host parameter in bigip_pool_member

The

host

parameter is the F5 device the want to pass the module task to, in this case is a variable passed it it.

With Ansible

gather_facts

is set to 'on' (it is on by default) then you have access to a load of variables you can use in your playbooks.

With

gather_facts

you should get a dictionary variable set named

ansible_default_ipv4

which would look like the following:

"ansible_default_ipv4": {
    "address": "10.0.0.1",
    "alias": "eth0",
    "gateway": "10.0.0.254",
    "interface": "eth0",
    "macaddress": "REDACTED",
    "mtu": 1500,
    "netmask": "255.255.255.0",
    "network": "REDACTED",
    "type": "ether"
},

You can then use

ansible_default_ipv4.address

or

ansible_default_ipv4['address']

to reference the address index of the dictionary.

In your playbooks you will need to use

"{{ansible_default_ipv4.address}}"

or

"{{ansible_default_ipv4['address']}}"

See Ansible 2.6 Playbook Vaiables for more information.

The

host

parameter is not the F5 device. Rather that is the

server

parameter.

The

host

parameter is an alias for the

address

parameter which is the IP address of the pool member you are acting upon.

The

ansible_default_ipv4

variable is usually the self IP address of the external vlan of the LTM.

The use of the

ansible_default_ipv4

parameter in the examples is a bit confusing. It would have been better to just make up some IP addresses to represent the downstream servers in the pool.