Fix Ssh connection issues on openstack-ansible-ops mnaio builds

We normally see ssh connection issues during the lxc container setup
  portion of OSA builds. Most people usually end up tweaking ansible ssh
  pipeline and retry settings or nerfing the build via ansible fork lowering
  to work around it. This is an old issue that we normally put a more
  permanent fix in our physical environments by setting the ssh maxsessions
  and maxstartups. On the mnaio builds I have been working around this by
  stopping the build before deployment and making the changes in a script.

Change-Id: I54c223e1fb9edf6947bc7f76ff689bad22456420
Closes-Bug: 1752914

multi-node-aio/playbooks/deploy-vms.yml

@@ -177,6 +177,47 @@
     - deploy-vms
 
 
+- name: Set MaxSessions and MaxStartups to reduce connection failures
+  hosts: vm_servers
+  gather_facts: "{{ gather_facts | default(true) }}"
+  pre_tasks:
+    - name: Gather variables for each operating system
+      include_vars: "{{ item }}"
+      with_first_found:
+        - "{{ playbook_dir }}/vars/{{ ansible_distribution | lower }}-{{ ansible_distribution_version | lower }}.yml"
+        - "{{ playbook_dir }}/vars/{{ ansible_distribution | lower }}-{{ ansible_distribution_major_version | lower }}.yml"
+        - "{{ playbook_dir }}/vars/{{ ansible_os_family | lower }}-{{ ansible_distribution_major_version | lower }}.yml"
+        - "{{ playbook_dir }}/vars/{{ ansible_distribution | lower }}.yml"
+        - "{{ playbook_dir }}/vars/{{ ansible_os_family | lower }}.yml"
+      tags:
+        - always
+  tasks:
+    - lineinfile:
+        path: /etc/ssh/sshd_config
+        line: MaxStartups 100
+        state: present
+        regexp: '^MaxStartups.*$'
+      notify:
+        - restart sshd
+    - lineinfile:
+        path: /etc/ssh/sshd_config
+        line: MaxSessions 100
+        state: present
+        regexp: '^MaxSessions.*$'
+      notify:
+        - restart sshd
+  handlers:
+    - name: restart sshd
+      service:
+        name: "{{ ssh_service_name }}"
+        state: restarted
+
+  environment: "{{ deployment_environment_variables | default({}) }}"
+
+  tags:
+    - deploy-vms
+
+
 - name: Setup cinder host volume
   hosts: cinder_hosts:swift_hosts
   gather_facts: false
@@ -276,3 +317,5 @@
 
   tags:
     - deploy-vms
+
+

multi-node-aio/playbooks/vars/ubuntu.yml

@@ -43,3 +43,6 @@ mnaio_pkg_cache_server_distro_packages:
   - apt-cacher-ng
 
 mnaio_host_iptables_service: "{{ (ansible_distribution | lower + '-' + ansible_distribution_version | lower == 'ubuntu-14.04') | ternary('iptables-persistent', 'netfilter-persistent') }}"
+
+ssh_service_name: ssh
+