Reading more docs etc ... I think the file I'm actually looking for is located at
```ls -alh /var/lib/openstack-dashboard/_var_lib_openstack-dashboard_secret_key.lock -rw-r--r-- 1 horizon horizon 0 Feb 7 16:06 /var/lib/openstack-dashboard/_var_lib_openstack-dashboard_secret_key.lock ```
which appears to be owned by the correct user ( horizon ).
Reading more docs etc ... I think the file I'm actually looking for is located at
```ls -alh /var/lib/ openstack- dashboard/ _var_lib_ openstack- dashboard_ secret_ key.lock openstack- dashboard/ _var_lib_ openstack- dashboard_ secret_ key.lock
-rw-r--r-- 1 horizon horizon 0 Feb 7 16:06 /var/lib/
```
which appears to be owned by the correct user ( horizon ).