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From: Tom Barber <tom.barber@meteorite.bi>
Date: Mon, 27 Mar 2017 20:43:44 +0100
Message-ID: <CABML50cpHOUySvEu85uoiuQjoPNcR3FBqDhj3upu=-ZFa=c3FA@mail.gmail.com>
Subject: Re: GSoC 2017 - Rework OODT Configuration to make use of Zookeeper
To: "dev@oodt.apache.org" <dev@oodt.apache.org>
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archived-at: Mon, 27 Mar 2017 19:44:26 -0000

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Hi Imesha

I'm trying to figure out if/how I can get access to it on the dashboard. In
the mean time if you want to pastebin it, chuck it in a word doc, or
something completely different I'd be happy to take a look.

Tom

On Sun, Mar 26, 2017 at 3:09 PM, Imesha Sudasingha <imesha.13@cse.mrt.ac.lk>
wrote:

> Hi Tom,
>
> Did you get a chance to look at my proposal?
>
> Kind Regards,
> *Imesha Sudasingha*
> Undergraduate of Department of Computer Science and  Engineering,
> University of Moratuwa,
> Sri Lanka.
>
> <https://lk.linkedin.com/in/imeshasudasingha>  <https://github.com/IMS94>
> <http://stackoverflow.com/users/4012073/imesha-sudasingha>
> <https://twitter.com/Imesha94>
>
> On 23 March 2017 at 10:40, Imesha Sudasingha <imesha.13@cse.mrt.ac.lk>
> wrote:
>
> > Hi Tom,
> >
> > I have written a draft proposal and shared it with the Apache Software
> > Foundation through the GSoC dashboard. If you get a chance, can you
> please
> > review it and let me know what are the improvements required to be made.
> >
> > Thanks in advance!
> >
> > Kind Regards,
> > *Imesha Sudasingha*
> > Undergraduate of Department of Computer Science and  Engineering,
> > University of Moratuwa,
> > Sri Lanka.
> >
> > <https://lk.linkedin.com/in/imeshasudasingha>  <https://github.com/IMS94
> >
> > <http://stackoverflow.com/users/4012073/imesha-sudasingha>
> > <https://twitter.com/Imesha94>
> >
> > On 22 March 2017 at 14:36, Imesha Sudasingha <imesha.13@cse.mrt.ac.lk>
> > wrote:
> >
> >> Hi Tom,
> >>
> >> I think I had missed your point previously. I was referring to just
> >> storing the configuration of different components in different ZNodes
> and
> >> querying them later. Then I understood that we also need to have
> >> inheritance at zookeeper level in order to make it easy to configure
> OODT
> >> clusters as you have mentioned in the issue [1]. To configure clusters
> of
> >> OODT components with minimum configuration, I will have to review my
> design
> >> again and make a lot of improvements. For example, I have to think
> about a
> >> way to store configuration in zookeeper with minimum duplications and
> give
> >> components enough flexibility to initialize with no or minimum manual
> >> configuration.
> >>
> >> Since I have to submit the GSoC proposal before 3rd of April, I think
> >> that I won't have enough time to review the design and make the
> necessary
> >> improvements before that. Will that negatively affect the possibility
> of me
> >> being able to work on this project for GSoC 2017? Please let me know you
> >> opinion.
> >>
> >> Thank you!
> >>
> >> [1] https://issues.apache.org/jira/browse/OODT-945
> >>
> >> Kind Regards,
> >> *Imesha Sudasingha*
> >> Undergraduate of Department of Computer Science and  Engineering,
> >> University of Moratuwa,
> >> Sri Lanka.
> >>
> >> <https://lk.linkedin.com/in/imeshasudasingha>  <
> https://github.com/IMS94>
> >>   <http://stackoverflow.com/users/4012073/imesha-sudasingha>
> >> <https://twitter.com/Imesha94>
> >>
> >> On 21 March 2017 at 10:52, Imesha Sudasingha <imesha.13@cse.mrt.ac.lk>
> >> wrote:
> >>
> >>> Hi Tom,
> >>>
> >>> Sorry for the late reply. Zookeeper is just providing an ZNode
> >>> structure, which can be considered as a tree where a node is accessed
> as
> >>> directories. For example, in [1] the file manager properties of the
> >>> instance with name "*node1*" is stored at the ZPath (Path to that
> >>> ZNode) "*/oodt/node1/file-mgr/filemgr.properties*".
