Ubuntu 14.04 : automatic IP fail-over with ucarp

Reference

http://laurentbel.com/2012/04/04/simple-failover-cluster-on-ubuntu-using-carp/

http://manpages.ubuntu.com/manpages/lucid/man8/ucarp.8.html

vm1  eth1 ---  eth1 vm2

10.0.0.10        10.0.0.20

virtual IP : 10.0.0.30 ( vm1 is the master, vm2 is standy )

These VMs are running within KVM.

install ucarp on both machines

# apt-cache search ucarp ucarp - user-space replacement to VRRP -- automatic IP fail-over # apt-get install ucarp -y

configuration files are..

root@ubuntu1404-vm1:~# dpkg -L ucarp /. /usr /usr/sbin /usr/sbin/ucarp /usr/share /usr/share/ucarp /usr/share/ucarp/vip-up /usr/share/ucarp/vip-down /usr/share/man /usr/share/man/man8 /usr/share/man/man8/ucarp.8.gz /usr/share/doc /usr/share/doc/ucarp /usr/share/doc/ucarp/NEWS.gz /usr/share/doc/ucarp/examples /usr/share/doc/ucarp/examples/vip-down.sh /usr/share/doc/ucarp/examples/vip-up.sh /usr/share/doc/ucarp/README.gz /usr/share/doc/ucarp/NEWS.Debian.gz /usr/share/doc/ucarp/AUTHORS /usr/share/doc/ucarp/copyright /usr/share/doc/ucarp/changelog.Debian.gz /usr/share/doc/ucarp/README.Debian /usr/share/locale /usr/share/locale/en@quot /usr/share/locale/en@quot/LC_MESSAGES /usr/share/locale/en@quot/LC_MESSAGES/ucarp.mo /usr/share/locale/en@boldquot /usr/share/locale/en@boldquot/LC_MESSAGES /usr/share/locale/en@boldquot/LC_MESSAGES/ucarp.mo /etc /etc/network /etc/network/if-up.d /etc/network/if-up.d/ucarp

- vm1

copy vip-up.sh and vip-down.sh to /etc

root@ubuntu1404-vm1:~# cp /usr/share/doc/ucarp/examples/vip-*.sh /etc/

vip-up.sh and vip-down.sh

This script add or delete virtual IP with “ip addr” command.

root@ubuntu1404-vm1:~# cat /etc/vip-up.sh #! /bin/sh exec 2> /dev/null /sbin/ip addr add "$2"/24 dev "$1" # or alternatively: # /sbin/ifconfig "$1":254 "$2" netmask 255.255.255.0 root@ubuntu1404-vm1:~# cat /etc/vip-down.sh #! /bin/sh exec 2> /dev/null /sbin/ip addr del "$2"/24 dev "$1" # or alternatively: # /sbin/ifconfig "$1":254 down

root@ubuntu1404-vm1:~# ucarp -i eth1 -s 10.0.0.10 -p secret -a 10.0.0.30 --upscript=/etc/vip-up.sh --downscript=/etc/vip-down.sh -P -v 10 [INFO] Local advertised ethernet address is [52:54:00:83:81:7a] [WARNING] Switching to state: BACKUP [WARNING] Spawning [/etc/vip-down.sh eth1 10.0.0.30] [WARNING] Switching to state: MASTER [WARNING] Spawning [/etc/vip-up.sh eth1 10.0.0.30]

- vm2

root@ubuntu1404-vm2:~# cp /usr/share/doc/ucarp/examples/vip-*.sh /etc/

root@ubuntu1404-vm2:~# ucarp -i eth1 -s 10.0.0.20 -v 10 -p secret -a 10.0.0.30 --upscript=/etc/vip-up.sh --downscript=/etc/vip-down.sh [INFO] Local advertised ethernet address is [52:54:00:6c:f6:f9] [WARNING] Switching to state: BACKUP [WARNING] Spawning [/etc/vip-down.sh eth1 10.0.0.30]

on the vm1

the vm1 has the virtual IP 10.0.0.30

root@ubuntu1404-vm1:~# ip addr show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00    inet 127.0.0.1/8 scope host lo       valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000    link/ether 52:54:00:d6:2c:0b brd ff:ff:ff:ff:ff:ff    inet 192.168.11.8/24 brd 192.168.11.255 scope global eth0       valid_lft forever preferred_lft forever 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000    link/ether 52:54:00:83:81:7a brd ff:ff:ff:ff:ff:ff    inet 10.0.0.10/8 brd 10.255.255.255 scope global eth1       valid_lft forever preferred_lft forever    inet 10.0.0.30/24 scope global eth1       valid_lft forever preferred_lft forever

on the vm2.

