In addition, the createrepo command allows one to create a yum repository on any suitable server. Once a yum repository is prepared any client permitted to access the repository over the network can install, update, or remove one or more rpm-based packages from the repository. Yum can also be used as a more or less drop-in replacement for executing the familiar: rpm -Uvh whatever.
This alone is an enormous benefit compared to trying to work one's way out of "dependency hell" and track down and install by hand all of the dependencies of a typical RPM package. In addition, the yum client encapsulates various informational tools. It can list rpm's both installed and available for installation, extract and publish information from the rpm headers based on keywords or globs, find packages that provide particular files. Yum is therefore of great use to users of a workstation, either private or on a LAN; with yum they can look over the list of available packages to see if there is anything "interesting", search for packages that contain a particular tool or apply to a particular task, and more.
If this isn't enough, yum is the back end for a number of GUI tools that provide a user with "instant" visual access to the entire rather enormous range of packages available for any linux distribution that relies on it. For example, in Fedora 12 as of the current snapshot of this HOWTO there are over twenty thousand individual packages listed in the repositories connected to my personal laptop.
Not all of these are distinct applications as many applications have distinct packages such as the application itself, a development package, a library package and a documentation package, but it is safe to say that there are many thousands of actual applications, most of them well written and maintained and quite useful. Yum is designed to be a client-pull tool, permitting package management to be "centralized" to the extent required to ensure security and interoperability even across a broad, decentralized administrative domain.
No root privileges are required on the server by yum clients -- yum rquuires at most anonymous access restricted or unrestricted from the clients to a repository server often one that is maintained by a central -- and competent -- authority. This makes yum an espicially attractive tool for providing "centralized" scalable administration of linux systems in a decentralized network management environment, where a mix of machines maintained by their owners and by a variety of network managers naturally occurs such as a University or corporation.
One of yum's most common uses in any LAN environment is to be run from a nightly cron script on each yum-maintained system to update every rpm package on the system safely to the latest versions available on the repository, including all security or operationally patched updates.
Security and other updates will typically appear on all net-connected clients no more than 24 hours after the an updated rpm is placed on the repository by its trusted administrator who requires no root-level privileges on any of the clients. Consequently with yum a single trusterent name, possibly different contents.
This happens fairly regularly, if rarely, especially when the obsoleted package provides a configuration file that is shared by several tools. The Red Hat package manager tool, which is installed in all RPM based system, knows how to open and install these. RPM itself is a vast topic, so we will be covering that in separate post, in great detail.
RPM is the package manager tool which installs the package. YUM is a repository management tool which will fetch the appropriate package for your particular version of Linux along with all other required packages. Repositories is an organized collection of packages that YUM uses. YUM can use these repositories to fetch the correct and exact version of a particular package compatible for your system.
Previously before YUM or before the existence of such repository management tools , the user had to fetch the rpm package for installation, and if a dependency problem arises, the user had to fetch those dependencies from internet or some other sources.
You can in fact update all the installed applications on your system, with the help of a single YUM command yum will fetch different packages from appropriate different repositories. However all are not installed, when you install the operating system. Later on if you need a particular package, its not at all advisable to insert the installation disk once again, and fetch that required. Again if you face dependency problems, you need to fetch that dependency package once again sometimes there are yet another dependency package required for installing your dependency package.
So it becomes a tedious job. Let's go through a step by step method of creating a local YUM repository. Step 1: Copy all the. Step 2: For showing you this example, i will be copying all the. If you see the above output there are around packages in the installation disk, i have not shown the whole output. As i told before, a repository is nothing but a collection of packages in a directory.
YUM was made, so that an operating system can use different repositories at the same time. It is not at all feasible for an operating system to download the entire repository because a repository is sometimes very large in the size of Gigabytes. And YUM was designed to fetch and download only those packages that are required to install your required software on demand. For example, if i want to install a package called "Perl" , YUM must first have the list of all the package's in a repository note the fact that it only requires the list, not the package.
YUM will download the total list of packages available in a repository the list will contain the package names in the repository,package details etc. Not that it will download only the list of packages with details, not the packages. After downloading the list, If yum was able to fetch all the dependencies for your required package from that repository or other repositories yum will install it after confirming with you.
Now lets make that file, which will be containing the package names and other repository details. For this, there is another tool called "Createrepo".
Let's see what createrepo does. After running "createrepo" for our repository directory you will have an extra directory along with the packages inside the repository. You can clearly see there are four files inside that directory.
Let's understand the contents of each and every file in detail. Let's see what's inside that compressed file with the help of "zcat". For explanation i have copied one line from the file "filelists.
If you see the above line, the first entry tell's the package ID, which will uniquely identify the package. The second entry "name" ofcourse suggests the name of the package. An important fact to note is that, it also gives the information about the file's that are going to be installed on the system, if you install this package.
Installing this package, will install two files namely ,. Wow isnt that cool? So that filelists. This file will be used by YUM to fetch details of all the packages in the repository. Let's get the detail's of that exact same package from primary. Lets see what's inside this file. So this file also consists of package details. But it contains some additional information's like the following. If you have noticed the file "filelists.
So if you dont have "filelists. Most of the packages install a lot number of files on the system. RM Community Member 38 points.
Robert McGrath. Here are the common uses of Markdown. Learn more Close. Are you sure you want to update a translation? It seems an existing Japanese Translation exists already. However, the english version is more up to date.
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