Introduction to yum package management

Keywords: Linux yum CentOS RPM PHP

rpm can realize fast and simple installation of programs (compared with compilation and installation), but rpm can't solve dependency by itself, so many tools come into being to solve dependency automatically, among which yum is one of them.

yum solution to dependency:

  • There must be a file server where all the rpm packages and the package related metadata (- qi, - qR) are placed. Metadata can be created using createrepo. And put it in the repodata directory.

    This file server can use ftp, http, nfs protocol to transfer data, or file: / / (local service).

  • The client uses the yum program to install the package. During installation, query the file server, find the dependency from the file server, and install.

yum is a program. Check whether yum is installed on this computer:

# rpm -q yum
yum-3.4.3-161.el7.centos.noarch

To view the profile used by the yum program:

/etc/yum.conf is the main configuration file, which references the directory / etc/yum.repos.d/, so *. repo under the directory / etc/yum.repos.d/ is also the configuration file of Yum. It provides the public configuration of all warehouses.

The configuration file is divided into many independent small configuration files.

/*. repo: under the directory of etc/yum.repos.d/provides configuration information for the pointing of the warehouse.

# rpm -qc yum
/etc/logrotate.d/yum#log use
/etc/yum.conf
/etc/yum/version-groups.conf#version control

/etc/yum.conf content:

[main]
cachedir=/var/cache/yum/$basearch/$releasever
keepcache=0
debuglevel=2
logfile=/var/log/yum.log
exactarch=1
obsoletes=1
gpgcheck=1
plugins=1
installonly_limit=5
bugtracker_url=http://bugs.centos.org/set_project.php?project_id=23&ref=http://bugs.centos.org/bug_report_page.php?category=yum
distroverpkg=centos-release


#  This is the default, if you make this bigger yum won't see if the metadata
# is newer on the remote and so you'll "gain" the bandwidth of not having to
# download the new metadata and "pay" for it by yum not having correct
# information.
#  It is esp. important, to have correct metadata, for distributions like
# Fedora which don't keep old packages around. If you don't like this checking
# interupting your command line usage, it's much better to have something
# manually check the metadata once an hour (yum-updatesd will do this).
# metadata_expire=90m

# PUT YOUR REPOS HERE OR IN separate files named file.repo
# in /etc/yum.repos.d

[main]: the main configuration, equivalent to the point entry of the program

cachedir: cache path
keepcache: whether to keep the cache
debuglevel: debug level
logfile: log file
Exact arch: whether to make exact match. If the OS is centos7, the rpm package found includes both centos6 and centos7. If the value here is 1, select centos7.

gpgcheck: check the integrity and source validity during installation. 1 checks

plugins: whether plug-ins are supported. The 1 is support.

Use whatis to see if there is man help.

# whatis yum.conf
yum.conf (5)         - Configuration file for yum(8).

Use: man 5 yum.conf to get detailed help from the yum.conf configuration file.

Definition of warehouse point

  • [repository id]: id of the warehouse

  • Name = name of the warehouse

  • baseurl=url://path/to/repository /: where is the warehouse and there can be multiple addresses, which one should be selected? Select according to failovermethod.

    baseurl=url://server1/path/to/repository/

​ url://server2/path/to/repository/
url://server3/path/to/repository/

  • failovermethod={roundrobin|priority}. The default is round robin, which means randomly selecting a url
  • gpgcheck={1|0}: 1. The default is 1..
  • enabled={1|0}: use this repo or not
  • gpgkey=URL: public key
  • enablegroups={1|0}: 1 uses the group function. The default is 1..
  • const = the default value is 1000. If there are multiple matches, select cost.

There are several repo configuration files under / etc/yum.repos.d/ under centos7. Only the enabled repo in CentOS-Base.repo file is 1, that is, it can be used. The enabled repo in other configuration files is 0

# ls /etc/yum.repos.d/
CentOS-Base.repo           CentOS-CR.repo         CentOS-fasttrack.repo  CentOS-Sources.repo
CentOS-Base.repo_20191129  CentOS-Debuginfo.repo  CentOS-Media.repo      CentOS-Vault.repo

View the contents of the configuration file: / etc/yum.repos.d/CentOS-Base.repo.

[base]
name=CentOS-$releasever - Base
baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/os/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

#released updates
[updates]
name=CentOS-$releasever - Updates
baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/updates/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/extras/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/centosplus/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

Tips for specifying base URL: refers to the URL of the web page where repodata is located.

The value of the baseurl of the above updates is the URL of the address bar of the following page. The reason is that repodata is here.

