flume | WE HAVE MOVED to Apache Incubator. https://cwiki.apache.org/FLUME/ . Flume is a distributed, relia

Solved my problem by changing the mapreduce.framework.name from yarn to local in mapred-site.xml.

The problem seemed to be happening due to resource crunch in the machine.

Also after changing the properties, restart Hadoop services once again.

What worked is changing memory channel with jdbc channel.

Replace this

The following exception implies that the flume agent doesn't have sufficient memory (Heap to be specific) to do the task.

Increase the flume agent's java memory in flume_env.sh file or specify memory at the time of deploying using flume-ng agent -n NetcatAgent -f net.conf -Xmx2048m (Note: This sets the flume heap size to 2GB = 2048MB)

You can specify -D and -X java options from the command line.

Inside the flume directory, go to conf dir, there should be either flume-env.sh or flume-env.sh.template file, if there's .template file copy the file using

The look-aheads and look-behinds for year and day will only match the tab character. They will not match multiple whitespaces. You'd be better off using \\s.

Also Flume requires two backslashes for regex symbols, \\t rather than \t.

Alternatively, you could use one regex to grab the whole date and with multiple capture groups assign them to different serializers. For example, (\\d{4})-(\\d{2})-(\\d{2})

The Flume User Guide has a good example:

If the Flume event body contained 1:2:3.4foobar5 and the following configuration was used

You have a complex scenario here, composed of an end-to-end chain of 5 components:

• Prosys OPC-UA Server Simulation
• OPC-UA FIWARE IoT Agent
• Orion Context Broker
• FIWARE Cygnus Connector
• PostgreSQL database

My recomendation here would be to check every step in the chain (looking in logs, etc.) to ensure everything is correct before of checking the next step.

That schema says map values are not unions, so they must be non-null strings. The map itself can be null, though

I'm not if this is valid in IDL, but you can try, assuming you didn't want the map to be nullable

You can do something like this:

Your deployment on Apache Flume is using a version of Jetty older than 9.4.29 (where Attributes.unwrap() was first introduced).

Double check the startup logs of the Jetty server, it will announce the version it thinks it is running.

Example:

1. Can I consume message foo again with another consumer process somewhere else?

Yes. It can be consumed as many times as we want, either by using a new consumer group or by resetting the offset of the existing consumer group.

2.To the opposite,I don't want to consume message foo again, so when I try to consume with another consumer,I should obtain nothing.How can I achieve this?

It's all tied to a consumer group name, which typically tied to one application that is needing these messages. we need to keep the same consumer group name, and typically commited offset is retained for a week(can be changed), so, we can run the app n no of times from n different places by keeping same consumer group name, we will not consume it again, unless we reset the offset.

3.What if there are two messages foo and bar.Can I specify consumers precisely?(For example,I want process A consumes message foo and process B consumes message bar.To go further ,can O specify a range of message offsets? Does it have something to do with consumer group?

We can always consume particular message of a given partition and offset by positioning the consumer group at that offset. Its called seeking an offset, rather than seeking to earliest or latest.