Docker 1.12: Now with Built-In Orchestration

Re:Docker 1.12: Now with Built-In Orchestration by bboreham on Tuesday June 21, 2016 @08:43AM (#11945212)

> a given hostname lookup by a given container in a given service discovery scope will always return the same IP

Did you mean this to cover the situation where N containers have registered the same name? I thought Docker DNS returned all such results in random order.

Given that, if one of those containers goes offline and Java has cached its address, you have the problem the parent was alluding to.

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Re:Docker 1.12: Now with Built-In Orchestration by shykes on Tuesday June 21, 2016 @10:10AM (#11945694)

That's incorrect. You are describing DNS-based load-balancing, which would indeed rely on the container's resolver implementation. But Docker doesn't do that. Instead it always resolves the service name to the same IP, which is load-balanced by IPVS. That way even the world's crappiest dns caching implementation will still be handled properly.

So when I said that Docker doesn't rely on the container's DNS resolver, I really meant it. We have seen in past lives the consequences of "DNS abuse" and have been careful to avoid it.

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Re:Docker 1.12: Now with Built-In Orchestration by bboreham on Tuesday June 21, 2016 @10:31AM (#11945855)

I was going by https://blog.docker.com/2016/04/docker-engine-1-11-runc/ which advertised "DNS round robin load balancing".

EDIT: calmer tone

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Re:Docker 1.12: Now with Built-In Orchestration by theod on Tuesday June 21, 2016 @10:43AM (#11945945)

Docker 1.12 built-in load-balancing supports both VIP based LB using IPVS and also DNS-RR and it is configurable per-service. VIP based LB is the default though. All of these will be fully documented shortly.

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