[VMware to KVM Migration] Issue on migration when ovftool is not installed on the conversion KVM hosts

[nvazquez]

Problem

There is a problem on VMware to KVM migration in case the converting host doesn't have ovftool installed: conversion process fails with:

Cannot invoke org.apache.cloudstack.vm.UnmanagedInstanceTO.setCpuCores(java.lang.Integer)" because "convertedInstance is null

Workaround: install ovftool on the KVM hosts used for conversion

The reason of the failure is that the returned converted instance on line: https://github.com/apache/cloudstack/blob/4.20/server/src/main/java/org/apache/cloudstack/vm/UnmanagedVMsManagerImpl.java#L1985 is null. This logic is missing the import instance logic that is present on: https://github.com/apache/cloudstack/blob/4.20/server/src/main/java/org/apache/cloudstack/vm/UnmanagedVMsManagerImpl.java#L2036-L2056.

Versions

CloudStack 4.20.1 RC3
KVM hosts installing virt-v2v

The steps to reproduce the bug

1. Install only virt-v2v on KVM host used for conversion, but not ovftool
2. Migrate VMware VM to KVM through CloudStack

What to do about it?

Install ovftool on the KVM hosts used for conversion