Keepalived

Refs

• https://github.com/acassen/keepalived/blob/master/keepalived/etc/keepalived/keepalived.conf.in-
• https://nutss.wordpress.com/2019/07/12/high-availability-support-keepalived-and-nginx-on-ubuntu-debian/
• https://askubuntu.com/questions/1312333/keepalived-not-working-on-20-04

apt update && apt install keepalived
sudo useradd -r -s /bin/false keepalived_script

/etc/keepalived/keepalived.conf

global_defs {
    notification_email {
        sysadmin@example.com
        failover@example.com
    }
    # notification_email_from no-reply@example.com
    # smtp_server 192.168.200.1
    # smtp_connect_timeout 30
    # vrrp_strict  # Breaks auth_type PASS restriction - https://askubuntu.com/questions/1312333/keepalived-not-working-on-20-04
    router_id ADC_DEV
    vrrp_skip_check_adv_addr
    vrrp_garp_interval .001
    vrrp_gna_interval .001
    enable_script_security
    script_user nobody
}


vrrp_script chk_ipaddr {
    script "/usr/bin/ping -c 1 172.16.0.1"
    interval 2
    weight 2
}


vrrp_script chk_nginx {
    script "/usr/bin/pgrep '^nginx$'"
    interval 2
    weight 2
}


vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.200.16
        192.168.200.17
        192.168.200.18
    }
    track_script {
        chk_ipaddr
        chk_nginx
    }
}

Logs

systemctl status keepalived
journalctl -f

capture multicast traffic

sudo tcpdump -npi eth0 net 224
16:10:05.472897 IP 172.16.0.167 > 224.0.0.18: VRRPv2, Advertisement, vrid 51, prio 100, authtype none, intvl 1s, length 28

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