Ansible Role: manage-bind 2.0

This role is built as an abtraction layer to configure bind and create DNS zones using YAML syntax.

• Install and manage your bind9 server on Debian/Ubuntu servers.
• Use YAML syntax/files to configure Bind options, zones, etc.

Requirements

Ansible 2.4+

Note: this role requires root access to the bind server

playbook.yml:

- hosts: dnsserver
  roles:
    - role: aalaesar.manage-bind
      become: yes

Role Variables

# host configuration
bind_user:  bind
bind_group: bind
host_dns_srv: self
# log directory
bind_log_dir: /var/log/bind
# Installation configuration
bind_pkg_state: present
bind_pkgs: ['bind9', 'dnsutils']
bind_service_state: started
bind_service_enabled: yes
# Configs
bind_configs_dir: /etc/bind
bind_config_master_zones: []
bind_config_default_zones: 'yes'
RFC1918: no
# Zones files
bind_zones_dir: /var/lib/bind
# Zones default configuration
zones_config_ttl: 38400 #10h45m
zones_config_refresh: 10800 #3h
zones_config_retry: 3600 #1h
zones_config_expire: 604800 #1w
zones_config_minimum: 38400 #10h45m

# remove unmanaged files to keep the server clean
remove_unmanaged_files: true
# initialise list of managed zone files :
list_zone_files: []

Configuring Bind

Introduction to Bind's configuration

Bind uses clause's statements inheritance mechanism to allow precise configuration.

• A clause is a class with its own set of statements.
  • They can have specific or common statements.
  • A clause defined inside another clause will implicitly inherit its mother's common statements.
• A statement is a clause's property.
  • It describes the server's behavior on how to perform a task, whether, when, etc.
  • It may be explicitly or implicitly defined.
• Some inheritance rules:
• Options is the top clause that include all others.
• zone is the lowest clause. It can't have any child. It also contains zone records.
• a clause can override its parent's statement and pass on the new value to its child(ren) by redefining explicitly the statement.

  Here is an ASCII example of this rules:

|##########|  
|  zone1   |  |#########|
|==========|  |  zone2  |
|statement1|  |=========|
|  =john   |  |         |
|##########|  |#########|
     /\            /\
     ||            ||
|#######################|   |##############|   |##############|
|         view1         |   |   zone3      |   |    zone4     |
|=======================|   |==============|   |              |
|  statement2=kangaroo  |   |statement1=bar|   |##############|
|#######################|   |##############|          /\
           /\                     /\                  ||
           ||                     ||                  ||
|#############################################################|
|                          Options                            |
|=============================================================|
|                       statement1=foo                        |
|                      statement2=koala                       |
|#############################################################|
Final result:
According statement1 & statement2 are common to all clauses
zone1: statement1=john, statement2=kangaroo
zone2: statement1=foo, statement2=kangaroo
zone3: statement1=bar, statement2=koala
zone4: statement1=foo, statement2=koala

manage-bind support the following clauses:

• options
• zone
• key

The list of supported statements: See ./vars/main.yml

TODO: views

Caution when defining a statement !

• some statements are defined with complex mappings while others requires just a simple value. Just in case, each statement have its own template self documented.
• manage-bind uses bind's tools named-checkconf and named-checkzone for configuration and zone validation. However, thoses tools are limited to syntax and light coherence verification. This role do not provide advanced validation methods.
• Escape special chars like @ with quotes
• Some statements requires "yes|no" string values: Escape yes and no with quotes as Ansible evaluates them as boolean.

The Options clause

Note: The role comes with some default options.

Defining options' statements

When calling manage-bind, you can pass options statements:

• in an external YAML file declared with options_file.
  • it must contain a mapping of statements called options.
• in a mapping called options inside your playbook

Note: First method excludes the second: the role will load only the statements in the file if you declare it in your playbook.

playbook.yml:

- hosts: dnsserver
  become: yes
  roles:
    - role: aalaesar.manage-bind
      options_file: ./files/options.yml # the role will only load those options
      options: # the next lines are useless is this case
        statement1: ...
        statement2: ...

./files/options.yml:

---
options:
  statement1: ...
  statement2: ...

The list of all the statements available for the options is in ./tests/bind_options.yml

Changing the role's default options :

They are defined in ./defaults/default_options.yml

You may use this file to share a common policy over your infrastructure and override specific options easily

Zones clauses

Zone clauses are defined with statement and zone records

zone declaration

Each zone is declared as an element of the list named zones.

