Support __sshd_supports_validate

tasks/install.yml

@@ -103,6 +103,7 @@
       changed_when: false
       when:
         - __sshd_hostkeys_from_config | from_json == []
+        - __sshd_supports_validate
 
     - name: Generate temporary hostkey
       ansible.builtin.command: >

tasks/install_config.yml

@@ -16,7 +16,9 @@
     group: "{{ sshd_config_group }}"
     mode: "{{ sshd_config_mode }}"
     validate: >-
-      {% if sshd_test_hostkey is defined and sshd_test_hostkey.path is defined %}
+      {% if not __sshd_supports_validate %}
+        true %s
+      {% elif sshd_test_hostkey is defined and sshd_test_hostkey.path is defined %}
         {{ sshd_binary }} -t -f %s -h {{ sshd_test_hostkey.path }}/rsa_key
       {% else %}
         {{ sshd_binary }} -t -f %s
@@ -33,7 +35,9 @@
     group: "{{ sshd_config_group }}"
     mode: "{{ sshd_config_mode }}"
     validate: >-
-      {% if sshd_test_hostkey is defined and sshd_test_hostkey.path is defined %}
+      {% if not __sshd_supports_validate %}
+        true %s
+      {% elif sshd_test_hostkey is defined and sshd_test_hostkey.path is defined %}
         {{ sshd_binary }} -t -f %s -h {{ sshd_test_hostkey.path }}/rsa_key
       {% else %}
         {{ sshd_binary }} -t -f %s

tasks/install_namespace.yml

@@ -13,7 +13,9 @@
     create: yes
     marker: "# {mark} sshd system role managed block: namespace {{ sshd_config_namespace }}"
     validate: >-
-      {% if sshd_test_hostkey is defined and sshd_test_hostkey.path is defined %}
+      {% if not __sshd_supports_validate %}
+        true %s
+      {% elif sshd_test_hostkey is defined and sshd_test_hostkey.path is defined %}
         {{ sshd_binary }} -t -f %s -h {{ sshd_test_hostkey.path }}/rsa_key
       {% else %}
         {{ sshd_binary }} -t -f %s

vars/main.yml

@@ -47,3 +47,7 @@ __sshd_drop_in_dir_mode: '0755'
 # This is usually the case when the selection is up to the OpenSSH defaults or
 # drop-in directory is used.
 __sshd_verify_hostkeys_default: []
+
+# This switch can control if the validate step is supported by the target OS.
+# This is useful for very old OpenSSH or for tests that generate invalid configurations
+__sshd_supports_validate: true