API Developer Portal: Healthcheck URL fails intermittently

Products

• CA API Developer Portal
• CA API Management SaaS

Issue/Introduction

When accessing the healthcheck URL (https://<hostname>/portalhealth) of the API Developer Portal, "200 OK" and "500 Internal Server Error" will be alternately returned for each access.

Environment

API Portal 4.2.x

Cause

The cause is often a network/compatibility issue between the load balancer and Portal node when IPv6 is involved. 

Resolution

The workaround is to perform the following steps:

1. Login to the Portal server via SSH
2. Add the following line to the /etc/sysctl.conf file: net.ipv6.conf.all.disable_ipv6 = 1
3. Comment out the lines related to IPv6 from /etc/hosts file, such as this example: #::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
4. Reboot the operating system (full appliance reboot) so the changes will take effect on the network interface.