SaltStack Grains Python Function

• Adding a python function to salt grains, that can provide a value from each minion.
  • The requirement was to get the external ip from a minion

• Write the python function that returns the grains value and place it in your salt stack dir structure in ./salt/_grains/grains-external-ip.py

  • The actual python file name does not matter.

       1 #!/usr/bin/python
       2 '''
       3 Grain should return a dict, name of file does not matter
       4 '''
       5 import requests
       6 import socket
       7 import logging
       8 log = logging.getLogger(__name__)
       9 
      10 def external_ip():
      11     '''
      12     Return the external IP address reported by ipecho.net
      13     '''
      14     hostname = socket.gethostname().upper()
      15     log.debug("grain example hostname: " + hostname)
      16     # initialize a grains dictionary
      17     grains = {}
      18 
      19     try:
      20         r = requests.get('http://ipecho.net/plain')
      21         ip = r.content
      22     except:
      23         ip = ''
      24 
      25     grains['external_ip'] = ip
      26     grains['anothergrain'] = 'somevalue'
      27     return grains
      28 
      29 
      30 if __name__ == "__main__":
      31     print( external_ip() )
    

• Once saved on a salt minion with sudo salt-call or from salt master with sudo salt "<Minion>" refresh grains and retrieve value.

  • sudo salt "minion1" saltutil.sync_grains
    sudo salt "minion1" grains.get external_ip
    minion1:
        71.43.13.6

• once the grains function works, you might want to add it to the salt mine, to make it available to other nodes/minions.
  • Add to file pilla/common/mine.sls

    • mine_functions:
        #external_ip calculated by salt/_grains/grains-get-externalip.py
        external_ip:
          - mine_function: grains.get
          - external_ip