* Several race conditions were fixed, making Docker more stable under very high concurrency load. This makes Docker more stable and less likely to crash and reduces the memory footprint of many common operations
* All packaging operations are now built on the Go language’s standard tar implementation, which is bundled with Docker itself. This makes packaging more portable across host distributions, and solves several issues caused by quirks and incompatibilities between different distributions of tar
* Docker can now create, remove and modify larger numbers of containers and images graciously thanks to more aggressive releasing of system resources. For example the storage driver API now allows Docker to do reference counting on mounts created by the drivers
With the ongoing changes to the networking and execution subsystems of docker testing these areas have been a focus of the refactoring. By moving these subsystems into separate packages we can test, analyze, and monitor coverage and quality of these packages
* Many components have been separated into smaller sub-packages, each with a dedicated test suite. As a result the code is better-tested, more readable and easier to change
* The ADD instruction now supports caching, which avoids unnecessarily re-uploading the same source content again and again when it hasn’t changed
* The new ONBUILD instruction adds to your image a “trigger” instruction to be executed at a later time, when the image is used as the base for another build
* Docker now ships with an experimental storage driver which uses the BTRFS filesystem for copy-on-write
* Docker is officially supported on Mac OS X
* The Docker daemon supports systemd socket activation
## 0.7.6 (2014-01-14)
### Builder
* Do not follow symlink outside of build context
### Runtime
- Remount bind mounts when ro is specified
* Use https for fetching docker version
### Other
* Inline the test.docker.io fingerprint
* Add ca-certificates to packaging documentation
## 0.7.5 (2014-01-09)
### Builder
* Disable compression for build. More space usage but a much faster upload
- Fix ADD caching for certain paths
- Do not compress archive from git build
### Documentation
- Fix error in GROUP add example
* Make sure the GPG fingerprint is inline in the documentation
* Give more specific advice on setting up signing of commits for DCO
### Runtime
- Fix misspelled container names
- Do not add hostname when networking is disabled
* Return most recent image from the cache by date
- Return all errors from docker wait
* Add Content-Type Header "application/json" to GET /version and /info responses
### Other
* Update DCO to version 1.1
+ Update Makefile to use "docker:GIT_BRANCH" as the generated image name
* Update Travis to check for new 1.1 DCO version
## 0.7.4 (2014-01-07)
### Builder
- Fix ADD caching issue with . prefixed path
- Fix docker build on devicemapper by reverting sparse file tar option
- Fix issue with file caching and prevent wrong cache hit
* Use same error handling while unmarshalling CMD and ENTRYPOINT
### Documentation
* Simplify and streamline Amazon Quickstart
* Install instructions use unprefixed Fedora image
* Update instructions for mtu flag for Docker on GCE
+ Add Ubuntu Saucy to installation
- Fix for wrong version warning on master instead of latest
### Runtime
- Only get the image's rootfs when we need to calculate the image size
- Correctly handle unmapping UDP ports
* Make CopyFileWithTar use a pipe instead of a buffer to save memory on docker build
- Fix login message to say pull instead of push
- Fix "docker load" help by removing "SOURCE" prompt and mentioning STDIN
* Make blank -H option default to the same as no -H was sent
* Extract cgroups utilities to own submodule
### Other
+ Add Travis CI configuration to validate DCO and gofmt requirements
+ Add Developer Certificate of Origin Text
* Upgrade VBox Guest Additions
* Check standalone header when pinging a registry server
## 0.7.3 (2014-01-02)