[infinispan-dev] Adjusting memory settings in template

[Sebastian Laskawiec]

On Mon, Sep 25, 2017 at 11:54 AM Galder Zamarreño <galder at redhat.com> wrote:

> I don't understand your reply here... are you talking about Infinispan
> instances deployed on OpenShift Online? Or on premise?
>

TBH - I think there is no difference, so I'm thinking about both.


> I can understand having some limits for OpenShift Online, but these
> templates should also be applicable on premise, in which case I should be
> able to easily define how much memory I want for the data grid, and the
> rest of the parameters would be worked out by OpenShift/Kubernetes?
>

I have written a couple of emails about this on internal mailing list. Let
me just point of some bits here:

   - We need to set either Xmx or MaxRAM to tell the JVM how much memory it
   can allocate. As you probably know JDK8 is not CGroups aware by default
   (there are some experimental options but they set MaxRAM parameter equal to
   CGroups limit; this translates to Xmx=MaxRAM(CGroups limit) / 4. I guess
   allocating Xmx=(CGroups limit)/4 is too high for us, so we need to set it
   explicitly.
   - in our Docker image we set Xmx = 50% of CGroups limit. This is better
   than settings above but there is some risk in certain scenarios.
   - As I mentioned in my previous email, in the templates we are setting
   Requests (not Limits!!!). So you will probably get more memory than
   specified in the template but it depends on the node you're running on. The
   key point is that you won't get less than those 512 MB.
   - You can always edit your DeploymentConfig (after creating your
   application from template) and adjust Limits (or even requests).
   - For simple scenarios and bigger containers (like 4 GB) we can go more
   than 50% (see internal mailing list for details).

And as I said before - if you guys think we should do it differently, I'm
open for suggestions. I think it's quite standard way of configuring this
sort of stuff.

>
> To demand on premise users to go and change their template just to adjust
> the memory settings seems to me goes against all the usability improvements
> we're trying to achieve.
>

At some point you need to define how much memory you will need. Whether
it's in the template, your DeploymentConfiguration (created from template
using oc process), Quota - it doesn't matter. You must write it somewhere -
don't you? With current approach, the best way to do it is in Deployment
Configuration Requests. This sets CGroups limit, and based on that,
Infinispan bootstrap scripts will calculate Xmx.


>
> Cheers,
>
> > On 22 Sep 2017, at 14:49, Sebastian Laskawiec <slaskawi at redhat.com>
> wrote:
> >
> > It's very tricky...
> >
> > Memory is adjusted automatically to the container size [1] (of course
> you may override it by supplying Xmx or "-n" as parameters [2]). The safe
> limit is roughly Xmx=Xms=50% of container capacity (unless you do the
> off-heap, that you can squeeze Infinispan much, much more).
> >
> > Then there are Limits, Requests and QoS in Kubernetes [3][4]. We are in
> bustable memory category so if there is additional memory in the node,
> we'll get it. But if not, we won't go below 512 MB (and 500 mCPU).
> >
> > Thanks,
> > Sebastian
> >
> > [1]
> https://github.com/jboss-dockerfiles/infinispan/tree/master/server#adjusting-memory
> > [2]
> https://github.com/jboss-dockerfiles/infinispan/blob/master/server/docker-entrypoint.sh#L303-L308
> > [3] https://www.youtube.com/watch?v=nWGkvrIPqJ4
> > [4]
> https://docs.openshift.com/enterprise/3.2/dev_guide/compute_resources.html
> >
> > On Fri, Sep 22, 2017 at 2:33 PM Galder Zamarreño <galder at redhat.com>
> wrote:
> > Hi Sebastian,
> >
> > How do you change memory settings for Infinispan started via service
> catalog?
> >
> > The memory settings seem defined in [1], but this is not one of the
> parameters supported.
> >
> > I guess we want this as parameter?
> >
> > Cheers,
> >
> > [1]
> https://github.com/infinispan/infinispan-openshift-templates/blob/master/templates/infinispan-ephemeral.json#L308
> > --
> > Galder Zamarreño
> > Infinispan, Red Hat
> >
>
> --
> Galder Zamarreño
> Infinispan, Red Hat
>
>
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