What is Yum and Yum Repository Configuration / Advantages of YUM

<div dir="ltr" style="text-align: left;" trbidi="on"><div class="para"><strong><span style="color: blue;"><span style="font-size: x-large;">What is YUM ?</span></span> </strong></div><div class="para"><strong>YUM</strong> stands for <strong> Yellow dog Updater, Modified</strong> because it is based on <strong> YUP</strong>, the <strong> Yellow dog Updater.</strong> Yellow Dog is a version of Linux for the Power Architecture hardware. YUP, and later YUM, were written by the Linux community as a way to maintain an RPM-based system.</div><div class="para"> </div><div class="para"> </div><div class="para">Automatic resolution of software dependencies. If a package installation or upgrade request is made and requires the installation or upgrade of additional packages, YUM can list these dependencies and prompt the user to install or upgrade them.<br />Command-line and graphical versions. The command-line version can be run on a system with a minimal number of software packages. The graphical versions offer ease-of-use and a user-friendly graphical interface to software management.<br />Multiple software locations at one time. YUM can be configured to look for software packages in more than one location at a time.<br />Ability to specify particular software versions or architectures. Software locations accessible by YUM can contain multiple versions of the same RPM package and different builds for different architectures such as one for i686 and one for x86_64. yum can easily check the appropriate version and download it.<br /> </div><div class="para"> </div><div class="para">The Yum configuration file for <code class="command">yum</code> and related utilities is located at <code class="filename">/etc/yum.conf</code>. This file contains one mandatory  section, which allows you to set Yum options that have global effect, and can also contain one or more <code class="literal">[<em class="replaceable"><code>repository</code></em>]</code> sections, which allow you to set repository-specific options. However, it is recommended to define individual repositories in new or existing <code class="filename">.repo</code> files in the <code class="filename">/etc/yum.repos.d/</code>directory. The values you define in the <code class="literal">[main]</code> section of the <code class="filename">/etc/yum.conf</code> file can override values set in individual <code class="literal">[<em class="replaceable"><code>repository</code></em>]</code> sections. </div><div class="para"> This section shows you how to: </div><div class="itemizedlist"><ul><li class="listitem"><div class="para"> set global Yum options by editing the <code class="literal">[main]</code> section of the <code class="filename">/etc/yum.conf</code> configuration file; </div></li><li class="listitem"><div class="para"> set options for individual repositories by editing the <code class="literal">[<em class="replaceable"><code>repository</code></em>]</code> sections in <code class="filename">/etc/yum.conf</code> and <code class="filename">.repo</code> files in the <code class="filename">/etc/yum.repos.d/</code> directory; </div></li><li class="listitem"><div class="para"> use Yum variables in <code class="filename">/etc/yum.conf</code> and files in the <code class="filename">/etc/yum.repos.d/</code> directory so that dynamic version and architecture values are handled correctly; </div></li><li class="listitem"><div class="para"> add, enable, and disable Yum repositories on the command line; and, </div></li><li class="listitem"><div class="para"> set up your own custom Yum repository. </div><div class="para"> </div><div class="para"> </div><div class="para"> </div><div class="para"><span style="color: orange;"><span style="font-size: x-large;">Here we go again fallow Step by Step :</span></span><br /><br />1. Verify if ‘createrepo’ is already installed. If it is installed, skip step 2 and continue from step 3. Otherwise, proceed to the next step.<br /><br />[root@rep-serv ~]# rpm -qi createrepo<br /><br />2. If ‘createrepo’ isn’t already installed, since it isn’t by default; install it.<br /><br />[root@rep-serv ~]# yum -y install createrepo<br /><br />3. Launch your favorite text editor (for me it’s ‘vim’) to create a simple bash script called ‘repo-setup.sh’.<br /><br />[root@rep-serv ~]# vim repo-setup.sh<br /><br />4. Copy, paste and save the following bash script into newly created file (repo-setup.sh):<br /><br />#!/bin/sh -e<br /> mkdir -p /packages/centos/6/{SRPMS,updates,i386,x86_64}<br /> destdir="/packages/centos/6"<br /> for arch in i386 x86_64 updates<br /> do<br /> chown -R root:root ${destdir}/${arch}<br /> chmod -R o-w+r ${destdir}/${arch}<br /> pushd ${destdir}/${arch} >/dev/null 2>&1<br /> createrepo .<br /> popd >/dev/null 2>&1<br /> done<br /><br />Info: The script creates a directory structure, setups its ownership and permissions as necessary; and creates the repository using ‘createrepo’ command.<br /><br />5. Once saved, make it executable.<br /><br />[root@rep-serv ~]# chmod u+x repo-setup.sh<br /><br />6. Execute ‘repo-setup.sh.<br /><br />[root@rep-serv ~]# ./repo-setup.sh<br /><br />Info: Up to this point, basically, you have created the repository: if you do a ‘ls -lart’ of the directory structure ‘/packages/centos/6/*’ created by the script, you shall see the appropriate repository files listed there. Yet, you need to finish the last touches – that is configuring the repository. In this document, I called the repository ‘local’, but you may call yours whatever you prefer. To make this repository available to clients we need to create the following repository file ‘local.repo’ under ‘/etc/yum.repos.d/’.<br /><br />7. Launch your favorite text editor again (mine is ‘vim’) to create ‘/etc/yum.repos.d/local.repo’, your local repository’s configuration file:<br /><br />[root@rep-serv ~]# vim /etc/yum.repos.d/local.repo<br /><br />8. Copy the following, paste into ‘/etc/yum.repos.d/local.repo’ and save the file and exit :<br /><br />[local]<br /> name=CentOS-$releasever - local packages for $basearch<br /> baseurl=file:///packages/centos/$releasever/$basearch<br /> #baseurl=ftp://internalhost.com/yumrepo/centos/$releasever/$basearch<br /> #baseurl=http://internalhost.com/localrepo/centos/$releasever/$basearch<br /> enabled=1<br /> gpgcheck=1<br /> gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6-LocalRepo<br /> protect=1<br /><br />Before going further, let me explain some of the keywords above listed in the file:<br />name: is self explanatory – repository’s name.<br />baseurl: is the physical location of the repository. In the above file, NFS location is enabled while FTP and HTTP locations are disabled (commented).<br />enable: basically is self explanatory. When set to 1, it’s on. And when set to 0, it is off.<br />gpgcheck: enables or disables GPG-Key checking; can be turned either on or off by using (1 or 0).<br />gpgkey: gives the physical location of the public-ascii-gpg-key file.<br />protect: is basically something that yum uses to protect a repository from updating from other repositories. In this case it’s turned on, so this repository shall not update its files by downloading newer files from a mirror repository. This brings me to the concept of synchronizing to mirrors, which I am not going to explain further but simply show how it can be done next in case you want this feature.<br /><br />Synchronize to a mirror of your choice: list of mirror.<br />9. Following command triggers sync activity of the local repo with usc.edu’s mirrors (it basically gets all the updates from usc.edu mirror).<br /><br />[root@rep-serv ~]# rsync -avrt rsync://mirrors.usc.edu/centos/6/updates/i386 –exclude=debug/ /packages/centos/6/updates/<br /><br />In order for the protect feature to work, ‘yum-plugin-protectbase’ or ‘yum-protectbase’ must be installed. Basically for CentOS 4 and 6 you shall install ‘yum-plugin-protectbase’. For CentOS 5, however, you shall install ‘yum-protectbase’. They both do the same thing; the names are different because developers chose to give them different names.<br />10. Check if ‘protectbase pluin’ is installed:<br /><br />[root@rep-serv ~]# rpm -qi yum-plugin-protectbase # For CentOS version 4 or 6<br />[root@rep-serv ~]# rpm -qi yum-protectbase  # For CentOS version 5<br /><br />11. If not installed, install it as following<br /><br />[root@rep-serv ~]# yum install yum-plugin-protectbase # For CentOS version 4 or 6<br /> [root@rep-serv ~]# yum install yum-protectbase # For CentOS version 5</div><div class="para"> </div><div class="para"><span style="font-size: large;"><span style="color: purple;">Now you will success fully yum configuration.</span></span></div><div class="para"><span style="font-size: large;"><span style="color: purple;"> <span style="color: red;"><span style="font-size: small;">If <code class="literal">reposdir</code> is not set, <code class="command">yum</code> uses the default directory <code class="filename">/etc/yum.repos.d/</code>.   </span></span></span></span></div></li></ul></div></div>

