在平時使用時，為了減少存儲空間和加快網絡傳輸速度，我們總希望能把基礎鏡像做的盡量小，本文介紹如何制作清爽干凈的kvm基礎鏡像。

1. 根據自身需求，對系統進行配置：

   • 這一步是為了確保系統符合你的需求，比如安裝必要的軟件，配置網絡等。

2. 卸載不需要的軟件：

   • 使用 yum remove 或 dnf remove 命令卸載不需要的軟件包。例如：
     bash<button class="MuiButtonBase-root MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeSmall MuiButton-textSizeSmall MuiButton-colorPrimary MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeSmall MuiButton-textSizeSmall MuiButton-colorPrimary copyBtn___l3xJQ css-xox1ca" tabindex="0" type="button"></button>

     yum remove [package_name]
   • 確保不要卸載系統運行所必需的軟件。

3. 對系統緩存進行清理：

   • 清理臨時文件和日志可以減少鏡像大小。以下命令可以清理緩存：
     bash<button class="MuiButtonBase-root MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeSmall MuiButton-textSizeSmall MuiButton-colorPrimary MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeSmall MuiButton-textSizeSmall MuiButton-colorPrimary copyBtn___l3xJQ css-xox1ca" tabindex="0" type="button"></button>

     rm -rf /tmp/* rm -f /etc/udev/rules.d/70-persistent-net.rules rm -f /var/log/wtmp /var/log/btmp /var/log/anaconda/* cd /var/log for i in cron dmesg dmesg.old lastlog maillog messages pm-powersave.log secure Xorg.0.log Xorg.0.log.old Xorg.9.log Xorg.9.log.old do true > $i done dmesg -c echo >/root/.bash_history yum clean all cloud-init clean rm -rf /var/lib/cloud history -c

4. 使用 dd 命令將客戶機未使用的磁盤空間用0填滿：

   • 這一步確保未使用的磁盤空間被標記為0，從而在轉換為 qcow2 鏡像時不會被錯誤地認為是已使用空間。例如：
     bash<button class="MuiButtonBase-root MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeSmall MuiButton-textSizeSmall MuiButton-colorPrimary MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeSmall MuiButton-textSizeSmall MuiButton-colorPrimary copyBtn___l3xJQ css-xox1ca" tabindex="0" type="button"></button>

     dd if=/dev/zero of=~/junk rm -f ~/junk

5. 關機：

   • 使用 halt -p 命令安全地關閉系統：
     bash<button class="MuiButtonBase-root MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeSmall MuiButton-textSizeSmall MuiButton-colorPrimary MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeSmall MuiButton-textSizeSmall MuiButton-colorPrimary copyBtn___l3xJQ css-xox1ca" tabindex="0" type="button"></button>

     halt -p

6. 在宿主機上，執行鏡像整理：

   • 使用 virt-sysprep 命令清理鏡像中的臨時文件和日志，確保鏡像是干凈的。如果沒有安裝 libguestfs-tools，可以通過以下命令安裝：
     bash<button class="MuiButtonBase-root MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeSmall MuiButton-textSizeSmall MuiButton-colorPrimary MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeSmall MuiButton-textSizeSmall MuiButton-colorPrimary copyBtn___l3xJQ css-xox1ca" tabindex="0" type="button"></button>

     yum install libguestfs-tools -y
   • 然后執行：
     bash<button class="MuiButtonBase-root MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeSmall MuiButton-textSizeSmall MuiButton-colorPrimary MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeSmall MuiButton-textSizeSmall MuiButton-colorPrimary copyBtn___l3xJQ css-xox1ca" tabindex="0" type="button"></button>

     virt-sysprep -a kvm-base.qcow2

7. 壓縮并制作新鏡像：

   • 使用 qemu-img convert 命令將鏡像轉換為壓縮的 qcow2 格式：
     bash<button class="MuiButtonBase-root MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeSmall MuiButton-textSizeSmall MuiButton-colorPrimary MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeSmall MuiButton-textSizeSmall MuiButton-colorPrimary copyBtn___l3xJQ css-xox1ca" tabindex="0" type="button"></button>

     qemu-img convert -p -c -O qcow2 kvm-base.qcow2 new.qcow2

8. 檢查鏡像是否有錯誤：

   • 使用 qemu-img check 命令檢查新鏡像的完整性：
     bash<button class="MuiButtonBase-root MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeSmall MuiButton-textSizeSmall MuiButton-colorPrimary MuiButton-root MuiButton-text MuiButton-textPrimary MuiButton-sizeSmall MuiButton-textSizeSmall MuiButton-colorPrimary copyBtn___l3xJQ css-xox1ca" tabindex="0" type="button"></button>

     qemu-img check new.qcow2