"renew-timer": 1000,
"rebind-timer": 2000,
+# Kea supports two types of identifiers in DHCPv6: hw-address (hardware/MAC address
+# of the client) and duid (DUID inserted by the client). When told to do so, Kea can
+# check for each of those identifier types, but it takes a costly database lookup
+# to do so. It is therefore useful from performance perspective to use only
+# that reservation types that are actually used in a given network.
+ "host-reservation-identifiers": [ "duid", "hw-address" ],
+
# The following list defines subnets. Subnet, pools and interface definitions
# are the same as in the regular scenario, without host reservations.
# least subnet and pool entries.
},
# This is similar to the previous one, but this time the reservation is done
# based on hardware/MAC address. The server will do its best to extract
-# the hardware/MAC address from received packets.
+# the hardware/MAC address from received packets (see 'mac-sources' directive
+# for details). This particular reservation also specifies two extra options
+# to be available for this client. If there are options with the same code
+# specified in global, subnet or class scope, the values defined at host level
+# takes precedence.
{
"hw-address": "00:01:02:03:04:05",
- "ip-addresses": [ "2001:db8:1::101" ]
+ "ip-addresses": [ "2001:db8:1::101" ],
+ "option-data": [
+ {
+ "name": "dns-servers",
+ "data": "3000:1::234"
+ },
+ {
+ "name": "nis-servers",
+ "data": "3000:1::234"
+ }]
},
-# This is a bit more advanced configuration. The client with specified
-# DUID will get a reserved address, prefix and a hostname.
+# This is a bit more advanced reservation. The client with specified
+# DUID will get a reserved address, a reserved prefix and a hostname.
{
"duid": "01:02:03:04:05:06:07:08:09:0A",
"ip-addresses": [ "2001:db8:1::102" ],
<section id="reservation6-options">
<title>Reserving specific options</title>
- <!-- @todo: replace this with the actual text once #3573 is implemented -->
- <para>Currently it is not possible to specify options in host
- reservation. Such a feature will be added in the upcoming Kea
- releases.</para>
+
+ <para>Kea 1.1.0 introduced the ability to specify options on a
+ per host basis. The options follow the same rules as any other
+ options. These can be standard options (see <xref
+ linkend="dhcp6-std-options" />), custom options (see <xref
+ linkend="dhcp6-custom-options"/>) or vendor specific options
+ (see <xref linkend="dhcp6-vendor-opts" />). The following
+ example showcases how standard options can be defined.</para>
+
+ <screen>
+"reservations": [
+{
+ "hw-address": "aa:bb:cc:dd:ee:ff",
+ "ip-address": "192.0.2.1",
+ <userinput>"option-data": [
+ {
+ "duid": "01:02:03:05:06:07:08",
+ "ip-addresses": [ "2001:db8:1::2" ],
+ "option-data": [ {
+ "name": "dns-servers",
+ "data": "3000:1::234"
+ },
+ {
+ "name": "nis-servers",
+ "data": "3000:1::234"
+ }
+ } ]</userinput>
+} ]</screen>
+
+ <para>Vendor specific options can be reserved in similar manner:</para>
+
+ <screen>
+"reservations": [
+{
+ "duid": "aa:bb:cc:dd:ee:ff",
+ "ip-addresses": [ "2001:db8::1" ],
+ <userinput>"option-data": [
+ {
+ "name": "vendor-opts",
+ "data": 4491"
+ },
+ {
+ "name": "tftp-servers",
+ "space": "vendor-4491",
+ "data": "3000:1::234"
+ } ]</userinput>
+} ]</screen>
+
+<para>
+ Options defined on host level have the highest priority. In other words,
+ if there are option defined with the same type on global, subnet, class and
+ host level, the host specific values will be used.
+</para>
+
</section>
- <section id="reservation6-mode">
+ <section id="reservations6-tuning">
<title>Fine Tuning IPv6 Host Reservation</title>
- <note>
- <para><command>reservation-mode</command> in the DHCPv6 server is
- implemented in Kea 0.9.1 beta, but has not been tested and is
- considered experimental.</para>
- </note>
-
<para>Host reservation capability introduces additional restrictions for the
allocation engine during lease selection and renewal. In particular, three
major checks are necessary. First, when selecting a new lease, it is not
}
</screen>
</para>
+
+ <para>Another aspect of the host reservations are different types of
+ identifiers. Currently (June 2016) Kea supports two types of identifiers
+ in DHCPv6: hw-address and duid, but more identifier types
+ are likely to be added in the future. This is beneficial from the
+ usability perspective. However, there is a drawback. For each incoming
+ packet Kea has to to extract each identifier type and then query the
+ database to see if there's a reservation done by this particular
+ identifier. If there is not, the next identifier is extracted and next
+ query is issued. This process continues until either a reservation is
+ found or all identifier types were checked. Over time with increasing
+ number of supported identifier types, Kea would become slower and
+ slower.</para>
+
+ <para>To address this problem, a parameter called
+ <command>host-reservation-identifiers</command> has been introduced. It
+ takes a list of identifier types as a parameter. Kea will check only those
+ identifier types enumerated in host-reservation-identifiers. From the
+ performance perspective the number of identifier types should be kept to
+ minimum, ideally limited to one. If your deployment uses several
+ reservation types, please enumerate them from most to least frequently
+ used as this increases the chances of Kea finding the reservation using
+ fewer number of queries. An example of host reservation identifiers looks
+ as follows:
+
+<screen>
+<userinput>"host-reservation-identifiers": [ "duid", "hw-address" ],</userinput>
+"subnet4": [
+ {
+ "subnet": "192.0.2.0/24",
+ ...
+ }
+]</screen>
+</para>
+
+<para>
+ If not specified, the default value is <command>hw-address,duid</command>.
+</para>
+<!-- see CfgHostOperations::createConfig6() in
+ src/lib/dhcpsrv/cfg_host_operations.cc -->
+
</section>
<!-- @todo: add support for per IA reservation (that specifies IAID in
projects / thirdparty / kea.git / commitdiff
