From 7c63b49df6c35cf8c97369a5d6a1f13a17142ad0 Mon Sep 17 00:00:00 2001 From: Sebastiaan van Stijn Date: Mon, 19 Jan 2015 00:23:57 +0100 Subject: [PATCH] Document that ENV vars are not automatically updated Unlike the entries in `/etc/hosts`, environment-variables for linked containers are not automatically updated if the linked container is restarted. This adds a note to the documentation in; https://docs.docker.com/userguide/dockerlinks/#environment-variables and https://docs.docker.com/reference/run/#env-environment-variables To make users aware that this is the case and recommends them to use the `/etc/hosts` entries in stead. I added this change because users were expecting environment variables to be updated automatically as well (https://github.com/docker/docker/issues/10164). Signed-off-by: Sebastiaan van Stijn --- docs/sources/reference/run.md | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/docs/sources/reference/run.md b/docs/sources/reference/run.md index d594066ad0..8bf0d3633f 100644 --- a/docs/sources/reference/run.md +++ b/docs/sources/reference/run.md @@ -647,6 +647,12 @@ mechanism to communicate with a linked container by its alias: If you restart the source container (`servicename` in this case), the recipient container's `/etc/hosts` entry will be automatically updated. +> **Note**: +> Unlike host entries in the `/ets/hosts` file, IP addresses stored in the +> environment variables are not automatically updated if the source container is +> restarted. We recommend using the host entries in `/etc/hosts` to resolve the +> IP address of linked containers. + ## VOLUME (shared filesystems) -v=[]: Create a bind mount with: [host-dir]:[container-dir]:[rw|ro].