Master Tops System

In 0.10.4 the external_nodes system was upgraded to allow for modular subsystems to be used to generate the top file data for a highstate run on the master.

The old external_nodes option has been removed. The master tops system provides a pluggable and extendable replacement for it, allowing for multiple different subsystems to provide top file data.

Using the new master_tops option is simple:

  ext_nodes: cobbler-external-nodes

for Cobbler or:

    inventory_base_uri: /etc/reclass
    classes_uri: roles

for Reclass.

  varstack: /path/to/the/config/file/varstack.yaml

for Varstack.

It's also possible to create custom master_tops modules. Simply place them into salt://_tops in the Salt fileserver and use the saltutil.sync_tops runner to sync them. If this runner function is not available, they can manually be placed into extmods/tops, relative to the master cachedir (in most cases the full path will be /var/cache/salt/master/extmods/tops).

Custom tops modules are written like any other execution module, see the source for the two modules above for examples of fully functional ones. Below is a bare-bones example:


  customtop: True (custom master_tops module)

import logging
import sys
# Define the module's virtual name
__virtualname__ = 'customtop'

log = logging.getLogger(__name__)

def __virtual__():
    return __virtualname__

def top(**kwargs):
    log.debug('Calling top in customtop')
    return {'base': ['test']}

salt minion state.show_top should then display something like:

$ salt minion state.show_top

      - test


If a master_tops module returns top file data for a given minion, it will be added to the states configured in the top file. It will not replace it altogether. The Nitrogen release adds additional functionality allowing a minion to treat master_tops as the single source of truth, irrespective of the top file.