Add KVM support to VM Importer

Related to: harvester/harvester#9948

Signed-off-by: Volker Theile <vtheile@suse.com>

Author: votdev

docs/advanced/addons/vmimport.md

@@ -24,14 +24,15 @@ Currently, the following source providers are supported:
 * VMware
 * OpenStack
 * Open Virtual Appliance (OVA)
+* KVM
 
 ## API
 The vm-import-controller introduces two CRDs.
 
 ### Sources
 Sources allow users to define valid source clusters.
 
-For example:
+#### VMware
 
 ```yaml
 apiVersion: migration.harvesterhci.io/v1beta1
@@ -70,6 +71,8 @@ NAME    STATUS
 vcsim   clusterReady
 ```
 
+#### OpenStack
+
 For OpenStack-based source clusters, an example definition is as follows:
 
 ```yaml
@@ -110,6 +113,8 @@ NAME       STATUS
 devstack   clusterReady
 ```
 
+#### Open Virtual Appliance
+
 For OVA-based sources, an example definition is as follows:
 
 ```yaml
@@ -150,6 +155,40 @@ NAME      STATUS
 example   clusterReady
 ```
 
+#### KVM
+
+For KVM-based sources, an example definition is as follows:
+
+```yaml
+apiVersion: migration.harvesterhci.io/v1beta1
+kind: KVMSource
+metadata:
+  name: kvm
+  namespace: default
+spec:
+  libvirtURI: "qemu+ssh://192.168.0.1/system"
+  credentials:
+    name: example-kvm-credentials
+    namespace: default
+```
+
+Check out the libvirt documentation on how to configure the [libvirtURI](https://libvirt.org/uri.html) field.
+When configuring the secret, you can include the authentication credentials that are used to log into the source system via SSH.
+
+```yaml
+apiVersion: v1
+kind: Secret
+metadata: 
+  name: example-kvm-credentials
+  namespace: default
+stringData:
+  "username": "user"
+  "password": "password"
+  "privateKey": "pem-encoded-private-key"
+```
+
+As part of the reconciliation process, the controller issues a `virsh` command on the specified URI to confirm its validity before marking the source as ready.
+
 ### VirtualMachineImport
 The VirtualMachineImport CRD provides a way for users to define a source VM and map to the actual source cluster to perform VM export/import.