> >>>
> >>> Therefore, my idea is that we can make such directories (ZPaths) per
> >>> each instance in our cluster (ex: */oodt/node1 for instance "node1"*,
> */oodt/node2
> >>> for instance "node2"* and so on). Then inside each such path (assigned
> >>> per node), we will have separate ZNodes for each component. For
> example, in
> >>> */oodt/node1* we will have an ZNode /oodt/node1/file-mgr which stores
> >>> the configurations of file manager of node1. Similarly, an ZNode
> >>> /oodt/node1/res-mgr will store the configuration of the resource
> manager of
> >>> node1.
> >>>
> >>> Hope you got the idea. Since zookeeper is not some kind of a graph
> >>> database, I couldn't think of a method to keep inheritance among
> >>> configuration at Zookeeper's side. However, the design I suggest will
> store
> >>> the configuration independently and will allow the users/developers to
> >>> query those configuration. Therefore in my opinion, we should let the
> >>> developer to compare the configuration and make decisions. This way,
> we can
> >>> allow this distributed configuration manager to manage configuration
> of any
> >>> current component or any upcoming component making it more extend-able.
> >>>
> >>> Can you let me know what do you think of it?
> >>>
> >>> Thank you!
> >>>
> >>> [1] https://drive.google.com/open?id=0B415Bnipaf1lNThKYXZMN3pFemc
> >>>
> >>> Kind Regards,
> >>> *Imesha Sudasingha*
> >>> Undergraduate of Department of Computer Science and  Engineering,
> >>> University of Moratuwa,
> >>> Sri Lanka.
> >>>
> >>> <https://lk.linkedin.com/in/imeshasudasingha>
> >>> <https://github.com/IMS94>
> >>> <http://stackoverflow.com/users/4012073/imesha-sudasingha>
> >>> <https://twitter.com/Imesha94>
> >>>
> >>> On 20 March 2017 at 05:02, Tom Barber <tom.barber@meteorite.bi> wrote:
> >>>
> >>>> Hi Imesha
> >>>>
> >>>> Sorry for the delay, I've been travelling and only just got myself
> >>>> through
> >>>> my backlog.
> >>>>
> >>>> The overall design looks good. I was also thinking it would make sense
> >>>> if
> >>>> possible to have some form of inheritance in the config. So, for
> >>>> example,
> >>>> if you have 5 file managers, and they all share the same config
> except a
> >>>> base url or whatever, it would make sense to have a single set of
> >>>> configs
> >>>> and then individual overrides for configs that change. (My knowledge
> of
> >>>> Zookeeper isn't great, I'm assuming something along these lines is
> >>>> possible).
> >>>>
> >>>> It would also make sense, I think to register this stuff with the
> >>>> resource
> >>>> manager, but I'm not sure how that integration would work quite yet,
> so
> >>>> we'll need to figure that one out.
> >>>>
> >>>> Let me know if you have any questions about the above.
> >>>>
> >>>> Tom
> >>>>
> >>>>
> >>>> On Sat, Mar 18, 2017 at 12:39 PM, Imesha Sudasingha <
> >>>> imesha.13@cse.mrt.ac.lk
> >>>> > wrote:
> >>>>
> >>>> > Hi Tom,
> >>>> >
> >>>> > What do you think of the design? Do you agree on implementing this
> >>>> > configuration management section in a separate module?
> >>>> >
> >>>> > I was thinking on starting on the implementation as a proof of
> >>>> concept. Can
> >>>> > you give me your kind feedback before I start on that?
> >>>> >
> >>>> > Thank you!
> >>>> >
> >>>> > Kind Regards,
> >>>> > *Imesha Sudasingha*
> >>>> > Undergraduate of Department of Computer Science and  Engineering,
> >>>> > University of Moratuwa,
> >>>> > Sri Lanka.
> >>>> >
> >>>> > <https://lk.linkedin.com/in/imeshasudasingha>  <
> >>>> https://github.com/IMS94>
> >>>> > <http://stackoverflow.com/users/4012073/imesha-sudasingha>
> >>>> > <https://twitter.com/Imesha94>
> >>>> >
> >>>> > On 16 March 2017 at 17:51, Imesha Sudasingha <
> imesha.13@cse.mrt.ac.lk
> >>>> >
> >>>> > wrote:
> >>>> >
> >>>> > > Hi Tom,
> >>>> > >
> >>>> > > Thanks for the quick reply. I came up with a small design [1].
> >>>> > >
> >>>> > > What I suggest is a separate module for configuration management,
> >>>> which
> >>>> > > can be extended in future and used by many components as well.
