Keepalived can do this by combining the
nopreempt option and the
BACKUP state on the both nodes:
- Prevent VRRP Master from becoming Master once it has failed
- Prevent master to fall back to master after failure
How about the UCARP?
Name : ucarp Arch : x86_64 Version : 1.5.2 Release : 1.el5.rf Size : 81 k Repo : installed Summary : Common Address Redundancy Protocol (CARP) for Unix URL : http://www.ucarp.org/ License : BSD Description: UCARP allows a couple of hosts to share common virtual IP addresses in order : to provide automatic failover. It is a portable userland implementation of the : secure and patent-free Common Address Redundancy Protocol (CARP, OpenBSD's : alternative to the patents-bloated VRRP). : Strong points of the CARP protocol are: very low overhead, cryptographically : signed messages, interoperability between different operating systems and no : need for any dedicated extra network link between redundant hosts.
If I don't use the
--preempt option and set the
--advskew to the same value, both nodes become master.
# Virtual IP configuration file for UCARP # The number (from 001 to 255) in the name of the file is the identifier # $Id: vip-001.conf.example 1527 2004-07-09 15:23:54Z dude $ # Set the same password on all mamchines sharing the same virtual IP PASSWORD="pa$$w0rd" # You are required to have an IPADDR= line in the configuration file for # this interface (so no DHCP allowed) BIND_INTERFACE="eth0" # Do *NOT* use a main interface for the virtual IP, use an ethX:Y alias # with the corresponding /etc/sysconfig/network-scripts/ifcfg-ethX:Y file # already configured and ith ONBOOT=no VIP_INTERFACE="eth0:0" # If you have extra options to add, see "ucarp --help" output # (the lower the "-k <val>" the higher priority and "-P" to become master ASAP) OPTIONS="-z -k 255"
DEVICE=eth0:0 ONBOOT=no BOOTPROTO= IPADDR=192.168.6.8 NETMASK=255.255.255.0 USERCTL=yes IPV6INIT=no
eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000 link/ether c6:9b:8e:af:a7:69 brd ff:ff:ff:ff:ff:ff inet 192.168.6.192/24 brd 192.168.6.255 scope global eth0 inet 192.168.6.8/24 brd 192.168.6.255 scope global secondary eth0:0 inet6 fe80::c49b:8eff:feaf:a769/64 scope link valid_lft forever preferred_lft forever
eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000 link/ether 00:30:48:f7:0f:81 brd ff:ff:ff:ff:ff:ff inet 192.168.6.38/24 brd 192.168.6.255 scope global eth1 inet 192.168.6.8/24 brd 192.168.6.255 scope global secondary eth1:0 inet6 fe80::230:48ff:fef7:f81/64 scope link valid_lft forever preferred_lft forever