NexQloud Knowledge Base

The technology behind containerization leverages core features of the Linux kernel to create isolated user spaces. The process follows a clear, reproducible workflow:

1. Define: A developer writes a simple text file (e.g., a Dockerfile). This file acts as a blueprint, containing step-by-step instructions on how to build the application environment (e.g., "start with this base OS image," "copy my application code," "install these dependencies").‍
2. Build: A container engine (like Docker) uses this file to build a container image. This image is an immutable, read-only template that contains the layered filesystem of your application. Each instruction in the file creates a new layer, making images efficient to store and transfer.‍
3. Store: The completed image is pushed to a container registry (e.g., Nexqloud Container Registry), which acts as a library or repository for versioned container images.‍
4. Run: To start the application, the container engine pulls the image from the registry and creates a running container instance. The engine uses kernel features to provide isolation:
   • ‍Namespaces: Isolate the container's view of the system (processes, network, filesystem).‍
   • Cgroups (Control Groups): Limit and measure the resources (CPU, memory, I/O) a container can use.

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