Chapter 15. Sharing files between the host and its virtual machines

Procedure

1. On the host, export a directory with the files you want to share as a network file system (NFS):

   1. Share an existing directory with VMs. If you do not want to share any of the existing directories, create a new one:

      # mkdir shared-files

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   2. Obtain the IP address of each VM to share files from the host, for example, testguest1 and testguest2 :

      # virsh domifaddr testguest1
      Name       MAC address          Protocol     Address
      ----------------------------------------------------------------
      vnet0      52:53:00:84:57:90    ipv4         192.0.2.2/24
      
      # virsh domifaddr testguest2
      Name       MAC address          Protocol     Address
      ----------------------------------------------------------------
      vnet1      52:53:00:65:29:21    ipv4         192.0.2.3/24

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   3. Edit the /etc/exports file on the host and add a line that includes the directory you want to share, IPs of VMs to share, and additional options:

      /home/<username>/Downloads/<shared_directory>/ <VM1-IP(options)> <VM2-IP(options)>
      ...

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      The following example shares the /usr/local/shared-files directory on the host with testguest1 and testguest2, and enables the VMs to edit the content of the directory:

      /usr/local/shared-files/ 192.0.2.2(rw,sync) 192.0.2.3(rw,sync)

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      Note

      To share a directory with a Windows VM, you need to ensure the Windows NFS client has write permissions in the shared directory. You can use the all_squash, anonuid, and anongid options in the /etc/exports file.

      /usr/local/shared-files/ 192.0.2.2(rw,sync,all_squash,anonuid=<directory-owner-UID>,anongid=<directory-owner-GID>)

      The <directory-owner-UID> and <directory-owner-GID> are the UID and GID of the local user that owns the shared directory on the host.

      For other options to manage NFS client permissions, follow the Securing the NFS service guide.

   4. Export the updated file system:

      # exportfs -a

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   5. Start the nfs-server service:

      # systemctl start nfs-server

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   6. Obtain the IP address of the host system to mount the shared directory on the VMs:

      # ip addr
      ...
      5: virbr0: [BROADCAST,MULTICAST,UP,LOWER_UP] mtu 1500 qdisc noqueue state UP group default qlen 1000
      link/ether 52:54:00:32:ff:a5 brd ff:ff:ff:ff:ff:ff
      inet 192.0.2.1/24 brd 192.0.2.255 scope global virbr0
      valid_lft forever preferred_lft forever
      ...

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      Note that the relevant network connects the host with VMs to share files. Usually, this is virbr0.

2. Mount the shared directory on a Linux VM that is specified in the /etc/exports file:

   # mount 192.0.2.1:/usr/local/shared-files /mnt/host-share

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   • 192.0.2.1: The IP address of the host.
   • /usr/local/shared-files: A file-system path to the exported directory on the host.

   • /mnt/host-share: A mount point on the VM

     Note

     The mount point must be an empty directory.

3. To mount the shared directory on a Windows VM as mentioned in the /etc/exports file:

   1. Open a PowerShell shell prompt as an Administrator.

   2. Install the NFS-Client package on the Windows.

      1. To install on a server version, enter:

         # Install-WindowsFeature NFS-Client

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      2. To install on a desktop version, enter:

         # Enable-WindowsOptionalFeature -FeatureName ServicesForNFS-ClientOnly, ClientForNFS-Infrastructure -Online -NoRestart

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   3. Mount the directory exported by the host on a Windows VM:

      # C:\Windows\system32\mount.exe -o anon \\192.0.2.1\usr\local\shared-files Z:

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      In this example:

      • 192.0.2.1: The IP address of the host.
      • /usr/local/shared-files: A file system path to the exported directory on the host.

      • Z:: The drive letter for a mount point.

        Note

        You must choose a drive letter that is not in use on the system.