步骤 1：外网机器安装必备工具
联网安装同步工具和元数据生成工具
yum install -y yum-utils createrepo rsync
步骤 2：配置外网同步源（x86_64 + ARM 双架构）
创建两个 repo 文件，分别对应 x86_64 核心源和 aarch64 AltArch 源：
（1）配置 x86_64 架构阿里云源
bash
运行
cat > /etc/yum.repos.d/aliyun-centos7-x86_64.repo << 'EOF'
base-x86_64
name=CentOS-7 Base x86_64 - Aliyun
baseurl=https://mirrors.aliyun.com/centos/7/os/x86_64/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
updates-x86_64
name=CentOS-7 Updates x86_64 - Aliyun
baseurl=https://mirrors.aliyun.com/centos/7/updates/x86_64/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
extras-x86_64
name=CentOS-7 Extras x86_64 - Aliyun
baseurl=https://mirrors.aliyun.com/centos/7/extras/x86_64/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
epel-x86_64
name=EPEL-7 x86_64 - Aliyun
baseurl=https://mirrors.aliyun.com/epel/7/x86_64/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/epel/RPM-GPG-KEY-EPEL-7
EOF
（2）配置 aarch64（ARM）架构阿里云 AltArch 源
bash
运行
cat > /etc/yum.repos.d/aliyun-centos7-aarch64.repo << 'EOF'
base-aarch64
name=CentOS-7 Base aarch64 - Aliyun AltArch
baseurl=https://mirrors.aliyun.com/centos-altarch/7/os/aarch64/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos-altarch/RPM-GPG-KEY-CentOS-7
updates-aarch64
name=CentOS-7 Updates aarch64 - Aliyun AltArch
baseurl=https://mirrors.aliyun.com/centos-altarch/7/updates/aarch64/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos-altarch/RPM-GPG-KEY-CentOS-7
extras-aarch64
name=CentOS-7 Extras aarch64 - Aliyun AltArch
baseurl=https://mirrors.aliyun.com/centos-altarch/7/extras/aarch64/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos-altarch/RPM-GPG-KEY-CentOS-7
epel-aarch64
name=EPEL-7 aarch64 - Aliyun
baseurl=https://mirrors.aliyun.com/epel/7/aarch64/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/epel/RPM-GPG-KEY-EPEL-7
EOF
步骤 3：创建合并仓库目录结构（核心！）
按 "仓库类型→os→架构" 层级组织，确保双架构目录分离：
bash
运行
统一仓库根目录（后续拷贝到U盘）
mkdir -p /root/centos7-unified-repo
为每个仓库类型（base/updates/extras/epel）创建双架构目录
for repo in base updates extras epel; do
mkdir -p /root/centos7-unified-repo/${repo}/os/{x86_64,aarch64}
done
最终目录结构（关键，不能乱）：
plaintext
centos7-unified-repo/
├─ base/os/
│ ├─ x86_64/ # x86_64架构base包
│ └─ aarch64/ # ARM架构base包
├─ updates/os/
│ ├─ x86_64/
│ └─ aarch64/
├─ extras/os/
│ ├─ x86_64/
│ └─ aarch64/
└─ epel/os/
├─ x86_64/
└─ aarch64/
步骤 4：同步 x86_64 架构包到对应目录（目录要一一对应）
bash
运行
同步x86_64的base仓库（-r指定repo ID，-p指定目标目录，-m保留元数据）
reposync -r base-x86_64 -p /root/centos7-unified-repo/base/os/ -m --arch=x86_64
同步x86_64的updates仓库
reposync -r updates-x86_64 -p /root/centos7-unified-repo/updates/os/ -m --arch=x86_64
同步x86_64的extras仓库
reposync -r extras-x86_64 -p /root/centos7-unified-repo/extras/os/ -m --arch=x86_64
