Ticket #13: Add Dockerfile for health-check.sh

[PuneethM-06]

Description

Containerize the linux-sysmonitor health-check script so it can run identically on any machine with Docker installed, without requiring Bash or other dependencies on the host.

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Tasks

• Create a Dockerfile in the project root.
• Choose an appropriate base image (alpine:3.19 recommended for its small size) and document the reason in the README or commit.
• Install all required packages (e.g., bash, curl, etc.).
• Copy the project files into /app inside the image.
• Set the working directory using WORKDIR /app.
• Make the script executable (chmod +x health-check.sh).
• Define the container entry point:

  ENTRYPOINT ["./health-check.sh"]

• Build the image:

  docker build -t linux-sysmonitor:v1 .

• Run the container and verify it produces the same output as the native script:

  docker run --rm linux-sysmonitor:v1

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Acceptance Criteria

• Docker image builds successfully without errors.
• Container starts successfully using the configured ENTRYPOINT.
• Output matches the native execution of health-check.sh.
• No host-side Bash or additional dependencies are required.
• Dockerfile follows Docker best practices and is easy to understand.

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Commit Message

feat: add basic Dockerfile for health-check script (closes #13)

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Why This Matters

This is the foundation of Docker-based application packaging. Completing this ticket will help you understand:

• Selecting an appropriate base image.
• Installing dependencies inside a container.
• Docker image layers and build caching.
• COPY and WORKDIR.
• The difference between ENTRYPOINT and CMD.
• Building portable, reproducible environments.

Interview Tip: Be prepared to explain why you chose each Dockerfile instruction—not just what it does. Questions about base image selection, layer caching, and ENTRYPOINT vs CMD are very common in Docker interviews.

[PuneethM-06]

The ticket suggests using alpine:3.19, but after evaluating the requirements of the project, I chose debian:bookworm-slim instead for the following reasons:

• The linux-sysmonitor script depends on several standard Linux utilities. Debian provides a familiar GNU/Linux environment and uses the apt package manager, making dependency management straightforward.
• Debian uses glibc, which closely matches the environment found on many production Linux servers, reducing the likelihood of compatibility issues compared to Alpine's musl-based environment.
• Although the image is larger than Alpine, it offers a good balance between image size, compatibility, and ease of maintenance, which is appropriate for this learning project.

[PuneethM-06]

• Attaching the docker build here:

[PuneethM-06]

• Container started and ran successfully:

[PuneethM-06]

Enhancement in PR

• feat: containerize linux-sysmonitor health-check script linux-sysmonitor#18

[PuneethM-06]

@gayathrii12 Can I please get a review?