update_host_present.yml

# SPDX-License-Identifier: Apache-2.0
---
- name: Verify that variable node_ip is set
  ansible.builtin.assert:
    that: not( ( thishost.node_ip is undefined) or ( thishost.node_ip is none) or ( thishost.node_ip | trim == '') )
    msg: |
      "The IP address of this host not known. You can solve this problem by
       configuring your managed node accordingly or by setting one of the following variables:
       - sap_ip
       - sap_maintain_etc_hosts_list, member node_ip"

- name: Verify that variable node_ip is using the correct IP address format
  ansible.builtin.assert:
    that:
      - (thishost.node_ip | regex_search(sap_maintain_etc_hosts_regexp_ipv4) is not none
          and thishost.node_ip | regex_search(sap_maintain_etc_hosts_regexp_ipv4) | length > 0)
        or (thishost.node_ip | regex_search(sap_maintain_etc_hosts_regexp_ipv6) is not none
          and thishost.node_ip | regex_search(sap_maintain_etc_hosts_regexp_ipv6) | length > 0)
    msg: |
      "The IP address of this host does not have a correct format.
       Configure the IP address appropriately in of the following variables:
       - sap_ip
       - sap_maintain_etc_hosts_list, member node_ip"

- name: Verify that variable node_name is set
  ansible.builtin.assert:
    that: not( ( thishost.node_name is undefined) or ( thishost.node_name is none) or ( thishost.node_name | trim == '') )
    msg: |
      "The hostname of this host not known. You can solve this problem by
       configuring your managed node accordingly or by setting one of the following variables:
       - sap_hostname
       - sap_maintain_etc_hosts_list, member node_name"

- name: Ensure node_domain is set
  ansible.builtin.set_fact:
    __sap_maintain_etc_hosts_domain:
      "{{ thishost.node_domain if thishost.node_domain is defined and thishost.node_domain != ''
        else (sap_domain if sap_domain is defined and sap_domain != '' else ansible_facts['domain'] | d('')) }}"

- name: Verify that variable domain_name is set
  ansible.builtin.assert:
    that: >
      not( ( __sap_maintain_etc_hosts_domain is undefined) or
      ( __sap_maintain_etc_hosts_domain is none) or
      ( __sap_maintain_etc_hosts_domain | trim == '') )
    msg: |
      "The DNS domain of this host not known. You can solve this problem by
       configuring your DNS accordingly or by setting one of the following variables:
       - sap_domain
       - sap_maintain_etc_hosts_list, member node_domain"

- name: Set default values
  ansible.builtin.set_fact:
    __sap_maintain_etc_hosts_comment: "{{ (thishost.node_comment | d('') + ' ' + thishost.hana_site | d('')) | trim }}"
    __sap_maintain_etc_hosts_alias_mode: "{{ thishost.alias_mode | default('merge') }}"

- name: Prepend Hashtag to comment
  when: __sap_maintain_etc_hosts_comment|length > 0
  ansible.builtin.set_fact:
    __sap_maintain_etc_hosts_comment: "# {{ __sap_maintain_etc_hosts_comment }}"

# The following block reads the existing aliases of a host from /etc/hosts
# and merges it with the defined aliases in the struct
#
# 1. select the line where the first entry is the ip-adress thishost.node_ip
# 2. loop over all hostname entries in the selected line (2 bis NF=last element in line)
# 3. stop looping when a comment sign is found (because these are comments)
# 4. print an element if it is not the hostname or FQDN we want to add
#
# => __sap_maintain_etc_hosts_register_aliases.stdout contains a list of aliases of thishost.node_ip
#
# trunk-ignore(checkov/CKV2_ANSIBLE_3)
- name: Merge existing aliases with new alias list
  when: __sap_maintain_etc_hosts_alias_mode != "overwrite"
  block:
    - name: Get all existing hostname aliases of {{ thishost.node_ip }}
      ansible.builtin.shell: |
        awk '( $1 == "{{ thishost.node_ip }}" ) {
          for (i=2; i<=NF; ++i) {
            if ( $i == "#" ) { break }
            if (( $i != "{{ thishost.node_name }}" ) && ( $i != "{{ thishost.node_name }}.{{ __sap_maintain_etc_hosts_domain }}" )) { printf("%s ",$i) }
          }
        }' "{{ __sap_maintain_etc_hosts_file }}"
      register: __sap_maintain_etc_hosts_register_aliases
      changed_when: false

    - name: Add defined aliases
      ansible.builtin.set_fact:
        __sap_maintain_etc_hosts_aliases: "{{ (__sap_maintain_etc_hosts_register_aliases.stdout.split(' ')
           + thishost.aliases | d([])) | unique | join(' ') | trim }}"

- name: Overwrite existing aliases
  when: __sap_maintain_etc_hosts_alias_mode == "overwrite"
  ansible.builtin.set_fact:
    __sap_maintain_etc_hosts_aliases: "{{ thishost.node_aliases | d([]) | unique | join(' ') }}"

- name: Display host and domain name, and IP address before the modification
  ansible.builtin.debug:
    msg:
      - "hostname = '{{ thishost.node_name }}'"
      - "domain   = '{{ __sap_maintain_etc_hosts_domain }}'"
      - "ip       = '{{ thishost.node_ip }}'"
      - "comment  = '{{ __sap_maintain_etc_hosts_comment }}'"
      - "aliases  = '{{ __sap_maintain_etc_hosts_aliases }}'"
      - "alias mode = '{{ __sap_maintain_etc_hosts_alias_mode }}'"

