management and Docker for containerization. Because in the beginning, if you start with both, it can become complex for you to handle. If you are a well-established organization with in-house DevOps engineers, take leverage of both the tools in building some advanced automation.