1.2.0 RC3

This is a release candidate for Compose 1.2.0. To try it out, run the following commands:

curl -L https://github.com/docker/compose/releases/download/1.2.0rc3/docker-compose-`uname -s`-`uname -m` > /usr/local/bin/docker-compose
chmod +x /usr/local/bin/docker-compose

Optionally, you can also install command completion for the bash shell.

On top of the changes listed below for RC1 and RC2, the following bugs have been fixed:

• When copying a service's configuration with extends, image and build could come into conflict, resulting in an error, as it makes no sense to have both defined. Each now overwrites the other: if a service with image defined is extended and build is added, the image entry will be removed.
• When copying a service's configuration with extends, if both services defined a multi-value option such as ports or dns, the original value would be completely discarded. They are now concatenated instead.
• When a relative path is supplied to build, it is treated as relative to the directory of the configuration file, not the directory that docker-compose is being run in. In the majority of cases, those are the same, but if you use the -f|--file argument to specify a configuration file in another directory, this is a breaking change.

Here are the changes for RC2:

• A bug has been fixed where containers were being created with blank entries for "Dns" and "DnsSearch", causing DNS lookups from within a container to fail.

Here are the changes for RC1:

• docker-compose.yml now supports an extends option, which enables a service to inherit configuration from another service in another configuration file. This is really good for sharing common configuration between apps, or for configuring the same app for different environments. Here's the documentation.
• When using Compose with a Swarm cluster, containers that depend on one another will be co-scheduled on the same node. This means that most Compose apps will now work out of the box, as long as they don't use build.
• Repeated invocations of docker-compose up when using Compose with a Swarm cluster now work reliably.
• Filenames in env_file and volume host paths in volumes are now treated as relative to the directory of the configuration file, not the directory that docker-compose is being run in. In the majority of cases, those are the same, but if you use the -f|--file argument to specify a configuration file in another directory, this is a breaking change.
• A service can now share another service's network namespace with net: container:<service>.
• volumes_from and net: container:<service> entries are taken into account when resolving dependencies, so docker-compose up <service> will correctly start all dependencies of <service>.
• Problems with authentication when using images from third-party registries have been fixed.
• docker-compose run now accepts a --user argument to specify a user to run the command as, just like docker run.
• The up, stop and restart commands now accept a --timeout (or -t) argument to specify how long to wait when attempting to gracefully stop containers, just like docker stop.
• docker-compose rm now accepts -f as a shorthand for --force, just like docker rm.

Thanks, @abesto, @albers, @alunduil, @dnephin, @funkyfuture, @gilclark, @IanVS, @KingsleyKelly, @knutwalker, @moysesb, @thaJeztah and @vmalloc!