In 2018 I set out to replace our XenSever 7.2 based virtualisation after Citrix essentially screwed over free / open source users.
This project was to directly replace XenServer 7.2 with something supported and manageable for our traditional virtualisation needs.
High Level Selection Considerations I evaluated a number of options, with the primary candidates below.
Key criteria (at a high level) I was evaluating:
Ease of moving from our existing XenServer 7.2 based hypervisor clusters. Security (architecture, hardening, monitoring, logging). Cost (both licensing if any and self-support / management costs). VM Performance (Storage IOPs and throughput, Network latency and throughput, Processing latency, steal from over-provisioned workloads). Management UI/UX and performance (for BAU activities). Management / Cluster SPOFs, fail-over and redundancy. Installation and upgrade process. Update and security patching frequency. Networking design and complexity. Community (size, engagement, acceptance of suggestions / MRs). Reliable live VM migrations. Ease of management for a small team (Part of a low TCO). Risk of vendor and technology lock-in. Risk of survival (will it still be well maintained over the next 1-3 years). Stability and reliability above practically all else. XenServer 7.6 (w/ Paid License) For Potentially priority support from Citrix for issues. Easy upgrade from 7.2. Fresh installs and upgrades are simple, painless and easy to pxeboot, licensing can be a pain after install however. Against Slow moving development. Incredibly expensive, it would cost us something like $140,800 AUD per year (shelf price) for our 32 hosts (each with 2 sockets). Features heavily restricted by licensing model. Mostly older-fashioned enterprise users. No web management interface (although you can use Xen Orchestra from the folks behind XCP-ng). Diminishing community since XenServer licensing changes in 7.3. Poor storage performance compared to KVM based solutions. Many outdated packages, while kind of based on CentOS 7, there are a great deal of packages from older releases or completely custom rebuilt. Uses old technologies like EXT3 and doesn’t support SSD/Flash TRIM/DISCARD functions. SELinux not enforcing or supported. OpenvSwitch still uses a lot of Dom0 CPU (same as XenServer). Dom0 often ends up limiting VM storage operations (tapdisk maxing out Dom0 CPU). Applying updates can be painful or at least slow, requiring binary ISO files to be downloaded from Citrix. Uses Jira for bug tracking (I just can’t stand the thing, it’s painfully laggy, give my GitLab or Github over it any day). XCP-ng XCP-ng is a relatively recent fork from XenServer after it was open sourced, tracking upstream but clearly prioritising modernisation and community.
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