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Packages Repository
When an rpm package is installed with the rpm command and the rpm needs the installation of other rpms, these others rpms (called dependencies) must be also installed. In order to install automatically these dependencies we can use the yum command configured to use a Package Repository which is a group of rpms that can be dependent plus xml metadata files that contain the dependencies between these rpms. When yum is executed to install an rpm, yum goes to the package repository and automatically installs that rpm and all its dependencies.
Creating a repository
In order to create an rpm repository the createrepo rpm must be installed on your system. First copy all the rpms to a new directory and then run createrepo command on that directory :
The xml metadata files that contain the rpms dependencies are created and the repository is ready to be used by yum command.
Configuring yum to use a repository
Once the package repository has been created, yum command can be configured to 'point' to that repository. This action can be done using the configuration file /etc/yum.repos.d/reponame.repo where 'reponame' is the repository name. The content of this file is like :
'baseurl' parameter is the place that points to the repository physical location. It can be local ('file:///') if the repository is located in the same system where yum is or remote ('http://server/repo', 'nfs://server/repo', 'ftp://server/repo') if the repository is in another system.
'enabled' parameter tells to yum if that repository must be used (=1) or ignored (=0). This is because of multiple reponame.repo files can be used at once and in some cases can be helpful ignore some repositories.
'gpgcheck' parameter tells to yum if the GPG authenticity of each rpm package must be checked against imported keys from 'gpgkey' before the package will be installed.
Configuring yum
# By default all .repo files on /etc/yum.repos.d are active yum repositories
# PUT YOUR REPOS HERE OR IN separate files named file.repo
Using yum
Once yum configured and pointing to a package repository is time to use yum. As rpm command yum can be use to install/uninstall and query information about the rpms packages contained on the repository :
Installs package.rpm from repository
Update package.rpm from repository
Uninstalls package.rpm
List repository information about what package installs 'command'
List all packages available from repository
If run without any packages, update will update every currently installed package on the system
Is the same as the update command with the --obsoletes, so obsoletes packages are removed
Practical example :
With the command 'yum -y install anaconda' we are only asking to install the anaconda rpm, but as anaconda has a dependency on other 7 packages, all this packages are also installed. The yum command has connected to the 'centos-debuginfo' repository, downloaded the 8 rpm packages and installed them on the system. with the '-y' option we are telling to yum that the answer to all its interactive questions are 'yes'.
When an rpm package is installed with the rpm command and the rpm needs the installation of other rpms, these others rpms (called dependencies) must be also installed. In order to install automatically these dependencies we can use the yum command configured to use a Package Repository which is a group of rpms that can be dependent plus xml metadata files that contain the dependencies between these rpms. When yum is executed to install an rpm, yum goes to the package repository and automatically installs that rpm and all its dependencies.
Creating a repository
In order to create an rpm repository the createrepo rpm must be installed on your system. First copy all the rpms to a new directory and then run createrepo command on that directory :
Code:
$ mkdir -p /repo $ cp *.rpm /repo $ createrepo /repo
Configuring yum to use a repository
Once the package repository has been created, yum command can be configured to 'point' to that repository. This action can be done using the configuration file /etc/yum.repos.d/reponame.repo where 'reponame' is the repository name. The content of this file is like :
Code:
[reponame] name=reponame baseurl=file:///repo enabled=1 gpgcheck=1 gpgkey=file:///repo/RPM-GPG-KEY-reponame
'enabled' parameter tells to yum if that repository must be used (=1) or ignored (=0). This is because of multiple reponame.repo files can be used at once and in some cases can be helpful ignore some repositories.
'gpgcheck' parameter tells to yum if the GPG authenticity of each rpm package must be checked against imported keys from 'gpgkey' before the package will be installed.
