VyOS works well under QEMU in GNS3, but GNS3 projects get very large due to storing a (copy on write snapshot of a) disk image for each virtual router in the topology, when all we really need is one disk image and a config file for each router.

https://wiki.qemu.org/Documentation/9psetup

QEMU has a nice feature where the guest OS can mount a directory on the host using the 9p protocol and virtio. This could be used to mount /config so that the actual config files can be stored in plain text on the host machine rather than in the disk image. Even just a snapshot (delta) of the disk image can get to hundreds of megabytes per router; in a complex topology with multiple routers this adds up quickly. Storing just the config files instead of the entire disk image this way would have a number of benefits, such as:

• The disk image snapshot could be discarded when the router shuts down, keeping only the config, so that more GNS3 projects could be stored
• Sharing GNS3 projects would be much easier due to the smaller size
• (maybe?) GNS3 projects could be managed in revision control such as git.

The problem is that VyOS lacks the 9p kernel modules. Please would you consider including them in the stock image, even if they are disabled by default. If the modules were included there, hopefully it would be as simple as configuring QEMU and adding an entry in /etc/fstab to mount /config on boot.

I have tried building a modified VyOS iso with these modules as a proof of concept but am getting errors building it. When I tried building from the current branch fails with some error relating to initrd. I also tried checking out commits from when vyos-1.2.0-20171115-amd64-vrrp6.iso was built but I think this fails because the iso building process is looking for files on the apt repo that have changed.