> >>>> > >
> >>>> > > As shown in the design [1], File Manager (or any component that is
> >>>> > willing
> >>>> > > to have this extended functionality of distributed configuration
> >>>> > > management) will have an instance of *ConfigurationManager* which
> >>>> is an
> >>>> > > interface defined to load configuration (specifically, .properties
> >>>> files)
> >>>> > > and get configurations of each running instance of the same
> >>>> component (If
> >>>> > > distributed configuration management is enabled, this will return
> >>>> the
> >>>> > > configuration of all the other instances).
> >>>> > >
> >>>> > > There will be two implementing classes of that interface,
> >>>> > > *StandaloneConfigurationManager* and
> *DistributedConfigurationManag
> >>>> er.*
> >>>> > As
> >>>> > > the name implies, standalone configuration manager is to be used
> if
> >>>> the
> >>>> > > users do not intend to used distributed configuration management.
> >>>> Also
> >>>> > this
> >>>> > > will be same as the current mechanism of configuration management.
> >>>> Then
> >>>> > the
> >>>> > > distributed configuration manager will be the implementation using
> >>>> > > Zookeeper.
> >>>> > >
> >>>> > > At zookeeper level, we will need to have a proper naming mechanism
> >>>> and a
> >>>> > > structure to store configuration. For example,*
> >>>> > > /${nodeName}/${componentName}/{$configFileName}* will be the
> place
> >>>> where
> >>>> > > the configuration file contents will be stored. *getFile(String
> >>>> fileName)
> >>>> > > and getFiles(String directiryName)* of *NodeConfiguration* class
> >>>> will
> >>>> > > return the content of the configuration files and configuration
> >>>> > directories
> >>>> > > respectively. I have demonstrated the ZNode structre I'm expecting
> >>>> to
> >>>> > > design in [2]
> >>>> > >
> >>>> > > Please note that this is just a very high level overview of my
> >>>> design and
> >>>> > > the real difficulty of implementation comes when testing this and
> >>>> > > addressing the edge cases of zookeeper. Also, I have only added
> few
> >>>> > methods
> >>>> > > that came to my mind to the *ConfigurationManager* interface. If
> >>>> you find
> >>>> > > any fault in this design or have a better design in mind please
> let
> >>>> me
> >>>> > know
> >>>> > > so that I can optimize this design and do my best to come up with
> >>>> the
> >>>> > best
> >>>> > > possible solution.
> >>>> > >
> >>>> > > Thank you!
> >>>> > >
> >>>> > > [1] https://drive.google.com/open?id=0B415Bnipaf1ldnV1dWt4VVVLam8
> >>>> > > [2] https://drive.google.com/open?id=0B415Bnipaf1lNThKYXZMN3pFemc
> >>>> > >
> >>>> > > Kind Regards,
> >>>> > > *Imesha Sudasingha*
> >>>> > > Undergraduate of Department of Computer Science and  Engineering,
> >>>> > > University of Moratuwa,
> >>>> > > Sri Lanka.
> >>>> > >
> >>>> > > <https://lk.linkedin.com/in/imeshasudasingha>  <
> >>>> https://github.com/IMS94
> >>>> > >
> >>>> > > <http://stackoverflow.com/users/4012073/imesha-sudasingha>
> >>>> > > <https://twitter.com/Imesha94>
> >>>> > >
> >>>> > > On 16 March 2017 at 16:55, Tom Barber <tom.barber@meteorite.bi>
> >>>> wrote:
> >>>> > >
> >>>> > >> Hi Imesha,
> >>>> > >>
> >>>> > >> Basically, just allowing the dynamic registration of file
> managers
> >>>> so
> >>>> > that
> >>>> > >> new ones can come and go.
> >>>> > >>
> >>>> > >> Tom
> >>>> > >>
> >>>> > >> On Thu, Mar 16, 2017 at 10:00 AM, Imesha Sudasingha <
> >>>> > >> imesha.13@cse.mrt.ac.lk
> >>>> > >> > wrote:
> >>>> > >>
> >>>> > >> > Hi Tom,
> >>>> > >> >
> >>>> > >> > Need a small clarification. In the last reply, you mentioned
> >>>> that file
> >>>> > >> > managers may be designed to be *transient. *What do you mean by
> >>>> that?
> >>>> > A
> >>>> > >> > quick response would really help me as I'm trying to come up
> >>>> with a
> >>>> > >> design.
> >>>> > >> >
> >>>> > >> > Thank you!
