Added dhcpd failover configuration.

defaults/main.yml

@@ -161,4 +161,104 @@ dhcpd_hosts: []
 dhcpd_includes: []
   #- '/etc/dhcp/example.conf'
 
-
+# ---- ISC DHCP failover configuration ----
+#
+# Each failover declaration consists of primary and secondary host, no more 
+# than two nodes failover is allowed by isc-dhcpd currently.
+#
+# You must specify which failover each pool should use by specifying a
+# 'failover peer' option in pool declaration.
+#
+# Each failover declaration has a set of an mandatory fields, which is:
+#   primary: ""             Ansible inventory name of a primary DHCP host, if
+#                           you need failover to work on different IP, 
+#                           see primary_fo_addr option below.
+#
+#   secondary: ""           Ansible inventory name of a secondary DHCP host, if
+#                           you need failover to work on different IP, 
+#                           see secondary_fo_addr option below.
+#
+# Ansible inventory name is either IP ot hostname specified in inventory file.
+#
+#   mclt: 3600              Max Client Lead Time. The maximum amount of time 
+#                           that one server can extend a lease for a DHCP 
+#                           client beyond the time known by the partner server.
+#
+#   split: [0-255]          Specifies the split between the primary and
+#                           secondary for the purposes of load balancing.
+#                           Whenever a client makes a DHCP request, the DHCP
+#                           server runs a hash on the client identification,
+#                           resulting in value from 0 to 255. This is used as
+#                           an index into a 256 bit field. If the bit at that
+#                           index is set, the primary is responsible.  If
+#                           the bit at that index is not set, the secondary
+#                           is responsible.
+#    -- or --
+#   hba: ([0-9a-f]{2}:){32} Specifies the split between the primary and
+#                           secondary as a bitmap rather than a cutoff, which
+#                           theoretically allows for finer-grained control.
+#                           In practice, there is probably no need for such
+#                           fine-grained control, however.
+#   max_response_delay: 5   Tells the DHCP server how many seconds may pass
+#                           without receiving a message from its failover peer
+#                           before it assumes that connection has failed.
+#                           This is mandatory according to dhcpd.conf man page.
+#   max_unacked_updates: 10 Tells the remote DHCP server how many BNDUPD
+#                           messages it can send before it receives a BNDACK
+#                           from the local system.
+#                           This is mandatory according to dhcpd.conf man page.
+#
+# You must use either 'split' or 'hba' statement. Split has a preference, so
+# if it's defined, 'hba' will be omitted by configuration template.
+# Optional field are mostly desribed in dhcpd.conf man page:
+#   port: 647               Specifies port on which primary and secondary
+#                           nodes will listen for failover connection.
+#                           Diffirent ports for primary and secondary is
+#                           currently unsupported.
+#
+#   primary_fo_addr: ""     IP/Hostname of a primary DHCP host. This option
+#                           is used if you need failover address be different 
+#                           from ansible inventory IP/hostname.
+#                           If omitted, then 'primary' is used.
+#
+#   secondary_fo_addr: ""   IP/Hostname of a secondary DHCP host. This option
+#                           is used if you need failover address be different 
+#                           from ansible inventory IP/hostname.
+#                           If omitted, then 'secondary' is used.
+#
+#   auto_partner_down: 0    Number of second to start serving partners IPs
+#                           after the partner's failure.
+#
+#   load_balance_max_seconds: 5
+#   max_lease_misbalance: 15
+#   max_lease_ownership: 10
+#   min_balance: 60
+#   max_balance: 3600
+#
+dhcpd_failovers: []
+  ## Following is full cluster configuration
+  #- failover: 'failover-localsubnet'
+  #  primary: '10.0.10.1'
+  #  primary_fo_addr: '10.5.10.1'
+  #  secondary: '10.0.10.2'
+  #  secondary_fo_addr: '10.5.10.2'
+  #  port: 1337
+  #  split: 128
+  #  hba: aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa
+  #  max_response_delay: 5
+  #  max_unacked_updates: 10
+  #  load_balance_max_seconds: 5
+  #  auto_partner_down: 0
+  #  max_lease_misbalance: 15
+  #  max_lease_ownership: 10
+  #  min_balance: 60
+  #  max_balance: 3600
+  #
+  ## Following is minimal cluster configuration
+  #- failover: 'failover-san'
+  #  primary: '10.0.10.1'
+  #  secondary: '10.0.10.2'
+  #  mclt: 3600
+  #  split: 128
+  #  max_response_delay: 5
+  #  max_unacked_updates: 10

