yum由来
yum基本工作机制
yum的相关特点
yum的配置文件
yum的配置仓库示例
yum的命令使用
yum中常见问题
yum由来
yum是yellowdog updater修改而来,被yellowdog linux,rhel,centos,fedora所采用.其名为"Yellowdog Updater Modified".是一个基于rpm的前端管理工具.用于解决rpm包之间的依赖关系,并且一次安装所有依赖的软件包,无需繁琐下载,安装.
yum基本工作机制
yum程序如何获取rpm包呢? 一般有指定的服务器,或者光盘将大量rpm包保存其中.这些存储地方我们称其为"仓库",那么我们是直接将所有的包都下载到本地,还是怎么获取呢? 其实很简单,服务器端提供一些元数据文件,其元数据文件中包含了rpm包的名字,版本,以及包与包之间的依赖关系等信息.我们 直接将元数据缓存到本地,再根据所需,yum会自动将rpm下载到本地并安装. yum再安装完rpm包之后,会自动清除下载的rpm包,但其元数据文件保留,方便下次更快使用. 此方法虽然加快yum使用速度,但如果服务器发生文件更新或者依赖性的某些改动,则无法及时更新元数据文件,为了解决此问题 yum在每次使用之前都会与服务器对比校验码,如果校验码没有变动,则继续使用原来的元数据文件,否则下载新的元数据文件. 获取其rpm包的方式有多种,http,ftp,nfs,本地光盘都能获取仓库.
yum的相关特点
保持与rpm数据库的一致性 #如果rpm数据库损坏,yum也无法正常使用. 同时配置多个源 简单配置文件 解决依赖关系
yum的配置文件
/etc/yum.conf #为所有仓库提供公共配置
/etc/yum.repos.d/*.repo #yum的仓库相关配置文件
**man yum.conf 用来查询其帮助文档 **
/etc/yum.conf
[main]
cachedir=/var/cache/yum/$basearch/$releasever #缓存目录路径
keepcache=0 #本地缓存文件是否保存
debuglevel=2 #debug调试级别
logfile=/var/log/yum.log #yum自己的日志文件
exactarch=1 #是否严格平台匹配
obsoletes=1
gpgcheck=1 #是否检查包的来源合法性
plugins=1 #是否支持插件
installonly_limit=5 #一次同时安装几个程序包
bugtracker_url=http://bugs.centos.org/set_project.php?project_id=16&ref=http://bugs.centos.org/bug_report_page.php?category=yum
distroverpkg=centos-release #设定$releasever的值由哪个rpm包的主版本号
/etc/yum.repos.d/*.repo
[repositoryid] #仓库id,保持唯一性
name=Some name for this repository #仓库名称,仅作标识
baseurl=url://server1/path/to/repository/ #指定仓库访问路径,以下的行
url://server2/path/to/repository/
url://server3/path/to/repository/
gpgcheck={1|0} #是否检查包来源合法性及完整性,默认为1
gpgkey=RPM-GPG-KEY #指向RPM-GPG-KEY的位置
enabled={1|0} #是否启用,默认为1
failovermethod={"roundrobin"|"priority"} #roundrobin随机选择url,priority从第一个url开始,按顺序选择
cost=# #仓库开销,用来定义仓库优先级,默认为1000,数字越小优先级越大
mirrorlist=url://mirrorlist_path #镜像列表,其路径指向的是访问仓库路径的url,不能与baseurl同时使用
注意：仓库所指的路径一定是在repodata目录"上",并不是指向package目录.repodata目录中保存了元数据文件.