View repo list:

# yum repolist
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
repo id                                                     repo name                                                     status
!base/7/x86_64                                              CentOS-7 - Base                                               10,097
!extras/7/x86_64                                            CentOS-7 - Extras                                                323
!updates/7/x86_64                                           CentOS-7 - Updates                                             1,446
repolist: 11,866

repo id:

repo name: is the value of name in the configuration file / etc/yum.repos.d/CentOS-Base.repo

status: the number of rmp packets in this repo.

Introduction to yum command

yum [options][command] [package ...]

  • Display the repo list: repolist [all|enabled|disabled]

    • All: show all
    • Enabled: displays the available. Default value. That is, the repo with enabled=1 in the local repo configuration file will be displayed.
    • disabled: displays unavailable. That is, the repo with enabled=0 in the local repo configuration file will be displayed.
    # yum repolist all
# yum repolist enabled
# yum repolist disabled

  • Display which rpm packages are in the specified repo: yum list [all | glob_exp1] [glob_exp2] [etc.]

    Show all packages:

    # yum list

    Glob? Exp can be used.

    The third column of the display content: repoid in the repo configuration file

    # yum list php*
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
Available Packages
php.x86_64                  5.4.16-46.1.el7_7            updates
php-bcmath.x86_64           5.4.16-46.1.el7_7            updates
php-pear.noarch             1:1.9.4-21.el7               base
php-pecl-memcache.x86_64    3.0.8-4.el7                  base

    Show packages not installed in repo: yum list available [glob_exp1] [...]

    # yum list available

    Show upgradeable packages in repo: yum list updates [glob_exp1] [...]

    # yum list updates

    Show installed packages: yum list installed [glob_exp1] [...]

    • @anaconda: package installed when installing the system.
    • Installed: later installed by myself.
    # yum list installed
zlib.x86_64              1.2.7-18.el7                        @anaconda
zsh.x86_64               5.0.2-33.el7                        installed

    Show packages in extra repo that have been installed: yum list extras [glob_exp1] [...]

    # yum list extras

    Display the installed packages, which are obsolete: Yum list distro extras [glob_exp1] [...]

    # yum list distro-extras

  • Installation package: yum install package1 [package2

    If there are multiple versions in repo, you can specify the version, for example, yum install gcc-4.8.5

    You can also install the latest version without specifying the version: yum install gcc

  • Upgrade package: yum update [package1][package2] [...]

    # yum update gcc
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
No packages marked for update

  • Downgrade: downgrade package1 [package2] [...]

    Similar: rpm -Uvh --oldpackage

  • Reinstall: reinstall package1 [package2] [...]

    Similar: rpm -ivh --replacepkgs

  • Check which packages can be upgraded: Yum check update

  • Uninstall package: yum remove | erase package1 [package2] [...]

    When the uninstalled package is dependent on other packages, other packages are also uninstalled

    Uninstall cpp: since gcc depends on cpp, if you uninstall cpp, gcc will also be uninstalled.

  • View package information: yum info [glob_exp1] [...]

    Similar to rpm -qi

    # yum info gcc
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
Installed Packages
Name        : gcc
Arch        : x86_64
Version     : 4.8.5
Release     : 39.el7
Size        : 37 M
Repo        : installed
From repo   : base
Summary     : Various compilers (C, C++, Objective-C, Java, ...)
URL         : http://gcc.gnu.org
License     : GPLv3+ and GPLv3+ with exceptions and GPLv2+ with exceptions and LGPLv2+ and BSD
Description : The gcc package contains the GNU Compiler Collection version 4.8.
            : You'll need this package in order to compile C code

  • Check which package is provided by the program or file: yum provides | whatprovides feature1 [feature2]

    Similar to rpm -qf file

    # yum provides /usr/bin/gcc
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
gcc-4.8.5-39.el7.x86_64 : Various compilers (C, C++, Objective-C, Java, ...)
Repo        : base
Matched from:
Filename    : /usr/bin/gcc

gcc-4.8.5-39.el7.x86_64 : Various compilers (C, C++, Objective-C, Java, ...)
Repo        : @base
Matched from:
Filename    : /usr/bin/gcc

  • Clean [packages | metadata | expire cache | rpmdb | plugins | all]

    When yum presses a file, it will cache the package and metadata file locally. When the installation is finished, yum will delete the package file, but not the metadata file.

  • Build cache: yum makecache [fast]

  • Search information with keywords: yum search string1 [string2] [...]

    Searches the package name and the summary of the package for the specified keywords.

    # yum search bash
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
====================================================== N/S matched: bash =======================================================
bash-completion.noarch : Programmable completion for Bash
bash-doc.x86_64 : Documentation files for bash
libguestfs-bash-completion.noarch : Bash tab-completion scripts for libguestfs tools
libvirt-bash-completion.x86_64 : Bash completion script
pcp-pmda-bash.x86_64 : Performance Co-Pilot (PCP) metrics for the Bash shell
bash.x86_64 : The GNU Bourne Again shell

  Name and summary matches only, use "search all" for everything.

