I am hitting the same problem with (which used to work)
- name: Create Gluster volume
gluster_volume:
name: "{{ volume_name }}"
state: present
host: "{{ inventory_hostname }}"
bricks: "{{ brick_dir }}/{{ brick_name }}"
cluster: "{% for host in workers %}{{ host }},{% endfor %}{{ inventory_hostname }}"
replicas: "{{ workers|length + 1 }}"