Set up a Basic Ansible Lab

This article outlines the process for managing a switch using Ansible in a lab environment. This example is showing off Ansible’s ad-hoc commands. For repeated tasks, use an Ansible playbook; like this easy playbook example.

Requirements

  • One switch running Cumulus Linux (any version), called switch1
  • A server or virtual machine running Debian, with a basic installation (default packages only), called server1

On the server, set up the following:

  • DHCP
  • Ansible

Network Addresses

For this example the 192.168.0.0/24 subnet is being used.

IP AddressEntity
192.168.0.1The existing gateway
192.168.0.2server1
192.168.0.10switch1

Configure server1

Configure a DHCP server on the server, then install Ansible.

  1. Install the required packages:

    root@server:~# apt-get install isc-dhcp-server
    
  2. Assign the static IP address 192.168.0.2 to server1. Edit /etc/network/interfaces so it looks like:

    auto lo
    iface lo inet loopback
    
    auto eth0
    iface eth0 inet static
        address 192.168.0.2
        netmask 255.255.255.0
        gateway 192.168.0.1
    
  3. Configure the DHCP scope. Edit /etc/dhcp/dhcpd.conf and add this to the file:

    subnet 192.168.0.0 netmask 255.255.255.0 {
        range 192.168.0.100 192.168.0.200
        option routers 192.168.0.1;
        option domain-name-server 192.168.0.2;
        option domain-name "example.com";
        
        host switch1 {
          hardware ethernet 00:JJ:YU:38:AC:45;
          fixed-address 192.168.0.10;
        }
    
  4. Restart server1.

  5. Reboot switch1.

  6. Confirm that switch1 is reachable from server1:

     root@server:~# ping 192.168.0.10 
     64 bytes from 192.168.100.11: icmp_req=2 ttl=64 time=0.141 ms
    
  7. Install Ansible:

    root@server:~# apt-get install python-pip
    root@server:~# pip install ansible
    

Configure a MOTD via Ansible

This section describes how to create a simple message of the day (MOTD) using Ansible.

  1. Create a sample MOTD file:

     root@server:~#  echo "SAMPLE MOTD" > ~/sample.motd
    
  2. Create an inventory file with switch1 in the list:

     root@server:~#  echo "192.168.0.10" > ~/ansible.hosts
    
  3. Push the sample MOTD to switch1 (192.168.0.10). Enter the password for the cumulus user (the default user):

    root@server:~# ansible -k -K -u cumulus -i ~/ansible.hosts -m 'copy' -a 'src=~/sample.motd dest=/etc/motd' 192.168.0.10
         
        
    SSH password:
    sudo password [defaults to SSH password]: 
     sw1 | success >> {
        "changed": false, 
        "dest": "/etc/motd", 
        "gid": 0, 
        "group": "root", 
        "md5sum": "b04dde3768174a34f75fdde78142849d", 
        "mode": "0644", 
        "owner": "root", 
        "path": "/etc/motd", 
        "size": 12, 
        "state": "file", 
        "uid": 0
    }
    

See Also

Default username and password for Cumulus Linux