  • Show the packages a package depends on: deplist package1 [package2] [...]

    # yum deplist gcc
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
package: gcc.x86_64 4.8.5-39.el7
  dependency: /bin/sh
   provider: bash.x86_64 4.2.46-33.el7
  dependency: /sbin/install-info
   provider: info.x86_64 5.1-5.el7
...

  • View the history of installation, update, and uninstall of yum: yum history without parameters is history list

    history [info|list|packages-list|packages-info|summary|addon-info|redo|undo|rollback|new|sync|stats]

    # yum history
Loaded plugins: fastestmirror, langpacks
ID     | Login user               | Date and time    | Action(s)      | Altered
-------------------------------------------------------------------------------
     5 | root <root>              | 2020-02-15 23:00 | Install        |    2
     4 | root <root>              | 2020-02-15 22:59 | Erase          |    8
     3 | root <root>              | 2020-02-15 22:48 | Update         |   11  <
     2 | ys <ys>                  | 2019-11-29 17:38 | Install        |    8 >
     1 | System <unset>           | 2019-11-29 16:44 | Install        | 1458
history list

    The above is the summary information. If you want to see the details of id 5, that is, which packages have been installed with id 5, then use:

    # yum history info 5
Loaded plugins: fastestmirror, langpacks
Transaction ID : 5
Begin time     : Sat Feb 15 23:00:14 2020
Begin rpmdb    : 1459:fe9d7def2a5edd098cfe39ebe0732b67038170b5
End time       :            23:00:19 2020 (5 seconds)
End rpmdb      : 1461:ed3657ce694e0e90ea8bf62a092f06422c81ac28
User           : root <root>
Return-Code    : Success
Command Line   : install gcc
Transaction performed with:
    Installed     rpm-4.11.3-35.el7.x86_64                      @anaconda
    Installed     yum-3.4.3-161.el7.centos.noarch               @anaconda
    Installed     yum-plugin-fastestmirror-1.1.31-50.el7.noarch @anaconda
Packages Altered:
    Dep-Install cpp-4.8.5-39.el7.x86_64 @base
    Install     gcc-4.8.5-39.el7.x86_64 @base
history info

    To view the yumdb size:

    # yum history stats
Loaded plugins: fastestmirror, langpacks
File        : //var/lib/yum/history/history-2020-02-16.sqlite
Size        : 23,552
Transactions: 0
history stats

  • Local installation / upgrade: the package you want to install is not available in yum repo. You can download an rpm package to install it. But why not use rpm? rpm can't solve the dependency, but Yum can. So even the local rpm package can be installed using yum, but the parameter is the rpm filename.

    localinstall/localupdate is to be compatible with previous versions. You should use the intall/update parameter as the rpm filename.

    • localinstall rpmfile1 [rpmfile2][...]

    ​ (maintained for legacy reasons only - use install)

    • localupdate rpmfile1 [rpmfile2][...]

    ​ (maintained for legacy reasons only - use update)

  • Group install / update / uninstall / view

    • See which groups are available for installation:

      # yum groups list
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
Available Environment Groups:
   Minimal Install
   Compute Node
   Infrastructure Server
   File and Print Server
   Basic Web Server
   Virtualization Host
   Server with GUI
   GNOME Desktop
   KDE Plasma Workspaces
   Development and Creative Workstation
Installed Groups:
   Development Tools
Available Groups:
   Compatibility Libraries
   Console Internet Tools
   Graphical Administration Tools
   Legacy UNIX Compatibility
   Scientific Support
   Security Tools
   Smart Card Support
   System Administration Tools
   System Management
Done

    • To see which packages are in a group:

      # yum groups info Development\ Tools
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile

Group: Development Tools
 Group-Id: development
 Description: A basic development environment.
 Mandatory Packages:
    gcc
   =gcc-c++
    gettext
   =libtool
    make
 Default Packages:
    byacc
   =gcc-gfortran
    swig
   =systemtap
 Optional Packages:
   ElectricFence
   ant
   babel
   bzr

      Mandatory Packages: packages that must be installed

      Default Packages: packages installed by default

      Optional Packages: Optional Packages

    • Installation:

      # yum groups install "Development Tools"

    • To update:

      # yum groups update "Development Tools"
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
Maybe run: yum groups mark install (see man yum)
No packages in any requested group available to install or updates

    • Delete:

      # yum groups remove Development\ Tools

Take the CD as a repo

1. Mount the centos system installation disk to the / media directory.

2. Create the local.repo file

[base]
name=local repo centos
baseurl=file:///media/
enabled=1
gpgcheck=0

3. Then you can use the yum command normally.

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Posted by jiggens on Sat, 15 Feb 2020 18:47:48 -0800

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