一些常用变量:
arch #平台,当前系统的架构
basearch #基本平台架构,如果当前系统架构为i586,那么此匹配到基本平台的为i386
releasever #该发行版的主版本号
$YUM0-$YUM9 #用于将与同名的环境变量的值,替换为自身,如果不存在则不替换yum的配置仓库示例
配置本地源： vim /etc/yum.repos.d/centos-local.repo [local_1] name=local cdrom baseurl=file:///media/cdrom enabled=1 gpgcheck=1 gpgkey=file:///media/cdrom/RPM-GPG-KEY-CentOS-6 cost=50 显示仓库列表,以下为成功配置 [root@centos yum.repos.d]# yum repolist Loaded plugins: fastestmirror, refresh-packagekit, security Determining fastest mirrors local_1 | 4.0 kB 00:00 ... local_1/primary_db | 4.4 MB 00:00 ... repo id repo name status local_1 local iso 6,367 repolist: 6,367 epel源： vim /etc/yum.repos.d/epel.repo [epel_1] name=epel source baseurl=http://mirrors.aliyun.com/epel/$releasever/$basearch/ enabled=1 gpgcheck=1 gpgkey=http://mirrors.aliyun.com/epel/RPM-GPG-KEY-EPEL-6 cost=100 成功缓存元数据文件,以下为配置成功 [root@centos yum.repos.d]# yum makecache Loaded plugins: fastestmirror, refresh-packagekit, security Determining fastest mirrors epel_1 | 4.3 kB 00:00 epel_1/group_gz | 150 kB 00:00 epel_1/filelists_db | 7.8 MB 00:07 epel_1/updateinfo | 736 kB 00:00 epel_1/primary_db | 5.9 MB 00:05 epel_1/other_db | 2.9 MB 00:02 Metadata Cache Created
yum的命令使用
yum命令用于管理程序包和程序包组 yum [options] [command] [package ...] options: -y, --assumeyes #全部选y -q, --quiet #运行不输出 --disablerepo=repoidglob #临时不启用此仓库 --enablerepo=repoidglob #临时使用此仓库 --nogpgcheck #不检查包完整性和安全性 --disableplugin=plugins #不启用此插件 --noplugins #不启用插件 command: 安装: install package1 [package2] [...] #安装程序包 localinstall rpmfile1 [rpmfile2] [...] #本地安装rpm包,在安装不属于仓库的rpm包时,也能为其解决依赖关系 localupdate rpmfile1 [rpmfile2] [...] #本地更新rpm包 reinstall package1 [package2] [...] #重新安装 [root@centos ~]# yum install -y httpd ///安装httpd程序 Loaded plugins: fastestmirror, refresh-packagekit, security <--yum的插件 Loading mirror speeds from cached hostfile Setting up Install Process Resolving Dependencies <--检查依赖关系 --> Running transaction check ---> Package httpd.x86_64 0:2.2.15-29.el6.centos will be installed --> Finished Dependency Resolution Dependencies Resolved ========================================================================================================================================================= Package Arch Version Repository Size ========================================================================================================================================================= Installing: httpd x86_64 2.2.15-29.el6.centos local_1 821 k Transaction Summary ========================================================================================================================================================= Install 1 Package(s) Total download size: 821 k Installed size: 2.9 M Downloading Packages: Running rpm_check_debug Running Transaction Test Transaction Test Succeeded Running Transaction Installing : httpd-2.2.15-29.el6.centos.x86_64 1/1 Verifying : httpd-2.2.15-29.el6.centos.x86_64 1/1 Installed: httpd.x86_64 0:2.2.15-29.el6.centos Complete! 卸载: remove | erase package1 [package2] [...] #卸载程序包 [root@centos ~]# yum remove -y httpd Loaded plugins: fastestmirror, refresh-packagekit, security Setting up Remove Process Resolving Dependencies --> Running transaction check ---> Package httpd.x86_64 0:2.2.15-29.el6.centos will be erased --> Finished Dependency Resolution Dependencies Resolved ========================================================================================================================================================= Package Arch Version Repository Size ========================================================================================================================================================= Removing: httpd x86_64 2.2.15-29.el6.centos @local_1 2.9 M Transaction Summary ========================================================================================================================================================= Remove 1 Package(s) Installed size: 2.9 M Downloading Packages: Running rpm_check_debug Running Transaction Test Transaction Test Succeeded Running Transaction Erasing : httpd-2.2.15-29.el6.centos.x86_64 1/1 Verifying : httpd-2.2.15-29.el6.centos.x86_64 1/1 Removed: httpd.x86_64 0:2.2.15-29.el6.centos Complete! 