Understand Multi-Container Pod Design Patterns (e.g. Sidecar, Init and Others) CKAD Practice Questions (Page 1)

Questions 1–5

1. 1application · medium

   A team has a microservice that connects to a database using a connection string. The database endpoint changes between environments. They want to keep the microservice code unchanged and manage the endpoint externally. What multi-container Pod pattern should they use?

   • ASidecar container that writes the connection string to a shared volume before the microservice starts.
   • BAmbassador container that proxies database connections from the microservice to the actual database endpoint.
   • CAdapter container that transforms the database response format.
   • DInit container that runs a database migration before the microservice starts.
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2. 2application · easy

   A Pod has a main application that listens on port 8080 and a sidecar that must send health check requests to it. The sidecar needs to know the application's address. What should they use?

   • AThe sidecar can reach the main application at localhost:8080 because they share the Pod network namespace.
   • BThe sidecar cannot reach the main application because they are separate containers.
   • CThe sidecar must use a Service to reach the main application.
   • DThe sidecar must use the main application's Pod IP address.
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4. 3application · medium

   A Pod runs a Java application that requires a configuration file downloaded from a private S3 bucket before startup. The application fails if the file is missing. The team wants to keep the download logic separate from the application image. What should they do?

   • AAdd a sidecar container that downloads the file to a shared volume; the main container waits for the file to appear.
   • BAdd an init container that downloads the file to a shared emptyDir volume; the main container mounts the same volume and reads the file.
   • CEmbed the download logic in the Java application's startup script.
   • DUse a ConfigMap to store the file contents and mount it into the main container.
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5. 4expert · hard

   A Pod has two init containers: the first downloads a large dataset, and the second transforms it. The main application then serves the transformed data. The team wants to minimize Pod startup time while ensuring the transformation only runs after the download completes. What should they do?

   • ARun the download as a sidecar and the transformation as an init container.
   • BKeep both init containers; they run sequentially, and the second only starts after the first completes.
   • CCombine both tasks into a single init container to reduce overhead.
   • DRun the transformation as a sidecar and the download as an init container.
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6. 5foundation · easy

   How do containers in the same Pod communicate with each other over the network?

   • ABy using the Pod's IP address and a container-specific port
   • BBy using the container's IP address from the Pod's status
   • CBy using a Service that load-balances between containers
   • DBy using the container's hostname and a Service DNS name
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