❌ NOT RECOMMENDED
The mysql-check method (with or without a user specified) will flood the Connector logs with connection failure messages.
The mysql-check method (with or without a user specified) does NOT check for database presence nor database consistency. To do this, we must use an external check script (via xinetd) which is explained below.
Here is a practical example for deploying the HAProxy's native
mysql-check option.
#---------------------------------------------------------------------
# backend
#---------------------------------------------------------------------
listen connector
bind *:3306
mode tcp
option tcpka # enables keep-alive both on client and server side
balance roundrobin
option mysql-check user haproxy post-41
server conn1 db1:3306 check inter 5s rise 1 fall 1 weight 3 maxconn 5000
server conn2 db2:3306 check inter 5s rise 1 fall 1 weight 3 maxconn 5000
server conn3 db3:3306 check inter 5s rise 1 fall 1 weight 3 maxconn 5000This solution requires adding a user to MySQL with an empty password.
An example of using mysql-check without a username is not provided here because this functionality is deprecated by HAProxy and not recommended.
The first example uses a % to specify a source IP
wildcard during user creation:
mysql> CREATE USER 'haproxy'@'%' IDENTIFIED WITH mysql_native_password;For deployments that require MySQL to specify an IP address, which address you choose depends on the Connector mode you are using - Bridge or Proxy.
Bridge Mode
In Bridge mode, the IP address seen by the database server will be that of the calling application server (ip_of_application_host).
The below example shows the user creation for Bridge mode deployments that require MySQL to specify an IP address:
mysql> CREATE USER 'haproxy'@'{ip_of_application_host}' IDENTIFIED WITH mysql_native_password;Proxy Mode
In Proxy mode, the IP address seen by the database server will be that of the Tungsten Connector host (ip_of_connector_host).
This example shows the user creation for Proxy mode deployments that require MySQL to specify an IP address:
mysql> CREATE USER 'haproxy'@'{ip_of_connector_host}' IDENTIFIED WITH mysql_native_password;
In proxy Mode, the user.map file must also be
updated as follows:
haproxy - cluster_name_here
In the above example, replace cluster_name_here
with the name of the actual cluster service. Note that a hyphen (-) is
used to indicate a blank password.
MySQL 8 will let you create a user with an empty password provided you don’t have a password‐validation plugin rejecting it. By default, MySQL 8 does not install or enforce the validate_password plugin, so an empty‐string password is allowed. If you see an error when doing this, it usually means validate_password (or another authentication plugin) has been enabled and is enforcing a minimum length or complexity—disabling or tuning that plugin will then allow you to use '' as the password.