19.6. 使用 Buildah 从头开始创建镜像

1. 创建一个空容器：

   # buildah from scratch
   working-container

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2. 挂载 working-container 容器，并将挂载点路径保存到 scratchmnt 变量中：

   # scratchmnt=$(buildah mount working-container)
   
   
   # echo $scratchmnt
   /var/lib/containers/storage/overlay/be2eaecf9f74b6acfe4d0017dd5534fde06b2fa8de9ed875691f6ccc791c1836/merged

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3. 在全新镜像中初始化 RPM 数据库，并添加 redhat-release 软件包：

   # dnf install -y --releasever=8 --installroot=$scratchmnt redhat-release

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4. 将 httpd 服务安装到 scratch 目录中：

   # dnf install -y --setopt=reposdir=/etc/yum.repos.d \
         --installroot=$scratchmnt \
         --setopt=cachedir=/var/cache/dnf httpd

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5. 创建 $scratchmnt/var/www/html/index.html 文件：

   # mkdir -p $scratchmnt/var/www/html
   # echo "Your httpd container from scratch works!" > $scratchmnt/var/www/html/index.html

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6. 配置 working-container 以直接从容器运行 httpd 守护进程：

   # buildah config --cmd "/usr/sbin/httpd -DFOREGROUND" working-container
   # buildah config --port 80/tcp working-container
   # buildah commit working-container localhost/myhttpd:latest

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验证

1. 列出本地存储中的所有镜像：

   # podman images
   REPOSITORY                                 TAG     IMAGE ID      CREATED         SIZE
   localhost/myhttpd                          latest  08da72792f60  2 minutes ago   121 MB

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2. 运行 localhost/myhttpd 镜像，并配置容器和主机系统之间的端口映射：

   # podman run -p 8080:80 -d --name myhttpd 08da72792f60

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3. 测试 Web 服务器：

   # curl localhost:8080
   Your httpd container from scratch works!

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