Re: [PATCH 0/2] MEDIUM: checks: add post-80 option for mysql-check to support MySQL

[Christopher Faulet]

Le 28/01/2026 à 2:20 AM, Hyeonggeun Oh a écrit :

Hello HAProxy Team,

This patch adds MySQL 8.x compatibility to the mysql-check health check option.

Problem:
MySQL 8.0 changed the default authentication plugin from mysql_native_password
to caching_sha2_password. The existing post-41 option lacks CLIENT_PLUGIN_AUTH
capability, causing MySQL 8.x servers to reject health check connections with
error 1251.

Solution:
A new 'post-80' option that includes CLIENT_PLUGIN_AUTH capability and
explicitly requests mysql_native_password authentication.

Testing:
Built and tested on Linux (Debian bookworm)
Verified with MySQL 8.0.44 in Docker environment
Regression test with custom test configuration like below. (in 
reg-tests/checks/mysql-check.vtc)
```vtc
# MySQL 8.0 server responding to post-80 client (with CLIENT_PLUGIN_AUTH)
server s6 {
   sendhex 
"4A0000000A382E302E3139000A0000006F3C025E6249410D00FFFFFF0200FFC715000000000000000000007C182159106E2761144322200063616368696E675F736861325F70617373776F726400"
   recv 69
   sendhex "0700000200000002000000"
} -start
```

Limitation:
The health check user must still use mysql_native_password authentication.
This is a MySQL server-side requirement, not a HAProxy limitation.

This addresses GitHub issue https://github.com/haproxy/haproxy/issues/2934.

Please review my patch and leave comments.

Sincerely,
Hyeonggeun.

Hyeonggeun Oh (2):
   MEDIUM: tcpcheck: add post-80 option for mysql-check to support MySQL
     8.x
   DOC: add post-80 option for mysql-check to support MySQL 8.x

  doc/configuration.txt |  8 +++++++-
  src/tcpcheck.c        | 37 ++++++++++++++++++++++++++++++++++++-
  2 files changed, 43 insertions(+), 2 deletions(-)

Thanks, I will review it ASAP.

--
Christopher Faulet