yum 程序包管理简介

Posted xiaoshiwang

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rpm可以实现程序的快速，简单安装（跟编译安装比），但是rpm自己不能解决依赖，所以很多工具为了自动解决依赖应运而生，其中yum就是其中之一。

yum解决依赖的办法：

  • 必须有个文件服务器，里面放置所以的rpm包，以及包的相关元数据（-qi，-qR得到的数据）。元数据可以使用createrepo来创建。并放置在repodata目录下。

    这个文件服务器可以使用ftp，http，nfs协议来传输数据，也可以使用file:///（本地服务）。

  • 客户端使用yum程序，安装程序包。安装时，查询文件服务器，自己从文件服务器找依赖，并安装。

yum是一个程序，查看本机是否安装了yum：

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

查看yum程序所使用的配置文件：

/etc/yum.conf是主配置文件，它里面引用了目录/etc/yum.repos.d/，所以/etc/yum.repos.d/目录下的*.repo也是yum的配置文件.它提供了所以仓库的公共配置。

实现了把配置文件分割成了许多独立的小的配置文件。

/etc/yum.repos.d/目录下的*.repo:为仓库的指向提供配置信息。

# rpm -qc yum
/etc/logrotate.d/yum#log用
/etc/yum.conf
/etc/yum/version-groups.conf#版本控制

/etc/yum.conf内容：

[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]：主配置，相当于程序的指向入口

cachedir：缓存路径
keepcache：是否保持缓存
debuglevel：调试级别
logfile：日志文件
exactarch：是否做精确匹配。如果OS是centos7，当找到的rpm包，既有centos6的也有centos7的，如果此处的值是1，则选择centos7的。

gpgcheck：安装时，是否检查完整性和来源合法性。1则检查

plugins：yum是否支持插件。1则支持

使用whatis查看是否有man帮助。

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

使用：man 5 yum.conf可以得到详细的yum.conf配置文件的详细帮助。

仓库指向的定义

  • [repositoryid]：仓库的id

  • name=仓库的名字

  • baseurl=url://path/to/repository/：仓库在哪里，地址可以有多个，那么选哪个呢？根据failovermethod选。

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

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

  • failovermethod={roundrobin|priority}。默认为roundrobin，意味随机选一个url
  • gpgcheck={1|0}：1则检查。默认是1.
  • enabled={1|0}：是否使用此repo
  • gpgkey=URL：公钥
  • enablegroups={1|0}：1则使用组功能。默认是1.
  • const=默认是1000.有多个符合就选cost小的。

centos7下/etc/yum.repos.d/下的repo配置文件有几个，只有CentOS-Base.repo文件里repo的enabled是1，也就是可以使用状态，其余的配置文件里的repo的enabled都是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

查看配置文件：/etc/yum.repos.d/CentOS-Base.repo的内容。

[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

指定baseurl的技巧：指到repodata所在的网页的URL。

上面的updates的baseurl的值就是下图的网页地址栏的URL。理由是repodata在这里。

技术图片

查看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：是配置文件/etc/yum.repos.d/CentOS-Base.repo里的name的值

status：这个repo里的rmp包的数量。

yum命令介绍

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

  • 显示repo（仓库）列表（list）：repolist [all|enabled|disabled]

    • all：显示全部
    • enabled：显示可用的。默认值。就是本地repo配置文件里enabled=1的repo会显示出来。
    • disabled：显示不可用的。就是本地repo配置文件里enabled=0的repo会显示出来。
    # yum repolist all
# yum repolist enabled
# yum repolist disabled

  • 显示指定repo里有哪些rpm包：yum list [all | glob_exp1] [glob_exp2] [...]

    显示所有的包：

    # yum list

    可以使用glob_exp。

    显示内容的第三列：repo配置文件中的repoid

    # 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

    显示repo中还未安装的包：yum list available [glob_exp1][...]

    # yum list available

    显示repo中的可以升级的包：yum list updates [glob_exp1][...]

    # yum list updates

    显示已经安装的包：yum list installed [glob_exp1][...]

    • @anaconda：安装系统时，安装的包。
    • installed：后来自己安装的。
    # yum list installed
zlib.x86_64              1.2.7-18.el7                        @anaconda
zsh.x86_64               5.0.2-33.el7                        installed

    显示已经安装了的extra repo中的包：yum list extras [glob_exp1][...]

    # yum list extras

    显示已经安装的包，哪些已经废弃了：yum list distro-extras [glob_exp1][...]

    # yum list distro-extras

  • 安装包：yum install package1 [package2

    如果repo里有多个版本，可以指定版本，例如：yum install gcc-4.8.5

    也可以不指定版本,则安装最新版：yum install gcc

  • 升级包：yum update [package1][package2] [...]

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

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

    类似：rpm -Uvh --oldpackage

  • 重新覆盖安装：reinstall package1 [package2][...]

    类似：rpm -ivh --replacepkgs

  • 检查有哪些包可以升级：yum check-update

  • 卸载包：yum remove | erase package1 [package2][...]

    当卸载的包，被别的包依赖时，别的包也一并被卸载

    卸载cpp：由于gcc依赖于cpp，所有如果卸载cpp，则gcc也会被卸载。

  • 查看包的信息：yum info [glob_exp1][...]

    类似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

  • 查看程序或文件是有哪个包提供的：yum provides | whatprovides feature1 [feature2

    类似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

  • 清除元数据文件在本地的缓存：clean [ packages | metadata | expire-cache | rpmdb | plugins | all ]

    yum按文件时，会把程序包和元数据文件缓存在本地，当安装结束，yum会删除程序包文件，但是不会删除 元数据文件。

  • 构建缓存：yum makecache [fast]

  • 用关键字搜索信息：yum search string1 [string2][...]

    从包名和包的summary里搜索指定的关键字。

    # 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.

  • 显示某个包所依赖的包：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
...

  • 查看yum的安装，更新，卸载的历史：yum history不带参数则是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

    上面是汇总的信息，如果想看id为5的详细信息，也就是id为5的安装了哪些包，则使用：

    # 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

    查看yumdb大小：

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

  • 本地安装/升级：想安装的包在yum repo中没有，可以下载一个rpm包安装。但为什么不用rpm呢，因为rpm不能解决依赖，而yum可以，所以即使是本地的rpm包，也可以使用yum安装，但是参数是rpm文件名。

    localinstall/localupdate是为了兼容以前的版本，应该使用intall/update 参数是rpm文件名。

    • localinstall rpmfile1 [rpmfile2][...]

    ? (maintained for legacy reasons only - use install)

    • localupdate rpmfile1 [rpmfile2][...]

    ? (maintained for legacy reasons only - use update)

  • 组安装/更新/卸载/查看

    • 查看有哪些组可供安装：

      # 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

    • 查看某个组里有哪些包：

      # 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：必须安装的包

      Default Packages:默认安装的包

      Optional Packages:可选安装的包

    • 安装：

      # yum groups install "Development Tools"

    • 更新：

      # 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

    • 删除：

      # yum groups remove Development Tools

拿光盘作为repo

1，先挂载centos系统安装盘到/media目录。

2，创建文件local.repo

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

3，然后就可以正常使用yum命令了。

c/c++ 学习互助QQ群：877684253

技术图片

本人微信：xiaoshitou5854

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