Configuring yum
Code:
The file /etc/yum.conf controls the way yum is executed. A commented version of this file is the following: $ cat /etc/yum.conf [main] # The 'cachedir' directive specifies the directory where rpms packages downloads are stored cachedir=/var/cache/yum # The 'keepcache' specifies that rpms must be stored on 'cachedir', if keepcache=0 rpms are removed after installation keepcache=1 # Log parameters debuglevel=2 logfile=/var/log/yum.log # The 'distroverpkg' parameter takes the version from the /etc/redhat-release file distroverpkg=redhat-release # The 'tolerant' parameter allows yum to work even with minor errors tolerant=1 # The 'exactarch' parameter makes sure that yum downloads correspond to your CPU architecture exactarch=1 # The 'obsoletes' parameter checks for and uninstalls any obsolete packages during a 'yum update' command obsoletes=1 # The 'gpgcheck' parameter verifies package GPG authenticity gpgcheck=1 # The 'plugins' parameter includes plug-ins as defined in the /etc/yum/pluginconf.d/ and /usr/lib/yum-plugins/ directories plugins=1 # The 'exclude' parameter specifies the packages that must be ignored by yum #exclude= # The 'metadata_expire' parameter specifies a lifetime for xml info. Once is expired yum download xlms fresh info from repository # Note: yum-RHN-plugin doesn't honor this. metadata_expire=1h
# PUT YOUR REPOS HERE OR IN separate files named file.repo
Code:
# in /etc/yum.repos.d
Once yum configured and pointing to a package repository is time to use yum. As rpm command yum can be use to install/uninstall and query information about the rpms packages contained on the repository :
Code:
$ yum install package
Code:
$ yum update package
Code:
$ yum remove package
Code:
$ yum wharprovides command
Code:
$ yum list
Code:
$ yum update
Code:
$ yum upgrade
Practical example :
Code:
$ yum -y install anaconda Loading "rhnplugin" plugin Loading "security" plugin This system is not registered with RHN. RHN support will be disabled. Setting up Install Process Parsing package install arguments Resolving Dependencies --> Running transaction check ---> Package anaconda.i386 0:11.1.2.113-1 set to be updated --> Processing Dependency: booty for package: anaconda --> Processing Dependency: libbdevid-python for package: anaconda --> Processing Dependency: pyparted >= 1.7.2 for package: anaconda --> Processing Dependency: libdhcp6client-1.0.so.2 for package: anaconda --> Processing Dependency: python-pyblock >= 0.26-1 for package: anaconda --> Processing Dependency: libdhcp.so.1 for package: anaconda --> Processing Dependency: libdhcp4client.so.1 for package: anaconda --> Running transaction check ---> Package libdhcp4client.i386 12:3.0.5-13.el5 set to be updated ---> Package pyparted.i386 0:1.8.1-4.el5 set to be updated ---> Package python-pyblock.i386 0:0.26-1.el5 set to be updated ---> Package booty.noarch 0:0.80.4-6 set to be updated ---> Package libdhcp6client.i386 0:1.0.10-4.el5 set to be updated ---> Package libdhcp.i386 0:1.20-5.el5 set to be updated ---> Package libbdevid-python.i386 0:5.1.19.6-28 set to be updated --> Finished Dependency Resolution Dependencies Resolved ============================================================================= Package Arch Version Repository Size ============================================================================= Installing: anaconda i386 11.1.2.113-1 centos-debuginfo 5.5 M Installing for dependencies: booty noarch 0.80.4-6 centos-debuginfo 89 k libbdevid-python i386 5.1.19.6-28 centos-debuginfo 57 k libdhcp i386 1.20-5.el5 centos-debuginfo 59 k libdhcp4client i386 12:3.0.5-13.el5 centos-debuginfo 244 k libdhcp6client i386 1.0.10-4.el5 centos-debuginfo 88 k pyparted i386 1.8.1-4.el5 centos-debuginfo 25 k python-pyblock i386 0.26-1.el5 centos-debuginfo 55 k Transaction Summary ============================================================================= Install 8 Package(s) Update 0 Package(s) Remove 0 Package(s) Total download size: 6.1 M Downloading Packages: Running rpm_check_debug Running Transaction Test Finished Transaction Test Transaction Test Succeeded Running Transaction Installing: libbdevid-python ######################### [1/8] Installing: libdhcp6client ######################### [2/8] Installing: libdhcp4client ######################### [3/8] Installing: libdhcp ######################### [4/8] Installing: python-pyblock ######################### [5/8] Installing: booty ######################### [6/8] Installing: pyparted ######################### [7/8] Installing: anaconda ######################### [8/8] Installed: anaconda.i386 0:11.1.2.113-1 Dependency Installed: booty.noarch 0:0.80.4-6 libbdevid-python.i386 0:5.1.19.6-28 libdhcp.i386 0:1.20-5.el5 libdhcp4client.i386 12:3.0.5-13.el5 libdhcp6client.i386 0:1.0.10-4.el5 pyparted.i386 0:1.8.1-4.el5 python-pyblock.i386 0:0.26-1.el5 Complete!