The TechnoArt of LINUX & Windows

   Start doing it! I will show how to configure fencing on the Luci web tool. Login to the Luci tool, then follow the links as below: Click on Fence Devices ---> Add ---> Select Fence virt (Multicast Mode) ---> Type kvmfence as name, or any other name. Now you have to assign this fence name to all your cluster nodes. Click Nodes ---> click one by one on each node and repeat below process: Click Add Fence Method ---> Type kvmfence as Method Name ---> Click on Add Fence Instance ---> Select kvmfence as Fence Device, submit, then type the name of your virtual machine (VM) as Domain. This name should match the exact name of your VM that you have created earlier in libvirt / KVM. Repeat abovr process for all the nodes in your cluster. Host Configuration Host is your KVM machine on which the virtual cluster nodes are running. Install fence-virtd rpm on your host machine. # yum install fence-virtd Verify: # rpm -q fence-...

Error message: The error displayed is something like this: "node1 already a member of cluster1"   Cause Your first attempt to create a red hat cluster fails. You end up with few missing nodes in the cluster and only few of the nodes showing in the cluster. The reason cluster creation fails may be because of misconfigured YUM repository, wrong ricci password or ssh not running etc. Check out then proceed as told below to re create your cluster. Because of this you can't re create the cluster because few nodes are already added and this causes this error. Solving it! - already a cluster member error   Delete /etc/cluster/cluster.conf (from all nodes) You have to delete above file from all cluster nodes. In some nodes this may not be present and that's fine because it will be created later. After you delete cluster.conf you can proceed to create a new cluster by again specifying all nodes afresh in the Luci web interface. Here's a ...

You can't miss a NFS share with this script!   Pre-requisite Install Perl. About the script Many times, a sys admin will use command line to mount NFS share but forget to make it permanent. If such a server reboots, you loose that NFS share and you application will not start. Before rebooting just you need to run this script, it will check and report back if a NFS share is missing in /etc/fstab, but currently mounted. Screen shot displaying missing NFS share in /etc/fstab. This report shows that there is a NFS share mounted currently as /mnt/rhel64repo, but it is missing in /etc/fstab. Just add in /etc/fstab before reboot and you will not miss /mnt/rhel64repo after reboot and your application will also run without problems. Click here and get my NFS script from GitHub

This article will show how you can prepare a puppet client on Red Hat Enterprise Linux 6.4 (RHEL 6.4) server. I have installed a rhel 6.4 Base server  and also configured a local yum repository using the ISO image that was available to me. Please do the same before you start to configure puppet client. Pre-requisites Install Base RHEL 6.4 server Configure YUM repository Disk space: 8 GB for my setup, you can decide based on your needs. RAM: 1 GB, again it is up to you based on your work loads. Installing ruby The ruby package alongwith it's libraries are needed, please install them: # yum install ruby ruby-libs ruby-shadow Installing puppet client The puppet packages are available in the EPEL repository. You could install epel repository on the client server with below commands: # wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm # rpm -ivh epel-release-6-8.noarch.rpm warning: epel-release-6-8.noarch.rpm: Header V3 RSA/SHA25...

In 3 steps I will explain how to configure static IP address in a Ubuntu server, without using any graphical tool. Step 1: The configuration file that keeps network configuration is as below: /etc/networkinterfaces # This file describes the network interfaces available on your system # and how to activate them. For more information, see interfaces(5). # The loopback network interface auto lo iface lo inet loopback # The primary network interface auto eth0 iface eth0 inet static Above file has single network interface eth0, which is getting it's IP address via dhcp. We need to change this to static. Step 2: Edit this file to look like below: # vi /etc/networkinterfaces # This file describes the network interfaces available on your system # and how to activate them. For more information, see interfaces(5). # The loopback network interface auto lo iface lo inet loopback # The primary network interface auto eth0 iface eth0 inet static address 192.168.122.252 netmask 25...