Description of problem:

mysql-open-files-limit validation fails because of the following error:

{
    "task": {
        "hosts": {
            "overcloud-controller-0": {
                "_ansible_no_log": false,
                "action": "set_fact",
                "failed": true,
                "msg": "The task includes an option with an undefined variable. The error was: 'ansible.vars.hostvars.HostVarsVars object' has no attribute 'container_cli'\n\nThe error appears to be in '/usr/share/openstack-tripleo-validations/roles/mysql_open_files_limit/tasks/main.yml': line 2, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n---\n- name: Set container_cli fact from the inventory\n  ^ here\n"
            }
        },
        "name": "Set container_cli fact from the inventory",
        "status": "FAILED"
    }
}

It looks like the problem is caused by lack of container_cli definition.