Containers provide consistency and portability for applications, allowing for increased deployment efficiency and density, with Docker being a key tool in this ecosystem. Docker simplifies the creation, running, and sharing of containerized applications, facilitating scalable solutions like Kubernetes. Originating from the Linux Containers standard, Docker gained prominence for its ability to maintain uniformity across environments, promoting the concept of "write once, run anywhere." Although containers are immutable and ephemeral, which can pose challenges for stateful workloads, they offer significant benefits by packaging system libraries with applications, enabling right-sizing and high-density deployments. The article discusses the basics of using Docker, including pulling and running images, and hints at the complexity of orchestrating these containers with Kubernetes, which will be explored further in subsequent parts of a series by Harness.