feat: VM provisioning, and reboot_host on ESXi

create_vm_from_cloud_init takes the same qcow2/raw cloud images netOrk
offers for Proxmox. ESXi can neither boot nor download them, so the
driver does both: download with checksum check and one retry, convert
with qemu-img to a streamOptimized VMDK (cached by URL), import through
a minimal OVF descriptor over NFC, pin requested MACs, grow the disk,
and attach a NoCloud seed ISO placed next to the VM's files. NoCloud
rather than guestinfo because it needs nothing in the guest; the
user-data installs open-vm-tools, which the driver declares as its
guest agent. A failure after the import removes the VM again.

Placement is a pure decision over inventory rows: a connected host
outside maintenance mode that sees the datastore and every port group,
with the resource pool and VM folder found by walking up to the
datacenter -- one path for a standalone host and for a vCenter.

Two faults vcsim surfaced and the tests now pin: a chunked upload body
next to a Content-Length is refused with 500, so the disk goes up as a
sized file object that also reports lease progress; and a device edit
replaces the device as sent, so disk and NIC edits start from the live
objects, backing included (vcsim panicked on a disk without one).

destroy_vm, get_vm_status, get_network_targets (port groups with their
fixed VLAN) and get_image_storages complete the contract.

reboot_host on ESXi uses RebootHost_Task and refuses outside
maintenance mode: force=True would cut power to running VMs.

Tested against vcsim in ESXi and vCenter mode, end to end.

napalm_vmware/provision/ovf.py

@@ -0,0 +1,120 @@
+"""A minimal OVF 1.0 descriptor for importing one converted cloud image.
+
+vSphere builds the VM from this (``OvfManager.CreateImportSpec``) and then
+takes the disk contents over NFC. The descriptor only has to describe what
+the image does not: CPU, memory, one disk and the NICs.
+
+Devices are the ones VMware recommends for a 64-bit Linux guest -- PVSCSI and
+VMXNET3. Both drivers are in the mainline kernel; whether every distribution's
+*cloud* kernel carries them is one of the things #305 checks on real hardware.
+"""
+
+from __future__ import annotations
+
+from xml.sax.saxutils import escape, quoteattr
+
+_HW_VERSION = "vmx-13"  # ESXi 6.5 and later
+_GUEST_OS = "otherLinux64Guest"
+_STREAM_OPTIMIZED = "http://www.vmware.com/interfaces/specifications/vmdk.html#streamOptimized"
+
+
+def _item(**elements: str) -> str:
+    # CIM requires the rasd elements in alphabetical order.
+    body = "".join(f"<rasd:{k}>{escape(v)}</rasd:{k}>" for k, v in sorted(elements.items()))
+    return f"<Item>{body}</Item>"
+
+
+def _nic_items(nic_count: int, first_instance: int) -> str:
+    return "".join(
+        _item(
+            AutomaticAllocation="true",
+            Connection=f"net{i}",
+            ElementName=f"Network adapter {i + 1}",
+            InstanceID=str(first_instance + i),
+            ResourceSubType="VmxNet3",
+            ResourceType="10",
+        )
+        for i in range(nic_count)
+    )
+
+
+def ovf_descriptor(
+    name: str,
+    *,
+    cpu: int,
+    memory_mb: int,
+    capacity_bytes: int,
+    nic_count: int,
+    firmware: str = "bios",
+) -> str:
+    networks = "".join(
+        f'<Network ovf:name="net{i}"><Description>net{i}</Description></Network>'
+        for i in range(nic_count)
+    )
+    hardware = "".join(
+        [
+            _item(
+                AllocationUnits="hertz * 10^6",
+                ElementName=f"{cpu} virtual CPU(s)",
+                InstanceID="1",
+                ResourceType="3",
+                VirtualQuantity=str(cpu),
+            ),
+            _item(
+                AllocationUnits="byte * 2^20",
+                ElementName=f"{memory_mb} MB of memory",
+                InstanceID="2",
+                ResourceType="4",
+                VirtualQuantity=str(memory_mb),
+            ),
+            _item(
+                Address="0",
+                ElementName="SCSI controller 0",
+                InstanceID="3",
+                ResourceSubType="VirtualSCSI",
+                ResourceType="6",
+            ),
+            _item(
+                AddressOnParent="0",
+                ElementName="Hard disk 1",
+                HostResource="ovf:/disk/vmdisk1",
+                InstanceID="4",
+                Parent="3",
+                ResourceType="17",
+            ),
+            _nic_items(nic_count, first_instance=5),
+        ]
+    )
+    firmware_config = (
+        '<vmw:Config ovf:required="false" vmw:key="firmware" vmw:value="efi"/>'
+        if firmware == "efi"
+        else ""
+    )
+    return (
+        '<?xml version="1.0" encoding="UTF-8"?>'
+        '<Envelope xmlns="http://schemas.dmtf.org/ovf/envelope/1"'
+        ' xmlns:ovf="http://schemas.dmtf.org/ovf/envelope/1"'
+        ' xmlns:rasd="http://schemas.dmtf.org/wbem/wscim/1/cim-schema/2/CIM_ResourceAllocationSettingData"'
+        ' xmlns:vssd="http://schemas.dmtf.org/wbem/wscim/1/cim-schema/2/CIM_VirtualSystemSettingData"'
+        ' xmlns:vmw="http://www.vmware.com/schema/ovf">'
+        '<References><File ovf:href="disk.vmdk" ovf:id="file1"/></References>'
+        "<DiskSection><Info>Virtual disks</Info>"
+        f'<Disk ovf:capacity="{capacity_bytes}" ovf:capacityAllocationUnits="byte"'
+        f' ovf:diskId="vmdisk1" ovf:fileRef="file1" ovf:format="{_STREAM_OPTIMIZED}"/>'
+        "</DiskSection>"
+        f"<NetworkSection><Info>Networks</Info>{networks}</NetworkSection>"
+        f"<VirtualSystem ovf:id={quoteattr(name)}>"
+        "<Info>A virtual machine</Info>"
+        f"<Name>{escape(name)}</Name>"
+        f'<OperatingSystemSection ovf:id="101" vmw:osType="{_GUEST_OS}"><Info>Guest OS</Info>'
+        "</OperatingSystemSection>"
+        "<VirtualHardwareSection><Info>Virtual hardware</Info>"
+        "<System><vssd:ElementName>Virtual Hardware Family</vssd:ElementName>"
+        "<vssd:InstanceID>0</vssd:InstanceID>"
+        f"<vssd:VirtualSystemIdentifier>{escape(name)}</vssd:VirtualSystemIdentifier>"
+        f"<vssd:VirtualSystemType>{_HW_VERSION}</vssd:VirtualSystemType></System>"
+        f"{hardware}{firmware_config}"
+        "</VirtualHardwareSection>"
+        "</VirtualSystem>"
+        "</Envelope>"
+    )