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Docker Fundamentals
Solution: pull and smoke-test an image
This walkthrough matches the exercise. Adjust ports if 8080 is already in use on your machine. Step 1: Pull docker pull nginx:stable-alpine Docker downloads layer blobs from the ...
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Docker Fundamentals
Exercise: pull and smoke-test an image
Practice the chapter 2 verification habit: pull a public image, run it, prove it answers HTTP, and inspect what Docker stored locally. Work through the steps before you open the ...
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Docker Fundamentals
When build, pull, or cache goes wrong
Match the failing stage to the first command Build, push, and pull failures look alike in chat logs but have different root causes. Name the stage first, then run the smallest command that confirms or rules out the us...
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Docker Fundamentals
Build context and .dockerignore
Everything in the directory rides along with docker build The final argument to docker build is the build context path. Docker sends that directory tree to the builder before any instruction runs. .dockerignore is the...
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Docker Fundamentals
Fat bases, slim bases, and distroless choices
The FROM line sets the floor for every layer above it Every image is a stack of layers. The base image is the bottom one. Everything you add in RUN, COPY, and package installs sits on top of whatever FROM pulled in. P...
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Docker Fundamentals
Tags vs digests (sticky note vs serial number)
The simple rule When CI finishes a build, you get a boxed-up app called an image. That box does not change. You copy the same box to staging, then to production. The mistake teams make: they only write down a friendly...
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Docker Fundamentals
docker history, image size, and layer dedup
Measure layers instead of guessing Image size and rebuild time come from layer history, not from how tidy the Dockerfile looks. Build two near-identical images, change one source file, and let docker history show whic...
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Docker Fundamentals
Build, tag, and inspect an image locally
The local loop: build, name, inspect You can read Docker theory for a long time and still feel lost when CI fails. The useful floor skill is mechanical: turn a Dockerfile into a tagged artifact, run it once, and read ...
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Docker Fundamentals
Pull, run, and smoke-test an image
Pull an image, run it, prove it works This is the same loop you used with nginx in chapter 1 — now named in image vocabulary. See it { "ariaLabel": "docker pull then docker run", "segments&q...
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Docker Fundamentals
Image vs container and the layer stack
How layers stack at runtime An image is a stack of read-only layers. Each running container adds one thin writable layer on top. Most "Docker is weird" moments trace back to that stack. flowchart TD RW[&quot...
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Docker Fundamentals
Solution: add a healthcheck to nginx
healthcheck nginx Compare your Dockerfile and commands with the academy folder. GitHub example Academy repo: 1-install-docker/healthcheck-nginx Try it git clone https://github.com/stuarttodd-dev/halfshellstu...
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Docker Fundamentals
Exercise: add a healthcheck to nginx
Add a HEALTHCHECK to nginx You will run nginx with a Dockerfile you control, then prove Docker reports health status. GitHub example Academy repo: 1-install-docker/healthcheck-nginx Clone that folder when it is ready,...
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Docker Fundamentals
Verify with curl, logs, and healthchecks
Three ways to check a container “Running” is not the same as “healthy.” Build these habits early: Smoke test from outside: curl (or a browser) against a published port. Read logs: docker logs for startup error...
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Docker Fundamentals
One job per container and when to reach for Compose
One main job per container Docker stays understandable when each running container has a clear role. flowchart LR web["web container"] --> app["app container"] app --> db["database"...
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Docker Fundamentals
App code in the image, data in a volume
Two homes for two kinds of files App code and long-lived data do not belong in the same place in a container workflow. Put application code and runtime setup in the image (built from a Dockerfile). Put data that must ...
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Docker Fundamentals
Rebuild instead of patching by hand
When something breaks, resist the quick fix inside the container The tempting move is to jump into a running container and patch it by hand: docker exec -it hello-nginx sh Inside that shell, you might install a packag...
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Docker Fundamentals
Why teams use Docker
Why teams keep choosing Docker By now you can run a container. The next question is why teams standardise on Docker instead of everyone hand-building PHP, MySQL, and Redis on their laptops. Docker helps when: several ...
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Docker Fundamentals
The words you need first
Docker solves a setup problem you already know Most teams have seen some version of this: one laptop is on a different runtime version one developer is missing a dependency a local database behaves differently from th...
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Docker Fundamentals
Run your first container and learn the core commands
Run one useful container The fastest way to make Docker concrete is a tiny web server you can curl from your machine. See it { "ariaLabel": "docker run nginx with port publish and detach", "se...
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Docker Fundamentals
Check that Docker actually works
Use a tiny smoke test instead of guessing Installing Docker is not the same as proving it works. A short verification loop gives you a better baseline than just seeing the app icon open. Run: docker version docker inf...
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Docker Fundamentals
Install Docker on your machine
Get Docker running on your machine Before images, Compose, or a PHP stack, you need one clean starting point: Docker installed and the engine running. Use the official install path for your OS: macOS: Docker Desktop f...
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Browse the library

Topics

Courses

Solution: pull and smoke-test an image

Exercise: pull and smoke-test an image

When build, pull, or cache goes wrong

Build context and .dockerignore

Fat bases, slim bases, and distroless choices

Tags vs digests (sticky note vs serial number)

docker history, image size, and layer dedup

Build, tag, and inspect an image locally

Pull, run, and smoke-test an image

Image vs container and the layer stack

Solution: add a healthcheck to nginx

Exercise: add a healthcheck to nginx

Verify with curl, logs, and healthchecks

One job per container and when to reach for Compose

App code in the image, data in a volume

Rebuild instead of patching by hand

Why teams use Docker

The words you need first

Run your first container and learn the core commands

Check that Docker actually works

Install Docker on your machine