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From Павлухин Иван <vololo...@gmail.com>
Subject Re: Replacing NodeFilter functionality with label approach
Date Mon, 12 Aug 2019 09:11:47 GMT
Folks,

I feel that the picture still is not clear for the subject.

Pavel K., could you please highlight problems related to user code in
NodeFilter except classloading?

Nikolay, could you please provide some examples when node filtering
cannot be solved with label/regexp approach?

чт, 8 авг. 2019 г. в 15:39, Pavel Tupitsyn <ptupitsyn@apache.org>:
>
> I agree that attribute-based filtering is enough.
>
> We should get rid of predicates in configuration as much as possible:
> they introduce a lot of complexity for other platforms (.NET), among other
> things mentioned above.
>
> On Thu, Aug 8, 2019 at 2:04 PM Pavel Kovalenko <jokserfn@gmail.com> wrote:
>
> > Ivan,
> >
> > > And there is also one idea (I am not fan of it but still). Can we use
> > > some kind of scripting for nodes filtering? In that case node filter
> > > is represented by script string, e.g. javascript.
> >
> > I guess it can lead to the same situation as in Java NodeFilter's. We can't
> > control what happens in a filter in this case.
> > We can consider regex as an option instead of just labels. It's still
> > string and can be validated on correctness during node start.
> > But we still don't have any real examples that require more flexibility
> > than labels have.
> >
> > вт, 6 авг. 2019 г. в 14:46, Павлухин Иван <vololo100@gmail.com>:
> >
> > > Alexey,
> > >
> > > It seems that a problem has a solution with using 2 attributes or 2
> > > labels. Is not it more clear than using custom code?
> > >
> > > Folks,
> > >
> > > > I don't think we should take "hard to implement" as an argument in this
> > > discussion :)
> > > Did not fully get the point. KISS principle is not true anymore? Or is
> > > this discussion somehow special? I believe that every flexibility
> > > handle should be critically justified. Would be great to justify
> > > NodeFilter flexibility.
> > >
> > > > Filters based of hostname or ip address.
> > > Is it a good idea to use IP address for node filtering? IP can be
> > > changed for a node with persistence, does it mean that not relevant
> > > data (according to a filter) should be cleared, does it work now?
> > >
> > > And there is also one idea (I am not fan of it but still). Can we use
> > > some kind of scripting for nodes filtering? In that case node filter
> > > is represented by script string, e.g. javascript.
> > >
> > > вт, 6 авг. 2019 г. в 12:22, Alexey Kukushkin <kukushkinalexey@gmail.com
> > >:
> > > >
> > > > Pavel,
> > > >
> > > > Just a real example you asked for: we have a user attribute "ROLE_DC",
> > > > which is a comma separated list like "wfe_a, as_a, db_a" (server role
> > and
> > > > data center designator) and we have node filters to deploy services and
> > > > start caches on servers with specific role (like WFE) and sometimes
> > > > specific role and DC (like WFE_A). The node filter splits the list and
> > > uses
> > > > a regular expression to match each segment.
> > > >
> > > > If you replace generic node filter with a user attribute filter then we
> > > > still can achieve what we need  by creating 3 user attributes (ROLE_DC,
> > > > ROLE and DC) but we lose flexibility since now adding a new data center
> > > > requires updating all cache and service configurations. With regex
> > > matching
> > > > we do not need to update the configurations since we still match all
> > the
> > > > roles in the new DC.
> > > >
> > > > So we would have a solution with user attributes filter but I we lose
> > > some
> > > > flexibility.
> > > >
> > > > --
> > > > Best regards,
> > > > Alexey
> > >
> > >
> > >
> > > --
> > > Best regards,
> > > Ivan Pavlukhin
> > >
> >



-- 
Best regards,
Ivan Pavlukhin

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