commit 110d870eaac2efee2e131babacebc5337a15b3e3
Author: Bernd Finger <bfinger@redhat.com>
Date:   Thu Jul 16 11:56:22 2020 +0200

    do not modify /etc/hosts if there is more than one line containing sap_ip

diff --git a/tasks/RedHat/generic/check-dns-name-resolution.yml b/tasks/RedHat/generic/check-dns-name-resolution.yml
index 9450b60..b7b915d 100644
--- a/tasks/RedHat/generic/check-dns-name-resolution.yml
+++ b/tasks/RedHat/generic/check-dns-name-resolution.yml
@@ -9,11 +9,12 @@
       - "sap_domain = {{ sap_domain }}"
       - "sap_ip = {{ sap_ip }}"
 
-- name: Verify that the DNS domain is set
-  assert:
-    that:
-      not( (sap_domain is undefined) or (sap_domain is none) or (sap_domain | trim == '') )
-    msg: "You need to define the variable 'sap_domain' in defaults/main.yml."
+# moved to configure-etc-hosts.yml:
+#- name: Verify that the DNS domain is set
+#  assert:
+#    that:
+#      not( (sap_domain is undefined) or (sap_domain is none) or (sap_domain | trim == '') )
+#    msg: "You need to define the variable 'sap_domain' in defaults/main.yml."
 
 ### DNS is not that necessary and as such the errors are ignored
 ### for production it is strongly recommended to have proper DNS setup
diff --git a/tasks/RedHat/generic/configure-etc-hosts.yml b/tasks/RedHat/generic/configure-etc-hosts.yml
index 18872d1..488fba7 100644
--- a/tasks/RedHat/generic/configure-etc-hosts.yml
+++ b/tasks/RedHat/generic/configure-etc-hosts.yml
@@ -13,7 +13,7 @@
   shell: |
     awk '( $1 == "{{ sap_ip }}" ) {
       for (i=2; i<=NF; ++i) {
-        if (( $i != "{{ sap_hostname }}" ) && ( $i != "{{ sap_hostname }}.{{ sap_domain }}" )) { printf $i" " }
+        if (( $i != "{{ sap_hostname }}" ) && ( $i != "{{ sap_hostname }}.{{ sap_domain }}" )) { printf " "$i }
       }
     }' /etc/hosts
   register: sap_hostname_aliases
@@ -54,39 +54,48 @@
     msg:
       - "System {{ sap_hostname }}, {{ sap_hostname }}.{{ sap_domain }} has ipv4 address {{ sap_ip }}."
 
+# We allow more than one line containing sap_ip:
+- name: Check for duplicate entries of {{ sap_ip }} in /etc/hosts
+  shell: |
+    n=$(grep "^{{ sap_ip }}\s" /etc/hosts | wc -l)
+    if [ $n -gt 1 ]; then
+      echo "Duplicate IP entry in /etc/hosts!"
+      exit 1
+    else
+      exit 0
+    fi
+  register: shell_result
+  changed_when: false
+  ignore_errors: yes
+  when: not ansible_check_mode
+
+- name: Verify that variable sap_domain is set
+  assert:
+    that:
+      not( (sap_domain is undefined) or (sap_domain is none) or (sap_domain | trim == '') )
+    msg: "Variable 'sap_domain' is undefined or empty. Please define it in defaults/main.yml or via --extra-vars!"
+
 - debug:
     msg:
-      - "Hostname alias(es) found: {{ sap_hostname_aliases.stdout }}. So /etc/hosts will not be modified."
+      - "More than one line containing {{ sap_ip }}. File /etc/hosts will not be modified."
   when:
-    - sap_hostname_aliases.stdout != ''
+    - not ansible_check_mode
+    - shell_result.stdout == 'Duplicate IP entry in /etc/hosts!'
     - sap_preconfigure_modify_etc_hosts | bool
 
-# We only modify /etc/hosts if there is no hostname alias defined:
 - name: Ensure that the entry in /etc/hosts is correct
   lineinfile:
     path: /etc/hosts
     regexp: '^{{ sap_ip }}\s'
-    line: "{{ sap_ip }} {{ sap_hostname }}.{{ sap_domain }} {{ sap_hostname }}"
+    line: "{{ sap_ip }} {{ sap_hostname }}.{{ sap_domain }} {{ sap_hostname }}{{sap_hostname_aliases.stdout }}"
     backup: yes
   when:
-    - sap_hostname_aliases.stdout == ''
+    - not ansible_check_mode
+    - sap_domain != ''
+    - shell_result.stdout != 'Duplicate IP entry in /etc/hosts!'
     - sap_preconfigure_modify_etc_hosts | bool
 
-# We will allow more than one line containing sap_ip:
-- name: Check for duplicate entries of {{ sap_ip }} in /etc/hosts
-  shell: |
-    n=$(grep "^{{ sap_ip }}\s" /etc/hosts | wc -l)
-    if [ $n -eq 1 ]; then
-      exit 0
-    else
-      echo "Duplicate IP entry in /etc/hosts!"
-      exit 1
-    fi
-  changed_when: false
-  ignore_errors: yes
-  when: not ansible_check_mode
-
-- name: Check for duplicate entries of hostname and fqdn in /etc/hosts
+- name: Check for duplicate or missing entries of hostname and fqdn in /etc/hosts
   shell: |
     n=$(grep -w "{{ line_item }}" /etc/hosts | wc -l)
     if [ $n -eq 1 ]; then