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elft3r merged 5 commits into from
Jun 3, 2026
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Add multi-stage builds section to docker-training #42

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38b1901
Add multi-stage builds section to Docker training
claude Jun 3, 2026
7317acf
Fix card sizing and consistency in multistage-builds section
claude Jun 3, 2026
5d690d4
Shorten card text instead of reducing font size
claude Jun 3, 2026
756fbbf
Replace oversized cards with styled-list on Multi-Stage Builds slide
claude Jun 3, 2026
49e0d98
Fix accessibility and size unit consistency
claude Jun 3, 2026
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19 changes: 10 additions & 9 deletions docker-training/CLAUDE.md
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Original file line number Diff line number Diff line change
Expand Up @@ -19,15 +19,16 @@ Sections are loaded in this order (see `index.html`):
9. `docker-desktop.html` — Docker Desktop
10. `docker-commands.html` — CLI commands
11. `docker-images.html` — images & Dockerfiles
12. `docker-networking.html` — container networking
13. `docker-volumes.html` — persistent storage
14. `docker-compose.html` — Docker Compose
15. `devops-docker.html` — DevOps with Docker
16. `docker-swarm.html` — Swarm orchestration
17. `serverless.html` — serverless concepts
18. `docker-kubernetes.html` — Kubernetes overview
19. `monitoring.html` — container monitoring
20. `resources.html` — further resources
12. `multistage-builds.html` — multi-stage builds
13. `docker-networking.html` — container networking
14. `docker-volumes.html` — persistent storage
15. `docker-compose.html` — Docker Compose
16. `devops-docker.html` — DevOps with Docker
17. `docker-swarm.html` — Swarm orchestration
18. `serverless.html` — serverless concepts
19. `docker-kubernetes.html` — Kubernetes overview
20. `monitoring.html` — container monitoring
21. `resources.html` — further resources

## Local Development

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1 change: 1 addition & 0 deletions docker-training/index.html
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Expand Up @@ -40,6 +40,7 @@
<section data-external="sections/docker-commands.html"></section>
<section data-external="sections/docker-time.html"></section>
<section data-external="sections/docker-images.html"></section>
<section data-external="sections/multistage-builds.html"></section>
<section data-external="sections/docker-networking.html"></section>
<section data-external="sections/docker-volumes.html"></section>
<section data-external="sections/docker-compose.html"></section>
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142 changes: 142 additions & 0 deletions docker-training/sections/multistage-builds.html
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@@ -0,0 +1,142 @@
<section class="section-title" aria-label="Section: Multi-Stage Builds"><h2>Multi-Stage Builds</h2></section>

<section>
<h2>The Problem &mdash; Bloated Images</h2>
<div class="grid grid-cols-2 gap-6">
<div>
<pre><code class="language-dockerfile" data-trim>
FROM golang:1.23

WORKDIR /app
COPY main.go .
RUN go build -o hello main.go

EXPOSE 8080
CMD ["./hello"]
</code></pre>
<pre><code class="language-bash" data-trim>
$ docker image ls hello-single
REPOSITORY SIZE
hello-single 838 MB
</code></pre>
</div>
<div class="grid grid-cols-1 gap-4">
<div class="card fragment">
<span class="icon-accent"><i class="fa-solid fa-triangle-exclamation" aria-hidden="true"></i></span>
<p>Compiler &amp; build tools ship in the final image — never needed at runtime.</p>
</div>
<div class="card fragment">
<span class="icon-accent"><i class="fa-solid fa-shield-halved" aria-hidden="true"></i></span>
<p>More packages = more vulnerabilities, slower pulls, higher costs.</p>
</div>
</div>
</div>
</section>

<section>
<h2>Multi-Stage Builds</h2>
<div class="grid grid-cols-2 gap-6">
<div>
<pre><code class="language-dockerfile" data-trim>
# Stage 1: Build
FROM golang:1.23 AS builder
WORKDIR /app
COPY main.go .
RUN CGO_ENABLED=0 go build -o hello main.go

# Stage 2: Minimal runtime
FROM alpine:3.21
WORKDIR /app
COPY --from=builder /app/hello .
EXPOSE 8080
CMD ["./hello"]
</code></pre>
</div>
<ul class="styled-list">
<li class="fragment"><strong>Stage 1</strong> compiles using the full <code>golang:1.23</code> image.</li>
<li class="fragment"><strong>Stage 2</strong> copies only the binary into a fresh <code>alpine:3.21</code> image.</li>
<li class="fragment">Build tools never reach the final image.</li>
</ul>
</div>
</section>

<section>
<h2>The Result &mdash; 98% Smaller</h2>
<div class="grid grid-cols-2 gap-6">
<div class="card fragment">
<span class="icon-accent"><i class="fa-solid fa-box-open" aria-hidden="true"></i></span>
<h3>Single-Stage</h3>
<p>Go toolchain + compiler + sources + app</p>
<pre><code class="language-bash" data-trim>
hello-single 838 MB
</code></pre>
</div>
<div class="card fragment">
<span class="icon-accent"><i class="fa-solid fa-feather-pointed" aria-hidden="true"></i></span>
<h3>Multi-Stage</h3>
<p>Alpine Linux + compiled binary only</p>
<pre><code class="language-bash" data-trim>
hello-multi 12.1 MB
</code></pre>
</div>
</div>
</section>

<section>
<h2>Named Stages &amp; COPY --from</h2>
<div class="grid grid-cols-2 gap-6">
<div>
<h3>Assign names with AS</h3>
<pre><code class="language-dockerfile" data-trim>
FROM golang:1.23 AS builder
FROM alpine:3.21 AS runtime
</code></pre>
<h3>Reference by name or number</h3>
<pre><code class="language-dockerfile" data-trim>
# By name (preferred)
COPY --from=builder /app/hello .

# From an external image
COPY --from=nginx:latest \
/etc/nginx/nginx.conf /nginx.conf
</code></pre>
</div>
<div class="card">
<span class="icon-accent"><i class="fa-solid fa-layer-group" aria-hidden="true"></i></span>
<p>Copy from any build stage or external image — without including it in the final result.</p>
</div>
</div>
</section>

<section>
<h2>One Dockerfile, Multiple Targets</h2>
<div class="grid grid-cols-2 gap-6">
<div>
<pre><code class="language-bash" data-trim>
# Production: run all stages
$ docker image build \
--tag hello-multi:1.0 .

# Dev: stop at the builder stage
$ docker image build \
--target builder \
--tag hello-dev:1.0 .
</code></pre>
<pre><code class="language-bash" data-trim>
REPOSITORY SIZE
hello-multi 12.1 MB # production
hello-dev 838 MB # full toolchain
</code></pre>
</div>
<div class="grid grid-cols-1 gap-4">
<div class="card fragment">
<span class="icon-accent"><i class="fa-solid fa-rocket" aria-hidden="true"></i></span>
<p>Production — minimal image, binary only.</p>
</div>
<div class="card fragment">
<span class="icon-accent"><i class="fa-solid fa-wrench" aria-hidden="true"></i></span>
<p>Development — full toolchain, same Dockerfile.</p>
</div>
</div>
</div>
</section>
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