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From Tim Williams <>
Subject Re: what to do with shardServerList?
Date Wed, 16 Jul 2014 19:28:51 GMT
On Wed, Jul 16, 2014 at 2:09 PM, Chris Rohr <> wrote:
> The console has a notion of online and offline to show a status to the
> admins so they can be alerted if something goes offline and can take an
> action.

Typically that'd be a role of nagios or somesuch - I wonder if you
could maintain, internally, a list of 'recent' shard servers yourself
to provide some clue that there might be a problem?  In other words
you keep a cache of all the one's that you've seen with a TTL and let
them fall out after some period of time?


> On Wed, Jul 16, 2014 at 12:52 PM, Tim Williams <> wrote:
>> On Wed, Jul 16, 2014 at 12:31 PM, Chris Rohr <> wrote:
>> > Would this be from the Thrift calls only?  (i.e. not the
>> > ZookeeperClusterStatus object?)  The console uses the
>> > ZookeeperClusterStatus object to get online/offline shards and
>> controllers
>> > from ZK.
>> No, it'd be removed everywhere (thrift and zk path).  It'd basically
>> get rid of the notion of 'offline' shards - your usage is essentially
>> the same as the TopCommand I described. The trouble is that in a world
>> of random ports a lot of bookkeeping overhead would be necessary to
>> reliably maintain the notion of 'offline' or 'registered vs online'
>> shards.  As I understand it, the need for them was back when the
>> layout manager relied on that knowledge but the default layout manager
>> is more dynamic now.  Do you just display them or is there another
>> need in the console for them?
>> Thanks,
>> --tim

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