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The distinction between an image and a container is the foundation of everything Docker does. New users conflate the two, and the confusion persists until they hit a problem that forces them apart: an image that cannot be deleted because a container is using it, a container that loses data because the image is read-only,…
You have learned how to run a container. You can build an image, start a container, map a port, and view logs. That works on a single machine. But production is not a single machine. It is a fleet of servers, and the application must run across them, survive failures, scale with demand, and update…
The previous chapter introduced Kubernetes and the declarative model. This chapter covers the architecture that makes the model work: the components that make decisions, the components that run workloads, and the resource that sits between them. Kubernetes has two halves. The control plane makes global decisions about the cluster and responds to cluster events ….
The previous chapter covered the Kubernetes architecture. This chapter covers the tool you use to interact with that architecture: kubectl. It is the command-line interface for Kubernetes, and every action on the cluster goes through it . You use it to deploy applications, inspect resources, view logs, debug problems, and manage the cluster itself. The…
DevOps is a set of practices, cultural philosophies, and tools that integrate software development and IT operations. It is not a job title, a tool, or a single methodology. It is a response to a specific problem: the wall between the people who write software and the people who run it. That wall produces slow…
Continuous Integration and Continuous Delivery are the two practices that turn DevOps from a philosophy into a workflow. They are the engine of the software delivery pipeline: the automated system that takes code from a developer’s commit and moves it, step by step, toward production. The LFCA exam places CI/CD under DevOps Fundamentals, which carries…
Continuous Integration is the practice of merging code changes into a shared repository frequently, and verifying each merge with an automated build and test. It is the first half of CI/CD, and it is the foundation that makes Continuous Delivery possible. Without CI, the rest of the pipeline has nothing reliable to build on. The…
The previous chapter covered Continuous Integration — the practice of merging code frequently and verifying it automatically. This chapter covers the two practices that follow: Continuous Delivery and Continuous Deployment. They are often confused because they share the same abbreviation, CD. But they are different practices with different workflows, different risk profiles, and different requirements….
Every project that involves more than one person, or more than one day of work, needs version control. It is the system that records every change to a set of files, who made the change, when, and why. It allows a team to work on the same codebase simultaneously without overwriting each other’s work. It…
Version control is the foundation of collaborative software development. Git is the version control system that dominates the industry, and it is one of the core tools the LFCA exam expects you to know under DevOps Fundamentals, which carries 12–16% of the total weight. The study plan lists “Git” as a core DevOps tool alongside…