Linux, DevOps, Middleware and Cloud

basics of Clustering, advantages of Clustering and configuration of simple fail-over Cluster . Let’s start. What is a Cluster any way? Ans : A computer cluster is a group of linked computers , working together closely so that in many respects they form a single computer. The components of a cluster are commonly, but not always, connected to each other through fast local area networks. Clusters are usually deployed to improve performance and/or availability over that of a single computer, while typically being much more cost-effective than single computers of comparable speed or availability – www.wikipedia.org . Cluster terminology. Node : It’s one of the system/computer which participates with other systems to form a Cluster. Heartbeat : This a pulse kind of single which is send from all the nodes at regular intervals using a UDP packet so that each system will come to know the status of availability of other node. It’s a kind of door knocking activity like pinging...

1.)Setting Up A Subversion Repository Using Apache, With Auto Updatable Working Copy: What is Subversion? Subversion is a free/open-source version control system. That is, Subversion manages files and directories over time. A tree of files is placed into a central repository. The repository is much like an ordinary file server, except that it remembers every change ever made to your files and directories. This allows you to recover older versions of your data, or examine the history of how your data changed. In this regard, many people think of a version control system as a sort of “time machine”. SVN has few methods to serve its users. Below are some examples: 1, SVN+SSH 2, SVN+Apache 3, SVNServe In this case we are using the Apache method. Apache should be running as an normal user, not nobody. I won't guide people how to install apache in this how to. Install subversion using yum #yum install subversion Apache Configuration : Edit the default configuration file,...

Red Hat Enterprise Linux supports network installation using the NFS, FTP, or HTTP protocols. A network installation can be started from a boot CD-ROM or Red Hat Enterprise Linux CD #1, a bootable flash memory drive. Alternatively, Pre-Execution Environment (PXE) can also be used to install RHEL, if the system to be installed contains a network interface card (NIC) with Pre-Execution Environment (PXE) support. How PXE works: The client's NIC with PXE support sends out a broadcast request for DHCP information and the DHCP server provides the client with an IP address, name server information, the hostname or IP address of the tftp server and the location of the installation files on the tftp server. Basic steps required for preparation of PXE server Configure the network (either NFS or FTP or  HTTP) server to export the installation tree. Configure the files on the tftp server necessary for PXE booting. ...