[infinispan-dev] Using load balancers for Infinispan in Kubernetes

Thu Jun 1 02:59:38 EDT 2017

Hey Emmanuel,

Comments inlined.

Thanks,
Sebastian

On Wed, May 31, 2017 at 2:56 PM Emmanuel Bernard <emmanuel at hibernate.org>
wrote:

> To Sanne’s point, I think HTTP(/2) would be a better longer term path if
> we think we can make it as efficient as current HR. But let’s evaluate the
> numbers of cycles to reach that point. Doing Seb’s approach might be a good
> first step.
>

I will be looking into HTTP/2 implementation starting from today/tomorrow.
So it should be there soon. And of course I will do some benchmarks (or
even help Jiri to upgrade perfCheck to do benchmarks using HTTP/1.1 and
HTTP/2).

Also please bear in mind that there will probably be two ways of switching
protocols - using HTTP/1.1 Upgrade header and TLS/ALPN negotiation. As you
might expect, the latter enforces TLS (and therefore the throughput will be
lower).

> Speaking of Sebastian, I have been discussing with Burr, Edson on the idea
> of a *node* sidecar (as opposed to a *pod* sidecar). To your problem, could
> you use Daemonset to enforce one Load Balancer per node or at least per
> project instead of one per pod deployed with Infinispan in it?
>

Unless I missed anything, it won't buy us anything. The idea behind the POC
is to make all Infinispan nodes directly accessible from the outside world.
The client must be able to access whichever node it wishes. This is
achieved by creating a load balancer per Infinispan pod. So the load
balancer works more like an external IP rather than a "real" load balancer.

Just FYI, another round of comments on L3/L4 TCP Ingress has just started:
https://github.com/kubernetes/kubernetes/issues/23291
The rough estimate is to get it in Kube 1.8. Once this is implemented, we
could use a TCP Ingress per pod (instead of load balancer per pod). The
main difference will probably be in $$$. Load balancers are pretty
expensive.

>
> WDYT, is it possible?
>
> On 30 May 2017, at 20:43, Sebastian Laskawiec <slaskawi at redhat.com> wrote:
>
> Hey guys!
>
> Over past few weeks I've been working on accessing Infinispan cluster
> deployed inside Kubernetes from the outside world. The POC diagram looks
> like the following:
>
> <pasted1.png>
>
>
> As a reminder, the easiest (though not the most effective) way to do it is
> to expose a load balancer Service (or a Node Port Service) and access it
> using a client with basic intelligence (so that it doesn't try to update
> server list based on topology information). As you might expect, this won't
> give you much performance but at least you could access the cluster.
> Another approach is to use TLS/SNI but again, the performance would be even
> worse.
>
> During the research I tried to answer this problem and created "External
> IP Controller" [1] (and corresponding Pull Request for mapping
> internal/external addresses [2]). The main idea is to create a controller
> deployed inside Kubernetes which will create (and destroy if not needed) a
> load balancer per Infinispan Pod. Additionally the controller exposes
> mapping between internal and external addresses which allows the client to
> properly update server list as well as consistent hash information. A full
> working example is located here [3].
>
> The biggest question is whether it's worth it? The short answer is yes.
> Here are some benchmark results of performing 10k puts and 10k puts&gets
> (please take them with a big grain of salt, I didn't optimize any server
> settings):
>
>    - Benchmark app deployed inside Kuberenetes and using internal
>    addresses (baseline):
>       - 10k puts: 674.244 ±  16.654
>       - 10k puts&gets: 1288.437 ± 136.207
>    - Benchamrking app deployed in a VM outside of Kubernetes with basic
>    intelligence:
>       - *10k puts: 1465.567 ± 176.349*
>       - *10k puts&gets: 2684.984 ± 114.993*
>    - Benchamrking app deployed in a VM outside of Kubernetes with address
>    mapping and topology aware hashing:
>       - *10k puts: 1052.891 ±  31.218*
>       - *10k puts&gets: 2465.586 ±  85.034*
>
> Note that benchmarking Infinispan from a VM might be very misleading since
> it depends on data center configuration. Benchmarks above definitely
> contain some delay between Google Compute Engine VM and a Kubernetes
> cluster deployed in Google Container Engine. How big is the delay? Hard to
> tell. What counts is the difference between client using basic intelligence
> and topology aware intelligence. And as you can see it's not that small.
>
> So the bottom line - if you can, deploy your application along with
> Infinispan cluster inside Kubernetes. That's the fastest configuration
> since only iptables are involved. Otherwise use a load balancer per pod
> with External IP Controller. If you don't care about performance, just use
> basic client intelligence and expose everything using single load balancer.
>
> Thanks,
> Sebastian
>
> [1] https://github.com/slaskawi/external-ip-proxy
> [2] https://github.com/infinispan/infinispan/pull/5164
> [3] https://github.com/slaskawi/external-ip-proxy/tree/master/benchmark
>
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-- 

SEBASTIAN ŁASKAWIEC

INFINISPAN DEVELOPER

Red Hat EMEA <https://www.redhat.com/>
<https://red.ht/sig>
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