Scale Feature Request : File System Passthrough

[beaster]

Would like to request virtio file system share pass through for a virtualization host
Similar to https://libvirt.org/kbase/virtiofs.html
or in the case of KVM/RHEL http://www.linux-kvm.org/page/9p_virtio

I recognize the team is busy with SCALE and a multitude of sponsored requests and bugs but just wanted to table this.

Yes I recognize that I could setup a share and in a VLAN/BRIDGE that is common to the host and the guest

I regularly setup dedicated networks for Guest/Host share file access, however the time and complexity of securing this process is high.

Jails in CORE made this somewhat easier to manage, however with SCALE, that's not really an option at the moment.

The requirement is mainly around being able to secure a VM host & guest without the time and complexity of exposing a common network interface to one or more hosts that are normally isolated.
The requirement usually involves exposing a shared file system among 2 or more virtualization hosts that have different security needs.

 

[danb35]

Jails in CORE made this somewhat easier to manage

...but the parallel to jails in SCALE are the apps, and SCALE does support host path mapping for them. CORE doesn't have any way of directly mounting storage to a VM either--which really isn't relevant to whether it'd be a good idea under SCALE, but at least it isn't a feature SCALE is lacking compared to CORE. But in any event, the best place to make a feature request is using the "Report a Bug" link at the top of the page--the devs don't spend much time here.

 

[beaster]

...but the parallel to jails in SCALE are the apps, and SCALE does support host path mapping for them. CORE doesn't have any way of directly mounting storage to a VM either--which really isn't relevant to whether it'd be a good idea under SCALE, but at least it isn't a feature SCALE is lacking compared to CORE. But in any event, the best place to make a feature request is using the "Report a Bug" link at the top of the page--the devs don't spend much time here.

Scale apps have there place but they are not a replacement for virtualization requirements

Well noted on the advice regarding a bug for the devs.

 

[danb35]

Scale apps have there place but they are not a place for virtualization requirements

...but they are the parallel to jails. Both CORE and SCALE can act as hypervisors, and neither of those hypervisor solutions does filesystem passthrough as you're requesting. Both CORE and SCALE also support containers (jails in CORE, apps in SCALE), and both of those solutions do allow filesystem passthrough. Which doesn't really go to the merits of your suggestion, but their capabilities are comparable in this regard.

 

[beaster]

Closing this thread
I opened the a Bug under https://ixsystems.atlassian.net/browse/NAS-119764 for the feature.

 

[beaster]

...but they are the parallel to jails. Both CORE and SCALE can act as hypervisors, and neither of those hypervisor solutions does filesystem passthrough as you're requesting. Both CORE and SCALE also support containers (jails in CORE, apps in SCALE), and both of those solutions do allow filesystem passthrough. Which doesn't really go to the merits of your suggestion, but their capabilities are comparable in this regard.

"neither of those hypervisor solutions does filesystem pass-through as you're requesting"
Functionally that is not correct based on my testing

SCALE uses QEMU and libvirt.io, these additional features exist natively, the issue is that the dev team has not had the priority to implement them.
There a number of users that have already used various libvirt.io XML changes to support similar requirements, however as pointed out by developers when the VM restarts those changes are removed from the setup. (https://www.truenas.com/community/threads/truenas-scale-removing-custom-libvirt-options.90553/)

This is mainly about the cost of the UI and config/state development required for having specific qemu features exposed in the user experience.
It's not a capability issue it's business case issue for the IX-systems developers. Which I fully understand as a product manager myself.

I'm not trying to tell you or IX-systems what the appropriate business direction should be, just pointing out that file system pass-through is a heavily used feature for commercial hypervisor use cases. TRUENAS competes in the hyper-converged NAS/Virtualization space, having a persistent option for this feature or even to be able to have persistent QEMU / Virtio XML customization for a VM would be a boon for not using proprietary systems.