CmuLab: design_concerns

File design_concerns, 1.5 KB (added by pgunn@cs.cmu.edu, 11 years ago)

Design document for metavpn

Line 
1Function:
2        Metavpn has the task of dynamically creating/configuring openvpn
3        instances for nodes to connect to. This is useful in allowing nodes
4        with networking oddities (e.g. NAT or no internet routing at all)
5        to participate in experiments. One expected topology would be:
6
7        Testbed A (all nodes have public IPs)
8                nodew1
9                nodew2
10                nodew3
11        Testbed B (only boss/ops are public)
12                nodew4
13                nodew5
14        Experiment has a simple eth network that everyone is on
15        Done:
16                B-ops dynamically allocates a L2 OpenVPN during swapin,
17                all nodes join it as they come up, the A-nodes over
18                the public internet, the B-nodes through their connection
19                to B-ops.
20
21        Another topology:
22
23        Testbed B (only boss/ops are public)
24                nodew1
25                nodew2
26        Testbed C (only boss/ops are public)
27                nodew3
28        Experiment has a simple eth network that everyone is on
29        Done:
30                B-ops dynamically allocates a L2 OpenVPN during swapin,
31                C-ops dynamically allocates a L2 OpenVPN during swapin,
32                B-ops and C-ops are joined by an openvpn running in
33                        --server-bridge mode
34                        (we must enable packet forwarding from the vpn
35                        on each side to the bridge)
36
37
38metavpn does not run on boss. This is because:
39        metavpn does the dirty work of generating configfiles, starting and
40        stopping openvpn as needed, and configuring a SSL instance.
41        It's easier to do this on the same machine as the openvpn servers.
42        This does impose some challenges.
43
44For now, metavpn is assumed to run on ops. It is an explicit design factor
45        that it should not rely on running on ops (perhaps running on a
46        dedicated server).