I develop network emulators since 2011, and, even if I’m not a programmer, I can say I did a good job, putting iou-web (at first) and UNetLab (at last) as a good competitor of GNS3 and VIRL without any budget.
Below you can read a brief summary about my softwares, and the architecture of the UNetLabv2.
Basically UNetLabv2 has the same UNetLab features, plus:
- thousands of nodes for each lab;
- labs distributed between dozens of physical or virtual nodes;
- unlimited running labs for each user;
- support for Ansible/NAPALM/… automation tools
Previously on WebIOL/iou-web/UNL/UNetLab/EVE-NG
At the end of 2011, I needed a tool to emulate networks. Prerequisites were:
- portability: labs must be exportable and importable;
- stability: running labs must be stable, avoiding crash;
- performance: labs must be able to run into a cheap laptop or into a VM.
GNS3 was the only available option, and it couldn’t satisfy all prerequisites. I decided to develop a new network emulation software based on IOL (IOS on Linux, by Cisco). I knew many Cisco guys, and I would loved to be part of Cisco family, sooner or later. In the meantime I realized Cisco developed internally a similar software, called WebIOL.
WebIOL was developed in Perl and released for Cisco employers only. It contained some basic labs from Cisco 360 program.
After a couple of alpha version, on January 23th (2012) iou-web has been released to the public. iou-web (not webiou or web-iou) was developed in PHP and in few months counted hundreds of users worldwide. If GNS3 supported real IOSes only (via Dynamips), iou-web supported IOL only. But because IOL was faster than Dynamips, many users preferred iou-web.
In 2013 I realized iou-web was too limited, I needed a “unified” way to emulate a network, including firewalls, load-balancers and so on. Moreover multicasting using IOL was bugged. I had more prerequisites:
- include vendor virtual appliances in labs;
- include real IOS in labs;
- include (possibly) emulators from different vendors;
I entirely rewrote iou-web to make an extendable network emulator system. The idea was:
- each node (emulated device) must be attached to a common layer;
- a nice common layer could be an Ethernet Linux bridge (OVS was supported too).
On October 6th (2014) UNetLab has been released to the public. Developed in PHP using a REST API framework, and a single page application (jQuery). In few months I was able to count five to six hundreds of daily users. I would name it UNL, but the website wasn’t free.
Initially I had the idea to include Huawei eNSP, but because eNSP nodes expect a particular string, no one was able to run eNSP nodes outside eNSP.
From 2015 I didn’t have enough spare time for UNetLab, so a group of guys forked UNetLab and on January 5th (2017) EVE-NG has been released to the public, but that’s another story because I’m not part of EVE-NG team.
In the last two years my focus moved to network automation, and now I still need an unified network emulator platform but prerequisites changed. But before that, let me point out UNetLab limits:
- per host pod limit: currently each host can run up to 256 independent pod, because of console port limit;
- per lab node limit: currently each pod/lab can run up to 128 - 1 nodes, because of console port limit;
- per user pod limit: currently each user can run up to one pod/lab a time, because of console port limit;
- one host only: currently there is no way to make a distributed installation of UNetLab (OVS could be used, but many frame types are filtered by default);
- config management: getting and putting startup config is done through expect scripts, they are slow, non-predictive, and cannot cover all node types;
- Dynamips serial interfaces are not supported;
- no topology change is allowed while lab is running, by design.
The console port limit happen because each node console have a fixed console port, calculated as following: ts_port = 32768 + 128 * tenant_id + device_id. Moreover no more than 512 IOL nodes can run inside the same lab because device_id must be unique for each tenant.
So UNetLab v2 must be able to:
- run a distributed lab (between local or geographically distributed nodes);
- run lab with a non-limited number of nodes;
- allow each user to customize a lab without affecting the original copy;
- link serial interfaces between IOL and Dynamips;
- configure nodes via Ansible/NAPALM/whatever.
I knew how to make a distributed network emulator, but I missed a bit: how to easily run nodes within a dedicated namespace? I got the answer from vrnetlab: using Docker.
Because of UNetLab limits, I preferred to rewrite UNetLab from scratch, again. Even if EVE-NG is a UNetLab fork, the EVE-NG team is working to overcoming the limits described before.
The architecture could seem a little bit complex, but that’s not true, infact I was able to implement it by myself and in a relatively short time.
UNetLabv2 is based on:
- Docker: controller, routers and lab nodes run inside a Docker container;
- Python: no more C, PHP or Bash, only Python 3;
- Python-Flask + NGINX implement and expose APIs;
- Memcached caches authentication for a better user experience;
- Celery + Redis manages asynchronous long tasks in the background;
- MariaDB stores all data/user and running labs;
- Git stores original labs with a version control;
- jQuery + Bootstrap will implement the UI as a single page app;
- iptables + Linux bridge allow to connect to just started lab nodes via SSH;
- IOL, QEMU and Dynamips run lab nodes.
A UNetLabv2 cluster must have at least one node: it could be a physical or a virtual system. Each UNetLabv2 node run Docker: the first UNetLabv2 node is the master one and it contains a controller and a router, every additional UNetLabv2 node contains a router only. Each UNetLabv2 node run also many lab nodes. Controller, routers and lab nodes are Docker instances.
The controller container:
- exposes web UI and APIs to user clients, routers and lab nodes;
- receive register requests from routers and lab nodes;
- provision and manages lab nodes via routers;
- contact lab nodes via Ansible/NAPALM/… via routers;
- provides routing table to routers;
- can be reached via SSH using port 2222.
The router containers:
- register against the controller;
- expose Docker Remote API;
- expose lab node API;
- get routers and routing table from controller;
- route lab packets between nodes and routers;
- allow reachability between controller and remote lab nodes via OpenVPN.
The node containers:
- register against the controller;
- run the emulated node (IOL, Dynamips or QEMU);
- bind a management interface of emulated note to a local bridge;
- route and sNAT/dNAT packets to the management interface of the emulated node;
- route packets between the local router and the emulated node for the non-management interfaces;
- manage emulated links (up/down).
Because controller and routers knows inside and outside ip addresses; users can deploy UNetLabv2 nodes wherever they want (in the same LAN, in AWS, Google Compute Engine, Azure, behind a firewall…). As the above diagram explains, each UNetLabv2 cluster needs the following ports:
- TCP:2222 to connect to the controller via SSH;
- TCP:80/443 for HTTP/HTTPS requests to the controller;
- TCP:5443 for HTTPS requests to the router;
- UDP:5005 for routed packets between different UNetLabv2 nodes;
- UDP:1194 for network reachability between the controller and remote lab nodes.
UNetLabv2 is discontinued and thus not available to the public. Don’t ask for it and go with GNS3, VIRL or EVE-NG.