Package management is one of the main objectives of RHCSA and RHCE exams on RHEL6. It is required to install and configure packages during the certification exam. In previous posts we have discussed installing package using rpm command. In Redhat Enterprise Linux 6 (RHEL6), to install a package we also have to install its dependencies.
This could be a difficult process as some packages have more than 50 dependent packages so we have to find out those dependent packages and install all of them one by one, also there could be dependency for the dependency. In Linux this is called “Dependency Hell”. To make this process easier, we can create a local YUM server or can configure a YUM server on FTP/HTTP to make it as a centralized repository for all servers.
YUM (Yellow Dog updater, modifier) maintains a database regarding the packages. This database contains information about installed packages, available packages, and automatically resolves dependencies while installing packages. The yum database is also known as repository.
What is a repository?
A repository is collection of rpm packages. Repository can also include group of packages. For example RHN includes following RHEL6 repositories:
Red Hat Enterprise Linux Server: This is the main repository, which includes both packages associated with installation of RHEL6 and updated packages.
This could be a difficult process as some packages have more than 50 dependent packages so we have to find out those dependent packages and install all of them one by one, also there could be dependency for the dependency. In Linux this is called “Dependency Hell”. To make this process easier, we can create a local YUM server or can configure a YUM server on FTP/HTTP to make it as a centralized repository for all servers.
YUM (Yellow Dog updater, modifier) maintains a database regarding the packages. This database contains information about installed packages, available packages, and automatically resolves dependencies while installing packages. The yum database is also known as repository.
What is a repository?
A repository is collection of rpm packages. Repository can also include group of packages. For example RHN includes following RHEL6 repositories:
Red Hat Enterprise Linux Server: This is the main repository, which includes both packages associated with installation of RHEL6 and updated packages.
- RHN Tools: Repository for managing RHN connections and Kickstart installation.
- RHN Server Supplementary: Repository of packages other that open source like adobe and java.
- RHELV2VWIN: Repository to support package to read Microsoft formatted partitions.
- RHEL Server Optional: Large group of packages other than server package like desktop packages, etc.
Each repository contains a database about the packages in the repository. This database can be found under repodata directory in each repository. This database contains information about each package and its dependencies.
You can also create your own repository of packages. To create a repository, you need createrepo package installed.
In the next post we will see how to configure YUM server and Client. Also we will learn how to create YUM server for RHEL6 DVD iso to update packages on local and remote machines.
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