# Ansible role `dhcp`

Ansible role for setting up ISC DHCPD. The responsibilities of this role are to install packages and manage the configuration ([dhcpd.conf(5)](http://linux.die.net/man/5/dhcpd.conf)). Managing the firewall configuration is NOT a concern of this role. You can do this in your local playbook, or use another role (e.g. [bertvv.rh-base](https://galaxy.ansible.com/bertvv/rh-base).

Refer to the [change log](CHANGELOG.md) for notable changes in each release.

Do you use/like this role? Please consider giving it a star. If you [rate this role](https://galaxy.ansible.com/bertvv/dhcp) on Ansible Galaxy and find it lacking in some respect, please consider opening an Issue with actionable feedback or a PR so we can improve it. Thank you!

## Requirements

No specific requirements

## Role Variables

This role is able to set global options, and to specify subnet declarations.

See the [test playbook](https://github.com/bertvv/ansible-role-dhcp/blob/vagrant-tests/test.yml) for a working example of a DHCP server in a test environment based on Vagrant and VirtualBox. This section is a reference of all supported options.

### Global options

The following variables, when set, will be added to the global section of the DHCP configuration file. If there is no default value specified, the corresponding setting will be left out of `dhcpd.conf(5)`.

See the [dhcp-options(5)](http://linux.die.net/man/5/dhcp-options) man page for more information about these options.

| Variable                          | Comments                                                               |
| :---                              | :---                                                                   |
| `dhcp_global_authoritative`       | Global authoritative statement (`authoritative`, `not authoritative`)  |
| `dhcp_global_booting`             | Global booting (`allow`, `deny`, `ignore`)                             |
| `dhcp_global_bootp`               | Global bootp (`allow`, `deny`, `ignore`)                               |
| `dhcp_global_broadcast_address`   | Global broadcast address                                               |
| `dhcp_global_classes`             | Class definitions with a match statement(1)                            |
| `dhcp_global_default_lease_time`  | Default lease time in seconds                                          |
| `dhcp_global_domain_name_servers` | A list of IP addresses of DNS servers(2)                               |
| `dhcp_global_domain_name`         | The domain name the client should use when resolving host names        |
| `dhcp_global_domain_search`       | A list of domain names to be used by the client to locate non-FQDNs(1) |
| `dhcp_global_failover`            | Failover peer settings (3)                                             |
| `dhcp_global_failover_peer`       | Name for the failover peer (e.g. `foo`)                                |
| `dhcp_global_filename`            | Filename to request for boot                                           |
| `dhcp_global_includes_missing`    | Boolean.  Continue if `includes` file(s) missing from role's files/    |
| `dhcp_global_includes`            | List of config files to be included (from `dhcp_config_dir`)           |
| `dhcp_global_log_facility`        | Global log facility (e.g. `daemon`, `syslog`, `user`, ...)             |
| `dhcp_global_max_lease_time`      | Maximum lease time in seconds                                          |
| `dhcp_global_next_server`         | IP for PXEboot server                                                  |
| `dhcp_global_ntp_servers`         | List of IP addresses of NTP servers                                    |
| `dhcp_global_omapi_port`          | OMAPI port                                                             |
| `dhcp_global_omapi_secret`        | OMAPI secret                                                           |
| `dhcp_global_other_options`       | Array of arbitrary additional global options                           |
| `dhcp_global_routers`             | IP address of the router                                               |
| `dhcp_global_server_name`         | Server name sent to the client                                         |
| `dhcp_global_server_state`        | Service state (started, stopped)                                       |
| `dhcp_global_subnet_mask`         | Global subnet mask                                                     |

**Remarks**

(1) This role supports the definition of classes with a match statement, e.g.:

```Yaml
# Class for VirtualBox VMs
dhcp_global_classes:
  - name: vbox
    match: 'match if binary-to-ascii(16,8,":",substring(hardware, 1, 3)) = "8:0:27"'
```

Class names can be used in the definition of address pools (see below).

(2) The role variable `dhcp_global_domain_name_servers` may be written either as a list (when you have more than one item), or as a string (when you have only one). The following snippet shows an example of both:

```Yaml
# A single DNS server
dhcp_global_domain_name_servers: 8.8.8.8

# A list of DNS servers
dhcp_global_domain_name_servers:
  - 8.8.8.8
  - 8.8.4.4
```

(3) This role also supports the definition of a failover peer, e.g.:

```Yaml
# Failover peer definition
dhcp_global_failover_peer: failover-group
dhcp_global_failover:
  role: primary # | secondary
  address: 192.168.222.2
  port: 647
  peer_address: 192.168.222.3
  peer_port: 647
  max_response_delay: 15
  max_unacked_updates: 10
  load_balance_max_seconds: 5
  split: 255
  mclt: 3600
```

The variable `dhcp_global_failover_peer` contains a name for the configured peer, to be used on a per pool basis. The failover declaration options are specified with the variable `dhcp_global_failover`, a dictionary that may contain the following options:

| Option                     | Required | Comment                                                               |
| :---                       | :---:    | :--                                                                   |
| `address`                  | no       | This server's IP address                                              |
| `hba`                      | no       | colon-separated-hex-list                                              |
| `load_balance_max_seconds` | no       | Cutoff after which load balance is disabled (3 to 5 recommended)      |
| `max-balance`              | no       | Failover pool balance statement                                       |
| `max-lease-misbalance`     | no       | Failover pool balance statement                                       |
| `max-lease-ownership`      | no       | Failover pool balance statement                                       |
| `max_response_delay`       | no       | Maximum seconds without contact before engaging failover              |
| `max_unacked_updates`      | no       | Maximum BNDUPD it can send before receiving a BNDACK (10 recommended) |
| `mclt`                     | no       | Maximum Client Lead Time                                              |
| `min-balance`              | no       | Failover pool balance statement                                       |
| `peer_address`             | no       | Failover peer's IP addres                                             |
| `peer_port`                | no       | This server's port (generally 519/520 or 647/847)                     |
| `port`                     | no       | This server's port (generally 519/520 or 647/847)                     |
| `role`                     | no       | primary, secondary                                                    |
| `split`                    | no       | Load balance split (0-255)                                            |

The failover peer directive has to be in the definition of address pools (see below).

