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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>7. Bind zone file backend</title><link rel="stylesheet" href="docbook.css" type="text/css" /><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="PowerDNS manual" /><link rel="up" href="backends-detail.html" title="Appendix A. Backends in detail" /><link rel="prev" href="db2.html" title="6. DB2 backend" /><link rel="next" href="odbc.html" title="8. ODBC backend" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">7. Bind zone file backend</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="db2.html">Prev</a> </td><th width="60%" align="center">Appendix A. Backends in detail</th><td width="20%" align="right"> <a accesskey="n" href="odbc.html">Next</a></td></tr></table><hr /></div><div class="sect1" title="7. Bind zone file backend"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="bindbackend"></a>7. Bind zone file backend</h2></div></div></div><div class="toc"><dl><dt><span class="sect2"><a href="bindbackend.html#idp9651008">7.1. Operation</a></span></dt><dt><span class="sect2"><a href="bindbackend.html#bind-control-commands">7.2. Pdns_control commands</a></span></dt><dt><span class="sect2"><a href="bindbackend.html#idp9664912">7.3. Performance</a></span></dt><dt><span class="sect2"><a href="bindbackend.html#idp9667648">7.4. Master/slave configuration</a></span></dt><dt><span class="sect2"><a href="bindbackend.html#idp9672048">7.5. Commands</a></span></dt></dl></div><p>
</p><div class="table"><a id="idp9633888"></a><p class="title"><b>Table A.7. Bind zone file backend capabilities</b></p><div class="table-contents"><table summary="Bind zone file backend capabilities" border="1"><colgroup><col /><col /></colgroup><tbody><tr><td>Native</td><td>Yes</td></tr><tr><td>Master</td><td>Yes</td></tr><tr><td>Slave</td><td>Yes</td></tr><tr><td>Superslave</td><td>Experimental</td></tr><tr><td>Autoserial</td><td>No</td></tr><tr><td>DNSSEC</td><td>Yes, but no key storage</td></tr><tr><td>Module name</td><td>none (built in)</td></tr><tr><td>Launch</td><td>bind</td></tr></tbody></table></div></div><p><br class="table-break" />
</p><p>
The BindBackend started life as a demonstration of the versatility of PDNS but quickly gained in importance when there appeared to be demand
for a Bind 'work-alike'.
</p><p>
The BindBackend parses a Bind-style named.conf and extracts information about zones from it. It makes no attempt to honour other configuration flags,
which you should configure (when available) using the PDNS native configuration.
</p><p>
</p><div class="variablelist"><dl><dt><span class="term">--help=bind</span></dt><dd><p>
Outputs all known parameters related to the bindbackend
</p></dd><dt><span class="term">bind-example-zones</span></dt><dd><p>
Loads the 'example.com' zone which can be queried to determine if PowerDNS is functioning without configuring
database backends. This feature is no longer supported from 2.9.21 onwards.
</p></dd><dt><span class="term">bind-config=</span></dt><dd><p>
Location of the Bind configuration file to parse.
</p></dd><dt><span class="term">bind-check-interval=</span></dt><dd><p>
How often to check for zone changes. See 'Operation' section.
</p></dd></dl></div><p>
</p><div class="sect2" title="7.1. Operation"><div class="titlepage"><div><div><h3 class="title"><a id="idp9651008"></a>7.1. Operation</h3></div></div></div><p>
On launch, the BindBackend first parses the named.conf to determine which zones need to be loaded. These will then be parsed
and made available for serving, as they are parsed. So a named.conf with 100.000 zones may take 20 seconds to load, but after 10 seconds,
50.000 zones will already be available. While a domain is being loaded, it is not yet available, to prevent incomplete answers.
</p><p>
Reloading is currently done only when a request for a zone comes in, and then only after <span class="command"><strong>bind-check-interval</strong></span> seconds have passed
after the last check. If a change occurred, access to the zone is disabled, the file is reloaded, access is restored, and the question is answered.
