Cassandra Reaper Configuration

Cassandra Reaper 

Reaper is an open source tool that aims to schedule and orchestrate repairs of Apache Cassandra clusters.
It improves the existing nodetool repair process by
  • Splitting repair jobs into smaller tunable segments.
  • Handling back-pressure through monitoring running repairs and pending compactions.
  • Adding ability to pause or cancel repairs and track progress precisely.
  • It also gives us a simple web interface to schedule, run, pause or stop the repair process.
Cassandra Reaper Configuration
>> The main prerequisite to configure reaper is there must be some backend system to store the reaper data. 
>> These may be:
  • In-Memory
  • Cassanda
  • PostgresQL
  • H2
  • Astra
>> I'm choosing Cassandra as my backend. For that I must have Cassandra running on my machine.

>> Then visit this website http://cassandra-reaper.io/docs/ to know about the detailed documentation 

>> I downloaded rpm from the below link:

>> Reaper download
      wget https://github.com/thelastpickle/cassandra-reaper/releases/download/2.3.1/reaper-2.3.1-1.x86_64.rpm

>> To run the downloaded reaper first run below command
      sudo rpm -ivh  reaper-2.3.1-1.x86_64.rpm

>> Then in /etc/cassandra-reaper location we will see one cassandra-reaper.yaml file and configs          folder

>> open it by using sudo  sudo vi cassandra-reaper-cassandra.yaml  edit the cluster name, give it the reaper node ip, and we should create a keyspace for reaper to store the scheduled repairs data in the form of tables.


>> save it and close it.

>> After that move cassandra-reaper.yaml file to another name 
mv cassandra-reaper.yaml cassandra-reaper.bkp.yaml

>> After that create a softlink of the above file to cassandra.yaml.
ln -s /etc/cassandra-reaper/configs/cassandra-reaper-cassandra.yaml  /etc/cassandra-reaper/cassandra.yaml

>> Create a keyspace with name reaper_db 
create KEYSPACE reaper_db WITH replication = {'class': 'SimpleStrategy', 'replication_factor': '1'};

>> Make the changes accordingly to enable jmx. in "cassandra-env.sh" on the nodes in which repairs should be running. 


>> After that just start it by using the following command sudo service cassandra-reaper start

>> Check it's status by using sudo service cassandra-reaper status

>> Once the reaper's status is in running state, you can readily use the web interface provided by  the reaper.

>> Reaper also gives us a webui to schedule repairs easily.   

>> Then finally access the webui using http://44.195.148.178:8080/webui


>> The default username and password for this webui are:
       Username: admin
       Password: admin

>> Now schedule repairs by using cluster name.


>> In this way repairs are done pretty much easily by using reaper. The main advantage of using reaper is, we can pause, stop and run the scheduled repairs. 


>> Hence we can complete the repair works which are very painful in Cassandra easily. So, we can schedule, run, pause, abort the scheduled repairs. 


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