### Subnet declarations

The role variable `dhcp_subnets` contains a list of dicts, specifying the subnet declarations to be added to the DHCP configuration file. Every subnet declaration should have an `ip` and `netmask`, other options are not mandatory. We start this section with an example, a complete overview of supported options follows.

```Yaml
dhcp_subnets:
  - ip: 192.168.222.0
    netmask: 255.255.255.128
    domain_name_servers:
      - 10.0.2.3
      - 10.0.2.4
    range_begin: 192.168.222.50
    range_end: 192.168.222.127
  - ip: 192.168.222.128
    default_lease_time: 3600
    max_lease_time: 7200
    netmask: 255.255.255.128
    domain_name_servers: 10.0.2.3
    routers: 192.168.222.129
```

An alphabetical list of supported options in a subnet declaration:

| Option                | Required | Comment                                                               |
| :---                  | :---:    | :--                                                                   |
| `booting`             | no       | allow,deny,ignore                                                     |
| `bootp`               | no       | allow,deny,ignore                                                     |
| `default_lease_time`  | no       | Default lease time for this subnet (in seconds)                       |
| `domain_name_servers` | no       | List of domain name servers for this subnet(1)                        |
| `domain_search`       | no       | List of domain names for resolution of non-FQDNs(1)                   |
| `filename`            | no       | filename to retrieve from boot server                                 |
| `hosts`               | no       | List of fixed IP address hosts for each subnet, similar to dhcp_hosts |
| `ip`                  | yes      | **Required.** IP address of the subnet                                |
| `max_lease_time`      | no       | Maximum lease time for this subnet (in seconds)                       |
| `netmask`             | yes      | **Required.** Network mask of the subnet (in dotted decimal notation) |
| `next_server`         | no       | IP address of the boot server                                         |
| `range_begin`         | no       | Lowest address in the range of dynamic IP addresses to be assigned    |
| `range_end`           | no       | Highest address in the range of dynamic IP addresses to be assigned   |
| `ranges`              | no       | If multiple ranges are needed, they can be specified as a list (2)    |
| `routers`             | no       | IP address of the gateway for this subnet                             |
| `server_name`         | no       | Server name sent to the client                                        |
| `subnet_mask`         | no       | Overrides the `netmask` of the subnet declaration                     |

You can specify address pools within a subnet by setting the `pools` options. This allows you to specify a pool of addresses that will be treated differently than another pool of addresses, even on the same network segment or subnet. It is a list of dicts with the following keys, all of which are optional:

| Option                | Comment                                             |
| :---                  | :---                                                |
| `allow`               | Specifies which hosts are allowed in this pool(1)   |
| `default_lease_time`  | The default lease time for this pool                |
| `deny`                | Specifies which hosts are not allowed in this pool  |
| `domain_name_servers` | The domain name servers to be used for this pool(1) |
| `max_lease_time`      | The maximum lease time for this pool                |
| `min_lease_time`      | The minimum lease time for this pool                |
| `range_begin`         | The lowest address in this pool                     |
| `range_end`           | The highest address in this pool                    |

(1) For the `allow` and `deny` fields, the options are enumerated in [dhcpd.conf(5)](http://linux.die.net/man/5/dhcpd.conf), but include:

- `booting`
- `bootp`
- `client-updates`
- `known-clients`
- `members of "CLASS"`
- `unknown-clients`

(2) For multiple subnet ranges, they can be specified, thus:

```Yaml
ranges:
  - { begin: 192.168.222.50, end: 192.168.222.99 }
  - { begin: 192.168.222.110, end: 192.168.222.127 }
```

### Host declarations

You can specify hosts that should get a fixed IP address based on their MAC by setting the `dhcp_hosts` option. This is a list of dicts with the following three keys, of which `name` and `mac` are mandatory:

| Option | Comment                                   |
| :---   | :---                                      |
| `name` | The name of the host                      |
| `mac`  | The MAC address of the host               |
| `ip`   | The IP address to be assigned to the host |

```Yaml
dhcp_hosts:
  - name: cl1
    mac: '00:11:22:33:44:55'
    ip: 192.168.222.150
  - name: cl2
    mac: '00:de:ad:be:ef:00'
    ip: 192.168.222.151
```

### Specify PXEBoot server

Setting the variable `dhcp_pxeboot_server`, will redirect PXE clients to the specified PXEBoot server in order to boot over the network. The specified server should have boot images on the expected locations. Use e.g. [bertvv.pxeserver](https://galaxy.ansible.com/bertvv/pxeserver) to configure it.

## Dependencies

No dependencies.

## Example Playbook

See the [test playbook](https://github.com/bertvv/ansible-role-dhcp/blob/vagrant-tests/test.yml)

## Testing

Tests for this role are provided in the form of a Vagrant environment that is kept in a separate branch, `vagrant-tests`. For more information about setting up the test environment and running the tests, refer to the [README](https://github.com/bertvv/ansible-role-dhcp/blob/vagrant-tests/README.md) of the test branch.

## License

BSD

## Contributing

Issues, feature requests, ideas are appreciated and can be posted in the Issues section. Pull requests are also very welcome. Preferably, create a topic branch and when submitting, squash your commits into one (with a descriptive message).