For regular zones, reloading is fast enough to answer the question which lead to the reload within the DNS timeout.
</p><p>
If <span class="command"><strong>bind-check-interval</strong></span> is specified as zero, no checks will be performed until the <span class="command"><strong>pdns_control reload</strong></span>
is given.
</p></div><div class="sect2" title="7.2. Pdns_control commands"><div class="titlepage"><div><div><h3 class="title"><a id="bind-control-commands"></a>7.2. Pdns_control commands</h3></div></div></div><p>
</p><div class="variablelist"><dl><dt><span class="term">bind-domain-status <strong class="userinput"><code>domain</code></strong> [<strong class="userinput"><code>domain</code></strong>]</span></dt><dd><p>
Output status of domain or domains. Can be one of 'seen in named.conf, not parsed', 'parsed successfully at <time;>' or
'error parsing at line ... at <time>'.
</p></dd><dt><span class="term">bind-list-rejects</span></dt><dd><p>
Lists all zones that have problems, and what those problems are.
</p></dd><dt><span class="term">bind-reload-now <strong class="userinput"><code>domain</code></strong></span></dt><dd><p>
Reloads a zone from disk NOW, reporting back results.
</p></dd></dl></div><p>
</p></div><div class="sect2" title="7.3. Performance"><div class="titlepage"><div><div><h3 class="title"><a id="idp9664912"></a>7.3. Performance</h3></div></div></div><p>
The BindBackend does not benefit from the packet cache as it is fast enough on its own. Furthermore, on most systems, there will
be no benefit in using multiple CPUs for the packetcache, so a noticeable speedup can be attained by specifying
<span class="command"><strong>distributor-threads=1</strong></span> in <code class="filename">pdns.conf</code>.
</p></div><div class="sect2" title="7.4. Master/slave configuration"><div class="titlepage"><div><div><h3 class="title"><a id="idp9667648"></a>7.4. Master/slave configuration</h3></div></div></div><div class="sect3" title="Master"><div class="titlepage"><div><div><h4 class="title"><a id="idp9668208"></a>Master</h4></div></div></div><p>
Works as expected. At startup, no notification storm is performed as this is generally not useful. Perhaps in the future the Bind Backend
will attempt to store zone metadata in the zone, allowing it to determine if a zone has changed its serial since the last time
notifications were sent out.
</p><p>
Changes which are discovered when reloading zones do lead to notifications however.
</p></div><div class="sect3" title="Slave"><div class="titlepage"><div><div><h4 class="title"><a id="idp9670096"></a>Slave</h4></div></div></div><p>
Also works as expected. The Bind backend expects to be able to write to a directory where a slave domain lives. The incoming zone is stored
as 'zonename.RANDOM' and atomically renamed if it is retrieved successfully, and parsed only then.
</p><p>
In the future, this may be improved so the old zone remains available should parsing fail.
</p></div></div><div class="sect2" title="7.5. Commands"><div class="titlepage"><div><div><h3 class="title"><a id="idp9672048"></a>7.5. Commands</h3></div></div></div><p>
<span class="command"><strong>pdns_control</strong></span> offers commands to communicate instructions to PowerDNS. These are detailed here.
</p><div class="variablelist"><dl><dt><span class="term">rediscover</span></dt><dd><p>
Reread the bind configuration file (<code class="filename">named.conf</code>). If parsing fails, the old configuration
remains in force and pdns_control reports the error. Any newly discovered domains are read, discarded domains
are removed from memory.
</p><div class="note" title="Note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="note.png" /></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p>
Except that with 2.9.3, they are not removed from memory.
</p></td></tr></table></div><p>
</p></dd><dt><span class="term">reload</span></dt><dd><p>
All zones with a changed timestamp are reloaded at the next incoming query for them.
</p></dd></dl></div><p>
</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="db2.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="backends-detail.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="odbc.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">6. DB2 backend </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> 8. ODBC backend</td></tr></table></div></body></html>
