test_setup.splitbrain.yml

---
# ===========================================
#  QE configuration for invoking split brain
# ===========================================
#
# Requirements of this playbook:
#
# * gluster volume with AFR tranlator
# * 2 client machines in usm_client group
# * some already existing non empty text file on the gluster volume (a victiom
#   of a split brain related test case)
#
# To use this playbook, create 2 new groups in inventory file:
#
# * gluster_splitbrain0
# * gluster_splitbrain1
#
# Populating these groups requires you to understand replica set configuration
# of your volume. Moreover you need to figure out on which the file to be split
# brained resides.
#
# Besides that you need to update volume_name variable if you don't use
# volume_alpha_distrep_6x2.
#
# This playbook then makes sure that all network traffic is dropped for:
#
# * connections from usm_client[0] machine to gluster_splitbrain0 machines
# * connections from usm_client[1] machine to gluster_splitbrain1 machines
#
# This way, you can update some same already existing file from both clients
# and create a split brain situation.
#
# Based on upstream GlusterFS documentation:
#
# https://docs.gluster.org/en/latest/Administrator%20Guide/Split%20brain%20and%20ways%20to%20deal%20with%20it/#split-brain

- hosts: usm_client[0]
  remote_user: root
  tasks:
    - name: Drop all traffic to gluster_splitbrain0 machines
      iptables:
        action: insert
        state: present
        chain: OUTPUT
        destination: "{{ item }}"
        jump: DROP
      with_items: "{{ groups['gluster_splitbrain0'] }}"

- hosts: usm_client[1]
  remote_user: root
  vars:
    volume_mountpoint: "/mnt/volume_tmp_splitbrain"
    volume_name: "volume_alpha_distrep_6x2"
  tasks:

    - name: Create new mountpoint just for splitbrain
      file:
        path: "{{ volume_mountpoint }}"
        state: directory

    - name: Mount GlusterSF volume for splitbrain purposes there
      mount:
        path: "{{ volume_mountpoint }}"
        fstype: glusterfs
        src: "{{ groups['gluster_servers'][0] }}:{{ volume_name }}"
        state: mounted

    - name: Drop all traffic to gluster_splitbrain1 machines
      iptables:
        action: insert
        state: present
        chain: OUTPUT
        destination: "{{ item }}"
        jump: DROP
      with_items: "{{ groups['gluster_splitbrain1'] }}"