root@ubuntu1404-vm2:~# ip addr show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00    inet 127.0.0.1/8 scope host lo       valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000    link/ether 52:54:00:33:63:cf brd ff:ff:ff:ff:ff:ff    inet 192.168.11.9/24 brd 192.168.11.255 scope global eth0       valid_lft forever preferred_lft forever 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000    link/ether 52:54:00:6c:f6:f9 brd ff:ff:ff:ff:ff:ff    inet 10.0.0.20/8 brd 10.255.255.255 scope global eth1       valid_lft forever preferred_lft forever

Here are capture data between vm1 and vm2.

vm1 is sending VRRP advertisement packets every second, because the vm1 is master.

root@ubuntu1404-vm1:~# tshark -n -r a.pcap | grep -i vrrp Running as user "root" and group "root". This could be dangerous.  2 0.066233000    10.0.0.10 -> 224.0.0.18   VRRP 70 Announcement (v2)  7 1.066473000    10.0.0.10 -> 224.0.0.18   VRRP 70 Announcement (v2) 13 2.066714000    10.0.0.10 -> 224.0.0.18   VRRP 70 Announcement (v2) 18 3.066874000    10.0.0.10 -> 224.0.0.18   VRRP 70 Announcement (v2)

root@ubuntu1404-vm1:~# tshark -n -r a.pcap -Y '(frame.number==2)' -V Frame 2: 70 bytes on wire (560 bits), 70 bytes captured (560 bits) on interface 0    Interface id: 0    Encapsulation type: Ethernet (1)    Arrival Time: Sep  3, 2014 01:38:05.525315000 JST    [Time shift for this packet: 0.000000000 seconds]    Epoch Time: 1409675885.525315000 seconds    [Time delta from previous captured frame: 0.066233000 seconds]    [Time delta from previous displayed frame: 0.000000000 seconds]    [Time since reference or first frame: 0.066233000 seconds]    Frame Number: 2    Frame Length: 70 bytes (560 bits)    Capture Length: 70 bytes (560 bits)    [Frame is marked: False]    [Frame is ignored: False]    [Protocols in frame: eth:ip:vrrp] Ethernet II, Src: 00:00:5e:00:00:0a (00:00:5e:00:00:0a), Dst: 01:00:5e:00:00:12 (01:00:5e:00:00:12)    Destination: 01:00:5e:00:00:12 (01:00:5e:00:00:12)        Address: 01:00:5e:00:00:12 (01:00:5e:00:00:12)        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)        .... ...1 .... .... .... .... = IG bit: Group address (multicast/broadcast)    Source: 00:00:5e:00:00:0a (00:00:5e:00:00:0a)        Address: 00:00:5e:00:00:0a (00:00:5e:00:00:0a)        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)    Type: IP (0x0800) Internet Protocol Version 4, Src: 10.0.0.10 (10.0.0.10), Dst: 224.0.0.18 (224.0.0.18)    Version: 4    Header length: 20 bytes    Differentiated Services Field: 0x10 (DSCP 0x04: Unknown DSCP; ECN: 0x00: Not-ECT (Not ECN-Capable Transport))        0001 00.. = Differentiated Services Codepoint: Unknown (0x04)        .... ..00 = Explicit Congestion Notification: Not-ECT (Not ECN-Capable Transport) (0x00)    Total Length: 56    Identification: 0xa5bf (42431)    Flags: 0x02 (Don't Fragment)        0... .... = Reserved bit: Not set        .1.. .... = Don't fragment: Set        ..0. .... = More fragments: Not set    Fragment offset: 0    Time to live: 255    Protocol: VRRP (112)    Header checksum: 0xeb69 [validation disabled]        [Good: False]        [Bad: False]    Source: 10.0.0.10 (10.0.0.10)    Destination: 224.0.0.18 (224.0.0.18)    [Source GeoIP: Unknown]    [Destination GeoIP: Unknown] Virtual Router Redundancy Protocol    Version 2, Packet type 1 (Advertisement)        0010 .... = VRRP protocol version: 2        .... 0001 = VRRP packet type: Advertisement (1)    Virtual Rtr ID: 10    Priority: 0 (Current Master has stopped participating in VRRP)    Addr Count: 7    Auth Type: No Authentication (0)    Adver Int: 1    Checksum: 0xbe51 [correct]    IP Address: 118.254.242.18 (118.254.242.18)    IP Address: 16.243.147.236 (16.243.147.236)    IP Address: 129.117.234.104 (129.117.234.104)    IP Address: 218.22.250.106 (218.22.250.106)    IP Address: 144.81.21.163 (144.81.21.163)    IP Address: 37.200.37.85 (37.200.37.85)    IP Address: 73.224.151.88 (73.224.151.88)

