According to the release notes, Docker 1.12.3 updates the new Swarm Mode feature introduced in the Docker 1.12 series by improving the conversion of restart-policy and adding an up-to-date Swarmkit that now allows multiple randomly assigned and duplicate published ports with different protocols.
Moreover, it looks like a task that has already been restarted will no longer be restarted thanks to the updated Swarmkit included in Docker 1.12.3, which also addresses the panic that occurred when allocations happened at init time. Several fixes were applied to the libnetwork component in Docker 1.12.3 for better networking.
These include a race in load balancer’s state, a race discovered during deletion, a deadlock in the networking code, and a race that existed in the serializing sandbox. Additionally, the updated libnetwork library now automatically resets the endpoint port information when the connectivity is revoked in the bridge driver.
Apart from the networking and Swarm Mode improvements mentioned above, Docker 1.12.3 enhances the logging functionality by updating the fluent-logger-golang component to version 1.2.1, updates the buildtags for the ARMhf branch of the Ubuntu 14.04 LTS (Trusty Tahr) operating system, and adds AppArmor to runc buildtags for ARMhf architectures.
Submitted by: Arnfried Walbrecht