# We allow more than one line containing sap_ip:
- name: Check for duplicate entries of {{ thishost.node_ip }}
  ansible.builtin.shell: |
    n=$(grep "^{{ thishost.node_ip }}\s" {{ __sap_maintain_etc_hosts_file }} | wc -l)
    if [ $n -gt 1 ]; then
      echo "Duplicate IP entry in {{ __sap_maintain_etc_hosts_file }}!"
      exit 1
    else
      exit 0
    fi
  register: __sap_maintain_etc_hosts_register_duplicate_ip_check
  changed_when: false
  ignore_errors: true
  when: not ansible_check_mode

- name: Report if there is more than one line with the IP address
  ansible.builtin.debug:
    msg:
      - "More than one line containing {{ thishost.node_ip }}. File {{ __sap_maintain_etc_hosts_file }} will not be modified."
  when:
    - not ansible_check_mode
    - __sap_maintain_etc_hosts_register_duplicate_ip_check.rc == 1

- name: Ensure that thisthost.node_name is not part of the localhost entry
  ansible.builtin.replace:
    path: "{{ __sap_maintain_etc_hosts_file }}"
    regexp: '^(127.0.0.1 .*)\s{{ line_item }}(\s.*)$'
    replace: '\1\2'
    backup: true
  when:
    - not ansible_check_mode
    - __sap_maintain_etc_hosts_register_duplicate_ip_check.rc == 0
  become_user: root
  become: true
  loop:
    - "{{ thishost.node_name }}.{{ __sap_maintain_etc_hosts_domain }}"
    - "{{ thishost.node_name }}"
  loop_control:
    loop_var: line_item

- name: Ensure that the entry in hosts file is correct
  ansible.builtin.lineinfile:
    path: "{{ __sap_maintain_etc_hosts_file }}"
    regexp: '^{{ thishost.node_ip }}\s'
    line: "{{ thishost.node_ip }} {{ thishost.node_name }}.{{ __sap_maintain_etc_hosts_domain }} {{ thishost.node_name }} {{ __sap_maintain_etc_hosts_aliases }} {{ __sap_maintain_etc_hosts_comment }}"
    backup: true
  when:
    - not ansible_check_mode
    - __sap_maintain_etc_hosts_register_duplicate_ip_check.rc == 0
  become_user: root
  become: true

# After all nodes are added or deleted, run the consistency check against the hosts file
- name: Check for duplicate or missing entries of hostname and fqdn in {{ __sap_maintain_etc_hosts_file }}
  ansible.builtin.shell: |
    n=$(awk 'BEGIN{a=0}!/^#/&&(/^{{ line_item }}\s/||/\s{{ line_item }}\s/||/\s{{ line_item }}$/){a++}END{print a}' {{ __sap_maintain_etc_hosts_file }})
    if [ $n -eq 1 ]; then
      exit 0
    else
      exit 1
    fi
  loop:
    - "{{ thishost.node_name }}.{{ __sap_maintain_etc_hosts_domain }}"
    - "{{ thishost.node_name }}"
  changed_when: false
  loop_control:
    loop_var: line_item
  when: not ansible_check_mode

- name: Perform the hosts file completeness check
  ansible.builtin.command: awk 'BEGIN{a=0}!/^#/&&(/{{ thishost.node_ip }}/&&/{{ thishost.node_name }}.{{ __sap_maintain_etc_hosts_domain }}/&&/{{ thishost.node_name }}/){a++}END{print a}' {{ __sap_maintain_etc_hosts_file }}
  register: __sap_maintain_etc_hosts_register_ipv4_fqdn_sap_hostname_once_check
  changed_when: false

- name: Display the output of the hosts file completeness check
  ansible.builtin.debug:
    msg: |
      stdout:
      {{ __sap_maintain_etc_hosts_register_ipv4_fqdn_sap_hostname_once_check.stdout | d('') }}
      stderr:
      {{ __sap_maintain_etc_hosts_register_ipv4_fqdn_sap_hostname_once_check.stderr | d('') }}

- name: Display the expected output of the hosts file completeness check
  ansible.builtin.debug:
    msg:
      - "The expected entries in {{ __sap_maintain_etc_hosts_file }} are at least only once:"
      - "{{ thishost.node_ip }} {{ thishost.node_name }}.{{ __sap_maintain_etc_hosts_domain }} {{ thishost.node_name }}"
  when:
    - __sap_maintain_etc_hosts_register_ipv4_fqdn_sap_hostname_once_check.stdout != "1"

- name: Fail if ip4 address, FQDN, or hostname are not in hosts file
  ansible.builtin.fail:
    msg:
      - "Server's ip4 address, FQDN, or hostname are not in {{ __sap_maintain_etc_hosts_file }}!"
      - "Expected:"
      - "{{ thishost.node_ip }} {{ thishost.node_name }}.{{ __sap_maintain_etc_hosts_domain }} {{ thishost.node_name }}"
  when:
    - __sap_maintain_etc_hosts_register_ipv4_fqdn_sap_hostname_once_check.stdout != "1"
  ignore_errors: "{{ ansible_check_mode }}"