- Nameserver holds a sorted list of (hostname, peer, container id, ip) tuples.
- Entries are gossiped using topology gossip / broadcast - only new/updated entries
are propogated as expected.
- Entries for a given peer are removed when the connection to the peer is lost.
- Entries are tombstoned when containers die. Tombstones are kept for 10mins,
as they do not need to survive partition, only gossip propagation delay.
- use 'host' to lookup MX record. It's shorter
- use getent everywhere else for dns lookups, instead of dig; this
tests more of the o/s name resolution machinery and is generally
shorter.
- introduce assert_dns_record helper that performs forward and reverse
- lookup introduce some vars for holding constants, so we don't have
to repeat them
It's more precise to use dig rather than ping. The stock ubuntu image
doesn't come with dig (in package dnsutils), but luckily Aanand made
an image which is exactly ubuntu+dnsutils.
Marc CARRE