We have designed CircleCI 2.0 to provide faster build performance and give users greater control over their environments. Users have full control over their customized build environments and do not have to worry about build environments being updated without your knowledge or becoming out of date.

We utilize the power of Docker to provide our users the flexibility of creating customized environments. Users can preinstall dependencies/tools in custom Docker images, so that you can have the exact versions and releases you want in your images.

The flexibility of creating custom Docker images has enabled our users to efficiently build many languages on our 2.0 platform. If your code builds on Linux, it will generally build on CircleCI 2.0. Users are building projects in C, C#, C++, Clojure, Elixir, Erlang, Go, Groovy, Haskell, Haxe, Java, Javascript, Node.js, Perl, PHP, Python, Ruby, Rust, Scala and many more languages on the platform today.

Languages that Build on Linux Build on CircleCI 2.0

Many of our 2.0 beta users have provided constructive feedback around setting up customized environments. We are listening. To address this feedback, we have added the following two options:

CircleCI Docker Images

We have created an initial set of Docker images for popular languages and databases to help get users started on 2.0. These images are generally supersets of official Docker images and have additional tooling for your builds and tests to successfully run on CircleCI.

We have images for the following:
Go
Node.js
Python
Ruby
MongoDB
MySQL
PostgreSQL

Many of these images have different variations. Please refer to our documentation for additional details.

Create your own

You can create your own custom image, upload it to a image registry (Dockerhub, Google Container Registry, Quay or Amazon ECR) and use this image with one of our executors.

Please refer to our documentation for instructions on creating your own custom Docker images.

Stay tuned

We will continue to add more features to our 2.0 platform in the coming weeks.

If you have questions or feedback, please do let us know by posting in our Discuss forums https://discuss.circleci.com/c/circleci-2-0

Update: As of July 11, 2017, CircleCI 2.0 is out of beta and publicly available. To see our new features click here.