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Flume, mail # user - Failover Processor + Load Balanced Processor?


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Re: Failover Processor + Load Balanced Processor?
Arvind Prabhakar 2012-08-17, 17:19
On Fri, Aug 17, 2012 at 10:11 AM, Chris Neal <[EMAIL PROTECTED]> wrote:

> Thanks Arvind,
>
> So in the load balanced scenario, if sink A goes down, and events go all
> to sink B, does sink A's status ever get re-checked to be added back to the
> pool?  Or once it's down, it's down?
>

It does get added back for the subsequent invocations. The Failover sink
processor on the other hand has a back-off semantic which
will exponentially increase the waiting period before a sink is retried.

Regards,
Arvind Prabhakar
>
> Chris
>
> On Fri, Aug 17, 2012 at 12:01 PM, Arvind Prabhakar <[EMAIL PROTECTED]>wrote:
>
>> Hi,
>>
>> FYI - the load balancing sink processor does support simple failover
>> semantics. The way it works is that if a sink is down, it will proceed to
>> the next sink in the group until all sinks are exhausted. The failover sink
>> processor on the other hand does complex failure handling and back-off such
>> as blacklisting sinks that repeatedly fail etc. The issue [1] tracks
>> enhancing this processor to support backoff semantics.
>>
>> The one issue with your configuration that I could spot by a quick glance
>> is that you are adding your active sinks to both the sink groups. This does
>> not really work and the configuration subsystem simply flags the second
>> inclusion as a problem and ignores it. By design, a sink can either be on
>> its own or in one explicit sink group.
>>
>> [1] https://issues.apache.org/jira/browse/FLUME-1488
>>
>> Regards,
>> Arvind Prabhakar
>>
>> On Fri, Aug 17, 2012 at 8:59 AM, Chris Neal <[EMAIL PROTECTED]> wrote:
>>
>>> Hi all.
>>>
>>> The User Guide talks about the various types of Sink Processors, but
>>> doesn't say whether they can be aggregated together.  A Failover Processor
>>> that moves between 1..n sinks is great, as is a Load Balancer Processor
>>> that moves between 1..n sinks, but what is the best would be an agent that
>>> can utilize both a Failover Processor AND a Load Balancer Processor!
>>>
>>> I've created a configuration which I believe supports this, and the
>>> Agent starts up and processes events, but I wanted to ping this group to
>>> make sure that this configuration is really doing what I think it is doing
>>> behind the scenes.
>>>
>>> Comments?
>>>
>>> # Define the sources, sinks, and channels for the agent
>>> agent.sources = avro-instance_1-source avro-instance_2-source
>>> agent.channels = memory-agent-channel
>>> agent.sinks = avro-hdfs_1-sink avro-hdfs_2-sink
>>> agent.sinkgroups = failover-sink-group lb-sink-group
>>>
>>> # Bind sources to channels
>>> agent.sources.avro-instance_1-source.channels = memory-agent-channel
>>> agent.sources.avro-instance_2-source.channels = memory-agent-channel
>>>
>>> # Define sink group for failover
>>> agent.sinkgroups.failover-sink-group.sinks = avro-hdfs_1-sink
>>> avro-hdfs_2-sink
>>> agent.sinkgroups.failover-sink-group.processor.type = failover
>>> agent.sinkgroups.failover-sink-group.processor.priority.avro-hdfs_1-sink
>>> = 5
>>> agent.sinkgroups.failover-sink-group.processor.priority.avro-hdfs_2-sink
>>> = 10
>>> agent.sinkgroups.failover-sink-group.processor.maxpenalty = 10000
>>>
>>> # Define sink group for load balancing
>>> agent.sinkgroups = lb-sink-group
>>> agent.sinkgroups.group1.sinks = avro-hdfs_1-sink avro-hdfs_2-sink
>>> agent.sinkgroups.group1.processor.type = load_balance
>>> agent.sinkgroups.group1.processor.selector = round_robin
>>>
>>> # Bind sinks to channels
>>> agent.sinks.avro-hdfs_1-sink.channel = memory-agent-channel
>>> agent.sinks.avro-hdfs_2-sink.channel = memory-agent-channel
>>>
>>> # avro-instance_1-source properties
>>> agent.sources.avro-instance_1-source.type = exec
>>> agent.sources.avro-instance_1-source.command = tail -F /somedir/Trans.log
>>> agent.sources.avro-instance_1-source.restart = true
>>> agent.sources.avro-instance_1-source.batchSize = 100
>>>
>>> # avro-instance_2-source properties
>>> agent.sources.avro-instance_2-source.type = exec
>>> agent.sources.avro-instance_2-source.command = tail -F