Guru Of Geeks

There are scenarios when checkpointing fails ( due to various reasons, for example network issues ). In those cases we can manually run checkpointing to allow NameNode and Secondary NameNode to sync in the metadata. Manual steps to checkpoint is as below: 1. On primary NameNode, we will try to save latest metadata to the fsimage as : hdfs dfsadmin -safemode enter   hdfs dfsadmin -saveNamespace   hdfs dfsadmin -safemode leave  2. we will now run manual checkpointing:  Stop secondary NN or HDFS service or Cluster . Now execute following command on the Secondary NameNode: mv /data/dfs/snn /data/dfs/snn.old hdfs secondarynamenode -checkpoint force Start the SNN  or HDFS service or Cluster   .

root@dgc:~# ./dgc_linux_5_2_1-FINAL.sh Unpacking JRE ... Preparing JRE ... Starting Installer ... java.lang.NoClassDefFoundError: Could not initialize class java.awt.Toolkit         at java.awt.Component.<clinit>(Component.java:593)         at javax.swing.ImageIcon$2.run(ImageIcon.java:130)         at javax.swing.ImageIcon$2.run(ImageIcon.java:128)         at java.security.AccessController.doPrivileged(Native Method)         at javax.swing.ImageIcon.createNoPermsComponent(ImageIcon.java:127)         at javax.swing.ImageIcon.access$000(ImageIcon.java:69)         at javax.swing.ImageIcon$1.run(ImageIcon.java:103)         at javax.swing.ImageIcon$1.run(ImageIcon.java:100)         at java.security.AccessController.doPrivileged(Native Method)         at javax.swing.ImageIcon.<clinit>(ImageIcon.java:100)         at com.install4j.runtime.installer.frontend.GUIHelper.loadIcon(GUIHelper.java:175)         at com.install4j.runtime.installer.frontend.GUIHelper.<clinit>(GUIHelper....

Had the same issue when trying to install GateOne on 16.04. Solved it with: wget http :// launchpadlibrarian . net / 109052632 / python - support_1 . 0.15 _all . deb sudo dpkg - i python - support_1 . 0.15 _all . deb Source:  https://github.com/ajenti/ajenti/issues/903#issuecomment-215569332

Today I get opportunity to upgrade jenkins,  Jenkins  is a very important tool for continuous integration and continuous delivery. All the Jenkins data i.e, jobs and configs are stored in JENKINS_HOME directory. Taking a periodic backup of JENKINS_HOME directory is one the best practice of Jenkins Managment. Jenkins can be extended with plugins for extra features. There is a plugin called Jenkins  thinBackup Plugin . This helps in automate the backup of JENKINS_HOME Directory. Install and Configure Jenkins thinBackup Plugin for Backup Strategy Steps to Install the thinBackup Plugin. 1) Go to Manage Jenkins 2) Click Manage Plugins 3) Under Available Plugins tab select ThinBackup 4) Click on Install without restart button. Steps to Configure thinBackup Plugin 1) Go to Manage Jenkins 2) Click thinBackup option 3) Click settings to configure the backup options as shown below. 4) Schedule the automated backups as shown sample below. All the configuration is self-explanatory. Download New Je...

When you wish to shrink an EBS root volume, you will need to start a new, small EC2 instance that you can attach the volume you wish to resize. A t2.micro instance should be more than sufficient for this task. Once you have this instance created, proceed with the following steps. Take a backup Create a new EBS volume that is the size you wish to shrink to, do this by creating a new t2.micro EC2 instance...ensure delete on termination is not enabled. After instance is created you will have an EBS volume that is partitioned and has valid boot partition. Terminate the temporary instance. Detach the volume you wish to resize from the current EC2 instance and attach both volumes to the new, small EC2 instance you created Mount the old volume as /dev/sdf (this becomes /dev/xvdf) Mount the new volume as /dev/sdg (this becomes /dev/xvdg) Power on the new, small instance and wait for it to come online SSH into the instance and run the following commands To ensure that the file...

This is a guide on installing the latest Nagios Core (4.2.1) on Ubuntu 12.04 and 14.04. Nagios is an open source computer system monitoring, network monitoring and infrastructure monitoring software application. Nagios offers monitoring and alerting services for servers, switches, applications, and services. It alerts the users when things go wrong and alerts them a second time when the problem has been resolved. The version in the Ubuntu 12.04 repositories is quite old, it is still the in the 3 branch. This guide helps to fix that by using the latest Nagios version. We also install Nagiosgraph, a plugin for Nagios which gives you graps of the metrics. You can find more information about Nagios on the official website: http://www.nagios.org/projects/nagioscore . The description of Nagios Core from their website: Nagios Core is the monitoring and alerting engine that serves as the primary application around which hundreds of Nagios projects are built. It serves as the ba...

Issue:- I am trying to launch an instance, and I'm adding an EBS volume on top of the root volume. In the extra EBS volume, I'm specifying a snapshot I created. When I click "Launch", I immediately get the following error: snapshotId can only be modified on EBS devices ​Solution:- The solution which worked for me was to use an available AWS recommended device name e.g. /dev/sdf . AWS recommended device name for attaching EBS volume is /dev/sd[f-p] ​ -- Thank You. Regards, Guru