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Connect a Container to a Service Running on the Docker Host
Learn how to access services running on the Docker host from a bridge-networked container, without hardcoding host IP addresses or disabling network isolation.
Challenges
Focused, hands-on DevOps and server-side problems with hints, feedback, and automated solution checks.
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Redirect a Container's Requests Without Modifying the App
Sometimes you need an app to talk to a different backend, but its configuration is unknown or the destination address is hard-coded. Practice overriding hostname resolution for a single Docker container to redirect its requests without modifying the app or rebuilding its image.
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Troubleshoot an Ingress That Returns 404 Not Found
by Omkar Shelke
An nginx Deployment runs fine, but its address returns an error. Trace the path from the Ingress to the Pod and fix the manifests.
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Docker 101: List Docker Networks and Inspect the Default Bridge
Explore the container networks of a freshly installed Docker host: find the default network, its subnet and gateway, and the Linux interface behind it.
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Docker 101: Publish a Redis Container Port on the Private Network Only
A common setup for small deployments: two servers (VM or bare-metal), each with a public and a private IP. The app listens on the public port but wants to talk to Redis over the private network. Can you set it up?
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Docker 101: Reach a Container Without Publishing a Port
Practice accessing a containerized service directly from the Docker host using its IP address.
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Docker 101: Publish a PostgreSQL Container Port on Localhost Only
Learn how to keep a database available to an app running on your workstation without exposing its port to other machines on the network.
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Docker 101: Publish a Container Port to Access the App from the Host
A web app is listening inside a container, but the browser can't reach its IP address. Recreate the container so the app is available on port 80 of the Docker host.
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Call an HTTP API with curl: Authenticating with Basic Auth and Bearer Tokens
Practice authenticating to an HTTP API from the command line using both a username and password and a bearer token, and learn a couple of tricks along the way.
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Call an HTTP API with curl: Processing JSON Responses with jq
Practice one of the most common command-line combinations for HTTP API access: fetch a JSON response with curl and pipe it into jq to pretty print, reshape, or get only the relevant parts.