templates/etc/dhcp/dhcpd.conf.j2

@@ -121,6 +121,71 @@ host {{ host.hostname }} {
 {% endif %}
 {% endmacro %}
 
+
+
+
+{% macro print_failover(failover) %}
+{% if failover.comment is defined and failover.comment %}
+# {{ failover.comment }}
+{% endif %}
+failover peer "{{ failover.failover }}" {
+{% if failover.primary is defined and failover.primary ==  inventory_hostname %}
+        primary;
+        mclt {{ failover.mclt|default(3600) }};
+{% if failover.primary_fo_addr is defined and failover.primary_fo_addr %}
+        address {{ failover.primary_fo_addr }};
+{% else %}
+        address {{ failover.primary }};
+{% endif %}
+{% if failover.secondary_fo_addr is defined and failover.secondary_fo_addr %}
+        peer address {{ failover.secondary_fo_addr }};
+{% else %}
+        peer address {{ failover.secondary }};
+{% endif %}
+{% if failover.split is defined and failover.split %}
+        split {{ failover.split }};
+{% elif failover.hba is defined and failover.hba %}
+        hba {{ failover.hba }};
+{% endif %}
+{% else %}
+        secondary;
+{% if failover.secondary_fo_addr is defined and failover.secondary_fo_addr %}
+        address {{ failover.secondary_fo_addr }};
+{% else %}
+        address {{ failover.secondary }};
+{% endif %}
+{% if failover.primary_fo_addr is defined and failover.primary_fo_addr %}
+        peer address {{ failover.primary_fo_addr }};
+{% else %}
+        peer address {{ failover.primary }};
+{% endif %}
+{% endif %}
+        max-response-delay {{ failover.max_response_delay|default(30) }};
+        max-unacked-updates {{ failover.max_unacked_updates|default(10) }};
+{% if failover.load_balance_max_seconds is defined and failover.load_balance_max_seconds %}
+        load balance max seconds {{ failover.load_balance_max_seconds }};
+{% endif %}
+{% if failover.max_lease_misbalance is defined and failover.max_lease_misbalance %}
+        max-lease-misbalance {{ failover.max_lease_misbalance }};
+{% endif %}
+{% if failover.max_lease_ownership is defined and failover.max_lease_ownership %}
+        max-lease-ownership {{ failover.max_lease_ownership }};
+{% endif %}
+{% if failover.min_balance is defined and failover.min_balance %}
+        min-balance {{ failover.min_balance }};
+{% endif %}
+{% if failover.max_balance is defined and failover.max_balance %}
+        max-balance {{ failover.max_balance }};
+{% endif %}
+{% if failover.auto_partner_down is defined and failover.auto_partner_down %}
+        auto-partner-down {{ failover.auto_partner_down }};
+{% endif %}
+}
+{% endmacro %}
+
+
+
+
 {% if dhcpd_authoritative is defined and dhcpd_authoritative %}
 authoritative;
 
@@ -143,6 +208,11 @@ not authoritative;
 {{ print_class(class) }}
 {% endfor %}
 {% endif %}
+{% if dhcpd_failovers is defined and dhcpd_failovers %}
+{% for failover in dhcpd_failovers %}
+{{ print_failover(failover) }}
+{% endfor %}
+{% endif %}
 {% if dhcpd_shared_networks is defined and dhcpd_shared_networks %}
 {% for network in dhcpd_shared_networks %}
 {% if network.subnets is defined and network.subnets %}