Mantl: Reset consul peers to recover from a cluster outage.

mantl-consul-reset-peers.yml

---
# https://www.consul.io/docs/guides/outage.html
# do a rolling restart; be nice to the cluster
- hosts: role=control
  serial: 1
  gather_facts: no
  tasks:

  - name: set consul maintenance enable
    command: consul maint -enable -reason "{{ lookup('env', 'USER') }} reset consul peers"
    tags:
       - reset

  - name: stop consul
    become: yes
    service: >
      name=consul
      state=stopped
    tags:
       - reset

  - copy:
      dest: /var/lib/consul/raft/peers.json
      content: "[{% for host in groups[consul_servers_group] | intersect(groups[consul_dc_group]) %}\"{{ hostvars[host].private_ipv4 }}:8300\"{% if not loop.last %}, {% endif %}{% endfor %}]"
    tags:
      - configure

  - name: start consul
    become: yes
    service: >
      name=consul
      state=started
    tags:
       - reset

  - name: wait for consul to listen
    wait_for:
      port: 8500
    tags:
       - restart

  - name: set consul maintenance disable
    command: consul maint -disable
    tags:
       - restart

Would you mind making a PR for this? Then we could close mantl/mantl#948