What is Yum and Yum Repository Configuration / Advantages of YUM

What is YUM ? YUM stands for Yellow dog Updater, Modified because it is based on YUP , the Yellow dog Updater. Yellow Dog is a versio...

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What is Mail Server ?

<div dir="ltr" style="text-align: left;" trbidi="on">The backbone of the mail system is the Mail Transport Agent (MTA). It will handle receiving mail addressed directly to your machine, sending it to the correct users mail box, and sending mail out from the machine. I determined Postfix to be the best choice for my MTA and after some reading found Procmail for sorting mail, SpamBayes for detecting spam, and Fetchmail for grabbing mail from my pop mailboxes<br /><br />. A mail server usually consists of a storage area where where e-mail is stored for local users, a set of user definable rules which determine how the mail server should react to the destination of a specific message, a database of user accounts that the mail server recognizes and will deal with locally, and communications modules which are the components that actually handle the transfer of messages to and from other mail servers and email clients. <br /><br /><h1>What is a Mail Server?</h1>With the click of a mouse button, you can send an email from one point of the globe to another in a matter of seconds. Most of us take this process for granted, giving little thought to how it actually works. It's easy to understand how standard snail-mail gets from point A to point B - but how does an email message make its way from a sender to a recipient? The answer to that question revolves around something called a mail server. You can learn more about the role that mail serves play in email delivery by reading on below.<br /> <h2>What is a Mail Server?</h2>A mail server is the computerized equivalent of your friendly neighborhood mailman. Every email that is sent passes through a series of mail servers along its way to its intended recipient. Although it may seem like a message is sent instantly - zipping from one PC to another in the blink of an eye - the reality is that a complex series of transfers takes place. Without this series of mail servers, you would only be able to send emails to people whose email address domains matched your own - i.e., you could only send messages from one example.com account to another example.com account.<br /><br /><img border="0" src="http://www.hypexr.org/gfx/mail_system_flow_tn.png" /> <br /><br /><br /><br /><br /></div>

