virt-manager设置主机和虚拟机之间文件共享

向右看齐 2022-09-11 07:23 582阅读 0赞

### 文章目录 ###

*   *  前言
     *  设置共享文件
     *  报错处理

## 前言 ##

前几天，我开始[使用virt-manager管理虚拟机][virt-manager]。现在遇到的第一个问题是，如何在主机和虚拟机之间共享文件。

我曾设置过[qemu虚拟机和主机之间共享文件][qemu]。所以通过virt-manager设置主机和虚拟机之间共享文件也并非难事。

参考网上的相关资料：[在KVM主机和来宾之间设置共享文件夹][KVM]、[QEMU/KVM - Virt-Manager | Folder sharing and USB Redirection - YouTube][QEMU_KVM - Virt-Manager _ Folder sharing and USB Redirection - YouTube]、[9p (libvirt/QEMU) share modes-askubuntu][9p _libvirt_QEMU_ share modes-askubuntu]

这里补充下，我当前使用的机器并没有SElinux活动安全模块，所以可以省却SElinux的相关配置。如何查看当前主机的活动安全模块，可以运行下方命令。详细内容见[残缺的LSM框架启动分析][LSM]。

➜ cat /sys/kernel/security/lsm
    lockdown,capability,yama,apparmor

--------------------

## 设置共享文件 ##

1.  修改libvirt runs VMs的权限。(不知道这样修改的具体原因，但在共享文件件的设置上，确实有效)
    
        sudo gedit /etc/libvirt/qemu.conf 
        
        # By default libvirt runs VMs as non-root and uses AppArmor profiles
        # to provide host protection and VM isolation. While AppArmor
        # continues to provide this protection when the VMs are running as
        # root, /dev/vhost-net, /dev/vhost-vsock and /dev/vhost-scsi access is
        # allowed by default in the AppArmor security policy, so malicious VMs
        # running as root would have direct access to this file. If changing this
        # to run as root, you may want to remove this access from
        # /etc/apparmor.d/abstractions/libvirt-qemu. For more information, see:
        # https://launchpad.net/bugs/1815910
        # https://www.redhat.com/archives/libvir-list/2019-April/msg00750.html
        # Some examples of valid values are:
        #
        # user = "qemu" # A user named "qemu"
        # user = "+0" # Super user (uid=0)
        # user = "100" # A user named "100" or a user with uid=100
        #
        user = "root"  <-----
        
        # The group for QEMU processes run by the system instance. It can be
        # specified in a similar way to user.
        group = "root"   <-----
2.  双击虚拟机，进入虚拟机的设置界面。  
    ![在这里插入图片描述][1d3b365eb1cc47ffa004d609734cf068.png]
3.  使用添加硬件，添加一个文件系统。其中`mnt/data/linux`是我希望共享的文件夹，其目录与子目录中所有文件的权限为777。`linux`为挂在标签。`mapped`使用管理程序（QEMU 进程）的权限访问源。  
    ![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5aSnMTIzNOiNiQ_size_20_color_FFFFFF_t_70_g_se_x_16]
4.  进入虚拟机，在虚拟机中创建一个挂载点，并挂载KVM主机系统的共享文件夹。
    
        sudo mkdir /usr/src/linux
        sudo mount -t 9p -o trans=virtio linux /usr/src/linux
5.  测试共享文件夹。保证共享文件夹可读可写。

--------------------

## 报错处理 ##

问题一：如果共享文件夹中存在符号链接。当虚拟机访问共享文件夹中的符号链接文件时，会报错：`too many levels of symbolic links`。

查看共享文件夹中是否存在符号链接文件，可运行下面命令。

ls -alR | grep ^l

解决一：参考[Sharing folder with VM through libvirt, 9p, permission denied][Sharing folder with VM through libvirt_ 9p_ permission denied]，我们将上面的`mapped`模式修改为`Squash`模式。

至于`passthrough`，`mapped`，`Squash`这三个模式，我不清楚区别。可自行参考[9p (libvirt/QEMU) share modes][9p _libvirt_QEMU_ share modes-askubuntu]。

[virt-manager]: https://blog.csdn.net/sinat_38816924/article/details/120177858
[qemu]: https://blog.csdn.net/sinat_38816924/article/details/116571783#t12
[KVM]: https://zh.codepre.com/linux-30774.html?__cf_chl_managed_tk__=pmd_Qn7feLDFnjNBnJVNep_nmLUKSawJKr7xC4NIJi_W11k-1631584934-0-gqNtZGzNArujcnBszRL9
[QEMU_KVM - Virt-Manager _ Folder sharing and USB Redirection - YouTube]: https://www.youtube.com/watch?v=crDuKm6XNv4
[9p _libvirt_QEMU_ share modes-askubuntu]: https://askubuntu.com/questions/772784/9p-libvirt-qemu-share-modes
[LSM]: https://blog.csdn.net/sinat_38816924/article/details/117170244
[1d3b365eb1cc47ffa004d609734cf068.png]: /images/20220828/9b1adc0b19ad44c287344e3b0a3868b4.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5aSnMTIzNOiNiQ_size_20_color_FFFFFF_t_70_g_se_x_16]: /images/20220828/12512ab99d4e49c9acedf973a6a36663.png
[Sharing folder with VM through libvirt_ 9p_ permission denied]: https://askubuntu.com/questions/548208/sharing-folder-with-vm-through-libvirt-9p-permission-denied