Changing keyspace replication strategy in Datastax Cassandra ( Part 5 )

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In production environment, network aware topology must be set. Default SimpleStrategy
will not work if you want to add rack and datacenter in to an existing cluster. In production environment use NetworkTopologyStrategy. Before changing topology we must make sure inter node communication is network aware for that change the Snitch properties.



Step 1) Change the snitch.

            cat /etc/dse/cassandra/cassandra.yaml | grep endpoint_snitch:

            endpoint_snitch: GossipingPropertyFileSnitch



Step 2) After changing snitch, specify the datacenter and rack information in 

             properties file.
  
            cat /etc/dse/cassandra/cassandra-rackdc.properties |grep -E 'dc=|rack='
    
            dc=SearchGraph
            rack=rack1

Step 3) Any change in cassandra.yaml file require node restart. Restart each node  one by one.
        
             service dse restart

Step 4) Changed keyspace topology.

             ALTER KEYSPACE tech_app1 WITH REPLICATION = {'class' : 'NetworkTopologyStrategy', 'SearchGraph' : 2};

            ALTER KEYSPACE tech_app2 WITH REPLICATION = {'class' : 'NetworkTopologyStrategy', 'SearchGraph' : 2};

             ALTER KEYSPACE tech_chat WITH REPLICATION = {'class' : 'NetworkTopologyStrategy', 'SearchGraph' : 2};


Step 5) Run a sequential repair and nodetool cleanup on each node.

             nodetool repair
             nodetool cleanup                      

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Datastax Error : Cannot start node if snitch's data center (dc1) differs from previous data center (dc2)

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This error occurs when the node try to start and see it has snitch information which differ from previous data center. In my case, i was using DseSimpleSnitch which name the datacenter based on workload type. Previously i had enabled solr in dse default
configuration file ( /etc/default/dse ) and datasenter name was Solr. Now i tried to start the dse with graph enabled, which change the name to datacenter SearchGraph which is default workload type name.

CassandraDaemon.java:698 - Cannot start node if snitch's data center (Solr) differs from previous data center (SearchGraph). Please fix the snitch configuration, decommission and rebootstrap this node or use the flag -Dcassandra.ignore_dc=true

Solution :

1) In the last line of cassandra-env.sh set in the jvm opts as given below :
JVM_OPTS="$JVM_OPTS -Dcassandra.ignore_dc=true"
2) If it starts successfully, execute:

nodetool repair nodetool cleanup
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Datastax Error : Cassandra - Saved cluster name Test Cluster != configured name

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While changing existing cluster name in datastax, i got name mismatch exception in log file. Process i followed was changed the cluster name in cassandra.yaml configuration file.

$ nano /etc/dse/cassandra/cassandra.yaml

cluster_name: 'Test Cluster1'








Solution : 


Change the cluster name  to "New Cluster Name" :

$ cqlsh `hostname -I`

cqlsh> UPDATE system.local SET cluster_name = 'New Cluster Name' where key='local';
cqlsh> exit;

$ nodetool flush system

Stop the cluster :

$ sudo service dse stop;sudo service datastax-agent stop

Edit the file :

$ sudo vi /etc/dse/cassandra/cassandra.yaml
cluster_name: 'New Cluster Name'

Start the cluster :

$ sudo service dse start;sudo service datastax-agent start

Check Installation log :

 $ cat /var/log/cassandra/output.log


Reference  : https://support.datastax.com/hc/en-us/articles/205289825-Change-Cluster-Name-

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Configure Nagios plugin " check_logfiles " for scanning log file

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I was checking for a nagios plugin which could filter the specified log file which i had mentioned and notify me whenever a warning or error appeared in log. Finally i get in hand check_logfilecreated by Gerhard Lausser. Check_logfiles is used to scan the lines of a file for regular expressions.

