Docker 1.12.4 釋出了，Docker 1.12 版本附帶了更新 rpm 的 systemd 單元檔案（包括 RHEL、Fedora、CentOS 和 Oracle Linux 7 ），當從舊版本的 docker 升級，升級過程可能不會自動安裝更新版本的單元檔案，或因為某些原因無法啟動 docker 服務。

更新內容：

Runtime

• Fix issue where volume metadata was not removed

• Asynchronously close streams to prevent holding container lock

• Fix selinux labels for newly created container volumes

• Remove hostname validation

• Fix deadlocks caused by IO races

• Return an empty stats if the container is restarting

• Fix volume store locking

• Ensure consistent status code in API

• Fix incorrect opaque directory permission in overlay2

• Detect plugin content and error out on docker pull 

Swarm Mode

• Update Swarmkit

• orchestrator/global: Fix deadlock on updates

• on leader switchover preserve the vxlan id for existing networks

• Refuse swarm spec not named "default" 

Networking

• Update libnetwork

• Fix panic in embedded DNS 

• Fix unmarhalling panic when passing --link-local-ip on global scope network

• Fix panic when network plugin returns nil StaticRoutes

• Fix panic in osl.(*networkNamespace).DeleteNeighbor

• Fix panic in swarm networking concurrent map read/write

• Allow encrypted networks when running docker inside a container

• Do not block autoallocation of IPv6 pool

• Set timeout for netlink calls

• Increase networking local store timeout to one minute

• Fix a panic in libnetwork.(*sandbox).execFunc

• Honor icc=false for internal networks

Logging

• Update syslog log driver

Contrib

• Run "dnf upgrade" before installing in fedora

• Add build-date back to RPM packages

• Update selinux policy for distros based on RHEL7.3