yum簡介
Yum(全稱為 Yellow dog Updater, Modified)是一個在Fedora和RedHat以及CentOS中的Shell前端軟件包管理器。基於RPM包管理，能夠從指定的服務器自動下載RPM包並且安裝，可以自動處理依賴性關系，並且一次安裝所有依賴的軟件包，無須繁瑣地一次次下載、安裝。
借助於YUM軟件倉庫，可以完成安裝、卸載、自動升級rpm軟件包等任務，能夠自動查找並解決rpm包之間的依賴關系，而無需管理員，手工去安裝每個rpm包，使管理員在維護大量Linux服務器時更加輕松自如。特別是擁有大量Linux主機的本地網絡中，構建一台源服務器可以大大緩解軟件安裝、升級等對lnterner的依賴。
yum服務器搭建
yum服務器概述
yum軟件倉庫通常借助HTTP或FTP協議來進行發布，這樣可以面向網絡中的所有客戶機提供軟件源服務。為了便於客戶機查詢軟件包，獲取依賴關系等信息，在軟件倉庫中需要提供倉庫數據(Repodata)，其中收集了目錄下所有rpm包的頭部信息。
准備網絡安裝源(服務器端)
(1)准備軟件倉庫目錄
光盤中的軟件包拷貝CentOS6.5第一張光盤內容到本地FTP服務器匿名訪問用戶的根目錄下
[root@localhost ~]# cd /var/ftp/
[root@localhost ftp]# mkdir centos6
[root@localhost ftp]# cp -rf /media/CentOS_6.5_Final/* /var/ftp/centos6/ &
[1] 45717
[root@localhost ftp]# jobs
[1]+ Done cp -i -rf /media/CentOS_6.5_Final/* /var/ftp/centos6/
[root@localhost ksh]# cp /media/CentOS_6.5_Final/Packages/ksh-20120801-10.el6.x86_64.rpm /var/ftp/ksh/
[root@localhost ksh]# cp /media/CentOS_6.5_Final/Packages/mksh-39-7.el6_4.1.x86_64.rpm /var/ftp/ksh/
[root@localhost ksh]# ls
ksh-20120801-10.el6.x86_64.rpm mksh-39-7.el6_4.1.x86_64.rpm
未安裝createrepo包需要先安裝
[root@localhost ksh]# yum -y install createrepo
[root@localhost ksh]# createrepo -v ./
Spawning worker 0 with 2 pkgs
Worker 0: reading ksh-20120801-10.el6.x86_64.rpm
Worker 0: reading mksh-39-7.el6_4.1.x86_64.rpm
Workers Finished
Gathering worker results
Saving Primary metadata
Saving file lists metadata
Saving other metadata
Generating sqlite DBs
Starting other db creation: Thu May 31 18:20:51 2018
Ending other db creation: Thu May 31 18:20:51 2018
Starting filelists db creation: Thu May 31 18:20:51 2018
Ending filelists db creation: Thu May 31 18:20:51 2018
Starting primary db creation: Thu May 31 18:20:51 2018
Ending primary db creation: Thu May 31 18:20:51 2018
Sqlite DBs complete
[root@localhost ksh]# ls
ksh-20120801-10.el6.x86_64.rpm mksh-39-7.el6_4.1.x86_64.rpm repodata
安裝並啟動vsftpd服務(詳見FTP服務內容)
[root@localhost ksh]# service vsftpd restart
關閉 vsftpd： [確定]
為 vsftpd 啟動 vsftpd： [確定]
[root@localhost ksh]# chkconfig vsftpd on
[root@localhost ksh]# chkconfig vsftpd --list
vsftpd 0:關閉 1:關閉 2:啟用 3:啟用 4:啟用 5:啟用 6:關閉
配置yum軟件倉庫位置(客戶機端)
典型倉庫配置
內網YUM源
[root@n2 ~]# cd /etc/yum.repos.d/
[root@n2 yum.repos.d]# ls
CentOS-Base.repo CentOS-Debuginfo.repo CentOS-Media.repo CentOS-Vault.repo
[root@n2 yum.repos.d]# mkdir bak
[root@n2 yum.repos.d]# mv *o ./bak/
[root@n2 yum.repos.d]# ls
bak
[root@n2 yum.repos.d]# vim amber.repo
[yum]
name=centos 6.5
baseurl=ftp://192.168.28.128/centos6/
gpgcheck=0
enabled=1
[ksh]
name=ksh
baseurl=ftp://192.168.28.128/ksh/
gpgcheck=0
enabled=1
~
[root@n2 ~]# yum -y clean all
Loaded plugins: fastestmirror, refresh-packagekit, security
