Docker Demo

In this demo, we explore Docker. If you successfully navigate through the scenario below, you should be able to interact with a containerized host to retrieve a question from a web server. This will require you to configure three emulated BGP peers.

Container Topology

HOST --- ROUTING --- WEB_SERVER

Emulated Network Topology

HOST --- R1 --- R2 --- WEB_SERVER
     	  | 	 |
	  ---R3---

R1, R2, R3 are eBGP peers emulated using Mininet.

Addressing

• HOST is part of the 10.0.0.0/24 subnet.
• WEB_SERVER is part of the 12.0.0.0/24 subnet.
• R3 notionally has an interface connected to the 11.0.0.0/24 subnet.
• R1 is part of AS 4500, R2 of AS 55000, and R3 of AS 65000.

Exercise

In order to standardize our environment, we utilize a Vagrantfile. Take a look at the provisioning section and try to understand what is happening.

• It installs quagga, a network routing software suite consisting of a core daemon (zebra), which sets up a socket enabling Quagga clients to communicate with the underlying Unix kernel using the ZServ API. The Quagga client we configure in this exercise is bgpd, which implements the BGP routing protocol and communicates BGP updates to the zebra daemon.

• It installs mininet, a network emulator that uses process-based virtualization in conjunction with Linux network namespaces to provide individual processes with separate network interfaces, routing tables, and ARP tables. Note that while this technique has the same basis as the mechanism underlying Docker, Mininet does not implement the full Linux container architecture nor provide full OS-level virutalization. Devices defined in Mininet are connected by virtual ethernet (veth) pairs. Mininet also integrates OpenFlow to enable highly flexible custom routing and Software-Defined Networking (SDN). It also installs and configures the OpenVSwitch Controller to enable Mininet.

• It clones and installs our fork of the Containernet git repository.

• It sets up Docker.

To complete the exercise, perform the following tasks.

1. Write a Dockerfile that can retrieve content from a webserver.
2. Write a Dockerfile that implements a simple webserver.
3. Write a Python script that implements the architecture above using Containernet and the Dockerfiles you wrote in the previous two steps.