How to create variables in Ansible where the number increments?

Question

I am writing an Ansible task where it installs a set of LDAP entries with the following objectClass and attributes and values.

dn: entry=101,cn=multicast,{{ ipa_base }}
objectClass: multicastAddress
objectClass: top
entry: 101
network: test
ipNumber: 224.0.0.1

I have multiple networks, and each network will have 62 IPs allocated, and each value of the entry and the ipNumber will increment.

Network A:
entry=101 ipNumber: 224.0.0.1
entry=102 ipNumber: 224.0.0.2

Network B:
entry=101 ipNumber: 224.0.1.1
entry=102 ipNumber: 224.0.1.2

Currently, I only have a task where it creates the entries statically, and I would like to write it efficiently where I don't have to create each of the static entries.

- name: Create entries
  ldap_entry:
    dn: entry=101,cn=multicast,{{ ipa_base }}
    state: present
    objectClass:
      - top
      - multicastAddress
    attributes:
      entry: 101
      network: test
      ipNumber: 224.0.0.1
    server_uri: localhost
    bind_dn: "cn=Directory Manager"
    bind_pw: '{{ dmgr_pass }}'

Zeitounator · Accepted Answer · 2023-08-27 13:16:07Z

There are several ways to achieve your goal depending on your exact requirement. Here is one to put you on track in a self explanatory playbook with intermediate debug. Note: for the example and legibility I limited the output to 2 networks with 2 ips each. Just change those figures to fit your needs.

---
- hosts: localhost
  gather_facts: false

  vars:
    number_of_networks: 2
    ips_per_network: 2

    networks_list: "{{ range(0, number_of_networks) }}"
    ips_list: "{{ range(1, ips_per_network + 1) }}"

    networks_ips_product: "{{ networks_list | product(ips_list) }}"

    ipa_base: "dc=whatever,dc=local"

  tasks:
    - name: Create a list of networks starting from 0
      ansible.builtin.debug:
        var: networks_list

    - name: Create a list of ips starting from 1
      ansible.builtin.debug:
        var: ips_list

    - name: Combine every network with every ip in a single list
      ansible.builtin.debug:
        var: networks_ips_product

    - name: Loop on that list in a debug tasks which mimics your ldap task
      vars:
        network_it: "{{ item.0 }}"
        ip_it: "{{ item.1 }}"
        entry: "10{{ ip_it }}"
        ip: "224.0.{{ network_it }}.{{ ip_it }}"
        ldap_entry:
          dn: entry={{ entry }},cn=multicast,{{ ipa_base }}
          state: present
          objectClass:
            - multicastAddress
            - top
          attributes:
            entry: "{{ entry }}"
            network: "Network{{ network_it }}"
            ipNumber: "{{ ip }}"
          server_uri: localhost
          bind_dn: "cn=Directory Manager"
          bind_pw: "v3rys3cr3t"
      ansible.builtin.debug:
        var: ldap_entry
      loop: "{{ networks_ips_product }}"

Running the above playbook gives:

PLAY [localhost] ***********************************************************************************************************************************************************************************************************************

TASK [Create a list of networks starting from 0] ***************************************************************************************************************************************************************************************
ok: [localhost] => {
    "networks_list": [
        0,
        1
    ]
}

TASK [Create a list of ips starting from 1] ********************************************************************************************************************************************************************************************
ok: [localhost] => {
    "ips_list": [
        1,
        2
    ]
}

TASK [Combine every network with every ip in a single list] ***************************************************************************************************************************************************************************************
ok: [localhost] => {
    "networks_ips_product": [
        [
            0,
            1
        ],
        [
            0,
            2
        ],
        [
            1,
            1
        ],
        [
            1,
            2
        ]
    ]
}

TASK [Loop on that list in a debug tasks which mimics your ldap task] ******************************************************************************************************************************************************************
ok: [localhost] => (item=[0, 1]) => {
    "ansible_loop_var": "item",
    "item": [
        0,
        1
    ],
    "ldap_entry": {
        "attributes": {
            "entry": "101",
            "ipNumber": "224.0.0.1",
            "network": "Network0"
        },
        "bind_dn": "cn=Directory Manager",
        "bind_pw": "v3rys3cr3t",
        "dn": "entry=101,cn=multicast,dc=whatever,dc=local",
        "objectClass": [
            "multicastAddress",
            "top"
        ],
        "server_uri": "localhost",
        "state": "present"
    }
}
ok: [localhost] => (item=[0, 2]) => {
    "ansible_loop_var": "item",
    "item": [
        0,
        2
    ],
    "ldap_entry": {
        "attributes": {
            "entry": "102",
            "ipNumber": "224.0.0.2",
            "network": "Network0"
        },
        "bind_dn": "cn=Directory Manager",
        "bind_pw": "v3rys3cr3t",
        "dn": "entry=102,cn=multicast,dc=whatever,dc=local",
        "objectClass": [
            "multicastAddress",
            "top"
        ],
        "server_uri": "localhost",
        "state": "present"
    }
}
ok: [localhost] => (item=[1, 1]) => {
    "ansible_loop_var": "item",
    "item": [
        1,
        1
    ],
    "ldap_entry": {
        "attributes": {
            "entry": "101",
            "ipNumber": "224.0.1.1",
            "network": "Network1"
        },
        "bind_dn": "cn=Directory Manager",
        "bind_pw": "v3rys3cr3t",
        "dn": "entry=101,cn=multicast,dc=whatever,dc=local",
        "objectClass": [
            "multicastAddress",
            "top"
        ],
        "server_uri": "localhost",
        "state": "present"
    }
}
ok: [localhost] => (item=[1, 2]) => {
    "ansible_loop_var": "item",
    "item": [
        1,
        2
    ],
    "ldap_entry": {
        "attributes": {
            "entry": "102",
            "ipNumber": "224.0.1.2",
            "network": "Network1"
        },
        "bind_dn": "cn=Directory Manager",
        "bind_pw": "v3rys3cr3t",
        "dn": "entry=102,cn=multicast,dc=whatever,dc=local",
        "objectClass": [
            "multicastAddress",
            "top"
        ],
        "server_uri": "localhost",
        "state": "present"
    }
}

PLAY RECAP *****************************************************************************************************************************************************************************************************************************
localhost                  : ok=4    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

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