How to Build a Local YUM Repository on CentOS: Scripts, ISO Mount, and Network Sharing

Method 1: Create a Local YUM Repository with a Bash Script

The script first checks whether the installation DVD is already mounted. If it is, the DVD is mounted at /mnt; otherwise, the script prints a prompt to mount the disc and exits with code 2.

It then changes to /etc/yum.repos.d/ and checks whether a directory named a exists. If the directory exists, the script reports that the file already exists; if not, it creates the directory.

All files beginning with Cent* are moved into the a directory, and a new repository file a.repo is created with the following content:

[base]
name=a
baseurl=file:///mnt
gpgcheck=0

The script runs yum clean all and yum makecache to clear and rebuild the YUM cache. If both commands succeed (exit code 0), it prints a success message.

#!/bin/bash
mount | grep sr0 > /dev/null
if [ $? -eq 0 ]; then
  mount /dev/cdrom /mnt > /dev/null
else
  echo "请挂载光盘！"
  exit 2
fi
cd /etc/yum.repos.d/
if [ -e a ]; then
  echo "文件已经存在"
else
  mkdir a
fi
mv Cent* a > /dev/null
cat << EOR >> a.repo
[base]
name=a
baseurl=file:///mnt
gpgcheck=0
EOR
yum clean all
yum makecache
if [ $? -eq 0 ]; then
  echo "本地yum仓库已经创建完成！"
fi

Method 2: Build a Local YUM Repository by Mounting an ISO Image

Upload the CentOS DVD ISO (e.g., CentOS-7-x86_64-DVD-1611.iso) to /opt. Create a mount point and mount the ISO:

mkdir /mnt/centos7.5
mount /opt/CentOS-7-x86_64-DVD-1611.iso /mnt/centos7.5

Backup existing repository files:

mv /etc/yum.repos.d/*.repo /etc/yum.repos.d/bak

Create a new repository file CentOS.Base.repo with the following content:

[centos7.5]
name=centos7.5
baseurl=file:///mnt/centos7.5
enabled=1
gpgcheck=0
gpgkey=file:///mnt/centos7.5/RPM-GPG-KEY-CentOS-7

Refresh the cache:

yum clean all
yum repolist

Method 3: Use the Official Aliyun YUM Mirror

Replace the existing repository files with the Aliyun mirror configuration. First, back up current .repo files:

mkdir bak
mv *.repo bak

Download the Aliyun base repository and the EPEL repository:

wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo

Verify the files exist and optionally install additional utilities such as cowsay:

yum -y install cowsay

Method 4: Share a Local YUM Repository Over a LAN

Install and start an HTTP server (e.g., httpd) on the machine that holds the mounted ISO:

yum install -y httpd
systemctl start httpd
systemctl stop firewalld

Mount the ISO to a directory served by the web server:

mount /opt/CentOS-7.5-1804.iso /var/www/html/CentOS7.5/

On client machines, create a repository file pointing to the server’s address:

vim /etc/yum.repos.d/CentOS-Base.repo

[local]
name=net_bendiyum
baseurl=http://192.168.1.8/CentOS7.5/
enabled=1
gpgcheck=0

Run yum clean all and yum makecache on the client to refresh metadata.

References

Aliyun official YUM source: https://developer.aliyun.com/article/675241