Commit graph

3 commits

Author SHA1 Message Date
Eelco Dolstra b3dbcbe249 * Use vde_switch instead of QEMU's multicast feature to tie QEMU VMs
together into virtual networks.  This has several advantages:

  - It's more secure because the QEMU instances use Unix domain
    sockets to talk to the switch.

  - It doesn't depend on the host's network interfaces.  (Local
    multicast fails if there is no default gateway, so for instance it
    fails if a laptop is not connected to any network.)

  - VDE devices can be connected together to form arbitrary network
    topologies.

  - VDE has a "wirefilter" tool to emulate delays and packet loss,
    which are useful for network testing.

svn path=/nixos/trunk/; revision=25526
2011-01-12 18:47:23 +00:00
Eelco Dolstra 2e38d8cd31 * ZOMG, fixed a giant bug in the networking of distributed VM tests.
It turns out that all network interfaces in all VMs had the same
  Ethernet address (52:54:00:12:34:56) because we didn't specify any
  with the macaddr=... option.  This can obviously lead to great
  confusion.  For instance, when a router forwards a packet, it can
  actually end up sending the packet to itself because the target
  machine has the same Ethernet address (causing a loop until the TTL
  expires), while the target *also* receives the packet.  It's amazing
  anything worked at all, really.

  So now we just set the Ethernet addresses to 52:54:00:12:<virtual
  network number>:<machine number>.

svn path=/nixos/trunk/; revision=25020
2010-12-07 00:44:29 +00:00
Eelco Dolstra 77a4004df1 * The installer test lost the QEMU flags to set up the NIC to talk to
the web server somewhere, so put them back in
  (http://hydra.nixos.org/build/424923).

svn path=/nixos/trunk/; revision=22003
2010-05-27 12:20:37 +00:00