Docker: All Containers Get Automatically Updated /etc/hosts (!?!?!?)

While I have always wanted such feature (automatically updated /etc/hosts for all running containers), I understand that Docker does not provide it natively (just yet - or at least AFAIK). I also understand some security issues that might come with such feature (not all running containers want other containers to connect to it).

Anyway, about 2 weeks ago, while I was dockerizing a system automation application that requires at least 2 running nodes (containers), I found that the feature was silently available*.

* I went through the Release Notes of almost all recent releases and could not find such feature being mentioned. If I got it wrong, please point me to the proper Release Notes. Thanks!

Before I forget, let me share with you the reason I have always wanted such feature. My reason is simple - I need all my running containers to know the "existence" of other related containers and have a way to communicate with them (in this case, through /etc/hosts).

My test environment was on CentOS 7.1 and Docker 1.8.2.

(1) Firstly, I started a container without any hostname and container name. You can see that the /etc/hosts file was updated with:
(a) the container ID as the hostname
(b) the container name as the hostname

(2) Next, I started another container with an assigned hostname of "node1". You can see that now the /etc/hosts was updated with:
(a) the assigned hostname
(b) the container name as the hostname

(3) To spice it up a little bit more, I started another container with an assigned hostname and gave the container a name. You can see that the /etc/hosts was updated with:
(a) the assigned hostname
(b) the given container name

(4) The next test was to start up 3 containers with different hostname and given name and left all of them running. You can see that "node1" was started and its /etc/hosts was updated accordingly.

(5) Next, I started "node2" and its /etc/hosts was updated with details of "node1" too.

(6) What happened to the /etc/hosts of "node1" at this moment? Surprise, surpirse...you can see that its /etc/hosts was updated with details of "node2" too.

(7) Just to make sure it's not devaju. I started the third container ("node1" and "node2" were still running). This time I wasn't surprised to see that the /etc/hosts of "node3" was updated with details of "node1" and "node2".

(8) Lastly, let's check the /etc/hosts of "node1" and "node2". Viola, they are updated too!

Seriously, I am not sure whether this feature has been available for some time or it is an experimental feature. Anyway, I like it...for the thing I do! So, I am not speaking for you :)