UCARP：防止原来的master在失败回来后接管VIP？

Question

Keepalived可以通过组合两个节点上的nopreempt选项和BACKUP状态来做到这一点：

• 防止 VRRP Master 一旦失败就成为 Master
• 防止master在失败后回退到master

怎么样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.

如果我不使用该--preempt选项并将 设置--advskew为相同的值，则两个节点都成为主节点。

/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

节点 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

节点 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

Answer 1

对于 UCARP，我认为技巧是使用--neutral标志以“中立”模式启动它，这样它就不会自动承担主角色或在启动时尝试任何操作。看看我的其中一项设置，这是完整的命令行。也许--neutral适用是因为我们在启动和关闭时应用了上标和下标，但值得一试。

/path/to/ucarp0 -v 42 -p kitteh0 --interface=bond0 -a 192.168.100.250 -s 192.168.100.172 -b 5 -r 3 --upscript=/path/to/ucarp/upscript0 --downscript=/path/to/ucarp/downscript0 --neutral -z -B