The statistic puller accidentally fails

The issue was found during 1.3 sanity checks. Source

server_1                  | ERRO[2022-05-11 08:35:15] periodicexecutor.go:169   Errors were encountered while pulling data from apps: missing arguments from Lease Stats response {ResponseHeader:{Result:2 Text:'stat-lease4-get' command not supported. Daemon:dhcp4} Arguments:<nil>}
server_1                  | isc.org/stork/server/apps/kea.(*StatsPuller).storeDaemonStats
server_1                  | 	/app/backend/server/apps/kea/statspuller.go:203
server_1                  | isc.org/stork/server/apps/kea.(*StatsPuller).processAppResponses
server_1                  | 	/app/backend/server/apps/kea/statspuller.go:355
server_1                  | isc.org/stork/server/apps/kea.(*StatsPuller).getStatsFromApp
server_1                  | 	/app/backend/server/apps/kea/statspuller.go:329
server_1                  | isc.org/stork/server/apps/kea.(*StatsPuller).pullStats
server_1                  | 	/app/backend/server/apps/kea/statspuller.go:61
server_1                  | isc.org/stork/util.(*PeriodicExecutor).executorLoop
server_1                  | 	/app/backend/util/periodicexecutor.go:166
server_1                  | runtime.goexit
server_1                  | 	/app/tools/golang/go/src/runtime/asm_amd64.s:1581 

The stats are sometimes pulled from daemons without the stat_cmd hook.

It breaks the stat pulling process.

I found this issue during experiments with the simulator. I generated traffic for the subnets from the agent-kea machine. Next, I closed the simulator page and opened the Grafana DHCP6 dashboard. Then, I reopened the simulator and tried to generate traffic for IPv6 networks without success. I couldn't also generate IPv4 traffic again.

The problem may be related to the HA-1 machine.