debug pacemaker cluster easily

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Debugging pacemaker cluster through logs will be much more easier post reading this article. This would help you in either troubleshooting or root cause analysis. It does not need any additional tools except your attention. Have reproduced and collected logs from various scenario to present here as example. I used SUSE 11 with HAE system for testing.

The first thing to do is look in system log for the terms ERROR and WARN.

#grep -e ERROR -e WARN /var/log/messages Continue reading “debug pacemaker cluster easily”


How to use SUDO Runas alias?

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Usually SUDO used by non-superuser to run command with root privileges. But in few scenario application/commands stick with it native user. Even with root user privileges it won’t work as expected. For example to run any oracle commands you need to be oracle user.

Here consider mission critical application “xapp1” and it uses user “app1”. Allowing others to login as app1 will result in trouble. The secure way is to allow user to execute limited commands as app1 user. Continue reading “How to use SUDO Runas alias?”


Easy way to open Linux X-Term in Windows

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Using Xming & Putty can connect to remote Linux X-server from windows desktop. By this way you will be able to view remote server GUI from windows desktop. This avoids need of physical console access to server.

Because granting server console access to application or normal user is a bad idea. One of my user pressed Ctr+Alt+Del while working on VMware virtual machine console. Which made system to reboot.

Continue reading “Easy way to open Linux X-Term in Windows”


Pacemaker Corosync Cluster Overview

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How does Pacemaker Corosync cluster operates? What is the relation between pacemaker and corosync? The functionality and concept overview has been explained here. SUSE Linux high availability and Redhat high availability using pacemaker corosync cluster majorly. Still many other flavors such as Ubuntu, Debian are using pacemaker with corosync as their high availability solution. Continue reading “Pacemaker Corosync Cluster Overview”


Password quality check for OpenLDAP

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Topic

1. Password quality check for OpenLDAP

2. Configure password quality check – Openldap

There is no standard OpenLDAP module for password quality check. How to make OpenLDAP server to check the strength and quality of password? How to reject the password which does not meet desired standards? There is an alternate solution available. Continue reading “Password quality check for OpenLDAP”


Linux library files

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What is lib files in Linux?
A library(lib) is a file containing compiled code from various object files stuffed into a single file. It may contain a group of functions that are used in a particular context. For example, the ‘pthread’ library is used when thread related functions are to be used in the program.

Broadly, a library (or Program Library) can be of two types : Continue reading “Linux library files”


Setup Linux Dynamic DNS Server

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Dynamic DNS configuration Guide

What is Dynamic DNS (DDNS)?

DNS stands for either Domain Name System or Domain Name Server. DNS used for name resolution between server hostname and IP Address. Many times there will be a change in system hostname or IP for some reason. During this time all DNS zone entries must be updated manually. Also accuracy of changes implemented to be considered. Think what happens if you have 500+ machines. Keeping them up-to-date by tracking manually is hectic. Continue reading “Setup Linux Dynamic DNS Server”


Understand SUSE Cluster Log

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SUSE cluster log is a single file where you found messages of cluster engine and all of it components. For each and every operation in cluster plenty of info will be logged into log file. While cluster is in smooth operation no one care about it. What if you run into some issue? Linux OS cluster do execute number of process in a second. With simple resource monitoring command we cannot trace out the whole operation history.

Having known about various parts of messages being written in SUSE cluster log file will help much during troubleshooting. The message to be written in logs with error code is predefined already. You may also see output of Continue reading “Understand SUSE Cluster Log”