"Invalid handshake packet sequence id -- not MySQL protocol" with mariadb

[Henrik Gemal]

I have a simple database check for if mariab is running:

check process mariadb with pidfile /var/run/mariadb/mariadb.pid
    group database
    start program = "/usr/sbin/service mariadb start"
    stop program = "/usr/sbin/service mariadb stop"
    if failed port 3306 protocol mysql for 3 cycles then restart
    if 10 restarts within 10 cycles then timeout

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but I keep getting:

2022-08-10 10:45:05 24 [Warning] Aborted connection 24 to db: 'unconnected' user: 'unauthenticated' host: '127.0.0.1' (This connection closed normally without authentication)

[2022-08-10T10:41:57+0000] debug    : Socket test failed for [127.0.0.1]:3306 -- Invalid handshake packet sequence id -- not MySQL protocol
[2022-08-10T10:41:57+0000] error    : 'mysqld' failed protocol test [MYSQL] at [localhost]:3306 [TCP/IP] -- Invalid handshake packet sequence id -- not MySQL protocol
[2022-08-10T10:41:57+0000] debug    : -------------------------------------------------------------------------------
[2022-08-10T10:41:57+0000] debug    :     monit() [0x42062b]
[2022-08-10T10:41:57+0000] debug    :     monit() [0x4212b4]
[2022-08-10T10:41:57+0000] debug    :     monit() [0x41a377]
[2022-08-10T10:41:57+0000] debug    :     monit() [0x43402c]
[2022-08-10T10:41:57+0000] debug    :     monit() [0x43597b]
[2022-08-10T10:41:57+0000] debug    :     monit() [0x4357d3]
[2022-08-10T10:41:57+0000] debug    :     monit() [0x40586d]
[2022-08-10T10:41:57+0000] debug    :     /lib64/libc.so.6(__libc_start_main+0xea) [0x7f1fed97613a]
[2022-08-10T10:41:57+0000] debug    :     monit() [0x406215]

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using:

This is Monit version 5.32.0
Built with ssl, with ipv6, with compression, with pam and with large files
Copyright (C) 2001-2022 Tildeslash Ltd. All Rights Reserved.

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with mariadb

Version: '10.5.10-MariaDB' socket: '/var/lib/mysql/mysql.sock' port: 3306 MariaDB Server

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[Tildeslash]

please can you send a network trace? (you can use for example Wireshark)

[Henrik Gemal]

I’m not really sure how to do that. I’m on a linux command line

Is there debug version of monit or something instead?

[Tildeslash]

you can use tcpdump then:

sudo tcpdump -i any -s 0 -w mysql.pcap port 3306

please send the mysql.pcap to [e-mail]

[Tildeslash]

Fixed: Issue #1047: If the MariaDB server doesn't allow access to the host from which Monit test is running, Monit reported "Invalid handshake packet sequence id -- not MySQL protocol".

→ <<cset 0a9f448df85a>>

[Tildeslash]

Fixed. It seems the error was MariaDB specific - it worked fine with true MySQL, as it returns packet sequence number #0 in the same error situation and Monit reported the error correctly.

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