Introduction
When it comes to container image creation, the two industry giants are Packer and Docker. While they both perform the same task, there are differences in how they can be utilized. In this blog post, we will take a closer look at Packer and Docker, compare their strengths and weaknesses, and ultimately determine which is the better option.
Packer
Packer is an open-source tool used for creating identical machine images in different environments (virtual machines, containers, etc.) from a single-source configuration. It provides the ability to build, version, and then deploy these images to different cloud environments. Packer is written in Go and can run on Windows, Linux, and macOS.
Packer comes with various builders, including Docker, Google Cloud Platform, and AWS, among others, which makes it versatile.
Docker
Docker is a well-known tool used for creating, deploying, and running applications in containers. Docker containers are lightweight, run on any platform, and are easy to deploy. Docker images are built based on a Dockerfile, which includes all the necessary components to run your application.
Docker provides a platform for developing and deploying applications, making it ideal for DevOps teams.
Comparison
Building Images
Packer requires a builder-specific JSON structure and provisioning scripts for building the image. Unlike Docker, Packer provides additional flexibility in image creation, such as the ability to use configuration management tools or scripting languages to install software on the created image. However, this requires more knowledge about the software and its installation.
Docker, on the other hand, uses Dockerfiles that are easier to understand and modify. They use simple commands and are built based on previous layers, which increases speed and provides more opportunities for caching.
Configuration
Both Packer and Docker offer the ability to use configuration files, but they differ in their implementation. Packer uses either JSON or HCL files, which can be difficult to modify compared to Docker Compose files.
Docker Compose uses a YAML format and provides the ability to define complex container configurations that span multiple services easily. This allows infrastructure architecture to be maintained in a declarative template, ensuring the infrastructure consistency regardless of the deployment environment.
Size
Packer images tend to be larger as they include the necessary infrastructure components and applications to run the created image. This is useful when deploying an image in multiple environments. However, it may not be practical for development or testing purposes.
Docker images are much smaller, as they only include the necessary components required to run the application. This makes it a more efficient platform for development and testing.
Conclusion
Both Packer and Docker provide excellent solutions for creating container images. However, it is essential to consider the pros and cons when choosing which tool is best suited for your needs.
Packer is the better option when more complex infrastructure needs to be built within the image, whereas Docker is the better option for creating smaller containers for testing and development purposes.
Ultimately, the choice between Packer and Docker will depend on the specific needs of the project.
References
- HashiCorp Packer: https://www.packer.io/
- Docker: https://www.docker.com/
- Packer vs Docker: What’s the Difference? https://www.scalyr.com/blog/what-is-packer-and-how-does-it-compare-to-docker/