[do not merge] Documented installation with HAProxy as a load balancer

[miminar]

Extended advanced install section for HAProxy bits using Ansible.

Modified masters components section acccordingly and added availability
matrix for HAProxy setup.

Depends on openshift-ansible PR#608

[miminar]

Ping @smarterclayton for technical review.

[smarterclayton]

Looks ok, didn't see anything obviously wrong.

[abutcher]

@miminar This looks good. I've made a few changes to the inventory variables to differentiate which HA method is being used (native or pacemaker). Take a look at https://github.com/abutcher/openshift-ansible/blob/native-ha/inventory/byo/hosts.example#L54-L73 and let me know if you have any questions / comments / concerns.

[miminar]

@abutcher thanks! I've updated config section. Please correct me if I'm wrong: native now describes a way of running discrete API and controllers with any load balancer admin may use. And if Ansible is told to use this method, it will configure HAProxy. Docs will need additional tweaks to reflect this.

[abutcher]

@miminar That is correct. The native method can be used with any load balancer but it must be pre-configured. An HAProxy instance will be configured for convenience if an lb group is defined.

[miminar]

@abutcher Thanks for clarification. The text should reflect it now.

[abutcher]

I think we should lead with the native method here something like

There are two high availability methods supported by the advanced installer: native and pacemaker. The former leverages the native HA capabilities built into OpenShift and can be combined with any load balancing solution. HAProxy will be configured as a load balancer if an lb group has been defined in the host inventory. If no lb group is specified, a pre-configured load balancer will be assumed.

The latter method configures Pacemaker, creating a Virtual IP on the active Master...

[abutcher]

I was talking with @adellape earlier about separating out the different HA methods into distinct sections to avoid confusing the steps:

• Single Master
• Multi-Master + a brief introduction to the supported methods
  • Native
    • Host table
    • Example inventory specific to the native method
    • Possibly include information on how to set up your own load balancer for the master api (masters port 8443 until the port is configurable in the installer)
  • Pacemaker
    • Host table
    • Example inventory specific to the pacemaker method
    • Current Pacemaker details...

[adellape]

@miminar Per Andrew's above comment, I think I'll pull in and build on your work here in another PR to continue to rework those sections of the topic. LMK if you have any issues with that approach.

@abutcher This stuff overall still shouldn't be merged until openshift/openshift-ansible#608 also merges, right?

[abutcher]

@adellape Yessir

[miminar]

@adellape you're free to take over the documentation part. I can focus on testing openshift/openshift-ansible#608.

[adellape]

Closing in favor of #1170.