ISC-DHCP DHCP Failover設定

目次

概要 †

ISC DHCPのDHCP Failover Protocolを使用したFailover構成の設定。
DHCP 2台によるFailover構成を組むことができるが、設定は個々のサーバに格納された設定ファイルに依存するため、設定の同期や再読み込みは別の方式と組み合わせる必要がある。

構成 †

DHCPはPrimary / Secondry構成となり、dhcpd.confは専用の設定が必要となる。

Primary設定 †

• /etc/dhcp/dhcpd.conf

  ## ---------------------------------
  ##  dhcpd.conf (primary)
  ## ---------------------------------
  ## Date : 2016/04/04
  ## Network : 
  ## 
  
  ## Global setting
  
  ddns-update-style none;
  not authoritative;
  log-facility local6;
  
  ## Failover setting
  failover peer "【Failoverルール名】" {
          primary;
          address 【Primary Server IPaddress】;
          port 519;
          peer address 【Secondry Server IPaddress】;
          peer port 520;
          max-response-delay 60;
          max-unacked-updates 10;
          mclt 300;
          split 128;
          load balance max seconds 3;
  }
  
  include "/etc/dhcp/conf.d/dynamic-lease.conf";
  include "/etc/dhcp/conf.d/static-lease.conf";
  
  # EOF

Secondry設定 †

• /etc/dhcp/dhcpd.conf

  ## ---------------------------------
  ##  dhcpd.conf (secondry)
  ## ---------------------------------
  ## Date : 2016/04/04
  ## Network : 
  ## 
  
  ## Global setting
  
  ddns-update-style none;
  authoritative;
  log-facility local6;
  
  ## Failover setting
  failover peer "【Failoverルール名】" {
          secondary;
          address 【Secondry Server IPaddress】;
          port 519;
          peer address 【Primary Server IPaddress】;
          peer port 520;
          max-response-delay 60;
          max-unacked-updates 10;
          load balance max seconds 3;
  }
  
  include "/etc/dhcp/conf.d/dynamic-lease.conf";
  include "/etc/dhcp/conf.d/static-lease.conf";
  
  # EOF

動的リースの設定 †

• /etc/dhcp/conf.d/dynamic-lease.conf

  ## ---------------------------------
  ##  dhcpd.conf (dynamic-lease)
  ## ---------------------------------
  ## Date : 2016/04/11
  ## Network : 
  ## 
  
  ## -------------------------
  ##  Dynamic Lease setting
  ## -------------------------
  
  subnet 【ネットワークアドレス】 netmask 【ネットマスク】 {
   pool {
    failover peer "【Failoverルール名】";
    ## IPaddress lease range
    range 【開始アドレス】【終了アドレス】;
    ## IPaddress lease time(Default)
    default-lease-time 3600;
    ## IPaddress lease time(Max)
    max-lease-time 259200;
    ## IPaddress segment rooter address
    option routers 【デフォルトゲートウェイ】;
    ## Domain name
    option domain-name "【ドメイン名】";
    option domain-name-servers 【DNS1】, 【DNS2】,【DNS3】;
    ## Access control
    allow unknown-clients;
    #deny unknown-clients;
   }
  }
  
  
  # EOF

動作ログ †

• Primary (/var/log/dhcpd/dhcpd.log)

  [TIMESTAMP] dhcp01 dhcpd: Internet Systems Consortium DHCP Server 4.1.1-P1
  [TIMESTAMP] dhcp01 dhcpd: Copyright 2004-2010 Internet Systems Consortium.
  [TIMESTAMP] dhcp01 dhcpd: All rights reserved.
  [TIMESTAMP] dhcp01 dhcpd: For info, please visit https://www.isc.org/software/dhcp/
  [TIMESTAMP] dhcp01 dhcpd: Wrote 11 leases to leases file.
  [TIMESTAMP] dhcp01 dhcpd: Listening on LPF/eth0/00:50:56:80:14:39/192.168.1.0/24
  [TIMESTAMP] dhcp01 dhcpd: Sending on   LPF/eth0/00:50:56:80:14:39/192.168.1.0/24
  [TIMESTAMP] dhcp01 dhcpd: Sending on   Socket/fallback/fallback-net
  [TIMESTAMP] dhcp01 dhcpd: failover peer localnet: I move from recover to startup

• Secondry (/var/log/dhcpd/dhcpd.log)

  [TIMESTAMP] dhcp02 dhcpd: Internet Systems Consortium DHCP Server 4.1.1-P1
  [TIMESTAMP] dhcp02 dhcpd: Copyright 2004-2010 Internet Systems Consortium.
  [TIMESTAMP] dhcp02 dhcpd: All rights reserved.
  [TIMESTAMP] dhcp02 dhcpd: For info, please visit https://www.isc.org/software/dhcp/
  [TIMESTAMP] dhcp02 dhcpd: Wrote 11 leases to leases file.
  [TIMESTAMP] dhcp02 dhcpd: Listening on LPF/eth0/00:50:56:80:fc:c4/192.168.1.0/24
  [TIMESTAMP] dhcp02 dhcpd: Sending on   LPF/eth0/00:50:56:80:fc:c4/192.168.1.0/24
  [TIMESTAMP] dhcp02 dhcpd: Sending on   Socket/fallback/fallback-net
  [TIMESTAMP] dhcp02 dhcpd: failover peer localnet: I move from recover to startup

参考 †

[Linux][DHCP] ISC DHCPの冗長化設定
DHCPサーバの２重化(failover)の設定