> >>>> > >> >
> >>>> > >> > *Imesha Sudasingha*
> >>>> > >> > Undergraduate of Department of Computer Science and
> Engineering,
> >>>> > >> > University of Moratuwa,
> >>>> > >> > Sri Lanka.
> >>>> > >> >
> >>>> > >> > <https://lk.linkedin.com/in/imeshasudasingha>  <
> >>>> > >> https://github.com/IMS94>
> >>>> > >> > <http://stackoverflow.com/users/4012073/imesha-sudasingha>
> >>>> > >> > <https://twitter.com/Imesha94>
> >>>> > >> >
> >>>> > >> > On 13 March 2017 at 22:03, Imesha Sudasingha <
> >>>> imesha.13@cse.mrt.ac.lk
> >>>> > >
> >>>> > >> > wrote:
> >>>> > >> >
> >>>> > >> > > Hi Tom,
> >>>> > >> > >
> >>>> > >> > > Thanks for the clarification. It really helped a lot to fill
> >>>> most of
> >>>> > >> the
> >>>> > >> > > gaps I had unanswered. I have a draft design in my mind and
> >>>> will
> >>>> > post
> >>>> > >> for
> >>>> > >> > > your review with details soon.
> >>>> > >> > >
> >>>> > >> > > As for my current understanding, my task is to implement a
> >>>> mechanism
> >>>> > >> to
> >>>> > >> > > switch/chose configuration mechanism (between local files and
> >>>> > zookeer
> >>>> > >> for
> >>>> > >> > > the moment) and then allow APIs to query those mechanisms (in
> >>>> the
> >>>> > >> > zookeeper
> >>>> > >> > > scenario) for future use (For File Managers to know about
> other
> >>>> > >> instances
> >>>> > >> > > and make decisions accordingly). That include
> synchronization,
> >>>> > >> fetching
> >>>> > >> > > configuration from zookeeper if an instance go down and come
> >>>> again
> >>>> > >> and so
> >>>> > >> > > on. Am I correct?
> >>>> > >> > >
> >>>> > >> > > I will try to come up with the design I mentioned, so that
> >>>> both of
> >>>> > us
> >>>> > >> can
> >>>> > >> > > discuss more about the improvements and requirements soon.
> >>>> > >> > >
> >>>> > >> > > Thank you for the support!
> >>>> > >> > >
> >>>> > >> > > Kind Regards,
> >>>> > >> > > *Imesha Sudasingha*
> >>>> > >> > > Undergraduate of Department of Computer Science and
> >>>> Engineering,
> >>>> > >> > > University of Moratuwa,
> >>>> > >> > > Sri Lanka.
> >>>> > >> > >
> >>>> > >> > > <https://lk.linkedin.com/in/imeshasudasingha>  <
> >>>> > >> https://github.com/IMS94
> >>>> > >> > >
> >>>> > >> > > <http://stackoverflow.com/users/4012073/imesha-sudasingha>
> >>>> > >> > > <https://twitter.com/Imesha94>
> >>>> > >> > >
> >>>> > >> > > On 13 March 2017 at 20:19, Tom Barber <
> tom.barber@meteorite.bi
> >>>> >
> >>>> > >> wrote:
> >>>> > >> > >
> >>>> > >> > >> Hi Imesha
> >>>> > >> > >>
> >>>> > >> > >> The best way to demonstrate this is to show you a reference
> >>>> build
> >>>> > for
> >>>> > >> > >> OODT..
> >>>> > >> > >>
> >>>> > >> > >> https://dl.dropboxusercontent.
> com/u/8503756/oodt-example.tgz
> >>>> > >> > >>
> >>>> > >> > >> If you can grab that archive and extract it, you'll see that
> >>>> is how
> >>>> > >> > >> currently OODT is deployed.
> >>>> > >> > >>
> >>>> > >> > >> If you take the file manager as the reference module inside
> >>>> > >> oodt/filemgr
> >>>> > >> > >> you'll see
> >>>> > >> > >>
> >>>> > >> > >> etc/filemgr.properties
> >>>> > >> > >>
> >>>> > >> > >> and
> >>>> > >> > >>
> >>>> > >> > >> policy/oodt/*
> >>>> > >> > >>
> >>>> > >> > >> These are the configuration locations of a single file
> >>>> manager.
