How to Replace YUM Repositories with Domestic Mirrors on CentOS 7

YUM (Yellowdog Updater Modified) is the package manager for CentOS. Its default repository servers are located abroad, which often leads to slow download speeds, connection timeouts, and outdated package versions for users in China.

Download speed is very slow (tens of KB/s).

Connection timeout errors (e.g., "Could not resolve host").

Package versions lag behind.

Recommended domestic mirrors:

Mirror Name

Features

Suitable Scenarios

Alibaba Cloud

Many nodes, fast updates

Production environments (preferred)

NetEase 163

Complete historical versions

Compatibility with legacy projects

Tencent Cloud

Dedicated line optimization, low latency

Games / real‑time applications

Huawei Cloud

Enterprise‑grade security hardening

Finance / government projects

Preparation

Connect to the CentOS 7 server using tools such as Xshell or FinalShell.

Install basic download tools.

yum install -y wget curl vim  # three essential tools: download + edit

Four Steps to Replace YUM Repositories (Alibaba Cloud example)

Step 1: Backup original configuration

cd /etc/yum.repos.d/      # enter config directory
mkdir backup               # create backup folder
mv *.repo backup/          # move all .repo files to backup

Step 2: Download new repository file

# Download Alibaba Cloud CentOS 7 repo
curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-7.repo

Step 3: Fix the version number

sed -i 's/\$releasever/7/g' /etc/yum.repos.d/CentOS-Base.repo  # force version 7

Step 4: Refresh the cache

yum clean all      # clear old cache
yum makecache      # generate new cache

Verification

yum update -y      # test system update

If you see a message like Complete! 已更新XXX个软件包 , the replacement was successful.

Common Issues

❌ Issue 1: Cannot connect to the mirror

ping mirrors.aliyun.com      # test network connectivity
vi /etc/resolv.conf          # add DNS, e.g., nameserver 8.8.8.8

❌ Issue 2: No valid baseurl

Check the baseurl in the .repo file and ensure the CentOS version is set to 7.

💡 Alternative mirror

wget http://mirrors.163.com/.help/CentOS7-Base-163.repo

Principle Explanation

YUM workflow: .repo configuration → check repository URL → download metadata → install/update packages.

Why change the version number? After CentOS 8 reached end‑of‑life, mirrors must explicitly specify version 7 to avoid automatic mismatches.

Advanced Tips

Use multiple mirrors simultaneously

# Add EPEL repository (recommended)
yum install -y epel-release
sed -i 's|^#baseurl|baseurl|' /etc/yum.repos.d/epel.repo  # uncomment baseurl

Restore original configuration

mv backup/*.repo /etc/yum.repos.d/  # move backup files back

Precautions

⚠️ Always back up before modifying production servers.

⚠️ Do not enable multiple base sources at the same time to avoid conflicts.

⚠️ If you encounter GPG key errors, you can temporarily disable verification with gpgcheck=0 .

By switching to domestic mirrors, your CentOS 7 server will enjoy faster download speeds and more stable updates.