5.2.3. IPv6 Tolerance

OpenShift Enterprise supports a mixed IPv4 and IPv6 topology. In such a deployment, node, broker, MongoDB, and ActiveMQ hosts must have IPv6 addresses and associated AAAA resource records, and all hosts must still have IPv4 addresses and associated A resource records.
In a mixed IPv4 and IPv6 deployment, the following OpenShift Enterprise services allow communications over IPv6:
  • OpenShift Enterprise client tools (rhc)
  • OpenShift Enterprise Management Console
  • ActiveMQ and MCollective
  • Application access
In a mixed IPv4 and IPv6 deployment, the following OpenShift Enterprise services have components that either require or may require communications over IPv4:
  • MongoDB can be configured to listen on IPv6 so that some client tools can connect over IPv6 if the mongo client is running version 1.10.0 or newer. However, the broker uses mongoid which currently requires IPv4.
  • Broker DNS updates may require IPv4, however IPv6 connectivity can be used when using the nsupdate DNS plug-in.

Caveats and Known Issues for IPv6 Tolerance

  • Inter-gear communication relies on IPv6 to IPv4 fallback. If for some reason the application or library initiating the connection does not properly handle the fallback, then the connection fails.
  • The OpenShift Enterprise installation script and Puppet module do not configure MongoDB to use IPv6 and configures IPv4 addresses for other settings where required, for example in the nsupdate DNS plug-in configuration.
  • OpenShift Enterprise internals explicitly query interfaces for IPv4 addresses in multiple places.
  • The apache-mod-rewrite and nodejs-websocket front-end server plug-ins have been tested, however the following components have not:
    • The apache-vhost and haproxy-sni-proxy front-end server plug-ins.
    • DNS plug-ins other than nsupdate.
    • Routing plug-in.
    • Rsyslog plug-in.
    • Individual cartridges for full IPv6 tolerance.
  • Known Issue: BZ#1104337
  • Known Issue: BZ#1107816