Install the plugin on client system : 

$ wget https://labs.consol.de/assets/downloads/nagios/check_logfiles-3.8.0.2.tar.gz

$ tar xvzf check_logfiles-3.8.0.2.tar.gz

$ cd check_logfiles-3.8.0.2/

$ ./configure

$ make

$ make install

check_logfiles executable file will get installed on location "/usr/local/nagios/libexec"


Configure Check Pattern :

$ nano  /etc/nagios-plugins/config/check_log.cfg

@searches = (
  {
    tag => 'Error',
    logfile => '/var/logs/error.log',
    criticalpatterns => 'Error',
  }
);

Here i am filtering pattern "Error" from log file which i had mentioned in logfile parameter section


Configure nrpe.cfg in client system :

$ nano /etc/nagio…
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Popular posts from this blog

Datastax Error : Cannot start node if snitch's data center (dc1) differs from previous data center (dc2)

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Image
This error occurs when the node try to start and see it has snitch information which differ from previous data center. In my case, i was using DseSimpleSnitch which name the datacenter based on workload type. Previously i had enabled solr in dse default
configuration file ( /etc/default/dse ) and datasenter name was Solr. Now i tried to start the dse with graph enabled, which change the name to datacenter SearchGraph which is default workload type name.

CassandraDaemon.java:698 - Cannot start node if snitch's data center (Solr) differs from previous data center (SearchGraph). Please fix the snitch configuration, decommission and rebootstrap this node or use the flag -Dcassandra.ignore_dc=true

Solution :

1) In the last line of cassandra-env.sh set in the jvm opts as given below :
JVM_OPTS="$JVM_OPTS -Dcassandra.ignore_dc=true"
2) If it starts successfully, execute:

nodetool repair nodetool cleanup
Continue Reading »»»»

Datastax Error : Cassandra - Saved cluster name Test Cluster != configured name

-
Image
While changing existing cluster name in datastax, i got name mismatch exception in log file. Process i followed was changed the cluster name in cassandra.yaml configuration file.

$ nano /etc/dse/cassandra/cassandra.yaml

cluster_name: 'Test Cluster1'








Solution : 


Change the cluster name  to "New Cluster Name" :

$ cqlsh `hostname -I`

cqlsh> UPDATE system.local SET cluster_name = 'New Cluster Name' where key='local';
cqlsh> exit;

$ nodetool flush system

Stop the cluster :

$ sudo service dse stop;sudo service datastax-agent stop

Edit the file :

$ sudo vi /etc/dse/cassandra/cassandra.yaml
cluster_name: 'New Cluster Name'

Start the cluster :

$ sudo service dse start;sudo service datastax-agent start

Check Installation log :

 $ cat /var/log/cassandra/output.log


Reference  : https://support.datastax.com/hc/en-us/articles/205289825-Change-Cluster-Name-

Continue Reading »»»»

Configure Nagios plugin " check_logfiles " for scanning log file

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I was checking for a nagios plugin which could filter the specified log file which i had mentioned and notify me whenever a warning or error appeared in log. Finally i get in hand check_logfilecreated by Gerhard Lausser. Check_logfiles is used to scan the lines of a file for regular expressions.

Install the plugin on client system : 

$ wget https://labs.consol.de/assets/downloads/nagios/check_logfiles-3.8.0.2.tar.gz

$ tar xvzf check_logfiles-3.8.0.2.tar.gz

$ cd check_logfiles-3.8.0.2/

$ ./configure

$ make

$ make install

check_logfiles executable file will get installed on location "/usr/local/nagios/libexec"


Configure Check Pattern :

$ nano  /etc/nagios-plugins/config/check_log.cfg

@searches = (
  {
    tag => 'Error',
    logfile => '/var/logs/error.log',
    criticalpatterns => 'Error',
  }
);

Here i am filtering pattern "Error" from log file which i had mentioned in logfile parameter section


Configure nrpe.cfg in client system :

$ nano /etc/nagio…
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