Cleaning repos: ksh yum
Cleaning up Everything
Cleaning up list of fastest mirrors
[root@n2 ~]# yum makecache
Loaded plugins: fastestmirror, refresh-packagekit, security
Determining fastest mirrors
ksh | 2.9 kB 00:00
ksh/filelists_db | 1.1 kB 00:00
ksh/primary_db | 3.3 kB 00:00
ksh/other_db | 2.2 kB 00:00
yum | 4.0 kB 00:00
yum/group_gz | 220 kB 00:00
yum/filelists_db | 5.8 MB 00:00
yum/primary_db | 4.4 MB 00:00
yum/other_db | 2.7 MB 00:00
Metadata Cache Created
查看yum緩存是否生成
[root@n2 ~]# ls /var/cache/yum/x86_64/6/
base extras ksh timedhosts.txt updates yum
[root@n2 ~]# ls /var/cache/yum/x86_64/6/yum/
0dafccfdbf892f02acca8267ade4bdcee7280a682e65dc7e29145f3341fd7a8c-primary.sqlite
594d4bb4a79ed01d66635adbcf76c45ca4a85b30fc3e3c3c28316e64f0a83f21-filelists.sqlite
ca525c73086186bfcb81ad9edd45796026dac7e4e50524e0f2daf901532aaf66-c6-x86_64-comps.xml.gz
cachecookie
fdd542ef36b0cde54ee0521fae90b98911db06483163aa1c049995b6d109349b-other.sqlite
gen
packages
repomd.xml
[root@n2 ~]# ls /var/cache/yum/x86_64/6/ksh
046862454d1aa798eb72c70668a54e25905c276a613fd0cc15abdf13fc20d6de-filelists.sqlite
38c945c0799d8cfb481c6145b8c227b1f2ef91100f3b7bc8cad97645594f4643-primary.sqlite
cachecookie
fe7ae063ad2b6e2c4bcdbc676581ac33eb74c0645132fb0c4bac78f24300ffb5-other.sqlite
packages
repomd.xml
測試
[root@n2 ~]# yum -y install dhcp
Loaded plugins: fastestmirror, refresh-packagekit, security
Loading mirror speeds from cached hostfile
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package dhcp.x86_64 12:4.1.1-38.P1.el6.centos will be installed
--> Finished Dependency Resolution
Dependencies Resolved
========================================================================================================================================================
Package Arch Version Repository Size
========================================================================================================================================================
Installing:
dhcp x86_64 12:4.1.1-38.P1.el6.centos yum 817 k
Transaction Summary
========================================================================================================================================================
Install 1 Package(s)
Total download size: 817 k
Installed size: 1.9 M
Downloading Packages:
dhcp-4.1.1-38.P1.el6.centos.x86_64.rpm | 817 kB 00:00
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Warning: RPMDB altered outside of yum.
Installing : 12:dhcp-4.1.1-38.P1.el6.centos.x86_64 1/1
Verifying : 12:dhcp-4.1.1-38.P1.el6.centos.x86_64 1/1
Installed:
dhcp.x86_64 12:4.1.1-38.P1.el6.centos
Complete!
注意;因為ksh包在光盤中存在，所以需先修改repo文件后重建yum緩存再進行安裝測試，否則安裝的是光盤中的包。