On Fri, 05 Aug 2011 01:08:22 +0300, Piavlo wrote:
Hi Jens,
I'm using names which resolve to internal EC2 addresses in haproxy
configs - the /etc/hosts of all instances are auto updated then new
instance is added/removed.
But the problem manifests then the instance is stoped and then
started - this makes the internal ip to change.
I can also use DNS CNAMES to public instance ip with very low TTL -
which get auto updated then instance boots by using route53 - but
it's
still the same problem - the ip changes in DNS and not in /etc/hosts
(getnameinfo does not really care from where from the name is
resolved) - in both cases haproxy will not know it has changed since
it probably uses getnameinfo once only on startup/reload. And never
later rechecks if the ip has changed.
Hi,
Haproxy resolves names into addresses at startup, so using names is
just an ugly way, and probably confusing, to define an ip address.
The only reliable way to work with IP addresses in EC2, without messing
with the whole /etc/hosts and applications reload, is to use static LAN
addresses, like in a real network. And you can do that just fine in a
VPC environment.
DO NOT use elastic IPs for internal traffic. Elastic IPs are routed
through the external network of EC2, so you will get charged $$$, your
interconnections will be slower and you don't even know where the hell
your packets are going....
Just the result of my personal experience... :)
Julien
