Chapter 14. Sharing files between the host and its virtual machines
You may frequently require to share data between your host system and the virtual machines (VMs) it runs. To do so quickly and efficiently, you can set up NFS or Samba file shares on your system.
14.1. Sharing files between the host and Linux virtual machines
For efficient file sharing between your host system and the Linux VMs it is connected to, you can export an NFS share that your VMs can mount and access.
Prerequisites
-
The
nfs-utils
package is installed on the host. A directory that you want to share with your VMs. If you do not want to share any of your existing directories, create a new one, for example named shared-files.
# mkdir shared-files
The host is visible and reachable over a network for the VM. This is generally the case if the VM is connected using the NAT and bridge type of virtual networks. However, for the macvtap connection, you must first set up the macvlan feature on the host. To do so:
Create a network device file, for example called
vm-macvlan.netdev
in the host’s/etc/systemd/network/
directory.# touch /etc/systemd/network/vm-macvlan.netdev
Edit the network device file to have the following content. You can replace
vm-macvlan
with the name you chose for your network device.[NetDev] Name=vm-macvlan Kind=macvlan [MACVLAN] Mode=bridge
Create a network configuration file for your macvlan network device, for example
vm-macvlan.network
.# touch /etc/systemd/network/vm-macvlan.network
Edit the network configuration file to have the following content. You can replace
vm-macvlan
with the name you chose for your network device.[Match] Name=_vm-macvlan_ [Network] IPForward=yes Address=192.168.250.33/24 Gateway=192.168.250.1 DNS=192.168.250.1
Create a network configuration file for your physical network interface. For example, if your interface is
enp4s0
:# touch /etc/systemd/network/enp4s0.network
If you are unsure what interface name to use, you can use the
ifconfig
command on your host to obtain the list of active network interfaces.Edit the physical network configuration file to make the physical network a part of the macvlan interface, in this case vm-macvlan:
[Match] Name=enp4s0 [Network] MACVLAN=vm-macvlan
- Reboot your host.
- Optional: For improved security, ensure your VMs are compatible with NFS version 4 or later.
Procedure
On the host, export a directory with the files you want to share as a network file system (NFS).
Obtain the IP address of each virtual machine you want to share files with. The following example obtains the IPs of testguest1 and testguest2.
# virsh domifaddr testguest1 Name MAC address Protocol Address ---------------------------------------------------------------- vnet0 52:53:00:84:57:90 ipv4 192.168.124.220/24 # virsh domifaddr testguest2 Name MAC address Protocol Address ---------------------------------------------------------------- vnet1 52:53:00:65:29:21 ipv4 192.168.124.17/24
Edit the
/etc/exports
file on the host and add a line that includes the directory you want to share, IPs of VMs you want to share with, and sharing options.Shared directory VM1-IP(options) VM2-IP(options) [...]
For example, the following 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/ 192.168.124.220(rw,sync) 192.168.124.17(rw,sync)
Export the updated file system.
# exportfs -a
Ensure the NFS process is started:
# systemctl start nfs-server
Obtain the IP address of the host system. This will be used for mounting the shared directory on the VMs later.
# 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 192.168.124.1/24 brd 192.168.124.255 scope global virbr0 valid_lft forever preferred_lft forever [...]
Note that the relevant network is the one being used use for connection to the host by the VMs you want to share files with. Usually, this is
virbr0
.
On the guest OS of a VM specified in the
/etc/exports
file, mount the exported file system.Create a directory you want to use as a mount point for the shared file system, for example
/mnt/host-share
:# mkdir /mnt/host-share
Mount the directory exported by the host on the mount point. This example mounts the
/usr/local/shared-files
directory exported by the192.168.124.1
host on/mnt/host-share
in the guest:# mount 192.168.124.1:/usr/local/shared-files /mnt/host-share
To verify the mount has succeeded, access and explore the shared directory on the mount point:
# cd /mnt/host-share # ls shared-file1 shared-file2 shared-file3
14.2. Sharing files between the host and Windows virtual machines
For efficient file sharing between your host system and the Windows VMs it is connected to, you can prepare a Samba server that your VMs can access.
Prerequisites
The
samba
packages are installed on your host. If they are not:# yum install samba
The host is visible and reachable over a network for the VM. This is generally the case if the VM is connected using the NAT and bridge type of virtual networks. However, for the macvtap connection, you must first set up the macvlan feature on the host. To do so:
Create a network device file, for example called
vm-macvlan.netdev
in the host’s/etc/systemd/network/
directory.# touch /etc/systemd/network/vm-macvlan.netdev
Edit the network device file to have the following content. You can replace
vm-macvlan
with the name you chose for your network device.[NetDev] Name=vm-macvlan Kind=macvlan [MACVLAN] Mode=bridge
Create a network configuration file for your macvlan network device, for example
vm-macvlan.network
.# touch /etc/systemd/network/vm-macvlan.network
Edit the network configuration file to have the following content. You can replace
vm-macvlan
with the name you chose for your network device.[Match] Name=_vm-macvlan_ [Network] IPForward=yes Address=192.168.250.33/24 Gateway=192.168.250.1 DNS=192.168.250.1
Create a network configuration file for your physical network interface. For example, if your interface is
enp4s0
:# touch /etc/systemd/network/enp4s0.network
If you are unsure what interface to use, you can use the
ifconfig
command on your host to obtain the list of active network interfaces.Edit the physical network configuration file to make the physical network a part of the macvlan interface, in this case vm-macvlan:
[Match] Name=enp4s0 [Network] MACVLAN=vm-macvlan
- Reboot your host.
Procedure
On the host, create a Samba share and make it accessible for external systems.
Add firewall permissions for Samba.
# firewall-cmd --permanent --zone=public --add-service=samba success # firewall-cmd --reload success
Edit the
/etc/samba/smb.conf
file:Add the following to the
[global]
section:map to guest = Bad User
Add the following at the end of the file:
#=== Share Definitions === [VM-share] path = /samba/VM-share browsable = yes guest ok = yes read only = no hosts allow = 192.168.122.0/24
Note that the
hosts allow
line restricts the accessibility of the share only to hosts on the VM network. If you want the share to be accessible by anyone, remove the line.
Create the
/samba/VM-share
directory.# mkdir -p /samba/VM-share
Enable the Samba service.
# systemctl enable smb.service Created symlink /etc/systemd/system/multi-user.target.wants/smb.service → /usr/lib/systemd/system/smb.service.
Restart the Samba service.
# systemctl restart smb.service
Allow the
VM-share
directory to be accessible and modifiable for the VMs.# chmod -R 0755 /samba/VM-share/ # chown -R nobody:nobody /samba/VM-share/
Add the SELinux Samba sharing label to
/etc/samba/VM-share/
# chcon -t samba_share_t /samba/VM-share/
On the Windows guest operating system, attach the Samba share as a network location.
- Open the File Explorer and right-click "This PC".
In the context menu, click
Add a network location
.- In the Add Network Location wizard that opens, select "Choose a custom network location" and click .
In the "Internet or network address" field, type host-IP/VM-share, where host-IP is the IP address of the host. Usually, the host IP is the default gateway of the VM. Afterwards, click .
- When the wizard asks if you want to rename the shared directory, keep the default name. This ensures the consistency of file sharing configuration across the VM and the guest. Click .
- If accessing the network location was successful, you can now click and open the shared directory.