更新: update [package1] [package2] [...] #更新程序包 check-update #检查能否更新($?的返回值为100,有更新的程序包;返回值为0,没有更新的程序包;返回值为1,有错误发生) downgrade package1 [package2] [...] #程序包降级 [root@centos ~]# yum check-update ///检查有哪些可更新的程序包 Loaded plugins: fastestmirror, refresh-packagekit, security Loading mirror speeds from cached hostfile Obsoleting Packages ibus-table-chinese-cangjie.noarch 1.4.6-1.el6 epel_1 ibus-table-cangjie.noarch 1.2.0.20100210-1.el6 @anaconda-CentOS-201311272149.x86_64/6.5 ... [root@centos ~]# yum update ibus-table-chinese-cangjie.noarch -y ///更新其中程序包 Loaded plugins: fastestmirror, refresh-packagekit, security Loading mirror speeds from cached hostfile Setting up Update Process Resolving Dependencies --> Running transaction check ---> Package ibus-table-cangjie.noarch 0:1.2.0.20100210-1.el6 will be obsoleted ---> Package ibus-table-chinese-cangjie.noarch 0:1.4.6-1.el6 will be obsoleting --> Processing Dependency: ibus-table-chinese = 1.4.6-1.el6 for package: ibus-table-chinese-cangjie-1.4.6-1.el6.noarch --> Running transaction check ---> Package ibus-table-chinese.noarch 0:1.4.6-1.el6 will be installed --> Finished Depende Dependencies Resolved ... 注意:当遇到以下错误时,添加--nogpgcheck可解决此次安装问题,如需永久解决,给对应仓库加gpgkey或修改gpgcheck为0. warning: rpmts_HdrFromFdno: Header V3 RSA/SHA256 Signature, key ID 0608b895: NOKEY Public key for ibus-table-chinese-cangjie-1.4.6-1.el6.noarch.rpm is not installed 查询: list [...] yum list available [glob_exp1] [...] #查询仓库中能安装的程序包 yum list updates [glob_exp1] [...] #查询仓库中能更新的程序包 yum list installed [glob_exp1] [...] #查询仓库已经安装的程序包 yum list extras [glob_exp1] [...] #查询安装在系统但不在仓库中的程序包 yum list obsoletes [glob_exp1] [...] #查询已安装程序包的旧版本 info [...] #查询程序包的信息 provides | whatprovides feature1 [feature2] [...] #根据特性查询由何程序包提供(特性也可是文件) search string1 [string2] [...] #根据指定strings查询程序包的names and summaries deplist package1 [package2] [...] #查询此程序包的所有依赖关系 repolist [all|enabled|disabled] #查询或生成配置的仓库列表 history [info|list|packages-list|packages-info|summary|addon-info|redo|undo|roll-back|new|sync|stats]
#查询用户执行yum历史记录 [root@centos ~]# yum list available|head ///列出可使用程序包 Loaded plugins: fastestmirror, refresh-packagekit, security Loading mirror speeds from cached hostfile Available Packages 2048-cli.x86_64 0.9.1-1.el6 epel_1 2048-cli-nocurses.x86_64 0.9.1-1.el6 epel_1 2ping.noarch 3.2.1-2.el6 epel_1 389-admin.i686 1.1.35-1.el6 epel_1 389-admin.x86_64 1.1.35-1.el6 epel_1 389-admin-console.noarch 1.1.8-1.el6 epel_1 389-admin-console-doc.noarch 1.1.8-1.el6 epel_1
[root@centos ~]# yum list httpd* ///列出以httpd开头的所有程序包 Loaded plugins: fastestmirror, refresh-packagekit, security Loading mirror speeds from cached hostfile Installed Packages <--已经安装的包 httpd-tools.x86_64 2.2.15-29.el6.centos @centos Available Packages <--可安装的包 httpd.x86_64 2.2.15-29.el6.centos local_1 httpd-devel.i686 2.2.15-29.el6.centos local_1 ...
*** yum whatprovides "*/COMMAND" 可以用来查询输入命令由哪个程序包生成 [root@centos ~]# yum whatprovides "*/createrepo" Loaded plugins: fastestmirror, refresh-packagekit, security Loading mirror speeds from cached hostfile createrepo-0.9.9-18.el6.noarch : Creates a common metadata repository <--此处为程序包名 Repo : local_1 Matched from: Filename : /usr/share/createrepo Filename : /usr/bin/createrepo Filename : /usr/lib/python2.6/site-packages/createrepo
[root@centos ~]# yum deplist httpd ///查询httpd程序包的依赖于哪些软件 Loaded plugins: fastestmirror, refresh-packagekit, security Loading mirror speeds from cached hostfile Finding dependencies: package: httpd.x86_64 2.2.15-29.el6.centos dependency: /usr/sbin/useradd <--依赖的文件 provider: shadow-utils.x86_64 2:4.1.4.2-13.el6 <--提供依赖文件的程序包 dependency: libz.so.1()(64bit) provider: zlib.x86_64 1.2.3-29.el6 dependency: system-logos >= 7.92.1-1 provider: redhat-logos.noarch 60.0.14-12.el6.centos ...
