zabbix server is not running after upgrading ubuntu from 18.04 to 20.04

[ketrelzhang]

Hi,

I was running Zabbix 5.4.12 on Ubuntu 18.04 with MYSQL 5.7

Last night I upgraded Ubuntu to 20.04, then my Zabbix stopped working.

I noticed that MYSQL was upgraded to 8.0 automatically, but I checked it is running.

I checked the log under /var/log/zabbix/zabbix_server.log.

It kept saying below:
[Z3001] connection to database 'zabbix' failed: [2002] Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

also
failed to accept an incoming connection: connection rejected, getpeername() failed: [107] Transport endpoint is not connected

Can't figure out, could anyone help?

Thanks.

[tim.mooney]

Is it possible AppArmor or some other techology (SELinux) is blocking access to the socket?

Have you verified that the path "/var/run/mysqld/mysqld.sock" is the actual path that MySQL has created for its local socket?

Is there a mysql log file, maybe /var/log/mysqld.log or /var/log/mysql/error.log or similar that might have a clue?

[ketrelzhang]

Is it possible AppArmor or some other techology (SELinux) is blocking access to the socket?

Have you verified that the path "/var/run/mysqld/mysqld.sock" is the actual path that MySQL has created for its local socket?

Is there a mysql log file, maybe /var/log/mysqld.log or /var/log/mysql/error.log or similar that might have a clue?

HI Tim,

Thanks for the information, I have checked mysql logs, it is fine. I am not too sure how to check if SELinux blocked the access to the socket?

Could you please give me some advise?

Thanks.

[tim.mooney]

Ubuntu, especially older Ubuntu, strongly prefers AppArmor, so it's more likely that AppArmor is enabled than SELinux. https://ubuntu.com/server/docs/security-apparmor