Cassandra Opscenter, No data collected

you might get this, the ring is correct, no data get collected from agent,

If you check log /var/log/opscenterd.log

2012-03-28 16:20:43-0700 [] Problem while calling MetricsController         Traceback (most recent call last):         Failure: telephus.cassandra.c08.ttypes.InvalidRequestException: InvalidRequestException(why='range finish must come after start in the order of traversal') 2012-03-28 16:20:44-0700 [] Problem while calling MetricsController         Traceback (most recent call last):         Failure: telephus.cassandra.c08.ttypes.InvalidRequestException: InvalidRequestException(why='range finish must come after start in the order of traversal') 2012-03-28 16:20:45-0700 [] Problem while calling MetricsController         Traceback (most recent call last):         Failure: telephus.cassandra.c08.ttypes.InvalidRequestException: InvalidRequestException(why='range finish must come after start in the order of traversal') 2012-03-28 16:20:46-0700 [] Problem while calling MetricsController         Traceback (most recent call last):         Failure: telephus.cassandra.c08.ttypes.InvalidRequestException: InvalidRequestException(why='range finish must come after start in the order of traversal') 2012-03-28 16:20:47-0700 [] Problem while calling MetricsController         Traceback (most recent call last):         Failure: telephus.cassandra.c08.ttypes.InvalidRequestException: InvalidRequestException(why='range finish must come after start in the order of traversal') 2012-03-28 16:20:48-0700 [] Problem while calling MetricsController         Traceback (most recent call last):         Failure: telephus.cassandra.c08.ttypes.InvalidRequestException: InvalidRequestException(why='range finish must come after start in the order of traversal') 2012-03-28 16:20:49-0700 [] Problem while calling MetricsController         Traceback (most recent call last):         Failure: telephus.cassandra.c08.ttypes.InvalidRequestException: InvalidRequestException(why='range finish must come after start in the order of traversal')

Basically, this means the time setting is incorrect, between the cluster nodes and your client machine, here will be the browser.

DataStax DSE 2.0, Hadoop/Hive quick tutorial - 2

Hive is used as a batch approach, once we get the analysis result, we need put it into a store which is available for real-time access, for Cassandra, it will be Cassandra keyspace.
Given the previous result, Let’s create one keyspace called OLDPks and one column family called result. for the result column family,
here we use the cityname as the rowid, and the number will be stored in the result:count


like the hbase-hive handler, we can create the keyspace, column family first, then add a external table in Hive.
or ask hive to create the underlying keyspace and column family.

now let’s do the second approach,
in the hive cli, create one external table served by cassandrafs


then from the Opscenter, you can see the keyspace/columnfamily is there

or via cassandra cli, show schema,


now, we can insert some data to the result cf via casansra-cli,


then list the result,

also you can view the data throught the opscenter data explorer,

Now, let’s query the data through hive,


Now we can Load the hive analysis result that we did last time to this external table

from the opscetner hadoop jobs, click full details, to go to the familiar jobtrackr admin ui.

Once done, result is there, in the hive external table called result, which is mapped to a Column family named result under OLAPks,

you can query it by Hive,

Or by Cassandra API,


So, we create one hbase-hive handler style approach in cassandra. run data analysis by Hive, and export to real time CassandraFS. then data is ready for real-time access by ad-hoc clients.

next stop will be solr integration, stay tuned.

DataStax DSE 2.0, Hadoop/Hive quick tutorial - 1

Just setup 8 VMS, and load it with the DSE 2.0, one new feature of the DSE 2.0 is the SOLR support. Now, when I run the node tool, you will see it create one virtual data center called Solr besides the Analytics for hadoop.

Ops Center has a visual layout, 3 virtual datacenters.

Now let’s test the first case, Loading one CSV file to the CassandraFS (like the hdfs)
I googled some sample csv file, and picked this one, http://jasperreports.sourceforge.net/sample.reference/csvdatasource/
it has some data like  "Dallas",47,"Janet Fuller","445 Upland Pl.","Trial" which maps to{"city", "id", "name", "address", "state"};

So paste this data to a local file called state.csv, and copy it to our cassandraFS


now let’s run a wordcount mapreduce job on the cluaster, powered by cassandra.



you can see the running job from opscenter

once done, we can view the result,


now the data is there, we just create one hive table and do the 1st test
Create Hive Table and Load data from CassandraFS

when you enable the Analytics role, those node will works like a hadoop node,So I can run this test in any node which is allocated to Analytics Datacenter zone.
run dsetool to identify the current jt node,


then just run dse hive, you will be in the hive CLI shell,



then load data from cassandrafs to hive using the hive standard syntax, then, the data is there,

then we can just write some query run a grouping by city,

from the opscenter, you can see the hadoop job is submitted to the jt,

once done , you will get the result like this, which is no surprise at all


the wraps the first test case, Load data to CassandraFS, and create hive table, then load data from cassandraFS and run a query.

Then Let’s create another case, LIke the Hbase-hive handler, we create one Hive table which maps to Cassandra ColumnFamily. then we can save the query result to this hive table powered by Cassandra CFS data.

Apache Solr and SolrNet quickstart, using the Netflix Dataset (Odata format)

Here is one quick tutorial to Send some movie data (netflix oData format) to solr for indexing, and do some basic querying.

Sample Dataset, http://odata.netflix.com/Catalog/


I picked up 5 fields and put them into the solr scheme.xml,


then add solrnet to your C# client, Define one POCO object used for the mapping. use the solrxxx attirbute will enable you bridge some naming conventions between solr schema and your C# obejct.



then use OData Helper, and Linq entitiy to load the data (using .net framework 4.0)


once it download the catalog, several parallel tasks will be created to post the data to solr for indexing, after done, you can see the data is there,



notes,
solrnet using the Microsoft.Practices.ServiceLocation.dll as a dependency to manage the object creation,
you can use nuget search Odata to download the Odata helper.

Jquery error, Uncaught ReferenceError: class2type is not defined

This is an entry-level error you might get when you try put Jquery into you web. if you use chrome. the error looks like this in the console tab of the developer tools.


the error means the method is not available when some anonymous function are invoked in the Jquery-UI lib.

 

So, why? there is standard jquery functions. the answer is short, when you call this anonymosu function, the calss2type function is not there yet. here is my script including order,


when 2 was loaded, it’s dependency lib which is 3 is not loaded yet.  drag line 3 before 2, will address the issues.

Hope this helps