Description of problem:
While running rolling_update.yml, the playbook will fail if the cluster isn't in an acceptable state(HEALTH_ERR). The playbook will run even if in HEALTH_WARN(let's assume 1/3 mons down). But while running this playbook, if the upgrade fails for one of the mon, we loose the quorum resulting in IO down/Cluster failure. So to avoid this situation, it would be good if we can add the below conditions/anything similar conditions:
 - Add another condition to check the running mons before starting the mon upgrade.
 - if we add the above condition, we should give an option to overide the situation where the system admin is okay to proceed with upgrading 2 mons(with minimum number of quorum)

Version-Release number of selected component (if applicable):
 * RHCS 4.2


Additional info:

 o Due to the below condition, it is not checking whether all the monitors are up and running:
---
    - name: set mon_host_count
      set_fact:
        mon_host_count: "{{ groups[mon_group_name] | length }}"

    - name: fail when less than three monitors
      fail:
        msg: "Upgrade of cluster with less than three monitors is not supported."
      when: mon_host_count | int < 3
---

 o The below condition will skip since the cluster not in 'HEALTH_ERR'(1/3 mons down)
---
          - name: fail if cluster isn't in an acceptable state
            fail:
              msg: "cluster is not in an acceptable state!"
        when: (check_cluster_health.stdout | from_json).status == 'HEALTH_ERR'
    when: inventory_hostname == groups[mon_group_name] | first
---