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From: Alexander Shraer <shralex@gmail.com>
Date: Mon, 15 Jul 2013 14:31:15 -0700
Message-ID: 
 <CANcXBFMk1f5z6CeoQLe7PX2AKSOEoDcj_NP3=YcDCgHus=Fkug@mail.gmail.com>
Subject: Re: Zookeeper Internals & Dyn. Reconf.
To: user@zookeeper.apache.org
Cc: zookeeper-user@hadoop.apache.org
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Hi Frank,

> - Are there any possible ways to let servers themselves cast requests lik=
e
> the ZooKeeper.class does?

not sure about this one, maybe someone else knows.

> - How can I extend the reconfig-request by certain parameters?

You need to change src/zookeeper.jute (look for ReconfigRequest) and
then recompile, which will update the relevant classes.

> - How can I implement fixed zNodes to the DataTree so they are created wh=
en
> servers startup, like the /zookeeper/config node?

DataTree.java is the right place, so I'm not sure why it doesn't work
for you. You can see how the quota node is implemented there. For
reconfiguration there were some cases where changing DataTree.java was
not enough. Here's a comment I made in QuorumPeer.java explaining
this:

       // There is no log record for the initial config, thus after syncing
       // with leader
       // /zookeeper/config is empty! it is also possible that last committ=
ed
       // config is propagated during leader election
       // without the propagation the corresponding log records.
       // so we should explicitly do this (this is not necessary when we're
       // already a Follower/Observer, only
       // for Learner):

       initConfigInZKDatabase();

this is a method in QuorumPeer.java. Perhaps in your case you need
something similar, don't know.

Alex


On Mon, Jul 15, 2013 at 11:31 AM, Chewy <f.loocke@gmx.net> wrote:
> Hi all,
>
> I could really need some help here.
>
> My task is to implement time-bound references for (not with) zookeeper. t=
hat
> is, server-configurations are bundled to grouped references (much like th=
e
> config-command provides) and each reference guarantees a certain lifetime=
.
> Furthermore, there are some security and reliancy issues to be considered=
.
> The specific topics are not so important here, I only got some more gener=
al
> Questions on adapting the Zookeeper code.
>
> I worked myself in the depth of the implementation, but there are still a
> lot of unsolved technical problems left Only some of them at this point o=
f
> time are these:
>
> - How can I extend the reconfig-request by certain parameters? What class=
es
> do i have to change? I found some, but most of time i=B4m searching, i=B4=
m
> ending up in dead ends.
>
> - How can I implement fixed zNodes to the DataTree so they are created wh=
en
> servers startup, like the /zookeeper/config node? I tried to by changing =
the
> DataTree.java, doing everythingthe same way it=B4s done with the config z=
Node.
> The Datatree structure can see the DataNode, but the standard-client does
> not. What did I miss?
>
> - Are there any possible ways to let servers themselves cast requests lik=
e
> the ZooKeeper.class does? I didnt find anything, so I guess I have to ext=
end
> the servers by a ZooKeeper-Instance. In what classes on server side would=
 I
> do that? I tried to insert an instance of zk in QuorumZooKeeperServer, bu=
t
> it doesnt seem to be able to establish a connection to the service (i wan=
t
> it to connect to its host-peer only). so i set the connectionstring to
> "localhost:" + clientportnumber of the server, which i got from the serve=
r
> itself. I created an instance of zk, but it threw an connection loss
> exception when trying to set up a request.
>
> I=B4s appreciate any help. Thank you in advance (and another thanks to Al=
ex
> who already helped me via mail 2 weeks ago)
>
> Cheers,
>
> Frank
>
>
>
>
>
>
> --
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