Heroku vs. Docker: What’s the Difference?

Heroku vs. Docker: What's the Difference?


Heroku and Docker are both highly popular container solutions. They deploy software in containers, which are virtual "packages" that bundle applications' source code together with their dependencies and configurations. This ensures that they always run predictably in different environments. But what's the difference between Heroku and Docker, and what are the Heroku vs. Docker issues you should know about?

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What is Heroku?

Heroku is a PaaS (platform as a service) for building and running software applications in the cloud. Although it was originally designed for the Ruby on Rails web application framework, Heroku now also supports programming languages such as Java, Python, and Node.js.

Some key Heroku terms are:

  • Heroku "dynos" are virtualized Linux containers that are the building blocks of Heroku applications, offering flexibility and scalability.
  • Heroku buildpack is a config script for the build automation process, describing how a container image should be created.
  • Heroku add-ons are tools and services for extending a Heroku application's functionality, such as data storage and processing, monitoring, or analytics.
  • The command-line interface (CLI) is Heroku's tool for building and running Heroku apps from within the terminal. (Docker, too, uses its own CLI for working with the platform.)
  • Git is a version control system for tracking changes to a software's source code. Heroku makes it easy to manage your app deployments with git, and has built-in integrations with the GitHub hosting platform for git repositories.

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What is Docker?

Docker is an open-source solution for building, deploying, and running applications within containers. Docker containers are standardized "units" of software that combine source code with libraries, frameworks, configuration settings, and other dependencies that the application needs to behave the same in different environments.

Methodologies such as DevOps frequently use containerization tools like Docker to deploy applications in a more predictable and reliable manner. In addition, solutions such as Kubernetes use Docker for managing and orchestrating containers at scale across multiple clusters.

Some key Docker terms are:

  • Docker image is a set of processes or templates for instantiating a Docker container (i.e. the "recipe" for containerization in the deployment pipeline).
  • Dockerfile (or Docker file) is a text configuration file that tells the Docker image what to install or update.
  • container registry is a repository that stores Docker images.
  • Docker Compose is a tool for running multiple containers as a single application service.
  • The docker ps command is used within Docker's CLI to see which containers are currently running.

Heroku vs. Docker: 3 Key Differences

The 3 biggest differences between Heroku vs. Docker are:

  • Environment: One of the most important differences between Heroku and Docker is that Heroku must run in its own cloud environment, while Docker can run in an environment of your choice—whether that's your laptop, a remote server, or a public cloud service like Amazon Web Services (AWS).
  • Flexibility: Because Heroku applications can only be run in the Heroku environment, this may create issues with vendor lock-in. Docker's flexibility frees you from these concerns, with deployment options ranging from on-premises servers to even the Heroku PaaS itself.
  • Pricing: As an open-source solution, Docker is free of charge (although business users will likely shell out for the enterprise edition). Meanwhile, each Heroku dyno costs between $25 and $50 per month with Heroku's standard plan.
Heroku vs. Docker: What's the Difference?

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When it comes to Heroku vs. Docker, the right answer depends on your own situation. So why not go with a tremendously flexible, scalable solution like IronWorker? Get in touch with our team today for a chat about your business needs and objectives, or to schedule a demo of IronWorker.

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