<title>Databases and Database Version Numbers</title>
<para>
- Kea stores leases in one of several supported databases.
- As future versions of Kea are released, the structure of those
- databases will change. For example, Kea currently only stores
- lease information: in the future, additional data - such as host
- reservation details - will also be stored.
+ Kea supports storing leases and host reservations (i.e. static
+ assignments of addresses, prefixes and options) in one of
+ the several supported databases. As future versions of Kea
+ are released, the structure of those databases will change.
+ For example, Kea currently only stores lease information
+ and host reservations: in the future, additional
+ data - such as subnet definitions - will also be stored.
</para>
<para>
</section>
</section> <!-- end of CQL sections -->
+ <section>
+ <title>Using read only databases with host reservations</title>
+ <para>If read only database is used for storing host reservations,
+ Kea must be explicitly configured to operate on the database in
+ the read only mode.
+ Sections <xref linkend="read-only-database-configuration4"/> and
+ <xref linkend="read-only-database-configuration6"/> describe when
+ such configuration may be desired and how to configure Kea to
+ operate using read only host database.
+ </para>
+ </section>
+
<section>
<title>Limitations related to the use of the SQL databases</title>
2147483647 seconds since the beginning of the epoch (around year 2038).
</para>
</section>
+
</section> <!-- End of Database sections -->
</chapter>
If there is no password to the account, set the password to the empty string
"". (This is also the default.)</para>
</section>
+
+<section id="read-only-database-configuration4">
+<title>Using Read Only Databases for Host Reservations</title>
+<para>
+In some deployments the database user, which name is specified in the database backend
+configuration, may not have write privileges to the database. This is often
+required by the policy within a given network to secure the data from being
+unintentionally modified. In many cases administrators have inventory databases
+deployed, which contain substantially more information about the hosts than
+static reservations assigned to them. Such database can be used to create
+a view of a Kea hosts database and such view is often read only.
+</para>
+<para>
+Kea host database backends operate with implicit configuration to both read
+and write from the database. If the host database is read only for the
+particular user, the backend will fail to start and consequently the server
+will refuse to start/reconfigure. If the administrator intends to use the
+read only host database for retrieving reservations for clients, to assign
+specific addresses and options, it is possible to explicitly configure
+Kea to start in "read-only" mode. This is controlled by the
+<command>readonly</command> boolean parameter as follows:
+<screen>
+"Dhcp4": { "hosts-database": { <userinput>"readonly": true</userinput>, ... }, ... }
+</screen>
+Setting this parameter to <userinput>false</userinput> would configure the
+database backend to operate in "read-write" mode, which is also a default
+configuration if the parameter is not specified.
+</para>
+<note><para>The <command>readonly</command> parameter is currently only supported
+for MySQL and PostgreSQL databases.</para></note>
+</section>
+
</section>
<section id="dhcp4-interface-configuration">
If there is no password to the account, set the password to the empty string
"". (This is also the default.)</para>
</section>
+
</section>
<section id="hosts6-storage">
If there is no password to the account, set the password to the empty string
"". (This is also the default.)</para>
</section>
+
+<section id="read-only-database-configuration6">
+<title>Using Read Only Databases for Host Reservations</title>
+<para>
+In some deployments the database user, which name is specified in the database backend
+configuration, may not have write privileges to the database. This is often
+required by the policy within a given network to secure the data from being
+unintentionally modified. In many cases administrators have inventory databases
+deployed, which contain substantially more information about the hosts than
+static reservations assigned to them. Such database can be used to create
+a view of a Kea hosts database and such view is often read only.
+</para>
+<para>
+Kea host database backends operate with implicit configuration to both read
+and write from the database. If the host database is read only for the
+particular user, the backend will fail to start and consequently the server
+will refuse to start/reconfigure. If the administrator intends to use the
+read only host database for retrieving reservations for clients, to assign
+specific addresses and options, it is possible to explicitly configure
+Kea to start in "read-only" mode. This is controlled by the
+<command>readonly</command> boolean parameter as follows:
+<screen>
+"Dhcp4": { "hosts-database": { <userinput>"readonly": true</userinput>, ... }, ... }
+</screen>
+Setting this parameter to <userinput>false</userinput> would configure the
+database backend to operate in "read-write" mode, which is also a default
+configuration if the parameter is not specified.
+</para>
+<note><para>The <command>readonly</command> parameter is currently only supported
+for MySQL and PostgreSQL databases.</para></note>
+</section>
+
</section>
--->
+
<section id="dhcp6-interface-selection">
<title>Interface selection</title>
projects / thirdparty / kea.git / commitdiff
