Keepalived is a routing software written in C. The main goal of this project is to provide simple and robust facilities for loadbalancing and high-availability to Linux system and Linux based infrastructures. Loadbalancing framework relies on well-known and widely used Linux Virtual Server (IPVS) kernel module providing Layer4 loadbalancing. Keepalived implements a set of checkers to dynamically and adaptively maintain and manage loadbalanced server pool according their health. On the other hand high-availability is achieved by VRRP protocol. VRRP is a fundamental brick for router failover. In addition, Keepalived implements a set of hooks to the VRRP finite state machine providing low-level and high-speed protocol interactions. Keepalived frameworks can be used independently or all together to provide resilient infrastructures.
Simple virtual IP on an interface:
keepalived:
cluster:
enabled: True
instance:
VIP1:
nopreempt: True
priority: 100 (highest priority must be on primary server, different for cluster members)
virtual_router_id: 51
auth_type: AH
password: pass
address: 192.168.10.1
interface: eth0
VIP2:
nopreempt: True
priority: 150 (highest priority must be on primary server, different for cluster members)
virtual_router_id: 52
auth_type: PASS
password: pass
address: 10.0.0.5
interface: eth1
Multiple virtual IPs on single interface:
keepalived:
cluster:
enabled: True
instance:
VIP1:
nopreempt: True
priority: 100 (highest priority must be on primary server, different for cluster members)
virtual_router_id: 51
password: pass
addresses:
- 192.168.10.1
- 192.168.10.2
interface: eth0
Use unicast:
keepalived:
cluster:
enabled: True
instance:
VIP1:
nopreempt: True
priority: 100 (highest priority must be on primary server, different for cluster members)
virtual_router_id: 51
password: pass
address: 192.168.10.1
interface: eth0
unicast_src_ip: 172.16.10.1
unicast_peer:
172.16.10.2
172.16.10.3
Disable nopreempt mode to have Master. Highest priority is taken in all cases:
keepalived:
cluster:
enabled: True
instance:
VIP1:
nopreempt: False
priority: 100 (highest priority must be on primary server, different for cluster members)
virtual_router_id: 51
password: pass
addresses:
- 192.168.10.1
- 192.168.10.2
interface: eth0
Notify action in keepalived:
keepalived:
cluster:
enabled: True
instance:
VIP1:
nopreempt: True
notify_action:
master:
- /usr/bin/docker start jenkins
- /usr/bin/docker start gerrit
backup:
- /usr/bin/docker stop jenkins
- /usr/bin/docker stop gerrit
fault:
- /usr/bin/docker stop jenkins
- /usr/bin/docker stop gerrit
priority: 100 # highest priority must be on primary server, different for cluster members
virtual_router_id: 51
password: pass
addresses:
- 192.168.10.1
- 192.168.10.2
interface: eth0
Track/vrrp scripts for keepalived instance:
keepalived:
cluster:
enabled: True
instance:
VIP2:
priority: 100
virtual_router_id: 10
password: pass
addresses:
- 192.168.11.1
- 192.168.11.2
interface: eth0
track_script: check_haproxy
VIP3:
priority: 100
virtual_router_id: 11
password: pass
addresses:
- 192.168.10.1
- 192.168.10.2
interface: eth0
track_script:
check_random_exit:
interval: 10
check_port:
weight: 50
vrrp_scripts:
check_haproxy:
name: check_pidof
args:
- haproxy
check_mysql_port:
name: check_port
args:
- 3306
- TCP
- 4
check_ssh:
name: check_port
args: "22"
check_mysql_cluster:
args:
# github: olafz/percona-clustercheck
# <user> <pass> <available_when_donor=0|1> <log_file> <available_when_readonly=0|1> <defaults_extra_file>
- clustercheck
- clustercheck
- available_when_donor=0
- available_when_readonly=0
check_random_exit:
interval: 10
timeout: 5
content: |
#!/bin/bash
exit $(($RANDOM%2))
weight: 50