Using Advanced Velocity Templates in Cisco DNA Center – Part 2

9 Comments

• Hi Adam,
  I’ve tried to make a similar setup using the dnac programmer python scripts. This works fine for basic setup but it doesn’t work with a foreach loop.

  #if($platform.matches(“C9300-48UXM.*”))
  #end

  #set ($stack_member_count = $stack_count)
  #foreach($switch in [1..${stack_member_count}])

  interface range TwoGigabitEthernet${switch}/0/1 – 12
  description DATA LAN
  switchport mode access
  switchport access vlan ${datavlan}
  logging event link-status
  no snmp trap link-status
  storm-control broadcast level 75.00 50.00
  storm-control multicast level 75.00 50.00
  storm-control action shutdown
  spanning-tree portfast
  spanning-tree guard root

  interface range TwoGigabitEthernet${switch}/0/13 – 24
  description DATA LAN
  switchport mode access
  switchport access vlan ${apvlan}
  logging event link-status
  no snmp trap link-status
  storm-control broadcast level 75.00 50.00
  storm-control multicast level 75.00 50.00
  storm-control action shutdown
  spanning-tree portfast
  spanning-tree guard root

  #end

  When I apply the template I’m running into the problem that he doesn’t know the switch variable , and nothing gets applied to the switch
   I have the impression that the API call has a problem with the foreach loop

  https://X.X.X.X:443/dna/intent/api/v1/template-programmer/template/0f5fbe57-b7ef-46a1-8d4b-618f87ea0fac
  Showing Template Body:
  #if($platform.matches(“C9300-48UXM.*”))
  #end

  #set ($stack_member_count = $stack_count)
  #foreach($switch in [1..${stack_member_count}])

  interface range TwoGigabitEthernet${switch}/0/1 – 12
  description DATA LAN
  switchport mode access
  switchport access vlan ${datavlan}
  logging event link-status
  no snmp trap link-status
  storm-control broadcast level 75.00 50.00
  storm-control multicast level 75.00 50.00
  storm-control action shutdown
  spanning-tree portfast
  spanning-tree guard root

  Did you see this problem before ?

  • two things:
    1) The if statement does not do anything? Is that your intention?
    2) Did you make the type of the $stack_count variable an integer, and pass it into the template as an integer?

    • How can we set $stack_count variable from dnac inventory?

      • you can. Indirectly. I normally look at the serialNu or pid. They will be a comma seperated list. You just count the number entries in the list. 2 switch stack members = 2 x serialNumbers and 2 x PID

        • This is the code you need. bind variable $serial to inventory-> device -> serialNumber
          #set ($stackcount = $serial.split(“,”))
          $stackcount.size()

• Tried using your example against a few switch types, 3850 and 9300, and it didn’t work. I traced the issue to the fact DNA doesn’t have any MediaType attributes set on the interfaces, all come back as null when using Postman. Is this a possible bug within DNA’s inventory process or do some switches not provide this? Currently on the latest DNA 1.3.3.5 and switches are running 16.12.3a.

  “series”: “Cisco Catalyst 9300 Series Switches”,
  “vlanId”: “1”,
  “mediaType”: null,
  “speed”: “1000000”,
  “status”: “up”

  • yes, it seems like there is an issue with “mediaType” now..

• One other little bonus…. If you want to configure pim sparse-mode for SDA, you can use this template with bound variable to configure it

  #foreach ($interface in ${interfaces})
  #if ($interface.interfaceType == “Virtual”)
  #if ($interface.description.matches(“vrf interface to External router”))
  int $interface.portName
  ip pim sparse-mode
  #end
  #end
  #end

  • probably need to remove the smart quotes above… ;-(

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