'zones' have to be defined in the playbook and is mandatory.

playbook.yml:

- hosts: dnsserver
  become: yes
  roles:
    - role: aalaesar.manage-bind
      zones:
        "zone 1":
          statements ...
        "zone 2":
          statements ...

Defining zone's statements

A zone is a mapping where the zone name is its main key and its statements are keys:value

• [statement]:value
• type is mandatory statements
• force_file [boolean]: Tell ansible to rewrite the records database file. Useful if your zone is dynamically populated by DNS. - false for slaves zones - true for others
• Some zone types have their own mandatory statements

playbook.yml:

zones:
  example.com: # The domain's name
    type: master # Mandatory. The type of the zone : master|slave|forward|stub
    recursion: "no" # statement overriding global option "recursion" for this zone.
    ... # etc

The list of all zone's statements available is in ./tests/zone_statements.md

Defining zone's records

the zone's records are defined in a mapping named 'records'

This mapping 'records' can be declared:

• in an YAML file specified in the yamlfile key.
• as a mapping inside its zone's mapping

Note: the content of the Yaml files is combined with the zone config: So, in case of duplicates records, the file content will have precedence.

playbook.yml:

zones:
  example.com:
    records:
      SOA: ...
      NS: ...
      ... # etc
    ... # etc
  test.tld:
    yamlfile: "./files/test.tld.yml"
    records:
      SOA: ...
      NS: ...
      A:
       localhost: 127.0.0.1
       test1: 9.8.7.6 # will be overriden by the yamlfile
    ... # etc

In the yaml file, records must be top level mapping:

./files/test.tld.yml:

---
records:
  SOA: ...
  NS: ...
  A:
   test1: 1.2.3.4
   test2: 5.6.7.8
  ... # etc

Adding records in the zone

Zone records have different types, they are declared by type inside records.

each records type is different and follow its own YAML structure.

Manage-bind support the following records

• SOA
• NS
• A
• AAAA
• MX
• SRV
• PTR
• CNAME
• DNAME
• TXT
• ttl can be declared along the zone's records

Dependencies

None.

Example Playbooks

Exemple configuration :

• You own the zones example.tld, example.com and example.org
• You have 2 name servers : dnserver1 (11.22.33.44) & dnserver2 (55.66.77.88)
• dnserver1 is master of example.tld and slave of example.com.
• dnserver2 is master of example.com and slave of example.tld
• example.tld is dynamically populated by a DHCP server

dnserver1's playbook :

---
- hosts: dnserver1
  roles:
    - role: aalaesar.manage-bind
      options:
        allow_recursion: '55.66.77.88'
        allow_transfer: '55.66.77.88'
      zones:
        example.tld:
          type: master
          force_file: no
          notify: '55.66.77.88'
          allow_update:
            - key dhcp_updater
          records:
            - SOA:
                serial: 2016080401
                ns: dnserver1.example.tld.
                email: admin.example.tld.
            - NS:
              - dnserver1.example.tld.
              - dnserver2.example.tld.
            - A:
                dnserver1: 11.22.33.44
                dnserver2: 55.66.77.88
        example.com:
          type: slave
          masters: '55.66.77.88'
      keys:
      - name: dhcp_updater
        algorithm: "hmac-md5"
        secret: "{{myvault_dhcp_key}}"

dnserver2's playbook :

---
- hosts: dnserver2
  roles:
    - role: aalaesar.manage-bind
      options:
        allow_recursion: '11.22.33.44'
        allow_transfer: '11.22.33.44'
      zones:
        example.com:
          type: slave
          notify: '11.22.33.44'
        example.tld:
         type: slave
         masters: '11.22.33.44'
         ymlfile: example.com.yml

YAML file for example.com.yml on dnserver2

---
records:
  ttl: 3d
  SOA:
    serial: 2016080401
    ns: dnserver2.example.com.
    email: admin.example.com.
  NS:
    - srvdns01.example.com.
  A:
    127.0.0.1:
      - '@'
      - dnserver2.example.com.
    host1: 12.34.56.78
    mailsrv: 98.76.54.32
    'ftp.domain.tld.': 95.38.94.196
  MX:
    '@':
      - target: backup.fqdn.
        priority: 20
  CNAME:
    host1: ftp
    '@':
      - www
      - webmail
  TXT:
    - text: '"v=spf1 mx -all"'
    - text: '( "v=DKIM1; k=rsa; t=s; n=core; p=someverylongstringbecausethisisakeyformailsecurity" )  ; ----- DKIM key mail for example.com'
      label: mail._domainkey

More examples are available in the tests folder

License

BSD