[pve-devel] last training week student feedback/request

DERUMIER, Alexandre Alexandre.DERUMIER at groupe-cyllene.com
Thu Jun 23 10:25:41 CEST 2022


I just finished my proxmox training week, 

here some student requests/feedback:


We have a usecase, with an HA enabled cluster, where student need to
shutdown the cluster cleaning through api or script. (electrical
unplanned shutdown, through UPS with nut).

He want to cleanly stop all the vm, then all the nodes.

Simply shutdown nodes one by one don't work, because some nodes can
loose quorum when half of the cluster is already shutdown, so ha is
stuck and nodes can be fenced by watchdog.

We have looked to cleany stop all the vms first.
pve-guest service can't be used for HA.
So we have done a script with loop to "qm stop" all the vms.
The problem is that, the HA state of the vms is going to stopped,
so when servers are restarting after the maintenance, we need to script
again a qm start of the vms.

Student asked if it could be possible to add some kind of "cluster
maintenance" option, to disable HA on the full cluster (pause/stop all
pve-ha-crm/lrm + disabling watchdog), and temporary remove all vms
services from ha.

I think it could be usefull too when adding new nodes to the cluster,
when a bad corosync new node could impact the whole cluster.

Also, related to this, maybe a "node maintenance option" could be great
too, like of vmware. (auto vms eviction with live migration).
when user need to change network config for example, withtout shutdown
the node.

Another student have a need with pci passthrough, cluster with
multiples nodes with multiple pci cards. 
He's using HA and have 1 or 2 backups nodes with a lot of cards,
to be able to failover 10 others servers.

The problem is that on the backups nodes, the pci address of the cards
are not always the same than production nodes.
So Ha can't work.

I think it could be great to add some kind of "shared local device
pool" at datacenter level, where we could define

pci:     poolname

usb:     poolname

so we could dynamicaly choose the correct pci address when restarting
the vm.

Permissions could be added too, maybe a migratable option when mdev
live migration support will be ready, ...

Related to 2), another student have a need of live migraton with nvidia
card with mdev.
I'm currently trying to test to see if it's possible, as they are some
experimental vfio option to enable it, but it doesn't seem to be ready.

Multi-cluster managements (I have a lot of request about this one at
the proxmox days conference too)

Usecase : Global management,

but maybe more important,for disaster recovery (1 active cluster + 1
passive cluster), be able to use zfs replication  or ceph mirroring
between 2 proxmox cluster + replicate  vm configuration.

All my students have windows reboot stuck problem since migration to
proxmox 7. (I have the problem too, randomly,I'm currently trying to
debug this).


PBS: all students are using pbs, and it's working very fine.

Some users have fast nvme in production, and slower hdd for pbs on a
remote site.

Student asked if it could be possible to add some kind of write cache
on a local pbs with fast nvme, forwarding to the remote slower pbs.
(Without the need to have a full pbs datastore on local site with nvme)

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