r/virtualization • u/Mdi1981 • Jul 13 '26
Opensource alternatives for Citrix PVS / Citrix MSC / Citrix HDX protocol / Opensource VDI
Hi all,
I'm wondering if there are opensource Citrix alternatives which has equivariant of the HDX protocol and VGPU support and disk imaging like MCS or PVS.
Thank you very much for your reply.
1
1
u/Mdi1981 Jul 15 '26
Thank you for the replies!.
In your opinion how does spice handle gpu and how does it compare to Citrix HDX. ?
1
u/anthony-kldload 11d ago
If I read it right MCS is essentially copy-on-write clones from a master image,
and ZFS does that natively — clone a golden zvol in ~100ms, no differencing-disk
chain to degrade over time.
That's the part I work on — https://kldload.com, OpenZFS goldens,
clones and replication. The ISO is a working base if you want to try that layer.
It's not a VDI stack and won't replace the broker or the protocol, but it covers
the imaging/provisioning half. You could also modify the default example to
customize your own images and technically build out the vdi part, this may help
you get started https://kldload.com/pages/build-vdi
atm, I haven't done anything that would address the vGPU vs NVENC so I'm not sure
if this helps, but it may get you started.
3
u/CleanLie1557 Jul 13 '26
Here’s the landscape, mapped to each Citrix piece:
PVS (Provisioning Services) — streams a single golden image to many stateless machines
No exact open-source equivalent, but closest approaches:
iPXE + NFS/iSCSI root — manual but replicates the “boot from network image” model
LTSP (Linux Terminal Server Project) — network boot + shared image, Linux-focused
Proxmox/oVirt with linked clones — different approach (copy-on-write from a template rather than streaming), achieves similar “one image, many VMs” goal
MCS (Machine Creation Services) — clones desktops from a master image on demand
Proxmox VE — clone templates, especially with ZFS/LVM-thin for fast linked clones
oVirt — thin/clone provisioning from templates, closer to enterprise MCS behavior
OpenNebula — has VDI-oriented provisioning workflows built in
HDX protocol — the remoting/display protocol
SPICE — best open-source analog; USB redirection, multi-monitor, decent audio, tightly integrated with oVirt/KVM
RDP (FreeRDP/xrdp) — most mature open client/server stack, good performance, widest compatibility
VNC (TigerVNC/noVNC) — simplest, weakest performance/feature parity
PCoIP is proprietary (Teradici/HP) so not relevant here, but worth knowing it’s the other commercial option
Full open-source VDI stacks (the “give me the whole platform” answer)
oVirt — closest overall architecture to a Citrix/Horizon-style VDI platform (templates, pools, SPICE, connection broker via “User Portal”)
Proxmox VE — not VDI-native out of the box, but pairs well with a broker layer
Apache CloudStack — has VDI-ish capabilities but is more IaaS-focused
UDS Enterprise (Virtual Cable) — open-source connection broker specifically built for VDI, supports RDP/SPICE/x2go, layers on top of Proxmox, oVirt, OpenNebula, KVM, etc. — probably the single closest thing to “Citrix Broker” in FOSS
Apache Guacamole — clientless (browser-based) gateway for RDP/VNC/SSH; great as the access layer, not a full broker/provisioning system
If you want something that most resembles the full Citrix experience (PVS+MCS+HDX+Broker in one), the realistic combo is: Proxmox or oVirt (provisioning/cloning) + SPICE or FreeRDP (protocol) + UDS Enterprise (broker/pooling layer). There isn’t a single FOSS project that replicates the whole Citrix stack end-to-end the way Citrix does it natively — you’re assembling it from these pieces.