Zabbix database is not available.

[W-P]

Hello, please let me ask about the following message detected on Zabbix.

---------------------------------------------------------------------------------------------------------------------------------
PostgreSQL database "zabbix" on "localhost:5432" is not available: could not connect to server: Connection refused
Is the server running on host "localhost" (127.0.0.1) and accepting
TCP/IP connections on port 5432?
---------------------------------------------------------------------------------------------------------------------------------

I have received the above message from Zabbix 3 times before (not frequently, approx. once per a half year), but not sure how to resolve it

At the time of the issue, I checked zabbix server, agent, postgresql services are active and found the following logs (/var/log/postgresql/postgresql-10-main.log.1).

2022-05-25 21:55:11.148 UTC [29934] zabbix@zabbix FATAL: the database system is shutting down
2022-05-25 21:55:11.154 UTC [9362] zabbix@zabbix FATAL: terminating connection due to administrator command
2022-05-25 21:55:11.302 UTC [9312] LOG: shutting down
2022-05-25 21:55:11.446 UTC [9310] LOG: database system is shut down
2022-05-25 21:56:28.579 UTC [30183] LOG: listening on IPv4 address "127.0.0.1", port 5432
2022-05-25 21:56:28.617 UTC [30183] LOG: listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
2022-05-25 21:56:28.816 UTC [30188] LOG: database system was shut down at 2022-05-25 21:55:11 UTC
2022-05-25 21:56:28.831 UTC [30189] zabbix@zabbix FATAL: the database system is starting up
2022-05-25 21:56:28.862 UTC [30183] LOG: database system is ready to accept connections
2022-05-25 21:56:29.420 UTC [30202] [unknown]@[unknown] LOG: incomplete startup packet
2022-05-25 21:56:29.940 UTC [30227] postgres@postgres FATAL: password authentication failed for user "postgres"
2022-05-25 21:56:29.940 UTC [30227] postgres@postgres DETAIL: Password does not match for user "postgres".
Connection matched pg_hba.conf line 85: "local all postgres md5"
2022-05-25 21:56:35.154 UTC [30286] [unknown]@[unknown] LOG: incomplete startup packet

Could you advise how to solve the issue?

[Bartosz Mickiewicz]

Hi,
Most likely your Postgres is getting SIGTERM and that's why it shuts down.
2022-05-25 21:56:29.420 UTC [30202] [unknown]@[unknown] LOG: incomplete startup packet is harmless.
Maybe someone is shutting down the database, or your system is running out of resources.