Jib vs containerd: What are the differences?

Introduction

Jib and containerd are both popular tools used in the containerization of applications. However, there are key differences between the two that set them apart. This Markdown code will provide a clear overview of these differences in a concise manner.

1. Architecture: Jib is a higher-level build tool that allows developers to containerize their applications without requiring knowledge of Docker or writing Dockerfiles. It provides a fast and simple build process by directly building containers from the application's source code. On the other hand, containerd is a low-level container runtime that focuses on running containers and managing their lifecycle. It is used as the container runtime for various container orchestration systems like Kubernetes.

2. Build process: With Jib, the container build process is integrated directly into the application build process. This means that developers can build and push their container images along with their application code using existing build tools like Maven or Gradle. In contrast, containerd does not directly handle the container build process. It relies on tools like Docker or BuildKit to build container images, which are then pushed to a container registry for storage.

3. Layering and caching: Jib uses a layered approach to container image building, where each layer represents a specific phase of the application build process (dependencies, resources, classes, etc.). This allows for better caching of layers during subsequent builds, resulting in faster build times. On the other hand, containerd relies on the layering mechanisms provided by the underlying container build tool (e.g., Docker). It does not have its own built-in layering or caching capabilities, and the caching behavior depends on the specific container build tool used.

4. Image distribution: Jib pushes container images directly to a registry, eliminating the need for an intermediate step of locally saving the image as a Docker image file. This ensures faster and more efficient image distribution. In contrast, containerd does not handle image distribution itself. It relies on external tools like Docker, BuildKit, or container registries to push and distribute container images.

5. Container runtime: Jib integrates with various container runtimes, allowing developers to choose their preferred runtime for running the containerized application. It abstracts away the complexities of the underlying runtime, making it easier to switch between different runtimes. On the other hand, containerd is itself a container runtime and is commonly used as the underlying runtime for container orchestration systems like Kubernetes.

6. Supported platforms: Jib is designed to support multiple platforms, including both the JVM and non-JVM applications. It provides separate plugins for Maven and Gradle to cater to the different build tools used in the Java ecosystem. Containerd, on the other hand, is a general-purpose runtime that can run containers for various platforms and languages, not limited to Java.

In summary, Jib is a higher-level build tool focused on simplifying the containerization process by integrating it into the application build process, while containerd is a low-level container runtime used for managing containers' lifecycle in a production environment.