Step 3. Verify the changes

About this task

Now that you have two separate customized configuration files for your TaskTracker nodes, the pullcentralconfig script will detect the new files in /var/mapr/configuration the next time it is launched. It overwrites the local version in /opt/mapr with the appropriate customized version for each of the five TaskTracker nodes.

Procedure

To launch the pullcentralconfig script, perform one of the following operations:
- Run pullcentralconfig from the command line to overwrite the old files immediately.
```
/opt/mapr/server/pullcentralconfig
```
- Wait five minutes (the interval between successive checks for updated configuration files) for the script to run automatically.
Look at the information messages in pullcentralconfig.log. Whenever the timestamp comparison is false, an INFO message indicates that the older file under /opt/mapr is copied into a backup file (.bkp) and the newer version is copied to replace it. Sample log output is shown here: $ cat pullcentralconfig.log Header: hostName: centos22, Time Zone: Pacific Standard Time, processName: CentralConfig, processId: 4041 2014-08-18 15:50:13,861 INFO com.mapr.centralconfig.CentralConfigCopyHelper [main]: Copied /var/mapr/configuration/default/hadoop/hadoop-0.20.2/conf/mapred-site.xml to /opt/mapr//hadoop/hadoop-0.20.2/conf/mapred-site.xml
```
$ cat pullcentralconfig.log
Header: hostName: centos22, Time Zone: Pacific Standard Time, processName: CentralConfig, processId: 4041
2014-08-18 15:50:13,861 INFO com.mapr.centralconfig.CentralConfigCopyHelper [main]: Copied /var/mapr/configuration/default/hadoop/hadoop-0.20.2/conf/mapred-site.xml to /opt/mapr//hadoop/hadoop-0.20.2/conf/mapred-site.xml
```
Restart the service.
- From the command line:
```
maprcli node services -nodes <hostname> -<service> restart
```
  For example, to restart the TaskTracker on nodes host1 through host5, enter:
```
maprcli node services -nodes host1,host2,host3,host4,host5 -tasktracker restart
```
- From the MCS:
  
  On the Nodes tab, use a filter to display the nodes that are running the service you want to restart (TaskTracker in this case). Mark the check boxes next to the nodes where you want to restart the service. For this example, two nodes are selected.
  
  Click on the Manage services for 2 nodes button at the top to display the Manage Services dialog, then click the dropdown menu next to TaskTracker and select Restart, then click OK.