How can I query in a bash script which of the haproxy load balancer hosts is currently the primary and which is the secondary?

Question

I want to be able to determine which LB is primary and which is secondary from a bash script running on both load balancers.

Background is: For the renewal of a Letsencrypt certificate on a HAproxy load balancer pair, where the service IP is usually bound to the master, it would be necessary to determine which server is the master (has the service IP bound) and which is only a secondary backup (without web access via port :80 and port:443)

Answer 1

If you follow this guide by Sebastian Schrader https://serverfault.com/a/871783, the following procedure will help to determine the master and backup:

IFS="/"

# /org/keepalived/Vrrp1/Instance/ens192/151/IPv4
vrrpInstance=$(/usr/bin/busctl tree | grep keepalived | grep IPv4)

set $vrrpInstance

#151
vrrpRouterID=$7

# (us) 2 "Master" or "Backup"
vrrpProp=$(/usr/bin/busctl get-property org.keepalived.Vrrp1 /org/keepalived/Vrrp1/Instance/ens192/"${vrrpRouterID}"/IPv4 org.keepalived.Vrrp1.Instance State)

# Master or Backup
vrrpStatus=$(echo ${vrrpProp} | cut -c 9-14)

unset IFS