Freedom of Choice for Automation

Such a setup has many benefits: First, you can use the switch in a considerably more versatile way than is possible with typical proprietary solutions. Quagga or Bird routing software can be easily installed on a switch using apt-get – for example, to handle Layer 3 routing via BGP for leaf-spine architectures. It is much more important, however, to integrate Linux easily into any automation solution. No longer do you need to check whether any suitable integration tools for Puppet, Chef, or another solution are provided by the company that built the switch. Instead, you can maintain the respective hardware with standard tools.

Layer 3 routing is a perfect example of this: Each port of the switch must be provided with an IP configuration, and a BGP daemon must deal with the announcement of the routes on the network. Ansible handles the task of configuring the network interface for the existing features. Connecting Quagga or Bird is handled through the use of Playbooks, many of which you can get on the web. Even a fully automated switch deployment should not comprise more than a few hundred lines of code. The situation is similar with Puppet or Chef, with which Linux switches can also be integrated.

The popularity of Cumulus has increased steadily in recent years, and you no longer need a magnifying glass to find compatible devices. Dell has some switches with Cumulus preinstalled, and the Mellanox Ethernet series (SN2700/SN2410) can be purchased with Cumulus hardware. Several white-label switch manufacturers also rely on Cumulus.

IPAM and DCIM with NetBox

The next tool in the collection, NetBox [9], targets not only network infrastructure but promises IP address management (IPAM; Figure 4) and data center infrastructure management (DCIM; Figure 5). Under the hood, NetBox works with Python, and Django provides the web interface. NetBox talks to a PostgreSQL database with the NetBox metadata in the background. Moreover, a web server gateway interface (WSGI)-compatible web server is necessary to operate the software (e.g., uWSGI or standard Apache with mod_wsgi enabled).

Figure 4: In addition to the DCIM functionality, NetBox provides genuine IPAM qualities; that is, it supports network management.

Figure 5: The NetBox DCIM solution can completely replace RackTables.

IPAM services are relatively clear-cut: IP address blocks and hosts are entered in NetBox, and the individual IP addresses are then assigned to specific hosts. On the IPAM side, you always have a list of the installed hardware with the IPs that are currently in use. Several IPs can be defined for each host – for example, if a host has an official IPv4, an official IPv6, and a management IP on a BNC interface. The IPs can be specified precisely down to the level of the interfaces in NetBox. Through the web interface, you discover which IP addresses a host currently possesses and which interface on the host belongs to which address.

The tool comes from DigitalOcean, who has been developing NetBox behind closed doors for a while, and the program is now publicly available. As one of the first public cloud providers, the admins at DigitalOcean were confronted with a huge number of hosts to manage. NetBox is therefore aimed at operators of large infrastructure environments with hundreds of hosts. The IPAM not only fulfils organizational purposes, it also acts as a single source of truth for various services in the cluster. The deployment of new servers can be automated to a far greater extent if the IP for the new host is defined centrally and can be queried automatically.

DCIM as a RackTables Substitute

To fulfill the DCIM functionality, software needs to map dependencies between IP addresses, interfaces in hosts, and locations. The NetBox developers implemented these features and created a complete DCIM, almost as a side-effect of their in-house work. NetBox thus poaches on RackTables' territory: Although hosts including the hardware they contain can be managed in RackTables, and you can even assign IP addresses, RackTables lacks the IPAM component.

Basically NetBox replaces two tools: RackTables [10] and the open source IPAM system NIPAP [11]. However, NetBox also easily maps the dependencies between hosts according to DCIM and IP addresses from address management. If you delete such a host, NetBox automatically detects that the IP addresses assigned to this host are now free.