Merge ~bjornt/maas:bug-2053033-3.3-hotfix into maas:branch-3.3.5-hotfix-bug-2053033

[Björn Tillenius]

Bug #2053033: Creating MAAS Virsh VM does not work (libvirt: error)

For some reason virsh prints out an error about executing
pkttyagent. This happens only on some machines, and we don't know why.

But the error seems harmless. This patch ignores the error and
lets the connection succeed.

(cherry picked from commit f0005e39bcadfc366c76e713c444739179743c84)
(cherry picked from commit 9eb3ca242e3c57f1b7ab1a1b6537ee4dfffb2aa6)
(cherry picked from commit 052a895bfac55e414bf5b02e5e28122bff12a532)

[Björn Tillenius (bjornt)]

Self-approve backport.

review: Approve

diff --git a/src/provisioningserver/drivers/pod/tests/test_virsh.py b/src/provisioningserver/drivers/pod/tests/test_virsh.py
index 629f277..4721db5 100644
--- a/src/provisioningserver/drivers/pod/tests/test_virsh.py
+++ b/src/provisioningserver/drivers/pod/tests/test_virsh.py
@@ -575,7 +575,30 @@ class TestVirshSSH(MAASTestCase):
         self.assertFalse(conn.login(poweraddr=factory.make_name("poweraddr")))
         self.assertThat(mock_close, MockCalledOnceWith())
 
+    def test_pkttyagent_permission_denied(self):
+        # Sometimes pkttyagent can't be executed in the snap. The connection
+        # itself still works, though.
+        # See https://bugs.launchpad.net/maas/+bug/2053033
+        virsh_outputs = [
+            "libvirt:  error : cannot execute binary /usr/bin/pkttyagent: Permission denied",
+            "Welcome to virsh, the virtualization interactive terminal.",
+            "",
+            "Type:  'help' for help with commands",
+            "       'quit' to quit",
+            "",
+            "virsh # ",
+        ]
+        conn = self.configure_virshssh_pexpect(virsh_outputs)
+        self.assertTrue(conn.login(poweraddr=factory.make_name("poweraddr")))
+
     def test_login_invalid(self):
+        virsh_outputs = ["Permission denied, please try again."]
+        conn = self.configure_virshssh_pexpect(virsh_outputs)
+        mock_close = self.patch(conn, "close")
+        self.assertFalse(conn.login(poweraddr=factory.make_name("poweraddr")))
+        mock_close.assert_called_once_with()
+
+    def test_unknown(self):
         virsh_outputs = [factory.make_string()]
         conn = self.configure_virshssh_pexpect(virsh_outputs)
         mock_close = self.patch(conn, "close")
diff --git a/src/provisioningserver/drivers/pod/virsh.py b/src/provisioningserver/drivers/pod/virsh.py
index c490cbc..94529ee 100644
--- a/src/provisioningserver/drivers/pod/virsh.py
+++ b/src/provisioningserver/drivers/pod/virsh.py
@@ -288,7 +288,8 @@ class VirshSSH(pexpect.spawn):
     PROMPT = r"virsh \#"
     PROMPT_SSHKEY = "(?i)are you sure you want to continue connecting"
     PROMPT_PASSWORD = "(?i)(?:password)|(?:passphrase for key)"
-    PROMPT_DENIED = "(?i)permission denied"
+    # Credential problems
+    PROMPT_DENIED = "(?i)permission denied, please try again"
     PROMPT_CLOSED = "(?i)connection closed by remote host"
 
     PROMPTS = [