CentOS 7.6 配置yum源（本地yum源和阿里云yum源）

本文主要介绍了Linux系统运维操作，包括使用ping命令检查网络连通性，切换到指定目录查看配置文件，备份配置文件，修改镜像路径，清理和生成yum缓存，以及使用本地镜像配置yum源并测试安装httpd服务等内容。

1 查看网络是否通
[root@os7-client01 ~]# ping -c 3 baidu.com
PING baidu.com (39.156.66.10) 56(84) bytes of data.
64 bytes from 39.156.66.10 (39.156.66.10): icmp_seq=1 ttl=128 time=109 ms
64 bytes from 39.156.66.10 (39.156.66.10): icmp_seq=2 ttl=128 time=91.9 ms
64 bytes from 39.156.66.10 (39.156.66.10): icmp_seq=3 ttl=128 time=82.8 ms

--- baidu.com ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 82.813/94.802/109.673/11.153 ms
[root@os7-client01 ~]#

2 切换到/etc/yum.repos.d/
[root@os7-client01 ~]# cd /etc/yum.repos.d/

3 查看CentOS-Base.repo
[root@os7-client01 yum.repos.d]# cat CentOS-Base.repo
# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client. You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the
# remarked out baseurl= line instead.
#
#

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

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

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

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

（重点）4 备份配置文件
[root@os7-client01 yum.repos.d]# cp -a CentOS-Base.repo CentOS-Base.repo.0804-bak
5 注释镜像获取路径
[root@os7-client01 yum.repos.d]# sed -i 's/mirrorlis/#mirrorlis/g' CentOS-Base.repo
6 取消基础路径的注释
[root@os7-client01 yum.repos.d]# sed -i 's/#baseurl/baseurl/g' CentOS-Base.repo
7 插入阿里云镜像路径
[root@os7-client01 yum.repos.d]# sed -i 's#http://mirror.centos.org/centos/#https://mirrors.aliyun.com/centos/#g' CentOS-Base.repo
8 清除缓存
[root@os7-client01 yum.repos.d]# yum clean all
Loaded plugins: fastestmirror
Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast
Cleaning repos: base extras updates
Cleaning up list of fastest mirrors
9 生成新的缓存
[root@os7-client01 yum.repos.d]# yum makecache
Loaded plugins: fastestmirror
Determining fastest mirrors
base | 3.6 kB 00:00:00
extras | 2.9 kB 00:00:00
updates | 2.9 kB 00:00:00
(1/10): base/7/x86_64/group_gz | 153 kB 00:00:01
(2/10): base/7/x86_64/primary_db | 6.1 MB 00:00:09
(3/10): base/7/x86_64/filelists_db | 7.2 MB 00:00:11
(4/10): extras/7/x86_64/filelists_db | 303 kB 00:00:01
(5/10): extras/7/x86_64/primary_db | 250 kB 00:00:01
(6/10): extras/7/x86_64/other_db | 150 kB 00:00:00
(7/10): base/7/x86_64/other_db | 2.6 MB 00:00:03
(8/10): updates/7/x86_64/filelists_db | 12 MB 00:00:15
(9/10): updates/7/x86_64/other_db | 1.4 MB 00:00:01
(10/10): updates/7/x86_64/primary_db | 22 MB 00:00:24
Metadata Cache Created

二、centos7.6配置yum本地源

1 挂载iso镜像到centos7.6系统上，在虚拟机设置中启用已连接、启动时链接，使用iso映像文件选择iso镜像在本地电脑位置。

2 挂载/dev/cdrom到/mnt/cdrom
[root@os-server ~]# mkdir -p /mnt/cdrom
[root@os-server ~]# mount /dev/cdrom /mnt/cdrom/
mount: /dev/sr0 is write-protected, mounting read-only
[root@os-server ~]# ls /mnt/cdrom
CentOS_BuildTag EULA images LiveOS repodata RPM-GPG-KEY-CentOS-Testing-7
EFI GPL isolinux Packages RPM-GPG-KEY-CentOS-7 TRANS.TBL

3 备份已有的yum配置文件
[root@os-server ~]# mkdir -p /etc/yum$(date "+%F")backups
[root@os-server ~]# cp -a /etc/yum.repos.d/* /etc/yum2023-08-05backups/
[root@os-server ~]# cd /etc/yum.repos.d/
[root@os-server yum.repos.d]# ls
CentOS-Base.repo CentOS-Debuginfo.repo CentOS-Media.repo CentOS-Vault.repo
CentOS-CR.repo CentOS-fasttrack.repo CentOS-Sources.repo CentOS-x86_64-kernel.repo
[root@os-server yum.repos.d]# mv CentOS-Base.repo CentOS-Base.repo.bak

