Horizon Dashboard times out with a 504 Gateway time out error

Solution Verified - Updated -

Environment

  • Red Hat OpenStack 7.0 (RHOS)

Issue

  • Horizon Dashboard fails to load page with HTTP 504 error ( Gateway timeout Error ) .

Resolution

  • If using a LDAP back-end for authentication, add the following clause in /etc/openldap/ldap.conf:

    NETWORK_TIMEOUT 2

  • Otherwise, please increase HAProxy timeouts as per Solution 1595673 and/or Solution 1465753.

Root Cause

  • This error indicates issue with haproxy reaching the backend server .
  • This can be cause due to considerable amount of time taken to reach the backend server .
  • If the backend server response is expected to take longer time that server timeout configured , server timeout can be increased in haproxy.conf .
  • Another possibility is that the maxconn limit is reached due to which all further connections to haproxy backend server fails .
  • This can be fixed by increasing maxconn in defaults/global section .

Diagnostic Steps

  • The issue is temporarily fixed by haproxy service restart .
  • Enable haproxy logging to confirm if timeout limit is hit by haproxy .

This solution is part of Red Hat’s fast-track publication program, providing a huge library of solutions that Red Hat engineers have created while supporting our customers. To give you the knowledge you need the instant it becomes available, these articles may be presented in a raw and unedited form.

Comments