同步x86_64的epel仓库
reposync -r epel-x86_64 -p /root/centos7-unified-repo/epel/os/ -m --arch=x86_64
首次同步约 20-25GB，耗时 1-2 小时（取决于网速）。
步骤 5：同步 aarch64（ARM）架构包到对应目录
bash
运行
同步ARM的base仓库（--arch指定aarch64架构）
reposync -r base-aarch64 -p /root/centos7-unified-repo/base/os/ -m --arch=aarch64
同步ARM的updates仓库
reposync -r updates-aarch64 -p /root/centos7-unified-repo/updates/os/ -m --arch=aarch64
同步ARM的extras仓库
reposync -r extras-aarch64 -p /root/centos7-unified-repo/extras/os/ -m --arch=aarch64
同步ARM的epel仓库（可选，包较少）
reposync -r epel-aarch64 -p /root/centos7-unified-repo/epel/os/ -m --arch=aarch64
ARM 架构总大小约 5-8GB，同步时间 30 分钟 - 1 小时。
步骤 6：为双架构分别生成元数据（必须！）一定要在外网生成，内网生成会报错
元数据是 yum 识别包的关键，需按架构单独生成，不能共用：
bash
运行
生成x86_64架构元数据（每个目录单独执行）
createrepo --update /root/centos7-unified-repo/base/os/x86_64/
createrepo --update /root/centos7-unified-repo/updates/os/x86_64/
createrepo --update /root/centos7-unified-repo/extras/os/x86_64/
createrepo --update /root/centos7-unified-repo/epel/os/x86_64/
生成aarch64架构元数据
createrepo --update /root/centos7-unified-repo/base/os/aarch64/
createrepo --update /root/centos7-unified-repo/updates/os/aarch64/
createrepo --update /root/centos7-unified-repo/extras/os/aarch64/
createrepo --update /root/centos7-unified-repo/epel/os/aarch64/
每个架构目录下会生成 repodata 文件夹，包含包索引和依赖信息。
步骤7：将centos7-unified-repo完整打包，传输到内网，可以用下面方法快速解压和切割
1. 使用 tar + pigz 进行并行压缩（推荐，速度快，支持多核）
tar -cf - /path/to/large/directory | pigz -p 8 > /backup/large_dir.tar.gz
2. 若需分卷（避免单文件过大，便于传输/存储）
tar -cf - /path/to/large/directory | pigz -p 8 | split -b 10G - /backup/large_dir.tar.gz.part_
步骤8:内网解压，通过nginx搭建centos7访问源
3. 恢复时合并并解压
cat /backup/large_dir.tar.gz.part_* | pigz -d | tar -xf -
nginx配置：百度一下就行
其他服务器yum配置：/etc/yum.repos.d/centos7.repo
local-centos7-base
name=Unified CentOS 7 Base ($basearch)
baseurl=http://192.168.1.1:8888/centos7/base/os/$basearch/
gpgcheck=0
gpgkey=http://192.168.1.1:8888/centos7/base/os/x86_64/RPM-GPG-KEY-CentOS-7
enabled=1
local-centos7-updates
name=Unified CentOS 7 Updates ($basearch)
baseurl=http://192.168.1.1:8888/centos7/updates/os/$basearch/
gpgcheck=0
gpgkey=http://192.168.1.1:8888/centos7/base/os/x86_64/RPM-GPG-KEY-CentOS-7
enabled=1
local-centos7-extras
name=Unified CentOS 7 Extras ($basearch)
baseurl=http://192.168.1.1:8888/centos7/extras/os/$basearch/
gpgcheck=0
gpgkey=http://192.168.1.1:8888/centos7/base/os/x86_64/RPM-GPG-KEY-CentOS-7
enabled=1
local-centos7-epel
name=Unified CentOS 7 EPEL ($basearch)
baseurl=http://192.168.1.1:8888/centos7/epel/os/$basearch/
gpgcheck=0
gpgkey=http://192.168.1.1:8888/centos7/epel/os/$basearch/RPM-GPG-KEY-EPEL-7
enabled=1