[mirror-admin] MM 1.3.2, now with automatic network lookups

[Matt Domsch]

MirrorManager 1.3.2 (plus a hotfix) is now running on all Fedora
Infrastructure application servers.  This brings one new interesting
feature - automatic mirror detection.  How's that you say?

As you know, Internet routing uses BGP (Border Gateway Protocol), and
Autonomous System Numbers (ASNs) to exchange IP prefixes
(aa.bb.cc.dd/nn).  By grabbing a copy of the global BGP table a few
times a day, MM can know the ASN of an incoming client request, and
Hosts in the MM database have grown two new fields: ASN and "ASN
Clients?".  MM then looks to see if there is a mirror with the same
ASN as each client, and offers it up earlier in the list.

I've pre-populated the MM database, for public servers only, with your
ASNs, and set "ASN Clients?" = True, meaning such will offer to serve
all clients on the same ASN.  If you have a private server and wish to
do likewise (remember, this doesn't work for home systems or those
behind NATs), you can fill in those fields yourself.
http://fedoraproject.org/wiki/Infrastructure/Mirroring gives an
example on how to look up your ASN.

The mirrorlist lookup code now goes in preferential order:
* same netblock
* same ASN
* both on Internet2
* same country
* same continent
* global

For ISPs and schools, this should mean that most of the possible
Fedora traffic will stay within your network - no transit costs.  And
as netblocks change, MM will keep up with them automatically.

To see this in action, try a query as such, and look for the 'Using
ASN ####' in the result comment line.

$ wget -O - 'http://mirrors.fedoraproject.org/mirrorlist?repo=fedora-11&arch=i386&ip=149.20.20.135'
# Using preferred netblock Using ASN 1280 country = US country = MX country = CA 
http://mirrors.kernel.org/fedora/releases/11/Everything/i386/os/
...

I hope you enjoy this new feature.

Thanks,
Matt

-- 
Matt Domsch
Technology Strategist, Dell Office of the CTO
linux.dell.com & www.dell.com/linux

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