[root@centos ~]# yum history ///显示用户使用yum的操作历史,查询不算在此 Loaded plugins: fastestmirror, refresh-packagekit, security ID | Login user | Date and time | Action(s) | Altered ------------------------------------------------------------------------------- 5 | root <root> | 2016-12-07 14:06 | Install | 1 4 | root <root> | 2016-12-05 01:11 | Install | 4 3 | root <root> | 2016-11-29 18:59 | Install | 1 history list [root@centos ~]# yum history info 3 ///查看历史操作详细信息 Loaded plugins: fastestmirror, refresh-packagekit, security Transaction ID : 3 Begin time : Tue Nov 29 18:59:51 2016 Begin rpmdb : 958:baaf47e48562c6ec3caea4724ad15a93040cea94 End time : 18:59:52 2016 (1 seconds) End rpmdb : 959:6a212fd01507b473b7b2abbf09e8cf98281e3411 User : root <root> Return-Code : Success Command Line : install tree -y ///使用的命令 Transaction performed with: Installed rpm-4.8.0-37.el6.x86_64 @anaconda-CentOS-201311272149.x86_64/6.5 Installed yum-3.2.29-40.el6.centos.noarch @anaconda-CentOS-201311272149.x86_64/6.5 Installed yum-plugin-fastestmirror-1.1.30-14.el6.noarch @anaconda-CentOS-201311272149.x86_64/6.5 Packages Altered: Install tree-1.5.3-2.el6.x86_64 @centos history info
[root@centos ~]# yum repolist all ///显示配置好的仓库信息,如需缓存,自动下载 Loaded plugins: fastestmirror, refresh-packagekit, security Loading mirror speeds from cached hostfile repo id repo name status local_1 local iso enabled: 6,367 epel_1 epel source enabled: 12,199 repolist: 18,566
缓存: clean [ packages | metadata | expire-cache | rpmdb | plugins | all ] #清楚各种各样由yum产生的缓存 makecache #下载可以使用的仓库的元数据文件 [root@centos ~]# yum clean all ///清除所有缓存 Loaded plugins: fastestmirror, refresh-packagekit, security Cleaning repos: local_1 epel_1 Cleaning up Everything Cleaning up list of fastest mirrors [root@centos ~]# yum makecache ///生成缓存,下载或加载元数据 Loaded plugins: fastestmirror, refresh-packagekit, security Determining fastest mirrors local_1 | 4.0 kB 00:00 ... local_1/group_gz | 220 kB 00:00 ... local_1/filelists_db | 5.8 MB 00:00 ... local_1/primary_db | 4.4 MB 00:00 ... local_1/other_db | 2.7 MB 00:00 ... epel_1 | 4.3 kB 00:00 epel_1/filelists_db | 7.8 MB 00:07 epel_1/primary_db | 5.9 MB 00:05 epel_1/other_db | 2.9 MB 00:02 Metadata Cache Created 检查: check #检查本地rpmdb和提供的一些信息 包组command: groupinstall group1 [group2] [...] #包组安装 groupupdate group1 [group2] [...] #包组更新 grouplist [hidden] [groupwildcard] [...] #显示包组信息(使用hidden选项,显示所有被隐藏的包组) groupremove group1 [group2] [...] #卸载包组 groupinfo group1 [...] #查询包组信息 安装CentOS6的开发组件: # yum groupinstall "Development tools" "Server Platform Development" -y
yum中常见问题:
解决没有repodata目录的方法 1 使用createrepo命令创建 createrepo [options] <directory> -c --cachedir <path> 指定需要缓存的rpm包路径 2 将rpm包复制到能正常使用仓库的Package目录中,重新生成元数据文件 # yum clean all; yum makecache 3 将其它能正常配置的仓库中的repodata目录中文件复制一份
当用yum卸载程序包时,会出现此类错误 Error: Trying to remove "yum", which is protected 其原因为: 此类包要卸载的依赖项有yum自身的文件或是正在被yum所使用 解决办法: 忽略依赖关系进行单独卸载其提示的包.
本地镜像DVD1跟DVD2是什么: CentOS-6.8-x86_64-bin-DVD1.iso CentOS-6.8-x86_64-bin-DVD2.iso 由于一个光盘最多只能刻制4G左右大小,而centos的仓库包有十分的多,因此将常用的包以及安装系统的包放在DVD1中,DVD2中的包算是扩展包.
当执行yum命令时出现以下报错,代表yum被其他进程所占用,需要等待其它执行中的yum命令完成. Existing lock /var/run/yum.pid: another copy is running as pid 2000. Another app is currently holding the yum lock; waiting for it to exit...
当遇到如下问题: 其原因: 仓库的包太旧,安装的软件包版本太低 解决办法: 更新仓库或者卸载新版本的包,再继续安装此包
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