4 测试yum命令失败
[root@os-server yum.repos.d]# yum install http
Loaded plugins: fastestmirror
Determining fastest mirrors
There are no enabled repos.
Run "yum repolist all" to see the repos you have.
To enable Red Hat Subscription Management repositories:
subscription-manager repos --enable <repo>
To enable custom repositories:
yum-config-manager --enable <repo>

5 配置yum本地源
[root@os-server yum.repos.d]# vim local.repo
[root@os-server yum.repos.d]# cat local.repo
[LocaleBaseOS]
name=LocaleBaseOS
baseurl=file:///mnt/cdrom
enabled=1
gpgcheck=0

6 清理已有的缓存
[root@os-server yum.repos.d]# yum clean all
Loaded plugins: fastestmirror
Cleaning repos: LocaleBaseOS
Cleaning up list of fastest mirrors
Other repos take up 180 M of disk space (use --verbose for details)

7 生成新的yum缓存
[root@os-server yum.repos.d]# yum makecacke
Loaded plugins: fastestmirror
No such command: makecacke. Please use /usr/bin/yum --help
[root@os-server yum.repos.d]# yum makecache
Loaded plugins: fastestmirror
Determining fastest mirrors
LocaleBaseOS | 3.6 kB 00:00:00
(1/4): LocaleBaseOS/group_gz | 153 kB 00:00:00
(2/4): LocaleBaseOS/filelists_db | 3.3 MB 00:00:01
(3/4): LocaleBaseOS/primary_db | 3.3 MB 00:00:01
(4/4): LocaleBaseOS/other_db | 1.3 MB 00:00:00
Metadata Cache Created
[root@os-server yum.repos.d]# cat local.repo
[LocaleBaseOS]
name=LocaleBaseOS
baseurl=file:///mnt/cdrom
enabled=1
gpgcheck=0

8 测试，安装httpd服务
[root@os-server yum.repos.d]# yum install http -y
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
No package http available.
Error: Nothing to do
[root@os-server yum.repos.d]# yum install httpd
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Resolving Dependencies
--> Running transaction check
---> Package httpd.x86_64 0:2.4.6-95.el7.centos will be installed
--> Processing Dependency: httpd-tools = 2.4.6-95.el7.centos for package: httpd-2.4.6-95.el7.centos.x86_64
--> Processing Dependency: /etc/mime.types for package: httpd-2.4.6-95.el7.centos.x86_64
--> Processing Dependency: libaprutil-1.so.0()(64bit) for package: httpd-2.4.6-95.el7.centos.x86_64
--> Processing Dependency: libapr-1.so.0()(64bit) for package: httpd-2.4.6-95.el7.centos.x86_64
--> Running transaction check
---> Package apr.x86_64 0:1.4.8-7.el7 will be installed
---> Package apr-util.x86_64 0:1.5.2-6.el7 will be installed
---> Package httpd-tools.x86_64 0:2.4.6-95.el7.centos will be installed
---> Package mailcap.noarch 0:2.1.41-2.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

================================================================================================
Package Arch Version Repository Size
================================================================================================
Installing:
httpd x86_64 2.4.6-95.el7.centos LocaleBaseOS 2.7 M
Installing for dependencies:
apr x86_64 1.4.8-7.el7 LocaleBaseOS 104 k
apr-util x86_64 1.5.2-6.el7 LocaleBaseOS 92 k
httpd-tools x86_64 2.4.6-95.el7.centos LocaleBaseOS 93 k
mailcap noarch 2.1.41-2.el7 LocaleBaseOS 31 k

Transaction Summary
================================================================================================
Install 1 Package (+4 Dependent packages)

Total download size: 3.0 M
Installed size: 10 M
Is this ok [y/d/N]: y
Downloading packages:
------------------------------------------------------------------------------------------------
Total 287 kB/s | 3.0 MB 00:00:10
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : apr-1.4.8-7.el7.x86_64 1/5
Installing : apr-util-1.5.2-6.el7.x86_64 2/5
Installing : httpd-tools-2.4.6-95.el7.centos.x86_64 3/5
Installing : mailcap-2.1.41-2.el7.noarch 4/5
Installing : httpd-2.4.6-95.el7.centos.x86_64 5/5
Verifying : httpd-tools-2.4.6-95.el7.centos.x86_64 1/5
Verifying : mailcap-2.1.41-2.el7.noarch 2/5
Verifying : apr-1.4.8-7.el7.x86_64 3/5
Verifying : httpd-2.4.6-95.el7.centos.x86_64 4/5
Verifying : apr-util-1.5.2-6.el7.x86_64 5/5