Keepalived is losing VIP upon "nmcli con up <con-name>" and failover does not occur

Resolution

If keepalived is in use, the system administrator should disable NetworkManager and revert back to initscripts to maintain interface configurations.

However, a workaround does exist that leverages NetworkManagers dispatcher scripts. Which can be used to inject events inline with device events. As NetworkManager ships with environment variables can be used in a script (A list of these variables can be found in man 8 NetworkManager in section DISPATCHER SCRIPTS).

For example, put-down.sh is created in /etc/NetworkManager/pre-down.d/put-down.sh, then symlinked to /etc/NetworkManager/pre-down.d/put-down.sh.If a connection profile is activated put-down.sh will be activated inline.

Disclaimer: The put-down.sh shell script is provided as is by Red Hat support to show proof of concept,not to be implemented in production.

% put-down.sh
  1 #!/bin/bash
  2 # author: openpgp:0x77604A02E1292C5A
  3 
  4 set -xeuo pipefail
  5 shopt -s nullglob
  6 
  7 advrt_int=1
  8 iface=${DEVICE_IP_IFACE:-}
  9 act=${NM_DISPATCHER_ACTION:-}
 10 
 11 function _go_set(){
 12  local ifa=${1:-}
 13  local op=${2:-}
 14 
 15  logger info "[$$] $0: DEVICE_IP_IFACE: ${ifa} NM_DISPATCHER_ACTION: ${op}"
 16 
 17         case ${op} in
 18             down)
 19                 ip link set ${ifa} down
 20                 ;;
 21               up)
 22                 ip link set ${ifa} down
 23                 sleep ${advrt}
 24                 ip link set ${ifa} up
 25                ;;
 26         esac
 27    return 0
 28 }
 29 
 30 function main(){
 31  declare -a argc=( "$#" )
 32  declare -a argv=( "$@" )
 33  local ifac=${argv[0]:-}
 34  local ac=${argv[1]:-}
 35 
 36   _go_set ${ifac} ${ac}
 37 
 38  return 0
 39 }
 40 
 41 main ${iface} ${act}