Automating network devices with Puppet
An easy way to get started with NetOps.
The first support for managing networking devices was provided by a Puppet agent acting as a proxy for the network device.
A node running
puppet device would log in to the network device to gather facts, then connect to a Puppet server and request a catalog for the device. The device agent would then apply the catalog resources to the network device. This proxy implementation allows for management of network devices incapable of running a Puppet agent on their own.
This works surprisingly well, and provides power and flexibility to manage Cisco routers and switches without an embedded Puppet agent. Let’s configure one now.
Configuring the Puppet Proxy Agent
Select a node that can complete both of the following network connections:
- SSH to the Cisco switch or router (destination TCP port 22)
- Connect to the Puppet server (destination TCP port 8140)
On this node, create a non-privileged user account to use for device management. There is no reason to use the
root account. You can use a single shared account for all devices, or a different user account for each device if you prefer. The process shown here will create a non-privileged user and an appropriate Puppet configuration file:
[vagrant@client ~]$ sudo useradd -U -m -c "Puppet Device Manager" devicemgr [vagrant@client ~]$ sudo -u devicemgr -i [devicemgr@client ~]$ mkdir -p .puppetlabs/etc/puppet [devicemgr@client ~]$ ln -s .puppetlabs/etc/puppet [devicemgr@client ~]$ $EDITOR .puppetlabs/etc/puppet/puppet.conf
Create ~/.puppetlabs/etc/puppet/puppet.conf with the following settings:
[agent] server = puppet.example.com
Create ~/.puppetlabs/etc/puppet/device.conf with a list of devices, their type, and a URL to access them. The URL must contain both the username and password to access the device, and the
enable password if required:
[switch01.example.com] type cisco url ssh://puppet:firstname.lastname@example.org/?enable=admin
Secure the file containing passwords, for obvious reasons:
[devicemgr@client ~]$ chmod 0600 .puppetlabs/etc/puppet/device.conf
Now we will connect this network device to the Puppet server, using a process very similar to how new nodes are connected. Initialize the proxy agent for this device with the command
puppet device followed by the node name:
$ puppet device switch01.example.com --verbose applying configuration to switch01.example.com at ssh://switch01.example.com/ Info: Creating a new SSL key for switch01.example.com Info: Caching certificate for ca Info: Creating a new SSL certificate request for switch01.example.com Info: Certificate Request fingerprint (SHA256): 65:FC:AA:E3:F5:E5:5D:05:D0:D9:… Info: Caching certificate for ca
You may need to run
puppet cert sign switch01.example.com on the Puppet server to authorize the network device, and then run the command again.
This process has created a new Puppet agent dedicated to managing this network device. All of the configuration files, TLS certificates, logs, and state files for this device can be found in the ~/.puppetlabs/ directory structure. They never mix or interfere with the Puppet agent running as
root on this node.
This network device can now be configured through idempotent declarations in Puppet manifests.