Single server to clustered environment upgrade?


New Member
Apr 27, 2018
Hi Everyone!

I am reading about Proxmox VE as planning to have it for our hosting (Appreciate the team for such a good admin guide - I haven't finished it yet) Now my question is, can I start with a single server PVE and later connect more servers and make clustered PVE without any downtime? If I can, how complex is the transition?

This post from Martin has a good explanation about the no-sub repo. But my question is how reliable is it to use with production server (I know it's not recommended but I get an impression from different forums that people are using no-sub repo in production and have been sweet as) anyone out there doing such? As I have to start with no-subscription and then later can afford to upgrade.

starting with one single node, and later creating a cluster and adding new, empty nodes is not a problem. switching from no-subscription to enterprise is also no problem. combining multiple standalone nodes with guests into a cluster should only be done if you really know what you are doing, as you might need to fixup storage configuration, handle guest ID conflicts beforehand, etc.pp.
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Just a small added vote of confidence / and a few comments ...

(A) It is basically trivial process, if you start with one node in production, run it standalone for a period of time (Months,etc) and then in future, wish to add more nodes / create a multi-node cluster. Simply clean-install the other nodes / keep their network config as 'identical' as possible to simplify life / in terms of moving VMs between nodes. Then follow steps for 'create a cluster' - starting with your 'old node' where VMs exist / and assuming you have zero VMs on any of the other new node(s) being created-added. Then add them into the cluster one-at-a-time. And you are all set.
(B) In terms of move from free to non-free subscription, you can do that anytime / as per your requirements, with no trouble. In my experience the repo subscription is more about "client expectations and requirements about a production platform that must be suitably supported" and also combined with "desire to give some $support back to proxmox for producing an amazing product".

Also for clarity, maybe not immediately obvious. At least in my experience
-- for cluster config, generally you will want if possible 2 NIC / subnets per node. First NIC is for "cluster management and communication between nodes". Second NIC is used for 'bridge the traffic to VMs and the LAN<s> they must communicate with'. If you have tons of NICs available (ie, 4 gig nic is pretty standard config in many commodity server hardware builds these days).... then you are probably better off with something like

nic0 = proxmox admin / inter-node communication. (is where VM Migration will happen if you push blocks between nodes when using non-shared storage)
nic1= VM bridge interface / for VM traffic to 'network<s>'
nic2 = optional use for dumping data to NFS-backup target, ie, you have an inexpensive NAS storage target which you use as a common shared storage tank for any-all proxmox nodes to dump VM Backups onto.
nic3 = optional use for NFS shared storage target for "live migrate capable" VM storage tank for "non-IO-intensive" VM Storage area.

in such a config as above, I would typically recommend you have discrete network for each NIC, ie, for nic0 for nic1 for nic2 for nic3

ie, it is nice if easily possible, to cleanly segregate your various traffic pools (ie, VM-admin; vs VM traffic ; vs Backup dump traffic ; vs VM image backing storage shared storage traffic).

Also for general "IMHO" reference. I am believer that above config is superior to something like:

- 4 gig nics
- create a 4-channel bond with all 4 interfaces as member
- then have all your 'stuff' attached to that one bond channel interface. (ie, VM admin; VM traffic; Backups; and network backing storage pool / assuming you have such various parallel use data requrements .. which often may be the case .. in my experience ..).

because - in my general experience - bond interface performance does not always work 'the way we might expect' despite what the 'theory' of the beast may be.

just my 2 cents though.

Tim Chipman

"Happily using Proxmox to support client projects for nearly a decade" :)
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