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= pvl-hosts =

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DNS/DHCP hosts management/integration for ISC bind9 and dhcpd.

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== Hosts ==

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The `pvl.hosts-*` tools read hosts files as input, which have an ini format, using section names as hostnames to configure attributes for that host:

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    [foo]

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        ip          = 192.0.2.1

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        ethernet    = 00:11:22:33:44:55

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    [bar]

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        ip          = 192.0.2.2

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        ethernet    = 01:23:45:67:89:ab

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The domain name for a host is determined from the basename of the config file, so this example file would generate something like the following output for use in a `zone "example.com" { ... }` zonefile:

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    $ bin/pvl.hosts-forward etc/hosts/example.com 

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    foo                               A     192.0.2.1

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    bar                               A     192.0.2.2

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And correspondingly, the reverse zone for `2.0.192.in-addr.arpa`:

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    $ bin/pvl.hosts-reverse --zone-prefix=192.0.2.0/24 etc/hosts/example.com

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    1                                 PTR   foo.example.com.

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    2                                 PTR   bar.example.com.

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And the associated DHCP hosts:

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    $ bin/pvl.hosts-dhcp etc/hosts/example.com 

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    host foo {

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        option host-name foo;

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        hardware ethernet 00:11:22:33:44:55;

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        fixed-address 192.0.2.1;

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    }

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    host bar {

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        option host-name bar;

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        hardware ethernet 01:23:45:67:89:ab;

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        fixed-address 192.0.2.2;

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    }

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=== Include directories ===

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Host configs can be included:

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    $ cat etc/hosts/test

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    include = test.d/

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    $ cat etc/hosts/test.d/foo 

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    ip = 192.0.2.1

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    $ cat etc/hosts/test.d/bar 

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    ip = 192.0.2.2

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    $ bin/pvl.hosts-forward etc/hosts/test

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    foo                               A     192.0.2.1

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    bar                               A     192.0.2.2

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Including a directory of files is equivalent to substituiting each file as a named section at the level of the include = statement. Note that this means that included files are treated directly as host definitions, IOW, you should NOT include a section name in an included host file unless you want to declare an additional subdomain:

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    $ cat etc/hosts/wrong.test 

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    include = wrong.d/

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    $ etc/hosts/wrong.d/host

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    [host]

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        ip  = 192.0.2.6

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Using the --root-zone option to generate the full FQDN for the host:

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    $ bin/pvl.hosts-forward --root-zone etc/hosts/wrong.test 

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    host.host.wrong.test              A     192.0.2.6

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=== Host aliases ===

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Hosts can specify DNS aliases:

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    [foo]

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        ip          = 127.0.0.1

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        alias       = test1

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    [bar]

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        ip          = 127.0.0.2

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        alias       = test2

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    $ bin/pvl.hosts-forward --forward-zone alias.test etc/hosts/alias.test 

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    foo                               A     127.0.0.1

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    test1                             CNAME foo

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    bar                               A     127.0.0.2

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    test2                             CNAME bar

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=== Generated hosts ===

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The hosts file format supports something similar to bind9's $GENERATE directive for hosts:

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    [asdf{1-3}]

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        ip  = 10.100.100.$

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    $ bin/pvl.hosts-dns --forward-zone=asdf etc/hosts/asdf 

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    asdf1@asdf                        A     10.100.100.1

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    asdf2@asdf                        A     10.100.100.2

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    asdf3@asdf                        A     10.100.100.3

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Note that the generate directives are interpreted and compiled directly by pvl.hosts. 

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Most of the $GENERATE options should be supported, with a little clever hackery:

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    [asdf{1-5/2}{0,2}]

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       ip  = 10.100.100.$${10}

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    $ bin/pvl.hosts-dns --forward-zone=asdf2 etc/hosts/asdf2

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    asdf01@asdf2                      A     10.100.100.11

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    asdf03@asdf2                      A     10.100.100.13

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    asdf05@asdf2                      A     10.100.100.15

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This feature can be used for generating reverse delegations:

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    [foo-{240-247}]

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        forward =

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        reverse = $.240/29.0.0.10.in-addr.arpa

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        ip      = 10.0.0.$

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    $ bin/pvl.hosts-dns --reverse-zone=10 etc/hosts/reverse 

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    240.0.0                           CNAME 240.240/29.0.0.10.in-addr.arpa.

