Lookup for Next Available Network

[#1]

I need to create a lookup for the next available network from a group of four possible aggregate blocks.  For example I have four different /24 subnets that I want to lookup and find the next available /28 I can then create.  The /28 can be from any of the 4 networks.  

vars:

  networks:

   - 10.0.0.0/24 

   - 10.0.1.0/24

   - 10.0.2.0/24

   - 10.0.3.0/24

    - name: Return the next available trans_lan IP subnet for network

      set_fact:

         trans_lan: "{{ lookup('nios_next_network', networks, cidr=28, provider=cli_infoblox ) }}"

I need it to lookup in 10.0.0.0/24 and if it doesn't find anything then lookup in 10.0.1.0/24 and continue through the list of subnets until it finds 1 available /28.

[#2]

Without looking at anything else, trying looping through the 0-255?

0 - 255

10.0.x.0/24

[#3]

I’m not sure I follow. Can you provide an example?

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[#4]

This is what I tried and I'm getting three networks from each subnet but I'm getting an error.

    - name: New Tran_Lan network

      set_fact:

         trans_lan0: "{{ lookup('nios_next_network', '206.201.%02d.0/24' | format(item), cidr=28, num=1, provider=cli_infoblox ) }}"

      loop: "{{ range(70, 73 + 1, 1)|list }}"

Here's the error:

TASK [New Tran_Lan network] ******************************************************************************************************************************
task path: /automation/ansible/gitlab/infoblox_ip_clt_rem/infoblox_rem_client.yml:98
ok: [10.x.x.22] => (item=70) => {
    "ansible_facts": {
        "trans_lan0": [
            "206.201.70.0/28"
        ]
    },
    "ansible_loop_var": "item",
    "changed": false,
    "item": 70
}
ok: [10.x.x.22] => (item=71) => {
    "ansible_facts": {
        "trans_lan0": [
            "206.201.71.64/28"
        ]
    },
    "ansible_loop_var": "item",
    "changed": false,
    "item": 71
}
ok: [10.x.x.22] => (item=72) => {
    "ansible_facts": {
        "trans_lan0": [
            "206.201.72.32/28"
        ]
    },
    "ansible_loop_var": "item",
    "changed": false,
    "item": 72
}
fatal: [10.x.x.22]: FAILED! => {
    "msg": "An unhandled exception occurred while running the lookup plugin 'nios_next_network'. Error was a <class 'ansible.errors.AnsibleError'>, original message: Can not find requested number of networks"

[#5 · Accepted solution]

Hi,

Is this because the last network in the loop has no free /28 blocks to give out?

You could probably try adding the ignore_errors flag as part of your play.

You can find more information about it here. This is not recommended in production though. You might miss out on actuall error scenarios.

Regards,

Krishna

[#6]

The lat network in the loop is 206.201.72.0/24 and from the output you can see that it finds an available network. I do plan to use this for production so I don’t want to ignore the error. It there another way to perform the lookup on multiple subnet?

[#7]

Sorry I checked my playbook again and you were correct. I had the range from 70 - 73 and it should have been 70 - 72. I changed it and it’s working now.