Set SSH server keep alive options

When os-net-config configures the network configuration on the overcloud nodes
ssh connections can be dropped.

Since we have ssh retries set to 8 in ansible.cfg, ansible would retry the task
since it was failed by a ssh connection error.

However, the first task was actually still running and it eventually succeeds.

The second task that was kicked off by ansible as a retry, sees that the
deployment is already applied, but the notification file (*.notify.json) does
not yet exist since the first task is still in progress. This causes the second
task to fail with the error reported in the bug and the whole ansible-playbook
run to then fail.

Setting ServerAliveInterval and ServerAliveCountMax ssh options seems to fix
the issue as ssh doesn't drop the first connection when these are configured.

Change-Id: I08781fe2aa6472d3fae5c5f5d0babd1f7a3b9b2d
Closes-Bug: #1792343

releasenotes/notes/set-ssh-server-keep-alive-options-071e1b3b570e78a7.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - The ServerAliveInterval and ServerAliveCountMax SSH options are now set in
+    the mistral ansible action so that when networking configuration is
+    performed on the overcloud nodes SSH will not drop the connection.

tripleo_common/actions/ansible.py

@@ -56,7 +56,9 @@ def write_default_ansible_cfg(work_dir,
                '-o UserKnownHostsFile=/dev/null '
                '-o StrictHostKeyChecking=no '
                '-o ControlMaster=auto '
-               '-o ControlPersist=30m')
+               '-o ControlPersist=30m '
+               '-o ServerAliveInterval=5 '
+               '-o ServerAliveCountMax=5')
     config.set('ssh_connection', 'control_path_dir',
                os.path.join(work_dir, 'ansible-ssh'))
     config.set('ssh_connection', 'retries', '8')