From 881ece355390cad2517524791cc73baf29974466 Mon Sep 17 00:00:00 2001 From: Tom Wilkie Date: Tue, 4 Aug 2015 10:47:36 +0000 Subject: [PATCH 1/2] Add note to explain dns shuffle effects. --- site/weavedns.md | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/site/weavedns.md b/site/weavedns.md index 5e9d261e..50ebc4b7 100644 --- a/site/weavedns.md +++ b/site/weavedns.md @@ -71,8 +71,16 @@ cluster. When weaveDNS is queried for a name in the `.weave.local` domain, it looks up the hostname its in memory database and responds with the IPs -of all containers for that hostname across the entire cluster, in a -random order. +of all containers for that hostname across the entire cluster. + +WeaveDNS returns IP addresses in a random order to facilitate basic +load balancing and failure tolerance. Most client side resolvers sort +the returned addresses based on reachability, sorting local addresses +to the top of the list (see [RFC 3484](https://www.ietf.org/rfc/rfc3484.txt)). +For example, if there is container with the desired hostname on the local +machine, the application will receive that container's IP address. +Otherwise, the application will receive the IP address of a random +container with the desired hostname. When weaveDNS is queried for a name in a domain other than `.weave.local`, it queries the host's configured nameserver, which is From f241e15ec128fd0402c9662b2b8ca8fca5a1280d Mon Sep 17 00:00:00 2001 From: Tom Wilkie Date: Tue, 4 Aug 2015 11:00:32 +0000 Subject: [PATCH 2/2] Review feedback --- site/weavedns.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/site/weavedns.md b/site/weavedns.md index 50ebc4b7..29a66fbf 100644 --- a/site/weavedns.md +++ b/site/weavedns.md @@ -75,8 +75,8 @@ of all containers for that hostname across the entire cluster. WeaveDNS returns IP addresses in a random order to facilitate basic load balancing and failure tolerance. Most client side resolvers sort -the returned addresses based on reachability, sorting local addresses -to the top of the list (see [RFC 3484](https://www.ietf.org/rfc/rfc3484.txt)). +the returned addresses based on reachability, placing local addresses +at the top of the list (see [RFC 3484](https://www.ietf.org/rfc/rfc3484.txt)). For example, if there is container with the desired hostname on the local machine, the application will receive that container's IP address. Otherwise, the application will receive the IP address of a random