UCARP: prevent the original master from taking over the VIP when it comes back after failure?
- by quanta
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.
/etc/sysconfig/carp/vip-010.conf
# 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"
/etc/sysconfig/network-scripts/ifcfg-eth0:0
DEVICE=eth0:0
ONBOOT=no
BOOTPROTO=
IPADDR=192.168.6.8
NETMASK=255.255.255.0
USERCTL=yes
IPV6INIT=no
node 1:
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
node 2:
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
