Prior to this update, the L3 agent failed to respawn keepalived process if the keepalived parent process died. This was because the child keepalived process was still running.
Consequently, the L3 agent could not recover from keepalived parent process death, breaking the HA router served by the process.
With this update, the L3 agent is made aware of the child keepalived process, and now cleans up it as well before respawning keepalived.
As a result, the L3 agent is now able to recover HA routers when the keepalived process dies.