Error log configuration in Nginx - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the effect of this nginx error_log directive?

Given the nginx configuration line:

error_log /var/log/nginx/error.log warn;

What is the effect of this directive?

Nginx

error_log /var/log/nginx/error.log warn;

A Logs only error messages to /var/log/nginx/error.log

B Logs messages with severity warn and higher to /var/log/nginx/error.log

C Disables error logging

D Logs all messages including debug to /var/log/nginx/error.log

💡 Hint

Severity levels in nginx error_log go from debug, info, notice, warn, error, crit, alert, emerg.

The 'warn' level means log messages with severity warn, error, crit, alert, emerg will be logged. Lower levels like info or debug are ignored.

❓ Configuration

intermediate

Choose the correct nginx error_log directive to log only critical errors

Which of the following nginx error_log directives will log only critical errors and above (crit, alert, emerg) to /var/log/nginx/critical.log?

A error_log /var/log/nginx/critical.log info;

B error_log /var/log/nginx/critical.log error;

C error_log /var/log/nginx/critical.log warn;

D error_log /var/log/nginx/critical.log crit;

💡 Hint

Higher severity levels include crit, alert, emerg. Lower levels include error, warn, info.

Setting level to 'crit' logs only critical and more severe messages. 'error' or 'warn' would log more messages than requested.

❓ Troubleshoot

advanced

Why does nginx not log debug messages despite error_log set to debug?

You set this directive:

error_log /var/log/nginx/debug.log debug;

But no debug messages appear in the log. What is the most likely reason?

A The debug log file path is incorrect

B The error_log directive must be inside the http block to work

C Nginx was not compiled with debug support enabled

D Debug messages are only logged if the server is restarted twice

💡 Hint

Debug logging requires special compile-time support in nginx.

Nginx must be compiled with the --with-debug option to enable debug logging. Without it, debug messages are ignored even if configured.

✅ Best Practice

advanced

What is the recommended way to separate error logs by server block in nginx?

You want to keep error logs separate for each server block in nginx. Which configuration is best practice?

A Set error_log inside each server block with a unique file path

B Set one global error_log in the main context for all servers

C Disable error_log and rely on access_log for errors

D Use syslog for all error logs instead of files

💡 Hint

Error logs can be set at different levels in nginx config hierarchy.

Setting error_log inside each server block allows logs to be separated by server. Global error_log applies to all servers if not overridden.

🔀 Workflow

expert

Order the steps to enable and verify nginx error logging at 'error' level

Put these steps in the correct order to enable error logging at 'error' level and verify it works:

A 1,2,3,4

B 2,1,3,4

C 1,3,2,4

D 3,1,2,4

💡 Hint

Configuration changes require reload before testing.

First configure error_log, then reload nginx to apply changes, then generate an error, finally check the log file.