Adding libvirt remote connection verification

Depending on the remote libvirt configuration, setting a password-less
login between the hosts isn't enough to ensure a password-less API
connection to the remote libvirt service.

This patch adds a virsh verification to ensure that this password-less
connection can be estabished before moving further with the live
migration process. If the verification fails, a proper error message
is given to warn the user about the need of making a manual configuration
in the libvirt service of the remote host.

Signed-off-by: Daniel Henrique Barboza <danielhb@linux.vnet.ibm.com>

i18n.py

@@ -140,6 +140,7 @@
     "KCHVM0087E": _("console parameter is only supported for s390x/s390 architecture."),
     "KCHVM0088E": _("invalid console type, supported types are sclp/virtio."),
     "KCHVM0089E": _("Unable to setup password-less login at remote host %(host)s using user %(user)s: remote directory %(sshdir)s does not exist."),
+    "KCHVM0090E": _("Unable to create a password-less libvirt connection to the remote libvirt daemon at host %(host)s with the user %(user)s. Please verify the remote server libvirt configuration. More information: http://libvirt.org/auth.html ."),
 
     "KCHVMHDEV0001E": _("VM %(vmid)s does not contain directly assigned host device %(dev_name)s."),
     "KCHVMHDEV0002E": _("The host device %(dev_name)s is not allowed to directly assign to VM."),

model/vms.py

@@ -25,6 +25,7 @@
 import platform
 import pwd
 import random
+import signal
 import socket
 import subprocess
 import string
@@ -1840,6 +1841,22 @@ def append_id_rsa_to_remote_authorized_keys(ssh_client, id_rsa_data):
             if ssh_client:
                 ssh_client.close()
 
+    def _check_remote_libvirt_conn(self, remote_host,
+                                   user='root', transport='ssh'):
+
+        dest_uri = 'qemu+%s://%s@%s/system' % (transport, user, remote_host)
+        cmd = ['virsh', '-c', dest_uri, 'list']
+        proc = subprocess.Popen(cmd, stdout=subprocess.PIPE,
+                                shell=True, preexec_fn=os.setsid)
+        timeout = 0
+        while proc.poll() is None:
+            time.sleep(1)
+            timeout += 1
+            if timeout == 5:
+                os.killpg(os.getpgid(proc.pid), signal.SIGTERM)
+                raise OperationFailed("KCHVM0090E",
+                                      {'host': remote_host, 'user': user})
+
     def _get_remote_libvirt_conn(self, remote_host,
                                  user='root', transport='ssh'):
         dest_uri = 'qemu+%s://%s@%s/system' % (transport, user, remote_host)
@@ -1853,6 +1870,7 @@ def migration_pre_check(self, remote_host, user, password):
             user,
             password
         )
+        self._check_remote_libvirt_conn(remote_host, user)
         self._check_if_migrating_same_arch_hypervisor(remote_host, user)
 
         if platform.machine() in ['ppc64', 'ppc64le']: