listings/exercises/ex12a-containerfile-steps/Containerfile

@@ -1,12 +0,0 @@
-FROM debian:12
-
-RUN apt-get update && apt-get install -y curl
-
-WORKDIR /app
-
-COPY hello.sh .
-RUN chmod +x hello.sh
-
-ENV NAME=Trainee
-
-CMD ["./hello.sh"]

listings/exercises/ex12a-containerfile-steps/commands.txt

@@ -1,75 +0,0 @@
-# Exercise 12a — Build a Containerfile step by step
-#
-# Start with an empty Containerfile and add one instruction at a time.
-# After each step: podman build -t myapp:latest .
-# Then inspect the result before moving on.
-
-cd listings/exercises/ex12a-containerfile-steps/
-
-# -----------------------------------------------------------------------
-# Step 1 — Base image
-# -----------------------------------------------------------------------
-# Containerfile:
-#   FROM debian:12
-
-podman build -t myapp:latest .
-podman images myapp:latest          # ~121 MB
-
-# -----------------------------------------------------------------------
-# Step 2 — Install software (creates a new layer)
-# -----------------------------------------------------------------------
-# Add to Containerfile:
-#   RUN apt-get update && apt-get install -y curl
-
-podman build -t myapp:latest .
-podman images myapp:latest          # ~159 MB — layer is visible
-
-# -----------------------------------------------------------------------
-# Step 3 — Working directory
-# -----------------------------------------------------------------------
-# Add to Containerfile:
-#   WORKDIR /app
-
-podman build -t myapp:latest .
-podman run --rm myapp:latest pwd    # prints /app
-
-# -----------------------------------------------------------------------
-# Step 4 — Copy your script into the image
-# -----------------------------------------------------------------------
-# Add to Containerfile:
-#   COPY hello.sh .
-#   RUN chmod +x hello.sh
-
-podman build -t myapp:latest .
-podman run --rm myapp:latest ls -la # hello.sh is there
-
-# -----------------------------------------------------------------------
-# Step 5 — Environment variable
-# -----------------------------------------------------------------------
-# Add to Containerfile:
-#   ENV NAME=Trainee
-
-podman build -t myapp:latest .
-podman run --rm myapp:latest env | grep NAME
-
-# -----------------------------------------------------------------------
-# Step 6 — Start command
-# -----------------------------------------------------------------------
-# Add to Containerfile:
-#   CMD ["./hello.sh"]
-
-podman build -t myapp:latest .
-podman run --rm myapp:latest                 # uses ENV NAME=Trainee
-podman run --rm -e NAME=Frank myapp:latest   # override at runtime
-
-# -----------------------------------------------------------------------
-# Bonus: layers — chained vs. separate RUN
-# -----------------------------------------------------------------------
-# Two separate RUN = two layers:
-#   RUN apt-get update
-#   RUN apt-get install -y curl
-#
-# One chained RUN = one layer:
-#   RUN apt-get update && apt-get install -y curl
-
-podman inspect myapp:latest --format '{{len .RootFS.Layers}} layers'

listings/exercises/ex12a-containerfile-steps/hello.sh

@@ -1,5 +0,0 @@
-#!/bin/bash
-echo "Hello, ${NAME:-World}!"
-echo "Hostname: $(hostname)"
-echo "Date: $(date)"
-curl --version | head -1