Micro-caching for dynamic content in Nginx - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the effect of this micro-caching configuration snippet?

Given the following nginx configuration snippet, what will be the output behavior when a user requests a dynamic page?

Nginx

location /dynamic/ {
    proxy_cache my_cache;
    proxy_cache_valid 200 1s;
    proxy_pass http://backend;
}

A All responses are cached indefinitely, causing stale content to be served.

B No caching occurs because proxy_cache_valid is set to 1 second, which is too short to cache.

C Responses with status 200 are cached for 1 second, reducing backend load for rapid repeated requests.

D Only error responses are cached for 1 second, normal responses bypass cache.

💡 Hint

proxy_cache_valid controls how long responses with specific status codes are cached.

The proxy_cache_valid 200 1s; directive caches successful (200) responses for 1 second. This short caching period is called micro-caching and helps reduce backend load for frequently requested dynamic content.

❓ Configuration

intermediate

Choose the correct nginx micro-caching configuration to cache only GET requests for 2 seconds

Which configuration snippet correctly enables micro-caching for only GET requests with a 2-second cache duration?

A

location / {
    proxy_cache my_cache;
    proxy_cache_methods GET;
    proxy_cache_valid 200 2s;
    proxy_pass http://backend;
}

B

location / {
    proxy_cache my_cache;
    proxy_cache_methods POST;
    proxy_cache_valid 200 2s;
    proxy_pass http://backend;
}

C

location / {
    proxy_cache my_cache;
    proxy_cache_valid 200 2s;
    proxy_pass http://backend;
}

D

location / {
    proxy_cache my_cache;
    proxy_cache_methods GET POST;
    proxy_cache_valid 200 2s;
    proxy_pass http://backend;
}

💡 Hint

proxy_cache_methods controls which HTTP methods are cached.

Setting proxy_cache_methods GET; ensures only GET requests are cached. The proxy_cache_valid 200 2s; caches successful responses for 2 seconds.

❓ Troubleshoot

advanced

Why does micro-caching not work despite correct configuration?

An nginx server has micro-caching configured with proxy_cache_valid 200 1s; but no caching occurs. Which is the most likely cause?

A The backend server is sending Cache-Control: no-cache headers, preventing caching.

B The proxy_cache_path directive is missing, so cache storage is undefined.

C The proxy_pass URL is incorrect, causing caching to fail silently.

D The proxy_cache_valid directive only works for status 404, not 200.

💡 Hint

Headers from backend can prevent caching even if nginx is configured.

If the backend sends headers like Cache-Control: no-cache, nginx will not cache the response despite proxy_cache_valid settings.

🔀 Workflow

advanced

Order the steps to enable micro-caching for dynamic content in nginx

Put these steps in the correct order to enable micro-caching for dynamic content in nginx.

A 3,1,2,4

B 2,1,3,4

C 1,3,2,4

D 1,2,3,4

💡 Hint

Cache zone must be defined before enabling cache in location.

First define cache storage with proxy_cache_path, then enable caching in location with proxy_cache, set cache duration, and finally reload nginx.

✅ Best Practice

expert

Which micro-caching strategy best balances freshness and backend load?

For a high-traffic dynamic website, which micro-caching configuration is best to balance content freshness and reduce backend load?

A Cache only 200 responses for 1 second and ignore Cache-Control headers from backend.

B Cache GET requests for 5 seconds and respect backend Cache-Control headers.

C Disable caching and rely on backend to handle all requests for freshest content.

D Cache all responses including errors for 10 minutes to reduce backend calls.

💡 Hint

Respecting backend headers helps avoid stale content while caching reduces load.

Caching GET requests for a short time like 5 seconds while respecting backend cache headers balances freshness and load effectively.