Speno's Pythonic Avocado 25.1.2004

load testing BIND using dnspython and queryperf

A new name server running BIND needed to be load tested. Included in BIND's distribution is a utility called queryperf which can be used to test a name server's performance. As input, queryperf takes a list of domain resource names and resource types seperated by whitespace and uses that list to generate queries to a name server. It should look like this:

foo.example.com. A
bar.example.com. A
mail.example.com.   MX
1.0.0.127.in-addr.arpa. PTR
2.0.0.127.in-addr.arpa. PTR

It would have been fairly easy to parse our zonefiles, looking for $ORIGIN tags and the like to construct our input file for performance testing. However, dnspython, an open-source DNS toolkit written in python, made it even easier. Here's the code:

# zoner.py
import dns.zone
import os.path
import sys

TYPES = ['A', 'PTR', 'MX']

for filename in sys.argv[1:]:
    zone = dns.zone.from_file(filename, os.path.basename(filename),
                              relativize=False)

    for type in TYPES:
        for (name, ttl, rdata) in zone.iterate_rdatas(type):
            print '%s\t%s' % (name, type)

This program parsed our zonefiles to produce an input file for queryperf. As for the new name server, it passed the test with flying circuses.