Actionable walkthroughs on containerization, multi-stage builds, microservices orchestration, container networking, and DevOps pipelines.
Containerization is the practice of packaging an application together with all its dependencies — libraries, runtime, system tools, and configuration — into a single, portable unit that can run consistently across any environment. Docker, released in 2013, did not invent this concept, but it standardized the tooling and workflow in a way that made containers…
Docker presents itself as a single command, but behind that command lies a layered architecture of cooperating processes. The Docker CLI you type into is only the outermost layer, a thin client that translates your input into API calls. Those calls reach the Docker daemon, which handles Docker-specific concerns like networking and volumes before delegating…
Linux namespaces are the kernel feature that makes containers possible. A namespace wraps a global system resource in an abstraction that makes it appear to processes within the namespace that they have their own isolated instance of that resource . Changes made by one process inside a namespace are visible to other processes that are…
Namespaces isolate what a container can see. Control groups determine how much of each resource it can use. These two kernel features are complementary and together they form the complete foundation of containerization. Without cgroups, a single container running a runaway process could consume all available memory on the host, saturate every CPU core, or…
Docker Engine does not install the same way on every operating system, and the differences are not cosmetic. On Linux, Docker Engine runs natively as a daemon that talks directly to the kernel’s namespaces and cgroups. On macOS, Docker Engine cannot run natively because macOS is not Linux — it has no namespaces and no…