What is Mail Server ?

The backbone of the mail system is the Mail Transport Agent (MTA). It will handle receiving mail addressed directly to your machine, sendi...

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Yum Client Configuration in Linux ,sent OS, Fedora ..

<div dir="ltr" style="text-align: left;" trbi<a href="http://www.ipv4-ipv6.blogspot.com"></a>di="on"> Configuring Additional Repositories:<br /><br />At first you are Create ''Yum.repos.d ''  file .<br />Create a file in /etc/yum.repos.d/ for your repository, name endig in .repo, Containing<br /><br /><ul style="text-align: left;"><li>[repo-name]</li><li>name=A nice Description</li><li>baseurl=http://yourserver.com/path/to/repo</li><li>enabled=1</li><li>gpgcheck=1</li></ul>Repository information is cached. To clear the cache:<br />yum clean dbcache| all.<br /><br />You will use Command: <br /><br /><b>Server configuration steps</b><br /><b> </b><br /><b>Yum server IP = 192.168.1.1</b><br /><b>Yum server hostname = server1.example.com</b><br /><br /><br /><br /><b><span style="font-family: "Times New Roman","serif";">[root@client~]#  cd /etc/yum.repos.d</span></b><br /><span style="font-family: "Times New Roman","serif";">[root@client~]#nano myser.repo</span><br /><span style="font-family: "Times New Roman","serif";">Or</span><br /><div class="MsoNormal"><span style="font-family: "Times New Roman","serif";">[root@client~]# <span style="mso-bidi-font-weight: normal;">vim /etc/yum.repos.d/client.repo</span></span></div><div class="MsoNoSpacing"><span style="font-family: "Times New Roman","serif";">[client]</span></div><div class="MsoNoSpacing"><span style="font-family: "Times New Roman","serif";">name=rhel6.1 yum client 64bit</span></div><div class="MsoNoSpacing"><span style="font-family: "Times New Roman","serif";">baseurl=</span><a href="ftp://192.168.1.2/pub"><span style="mso-bidi-font-weight: normal;"><span style="font-family: "Times New Roman","serif";">ftp://192.168.1.1/pub</span></span></a><span style="font-family: "Times New Roman","serif";"></span></div><div class="MsoNoSpacing"><span style="font-family: "Times New Roman","serif";">enabled=1</span></div><div class="MsoNoSpacing"><span style="font-family: "Times New Roman","serif";">gpgcheck=0</span></div><b style="mso-bidi-font-weight: normal;"> <div class="MsoNoSpacing"></div><div class="MsoNoSpacing"><span style="font-family: "Times New Roman","serif";">[root@client~]# ctrl + X</span></div></b><span style="mso-bidi-font-weight: normal;"><div class="MsoNoSpacing"><span style="font-family: "Times New Roman","serif";">[root@client~]# <span style="mso-bidi-font-weight: normal;">yum clean all</span></span></div><div class="MsoNoSpacing"><span style="font-family: "Times New Roman","serif";">[root@server ~]# <span style="mso-bidi-font-weight: normal;">yum makecahe</span></span></div><div class="MsoNoSpacing"><span style="font-family: "Times New Roman","serif";">[root@client~]# <span style="mso-bidi-font-weight: normal;">yum list all</span></span></div><div class="MsoNoSpacing"><span style="font-family: "Times New Roman","serif";">[root@server ~]# <span style="mso-bidi-font-weight: normal;">yum grouplist</span></span></div></span><b><b><span style="font-family: "Times New Roman","serif";"> </span></b> </b><br />more information: <a href="http://www.ipv4-ipv6.blogspot.com/" target="_blank">www.ipv4-ipv6.blogspot.com</a><br /><span style="font-size: large;"><a href="http://linux.duke.edu/projects/yum" name="tex2html9"><tt>http://linux.duke.edu/projects/yum</tt></a></span><br /><br /><br /><br /></div>

Yum Client Configuration in Linux ,sent OS, Fedora ..

di="on"> Configuring Additional Repositories: At first you are Create ''Yum.repos.d ''  file . Create a file in...

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