Interpret Logs F5N4 Practice Questions (Page 1)

Questions 1–5

1. 1foundation · easy

   A user reports a 502 Bad Gateway error. Which log file should you examine first to find the root cause?

   • AThe system log (e.g., /var/log/syslog)
   • BThe configuration file
   • CThe error log
   • DThe access log
   Reveal Solution Discussion Select an answer first
2. 2expert · medium

   An administrator is troubleshooting a slow API endpoint. The access log shows a request time of 5.2 seconds for a GET /api/report request. The error log shows no errors. What should the administrator do to determine if the slowness is caused by the upstream server?

   • ACheck the access log for the $request_time variable.
   • BIncrease the error_log level to debug.
   • CAdd $upstream_response_time to the access log format.
   • DSet proxy_read_timeout to a higher value.
   Reveal Solution Discussion Select an answer first
4. 3application · medium

   An error log entry shows: [crit] 1234#0: *789 open() "/var/www/html/index.html" failed (13: Permission denied) What is the most likely cause of this error?

   • AThe file does not exist on the server.
   • BThe client does not have permission to access the file.
   • CThe disk is full and NGINX cannot write to the file.
   • DThe NGINX worker process does not have read permission on the file.
   Reveal Solution Discussion Select an answer first
5. 4expert · medium

   A user reports that a POST request to /submit returns a 500 error. The access log shows the request was received, but the error log shows: [error] 1234#0: *123 connect() failed (111: Connection refused) while connecting to upstream What is the most likely cause of this error?

   • AThe upstream server is not running or is not listening on the expected port.
   • BThe upstream server returned a 500 Internal Server Error.
   • CThe client sent an invalid request body.
   • DThe DNS resolution for the upstream host failed.
   Reveal Solution Discussion Select an answer first
6. 5application · medium

   An NGINX server is returning 504 Gateway Timeout errors for a specific API endpoint. The error log shows: [error] 1234#0: *567 upstream timed out (110: Connection timed out) while reading response header from upstream What is the most likely cause of this error?

   • AThe client connection was closed before the response was sent.
   • BThe DNS resolution for the upstream host failed.
   • CThe upstream server returned a 500 Internal Server Error.
   • DThe upstream server is not responding within the proxy_read_timeout period.
   Reveal Solution Discussion Select an answer first