Adding old content "Virt-Manager: sharing data between host and guests (libvirt virtio-fs)" #1

content/tutorials/virt-manager-sharing-data-between-host-and-guests-libvirt-virtio-fs/index.md

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+---
+title: "Virt-Manager: sharing data between host and guests (libvirt virtio-fs)"
+description: "Share folder between host to guest VM (libvirt) and auto-mount virtio-fs the file system when the VM boots."
+# linkTitle:
+date: 2022-07-08T02:51:40+07:00
+lastmod:
+draft: false
+noindex: false
+# comments: false
+nav_weight: 1000
+# nav_icon:
+#   vendor: bootstrap
+#   name: toggles
+#   color: '#e24d0e'
+series:
+#  - Tutorial
+categories:
+#  - 
+tags:
+  - KVM
+  - libvirt
+  - QEMU
+images:
+# menu:
+#   main:
+#     weight: 100
+#     params:
+#       icon:
+#         vendor: bs
+#         name: book
+#         color: '#e24d0e'
+authors:
+  - ditatompel
+---
+
+I use **Virt-Manager** (Virtual Machine Manager GUI for `libvirt`) to easily manage virtual machine on my personal laptop. It's easy and works great for *"normal use"* of KVM/QEMU. But, you may need to do little extra steps to be able to **share data between host and multiple Linux guests**.
+
+<!--more-->
+
+Although it is possible to use network file systems such as **NFS/CIFS** for some of these tasks, they require configuration steps that are hard to automate, maintain, monitor, and you need to expose the storage network to the guests.
+
+The easiest way (at least for me) to solve these problems without configuring network file systems is using `virtio-fs`. It also takes advantage of the co-location of the guest and host to increase performance and provide semantics that are not possible with network file systems.
+
+Before going any further, let's take a look to my laptop disks allocation:
+```shell
+df -h | grep '/dev/sd'
+/dev/sda3       442G  164G  256G  40% /
+/dev/sdc1       469G   66G  380G  15% /mnt/msata
+/dev/sda1       511M  144K  511M   1% /efi
+/dev/sdb1       916G  588G  282G  68% /mnt/hdd2
+```
+- `/dev/sda`  500GB SATA SSD (main host operationg system).
+- `/dev/sdb1` 1TB SATA HDD mounted to `/mnt/hdd2` (which I want to share that path to Linux guests) .
+- `/dev/sdc1` 500GB mSATA SSD mounted to `/mnt/msata` (which I place all the VMs disks).
+
+## Setting up guest VMs
+Open **Virt-Manager** -> choose VM(s) -> **Add Hardware** -> **Filesystem**.
+
+Choose `virtio-9p` for **Driver**, `/path/to/mount_point/on/guest` for **Source path**, and `/mnt/hdd2` for **Target path**.
+
+> _**Target path** is the path where the share folder you want to share **on Host machine**, and **Source path** is the path where you mount the shared folder **on Guest(s) machine**._
+
+Login to your guest VM(s), install `qemu-guest-agent` and `virtio-fs` driver.
+
+For Debian based distros:
+```shell
+apt install qemu-guest-agent guestfsd
+```
+
+For Arch based distros:
+```shell
+pacman -S qemu-guest-agent qemu-virtiofsd
+```
+
+Mount the virtio-fs as root user:
+```shell
+mount -t 9p -o trans=virtio,version=9p2000.L /mnt/hdd2 /path/to/mount_point/on/guest
+```
+
+## Mount at boot using /etc/fstab
+You may want to auto-mount the file system when the VM boots. The kernel module for the `9p` transport will **not** be automatically loaded, so mounting the file system from `/etc/fstab` will fail and you will encounter an error.
+
+The solution is to preload the module during boot by creating `/etc/modules-load.d/9pnet_virtio.conf` file and fill with `9pnet_virtio` module.
+
+```shell
+echo 9pnet_virtio > /etc/modules-load.d/9pnet_virtio.conf
+```
+
+## Resources
+- [https://www.kernel.org/doc/html/v5.4/filesystems/virtiofs.html](https://www.kernel.org/doc/html/v5.4/filesystems/virtiofs.html)
+- [https://wiki.archlinux.org/title/libvirt#Virtio-FS](https://wiki.archlinux.org/title/libvirt#Virtio-FS)