mirror of
https://github.com/coredns/coredns.git
synced 2025-11-03 18:53:13 -05:00
16d489851e
nit-picking PR, when using the name of the plugin make it cursive. Signed-off-by: Miek Gieben <miek@miek.nl>
126 lines
4.0 KiB
Markdown
126 lines
4.0 KiB
Markdown
# hosts
|
|
|
|
## Name
|
|
|
|
*hosts* - enables serving zone data from a `/etc/hosts` style file.
|
|
|
|
## Description
|
|
|
|
The *hosts* plugin is useful for serving zones from a `/etc/hosts` file. It serves from a preloaded
|
|
file that exists on disk. It checks the file for changes and updates the zones accordingly. This
|
|
plugin only supports A, AAAA, and PTR records. The hosts plugin can be used with readily
|
|
available hosts files that block access to advertising servers.
|
|
|
|
The plugin reloads the content of the hosts file every 5 seconds. Upon reload, CoreDNS will use the
|
|
new definitions. Should the file be deleted, any inlined content will continue to be served. When
|
|
the file is restored, it will then again be used.
|
|
|
|
If you want to pass the request to the rest of the plugin chain if there is no match in the *hosts*
|
|
plugin, you must specify the `fallthrough` option.
|
|
|
|
This plugin can only be used once per Server Block.
|
|
|
|
## The hosts file
|
|
|
|
Commonly the entries are of the form `IP_address canonical_hostname [aliases...]` as explained by
|
|
the hosts(5) man page.
|
|
|
|
Examples:
|
|
|
|
~~~
|
|
# The following lines are desirable for IPv4 capable hosts
|
|
127.0.0.1 localhost
|
|
192.168.1.10 example.com example
|
|
|
|
# The following lines are desirable for IPv6 capable hosts
|
|
::1 localhost ip6-localhost ip6-loopback
|
|
fdfc:a744:27b5:3b0e::1 example.com example
|
|
~~~
|
|
|
|
### PTR records
|
|
|
|
PTR records for reverse lookups are generated automatically by CoreDNS (based on the hosts file
|
|
entries) and cannot be created manually.
|
|
|
|
## Syntax
|
|
|
|
~~~
|
|
hosts [FILE [ZONES...]] {
|
|
[INLINE]
|
|
ttl SECONDS
|
|
no_reverse
|
|
reload DURATION
|
|
fallthrough [ZONES...]
|
|
}
|
|
~~~
|
|
|
|
* **FILE** the hosts file to read and parse. If the path is relative the path from the *root*
|
|
plugin will be prepended to it. Defaults to /etc/hosts if omitted. We scan the file for changes
|
|
every 5 seconds.
|
|
* **ZONES** zones it should be authoritative for. If empty, the zones from the configuration block
|
|
are used.
|
|
* **INLINE** the hosts file contents inlined in Corefile. If there are any lines before fallthrough
|
|
then all of them will be treated as the additional content for hosts file. The specified hosts
|
|
file path will still be read but entries will be overridden.
|
|
* `ttl` change the DNS TTL of the records generated (forward and reverse). The default is 3600 seconds (1 hour).
|
|
* `reload` change the period between each hostsfile reload. A time of zero seconds disables the
|
|
feature. Examples of valid durations: "300ms", "1.5h" or "2h45m". See Go's
|
|
[time](https://godoc.org/time). package.
|
|
* `no_reverse` disable the automatic generation of the `in-addr.arpa` or `ip6.arpa` entries for the hosts
|
|
* `fallthrough` If zone matches and no record can be generated, pass request to the next plugin.
|
|
If **[ZONES...]** is omitted, then fallthrough happens for all zones for which the plugin
|
|
is authoritative. If specific zones are listed (for example `in-addr.arpa` and `ip6.arpa`), then only
|
|
queries for those zones will be subject to fallthrough.
|
|
|
|
## Metrics
|
|
|
|
If monitoring is enabled (via the *prometheus* plugin) then the following metrics are exported:
|
|
|
|
- `coredns_hosts_entries{}` - The combined number of entries in hosts and Corefile.
|
|
- `coredns_hosts_reload_timestamp_seconds{}` - The timestamp of the last reload of hosts file.
|
|
|
|
## Examples
|
|
|
|
Load `/etc/hosts` file.
|
|
|
|
~~~ corefile
|
|
. {
|
|
hosts
|
|
}
|
|
~~~
|
|
|
|
Load `example.hosts` file in the current directory.
|
|
|
|
~~~
|
|
. {
|
|
hosts example.hosts
|
|
}
|
|
~~~
|
|
|
|
Load example.hosts file and only serve example.org and example.net from it and fall through to the
|
|
next plugin if query doesn't match.
|
|
|
|
~~~
|
|
. {
|
|
hosts example.hosts example.org example.net {
|
|
fallthrough
|
|
}
|
|
}
|
|
~~~
|
|
|
|
Load hosts file inlined in Corefile.
|
|
|
|
~~~
|
|
example.hosts example.org {
|
|
hosts {
|
|
10.0.0.1 example.org
|
|
fallthrough
|
|
}
|
|
whoami
|
|
}
|
|
~~~
|
|
|
|
## See also
|
|
|
|
The form of the entries in the `/etc/hosts` file are based on IETF [RFC 952](https://tools.ietf.org/html/rfc952) which was updated by IETF [RFC 1123](https://tools.ietf.org/html/rfc1123).
|