reboot the vm1

root@ubuntu1404-vm1:~# reboot root@ubuntu1404-vm1:~#

on the vm2

vm2 took over the virtual IP 10.0.0.30.

root@ubuntu1404-vm2:~# ip addr show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00    inet 127.0.0.1/8 scope host lo       valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000    link/ether 52:54:00:33:63:cf brd ff:ff:ff:ff:ff:ff    inet 192.168.11.9/24 brd 192.168.11.255 scope global eth0       valid_lft forever preferred_lft forever 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000    link/ether 52:54:00:6c:f6:f9 brd ff:ff:ff:ff:ff:ff    inet 10.0.0.20/8 brd 10.255.255.255 scope global eth1       valid_lft forever preferred_lft forever    inet 10.0.0.30/24 scope global eth1       valid_lft forever preferred_lft forever

vm2 is sending VRRP advertisement every second, because vm2 is master.

root@ubuntu1404-vm2:~# tshark -n -r a.pcap | grep -i vrrp Running as user "root" and group "root". This could be dangerous.  1 0.000000000    10.0.0.20 -> 224.0.0.18   VRRP 70 Announcement (v2)  4 1.000224000    10.0.0.20 -> 224.0.0.18   VRRP 70 Announcement (v2) 10 2.000407000    10.0.0.20 -> 224.0.0.18   VRRP 70 Announcement (v2) 15 3.000530000    10.0.0.20 -> 224.0.0.18   VRRP 70 Announcement (v2)

start ucarp on the vm1 again.

root@ubuntu1404-vm1:~# ucarp -i eth1 -s 10.0.0.10 -p secret -a 10.0.0.30 --upscript=/etc/vip-up.sh --downscript=/etc/vip-down.sh -P -v 10 [INFO] Local advertised ethernet address is [52:54:00:83:81:7a] [WARNING] Switching to state: BACKUP [WARNING] Spawning [/etc/vip-down.sh eth1 10.0.0.30]

vm1 does not take over the VIP, because I start ucarp with preempt option.

-P --preempt                 Turn on preemptive failover. This causes an instance of ucarp                 to assume master status right immediately.

reboot the vm2

root@ubuntu1404-vm2:~# reboot root@ubuntu1404-vm2:~#

root@ubuntu1404-vm1:~# ip addr show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00    inet 127.0.0.1/8 scope host lo       valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000    link/ether 52:54:00:d6:2c:0b brd ff:ff:ff:ff:ff:ff    inet 192.168.11.8/24 brd 192.168.11.255 scope global eth0       valid_lft forever preferred_lft forever 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000    link/ether 52:54:00:83:81:7a brd ff:ff:ff:ff:ff:ff    inet 10.0.0.10/8 brd 10.255.255.255 scope global eth1       valid_lft forever preferred_lft forever    inet 10.0.0.30/24 scope global eth1       valid_lft forever preferred_lft forever

you can start ucarp as daemon with -B option.

-B --daemonize                 Causes  ucarp  to  detach  from  the  terminal and run in the                 background as a daemon.