Add healthcheck role as post-update quality gate for Docker containers

roles/healthcheck/defaults/main.yml

@@ -0,0 +1,11 @@
+# Post-update health check (quality gate) defaults.
+# The role verifies that every Docker container is running after an OS update
+# and records the result in the same update log used by the os-updates role.
+
+healthcheck_logging_enabled: "{{ os_update_logging_enabled | default(true) }}"
+healthcheck_log_dir: "{{ os_update_log_dir | default('/ansible/logs') }}"
+healthcheck_log_inventory: "{{ inventory_file | basename | splitext | first }}"
+healthcheck_log_file: "{{ healthcheck_log_dir }}/{{ healthcheck_log_inventory }}/{{ ansible_facts['hostname'] }}/update.log"
+
+# When true, the role fails the playbook if any container is not running.
+healthcheck_fail_on_unhealthy: false