Comment 3 for bug 1593424

ceph-osd

def emit_cephconf():
    # Install ceph.conf as an alternative to support
    # co-existence with other charms that write this file
    charm_ceph_conf = "/var/lib/charm/{}/ceph.conf".format(service_name())
    mkdir(os.path.dirname(charm_ceph_conf), owner=ceph.ceph_user(),
          group=ceph.ceph_user())

mkdir has default permissions of 0o555 (which would explain why this happens)