Docker is an open platform for distributing software application in containers. It utilizes operating system-level virtualization for process and full resource isolation through cgroups, capabilities, SELinux, AppArmor, netfilter, and Linux kernel namespaces. Its libcontainer is based on libvirt and lxc. Docker Engine is the application and environment packaging tool. And Docker Hub is a cloud service for sharing prepackaged containers.
minor feature: Builder: Add multi-stage build support. Allow using build-time args (`ARG`) in `FROM`. Add an option for specifying build target. Accept `-f -` to read Dockerfile from `stdin`, but use local context for building. The values of default build time arguments (e.g `HTTP_PROXY`) are no longer displayed in docker image history unless a corresponding `ARG` instruction is written in the Dockerfile.. setting command if a custom shell is used in a parent image. `docker build --label` when the label includes single quotes and a space. Client: Add `--mount` flag to `docker run` and `docker create`. Add `--type=secret` to `docker inspect`. Add `--format` option to `docker secret ls`. Add `--filter` option to `docker secret ls`. Add `--filter scope=` to `docker network ls`. Add `--cpus` support to `docker update`. Add label filter to `docker system prune` and other `prune` commands. `docker stack rm` now accepts multiple stacks as input. Improve `docker version --format` option when the client has downgraded the API version. Prompt when using an encrypted client certificate to connect to a docker daemon. Display created tags on successful `docker build`. Cleanup compose convert error messages. Contrib: Add support for building docker debs for Ubuntu 17.04 Zesty on amd64. Daemon: `--api-cors-header` being ignored if `--api-enable-cors` is not set. Cleanup docker tmp dir on start. Deprecate `--graph` flag in favor or `--data-root`. Logging: Add support for logging driver plugins. Add support for showing logs of individual tasks to `docker service logs`, and add `/task/ id /logs` REST endpoint. Add `--log-opt env-regex` option to match environment variables using a regular expression. Networking: Allow user to replace, and customize the ingress network. UDP traffic in containers not working after the container is restarted. files being written to `/var/lib/docker` if a different data-root is set. Runtime: Ensure health probe is