metadata/service/proxy/admin.yml

applications:
- haproxy
parameters:
  _param:
    haproxy_admin_password: password
  haproxy:
    proxy:
      listen:
        admin_page:
          type: admin
          check: false
          binds:
          - address: '0.0.0.0'
            port: 9600
          user: admin
          password: ${_param:haproxy_admin_password}