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    241.0.0                           CNAME 241.240/29.0.0.10.in-addr.arpa.

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    242.0.0                           CNAME 242.240/29.0.0.10.in-addr.arpa.

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    243.0.0                           CNAME 243.240/29.0.0.10.in-addr.arpa.

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    244.0.0                           CNAME 244.240/29.0.0.10.in-addr.arpa.

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    245.0.0                           CNAME 245.240/29.0.0.10.in-addr.arpa.

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    246.0.0                           CNAME 246.240/29.0.0.10.in-addr.arpa.

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    247.0.0                           CNAME 247.240/29.0.0.10.in-addr.arpa.

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=== DHCP Options ===

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The hosts need not specify any fixed ip address, leaving IP address allocation to dhcpd:

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    [foo]

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        ethernet    = 00:11:22:33:44:55 

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    $ bin/pvl.hosts-dhcp etc/hosts/dhcp1 

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    host foo {

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        option host-name foo;

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        hardware ethernet 00:11:22:33:44:55;

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    }

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=== DHCP Boot options ===

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The hosts can specify DHCP boot server/file options:

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    [foo]

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        ethernet    = 00:11:22:33:44:55

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        boot        = boot.lan:debian/wheezy/pxelinux.0

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    $ bin/pvl.hosts-dhcp etc/hosts/boot.dhcp 

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    host foo {

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        option host-name foo;

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        hardware ethernet 00:11:22:33:44:55;

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        next-server boot.lan;

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        filename debian/wheezy/pxelinux.0;

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    }

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=== DHCP hosts in multiple subnets/domains ===

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A host with different interfaces in multiple domains must specify unique interface names:

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    [foo.dhcp]

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        [[asdf]]

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            ip              = 10.1.0.1

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            ethernet.eth1   = 00:11:22:33:44:55

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    [bar.dhcp]

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        [[asdf]]

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            ip              = 10.2.0.1

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            ethernet.eth2   = 55:44:33:22:11:00

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    $ bin/pvl.hosts-dhcp etc/hosts/dhcp2 

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    host asdf-eth1 {

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        option host-name asdf;

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        hardware ethernet 00:11:22:33:44:55;

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        fixed-address 10.1.0.1;

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    }

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    host asdf-eth2 {

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        option host-name asdf;

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        hardware ethernet 55:44:33:22:11:00;

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        fixed-address 10.2.0.1;

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    }

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== Host structure ==

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Creating a tree of symlinks for managing split zonefile domains can be useful:

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    $ tree etc/zones/

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    etc/zones/

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    ├── forward

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    │   └── test

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    │       ├── asdf.test -> ../../../hosts/asdf.test

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    │       └── test -> ../../../hosts/test

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    └── reverse

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        └── 192.0.2

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            ├── asdf.test -> ../../../hosts/asdf.test

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            └── test -> ../../../hosts/test

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Given a structure like above, the `pvl.hosts-forward` can generate a single forward zone containing all sub-domains:

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    $ bin/pvl.hosts-forward --hosts-include etc/hosts/ etc/zones/forward/test/

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    foo                               A     192.0.2.1

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    bar                               A     192.0.2.2

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    quux.asdf                         A     192.0.2.5

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Note that the directory name is treated separately as a zone origin; the file names within the domain are still treated as a flat namespace independent of the directory name (which is different than *pvl.hosts* would behave for `include = etc/zones/forward/test/`).

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The same trick also works for `pvl.hosts-reverse`:

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    $ bin/pvl.hosts-reverse --hosts-include etc/hosts/ etc/zones/reverse/192.0.2/

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    1                                 PTR   foo.test.

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    2                                 PTR   bar.test.

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    5                                 PTR   quux.asdf.test.

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