[root@vqc004d ~]#  mysql -h karma150 -u maxscale -pmaxscale_pw -P 4008

ERROR 1045 (28000): Access denied for user 'maxscale'@'10.2.13.246' (using password: YES)

2020-12-08 22:35:23   notice : Starting a total of 1 services...

2020-12-08 22:35:23   notice : (Backend-Read-Only-Listener) Listening for connections at [0.0.0.0]:4008

2020-12-08 22:35:23   warning: Service 'Backend-Read-Only-Service' has a listener but no servers

2020-12-08 22:35:23   notice : Service 'Backend-Read-Only-Service' started (1/1)

2020-12-08 22:35:24   notice : Server '@@Backend-Monitor:node-2' version: 5.0.45-Xpand-glassbutte-16694

2020-12-08 22:35:24   warning: Service user 'maxscale' of service 'Backend-Read-Only-Service' does not have 'SHOW DATABASES' or a similar global privilege on '@@Backend-Monitor:node-2'. This may cause authentication errors on clients logging in to a specific database.

2020-12-08 22:35:24   notice : Read 10 user@host entries from '@@Backend-Monitor:node-2' for service 'Backend-Read-Only-Service'.

2020-12-08 22:36:28   info   : Accept authentication from 'admin', using password. Request: /v1/servers

2020-12-08 22:38:37   info   : (1) Found matching user 'maxscale'@'%' for client 'maxscale'@'10.2.13.246' with sufficient privileges.

2020-12-08 22:38:37   warning: (1) [mariadbclient] Authentication failed for user 'maxscale'@[10.2.13.246] to service 'Backend-Read-Only-Service'. Originating listener: 'Backend-Read-Only-Listener'. MariaDB error: 'Access denied for user 'maxscale'@'10.2.13.246' (using password: YES)'.

2020-12-08 22:38:37   info   : Stopped Backend-Read-Only-Service client session [1]

2020-12-08 22:38:37   warning: Service user 'maxscale' of service 'Backend-Read-Only-Service' does not have 'SHOW DATABASES' or a similar global privilege on '@@Backend-Monitor:node-2'. This may cause authentication errors on clients logging in to a specific database.

2020-12-08 22:38:37   info   : Read 10 user@host entries from '@@Backend-Monitor:node-2' for service 'Backend-Read-Only-Service'. The data was identical to existing user data.

2020-12-08 22:39:37   info   : Accept authentication from 'admin', using password. Request: /v1/servers

CREATE USER 'maxscale'@'%' IDENTIFIED BY 'maxscale_pw';

    GRANT SELECT ON system.membership TO 'maxscale'@'%';

    GRANT SELECT ON system.nodeinfo TO 'maxscale'@'%';

    GRANT SELECT ON system.softfailed_nodes TO 'maxscale'@'%';

    GRANT SUPER ON *.* TO 'maxscale'@'%’;

MySQL [system]> show grants for maxscale@'%';

+---------------------------------------------------------------+

| Grants for maxscale@%                                         |

+---------------------------------------------------------------+

| GRANT SUPER ON *.* TO 'maxscale'@'%'                          |

| GRANT SELECT ON `system`.`membership` TO 'maxscale'@'%'       |

| GRANT SELECT ON `system`.`nodeinfo` TO 'maxscale'@'%'         |

| GRANT SELECT ON `system`.`softfailed_nodes` TO 'maxscale'@'%' |

+---------------------------------------------------------------+

[root@karma150 ~]# cat /etc/maxscale.cnf

[maxscale]

log_info=1

logdir=/data/clustrix/log

threads=auto

# ------------------------------

# Config to connect to backend directly:

[karma055-backend]

type=server

address=karma055.colo.sproutsys.com

port=3306

protocol=MariaDBBackend

# Backend specific monitor and router:

[Backend-Monitor]

type=monitor

module=xpandmon

servers=karma055-backend

user=maxscale

password=maxscale_pw

monitor_interval=10000

#dynamic_node_detection=false

#health_check_port=3581

[Backend-Read-Only-Service]

type=service

router=readconnroute

user=maxscale

password=maxscale_pw

router_options=running

cluster=Backend-Monitor

[Backend-Read-Only-Listener]

type=listener

service=Backend-Read-Only-Service

protocol=MariaDBClient

address=0.0.0.0

port=4008

[root@karma150 ~]# maxctrl list servers

┌──────────────────────────┬─────────────────────────────┬──────┬─────────────┬─────────────────┬──────┐

│ Server                   │ Address                     │ Port │ Connections │ State           │ GTID │

├──────────────────────────┼─────────────────────────────┼──────┼─────────────┼─────────────────┼──────┤

│ @@Backend-Monitor:node-3 │ 10.2.15.126                 │ 3306 │ 0           │ Master, Running │      │

├──────────────────────────┼─────────────────────────────┼──────┼─────────────┼─────────────────┼──────┤

│ @@Backend-Monitor:node-1 │ 10.2.15.139                 │ 3306 │ 0           │ Master, Running │      │

├──────────────────────────┼─────────────────────────────┼──────┼─────────────┼─────────────────┼──────┤

│ @@Backend-Monitor:node-2 │ 10.2.15.144                 │ 3306 │ 0           │ Master, Running │      │

├──────────────────────────┼─────────────────────────────┼──────┼─────────────┼─────────────────┼──────┤

│ karma055-backend         │ karma055.colo.sproutsys.com │ 3306 │ 0           │ Down            │      │

└──────────────────────────┴─────────────────────────────┴──────┴─────────────┴─────────────────┴──────┘