Linux – How to find the name of the second NIC using ansible

ansibleautomationlinuxnetworking

I'm deploying something with Ansible to a Linux host, and I need it to listen only on the second NIC on the host.

Looking at the facts available, I can see ansible_interfaces lists all of my NICs, e.g.

 "ansible_interfaces": [
        "lo", 
        "ens9f0", 
        "ens9f1"
 ]

I know that it's not lo, so I can discount that. And by looking at ansible_default_ipv4.alias, I can see that my primary is ens9f0.

In a play / playbook, how could I then work out that ens9f1 is the secondary ?

The use case for this is that I want to do something like the following in a template:

Listen {{ ansible_second_nic.ipv4.address }}

Each machine I work on may have different NIC names, so I can't hard-code these in my roles. Historically I would just assume eth1, but that's no longer safe.

Best Answer

Take ansible_interfaces, subtract 'lo' and ansible_default_ipv4.alias, take first element of remaining list:

- debug:
    msg: "{{ ansible_interfaces | difference(['lo',ansible_default_ipv4.alias]) | first }}"

Related Solutions

Vagrant Ansible – How to Execute Provisioner on Windows Host

I've had success installing Ansible (and subsequently running a playbook) onto a new Vagrant guest with the following bash script (tested with Ubuntu 13.04):

#!/usr/bin/env bash

export DEBIAN_FRONTEND=noninteractive

apt-get update -qq
apt-get install -y make git-core

if [[ ! -d /home/vagrant/ansible ]]; then
    # Install Ansible dependencies.
    apt-get install -y python-mysqldb python-yaml python-jinja2 python-paramiko sshpass

    # Checkout the Ansible repository.
    git clone https://github.com/ansible/ansible.git /home/vagrant/ansible

    mkdir /etc/ansible

    echo "localhost" > /etc/ansible/hosts

    source /home/vagrant/ansible/hacking/env-setup
    echo "source /home/vagrant/ansible/hacking/env-setup" >> /home/vagrant/.bashrc
fi

cd /srv/vagrant
ansible-playbook playbook.yml

Linux – Ansible: run different plays on the same host as different users

You might as well use 2 distinct inventory hostnames and specify ansible_ssh_host host variable:

[personal_computers]
personal-laptop ansible_ssh_host=mylaptop ansible_ssh_user=personal-user

[work_computers]
work-laptop ansible_ssh_host=mylaptop ansible_ssh_user=work-user

Best Answer

Related Solutions

Vagrant Ansible – How to Execute Provisioner on Windows Host

Linux – Ansible: run different plays on the same host as different users

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