Add automatic retry on machine ID conflict

[LukasK32]

Description

When deploying a large count of machines at the same time (e.g. large cluster in Rancher), Proxmox can return the same "next ID" multiple times, and only one deployment will succeed. Rancher will retry deployment, but it takes a long time (there is no ID set in that case so Rancher tries to remove non-existing VM multiple times first).

How Has This Been Tested?

You can force specific ID to be set for the new machine like so:

--- i/cmd/docker-machine-driver-pve/driver/pve.go
+++ w/cmd/docker-machine-driver-pve/driver/pve.go
@@ -31,6 +31,7 @@ func (d *Driver) createPVEVirtualMachine(ctx context.Context) (int, error) {
                Name: d.MachineName,
                Pool: d.ResourcePoolName,
                Full: 0,
+               NewID: 108,
        })
        if err != nil {
                return vmid, fmt.Errorf("failed to clone template ID='%d': %w", d.TemplateID, err)

I created a machine with 108 first, then started creation of a second one, waited for retires to start and removed the initial machine - the driver created the new machine correctly.

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[keyaray]

LGTM