> >>>> > >> > >>
> >>>> > >> > >> The problem I want to solve is this:
> >>>> > >> > >>
> >>>> > >> > >> a) If I run > 1 file manager they are completely separate
> and
> >>>> they
> >>>> > >> don't
> >>>> > >> > >> know of each other. So using Zookeeper will allow multiple
> >>>> file
> >>>> > >> managers
> >>>> > >> > >> to
> >>>> > >> > >> register against ZK and learn of each other.
> >>>> > >> > >>
> >>>> > >> > >> b) Backing them onto ZK will allow file managers to come and
> >>>> go on
> >>>> > >> the
> >>>> > >> > >> fly,
> >>>> > >> > >> providing scaling capabilities or maybe fm's that are
> >>>> designed to
> >>>> > be
> >>>> > >> > >> transient.
> >>>> > >> > >>
> >>>> > >> > >> Just for clarity, the ZK configuration will be an optional
> >>>> > >> requirement,
> >>>> > >> > so
> >>>> > >> > >> we need to extend the existing configuration mechanism, to
> >>>> support
> >>>> > >> both
> >>>> > >> > >> the
> >>>> > >> > >> current config and the ZK config instead of  ZK being
> >>>> mandatory.
> >>>> > >> > >>
> >>>> > >> > >> Tom
> >>>> > >> > >>
> >>>> > >> > >> On Mon, Mar 13, 2017 at 3:20 AM, Imesha Sudasingha <
> >>>> > >> > >> imesha.13@cse.mrt.ac.lk>
> >>>> > >> > >> wrote:
> >>>> > >> > >>
> >>>> > >> > >> > Hi Tom,
> >>>> > >> > >> >
> >>>> > >> > >> > Related to the conversation on JIRA [1] ;
> >>>> > >> > >> >
> >>>> > >> > >> > I went through the CAS-File manager module and I now
> >>>> understand
> >>>> > >> how to
> >>>> > >> > >> > address ".properties" files. Since you mentioned in JIRA
> >>>> [2] that
> >>>> > >> > there
> >>>> > >> > >> are
> >>>> > >> > >> > occasions where we use *spring configuration files *for
> >>>> > >> configuration
> >>>> > >> > >> > purposes, I want to have a look at that type of
> >>>> configuration
> >>>> > too.
> >>>> > >> Can
> >>>> > >> > >> you
> >>>> > >> > >> > give me an example module where spring configuration files
> >>>> are
> >>>> > >> used to
> >>>> > >> > >> load
> >>>> > >> > >> > configuration?
> >>>> > >> > >> >
> >>>> > >> > >> > Also, will the content of a configuration file exceed 1MB
> >>>> > (Maximum
> >>>> > >> > data
> >>>> > >> > >> > size allowed in an ZNode) in any case?
> >>>> > >> > >> >
> >>>> > >> > >> > Thank you!
> >>>> > >> > >> >
> >>>> > >> > >> > [1]
> >>>> > >> > >> > https://issues.apache.org/jira
> >>>> /browse/OODT-945?focusedCommen
> >>>> > >> > >> tId=15906204&
> >>>> > >> > >> > page=com.atlassian.jira.plugin.system.issuetabpanels:
> >>>> > >> > >> > comment-tabpanel#comment-15906204
> >>>> > >> > >> >
> >>>> > >> > >> > [2]
> >>>> > >> > >> > https://issues.apache.org/jira
> >>>> /browse/OODT-945?focusedCommen
> >>>> > >> > >> tId=15906524&
> >>>> > >> > >> > page=com.atlassian.jira.plugin.system.issuetabpanels:
> >>>> > >> > >> > comment-tabpanel#comment-15906524
> >>>> > >> > >> >
> >>>> > >> > >> > Kind Regards,
> >>>> > >> > >> > *Imesha Sudasingha*
> >>>> > >> > >> > Undergraduate of Department of Computer Science and
> >>>> Engineering,
> >>>> > >> > >> > University of Moratuwa,
> >>>> > >> > >> > Sri Lanka.
> >>>> > >> > >> >
> >>>> > >> > >> > <https://lk.linkedin.com/in/imeshasudasingha>  <
> >>>> > >> > >> https://github.com/IMS94>
> >>>> > >> > >> > <http://stackoverflow.com/users/4012073/imesha-sudasingha
> >
> >>>> > >> > >> > <https://twitter.com/Imesha94>
> >>>> > >> > >> >
> >>>> > >> > >>
> >>>> > >> > >
> >>>> > >> > >
> >>>> > >> >
> >>>> > >>
> >>>> > >
> >>>> > >
> >>>> >
> >>>>
> >>>
> >>>
> >>
> >
>

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