nsqd/nsqadmin: "busy out" mode

[danbf]

right now we need to go on a node manually and shut down the ingress services manually to a box to busy it out. it would be nice if that was exposed so we don't have to ssh into each box.

http://www.yourdictionary.com/busy-out

busy out - Computer Definition
To invoke a feature of a telecommunications system that rejects incoming calls.

[mreiferson]

I'm on the fence whether this belongs in NSQ proper or not :)

[jehiah]

Since so many things live in a container world, i can see a control exposed from nsqd that makes it easier to put that node into a mode where it rejects incoming messages but allows any messages it does have to drain.

You could then combine that with clients that properly handler write errors (which is actually infrequent in my experience) to retry against a secondary nsqd target.

On the consumer side, this can be handled outside of NSQ pretty straight forwardly; I do this by watching for a touch file and having QR's go into "RDY 0" mode when that touch file is present.

[mreiferson]

ping #1254