[Unit]
Denoscription=NGINX Prometheus Exporter
After=network.target

[Service]
Type=simple
User=nginx_exporter
Group=nginx_exporter
Type=simple
ExecStart=/usr/local/bin/nginx-prometheus-exporter \
    -web.listen-address=0.0.0.0:9113 \
    -nginx.scrape-uri http://IP_hostnginx:9113/metrics

SyslogIdentifier=nginx_prometheus_exporter
Restart=always

[Install]
WantedBy=multi-user.target

#backup/keepalived.conf
global_defs {
    router_id backup_node
}

vrrp_noscript check_nginx {
    noscript "/etc/keepalived/check_nginx.sh"
    interval 1
    weight -20
    fall 3
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth1
    virtual_router_id 50
    mcast_src_ip 192.168.33.11
    priority 90
    advert_int 1

    track_noscript {
        check_nginx
    }

    virtual_ipaddress {
        192.168.33.50/24
    }
}

#master/keepalived.conf
global_defs {
    router_id master_node # name of this node
}

vrrp_noscript check_nginx {
    noscript "/etc/keepalived/check_nginx.sh" # success when noscript returns 0; otherwise failed
    interval 1 # call noscript interval 1 second
    weight -20
    fall 3 # if failed for 3 times, set priority += weight, which means 100-20=80 here
}

vrrp_instance VI_1 {
    state MASTER
    interface eth1 # binding virtual IP to
    virtual_router_id 50 # must be identical to backup
    mcast_src_ip 192.168.33.10 # IP of this node
    priority 100 # master 100-20=80 must be less than backup priority 90
    advert_int 1 # advert interval 1 second

    track_noscript {
        check_nginx
    }

    virtual_ipaddress {
        192.168.33.50/24 # virtual IP
    }
}

#!/bin/bash

if [ $(ps -C nginx --no-headers | wc -l) -eq 0 ]; then
    exit 1
fi

#master1
global_defs {
    router_id master_node_1
}

vrrp_noscript check_nginx {
    noscript "/etc/keepalived/check_nginx.sh"
    interval 1
    weight -20
    fall 3
}

vrrp_instance VI_1 {
    state MASTER
    interface eth1
    virtual_router_id 51
    mcast_src_ip 192.168.33.10
    priority 100
    advert_int 1

    track_noscript {
        check_nginx
    }

    virtual_ipaddress {
        192.168.33.51/24
    }
}

vrrp_instance VI_2 {
    state BACKUP
    interface eth1
    virtual_router_id 52
    mcast_src_ip 192.168.33.10
    priority 90
    advert_int 1

    track_noscript {
        check_nginx
    }

    virtual_ipaddress {
        192.168.33.52/24
    }
}

#master2
global_defs {
    router_id master_node_2
}

vrrp_noscript check_nginx {
    noscript "/etc/keepalived/check_nginx.sh"
    interval 1
    weight -20
    fall 3
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth1
    virtual_router_id 51
    mcast_src_ip 192.168.33.11
    priority 90
    advert_int 1

    track_noscript {
        check_nginx
    }

    virtual_ipaddress {
        192.168.33.51/24
    }
}

vrrp_instance VI_2 {
    state MASTER
    interface eth1
    virtual_router_id 52
    mcast_src_ip 192.168.33.11
    priority 100
    advert_int 1

    track_noscript {
        check_nginx
    }

    virtual_ipaddress {
        192.168.33.52/24
    }
}

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