The Ultimate Guide to High Availability with MariaDB

Monitor Resource

Monitor Resource

A monitor resource represents a monitor inside MaxScale that monitors one or more servers.

Resource Operations

The :name in all of the URIs must be the name of a monitor in MaxScale.

Get a monitor

GET /v1/monitors/:name

Get a single monitor.

Response

Status: 200 OK

{
    "data": {
        "attributes": {
            "module": "mariadbmon",
            "monitor_diagnostics": {
                "master": "server1",
                "master_gtid_domain_id": 0,
                "primary": null,
                "server_info": [
                    {
                        "gtid_binlog_pos": "0-3000-5",
                        "gtid_current_pos": "0-3000-5",
                        "lock_held": null,
                        "master_group": null,
                        "name": "server1",
                        "read_only": false,
                        "server_id": 3000,
                        "slave_connections": [],
                        "state_details": null
                    },
                    {
                        "gtid_binlog_pos": "0-3000-5",
                        "gtid_current_pos": "0-3000-5",
                        "lock_held": null,
                        "master_group": null,
                        "name": "server2",
                        "read_only": false,
                        "server_id": 3001,
                        "slave_connections": [
                            {
                                "connection_name": "",
                                "gtid_io_pos": "",
                                "last_io_error": "",
                                "last_sql_error": "",
                                "master_host": "127.0.0.1",
                                "master_port": 3000,
                                "master_server_id": 3000,
                                "master_server_name": "server1",
                                "seconds_behind_master": 0,
                                "slave_io_running": "Yes",
                                "slave_sql_running": "Yes"
                            }
                        ],
                        "state_details": null
                    }
                ],
                "state": "Idle"
            },
            "parameters": {
                "assume_unique_hostnames": true,
                "auto_failover": false,
                "auto_rejoin": false,
                "backend_connect_attempts": 1,
                "backend_connect_timeout": "3000ms",
                "backend_read_timeout": "3000ms",
                "backend_write_timeout": "3000ms",
                "cooperative_monitoring_locks": "none",
                "cs_admin_api_key": null,
                "cs_admin_base_path": "/cmapi/0.4.0",
                "cs_admin_port": 8640,
                "demotion_sql_file": null,
                "disk_space_check_interval": "0ms",
                "disk_space_threshold": null,
                "enforce_read_only_slaves": false,
                "enforce_simple_topology": false,
                "enforce_writable_master": false,
                "events": "all,master_down,master_up,slave_down,slave_up,server_down,server_up,synced_down,synced_up,donor_down,donor_up,lost_master,lost_slave,lost_synced,lost_donor,new_master,new_slave,new_synced,new_donor",
                "failcount": 5,
                "failover_timeout": "90000ms",
                "handle_events": true,
                "journal_max_age": "28800000ms",
                "maintenance_on_low_disk_space": true,
                "master_conditions": "primary_monitor_master",
                "master_failure_timeout": "10000ms",
                "module": "mariadbmon",
                "monitor_interval": "5000ms",
                "password": "*****",
                "promotion_sql_file": null,
                "rebuild_port": 4444,
                "replication_master_ssl": false,
                "replication_password": "*****",
                "replication_user": "maxuser",
                "script": null,
                "script_max_replication_lag": -1,
                "script_timeout": "90000ms",
                "servers_no_promotion": null,
                "slave_conditions": "",
                "ssh_check_host_key": true,
                "ssh_keyfile": null,
                "ssh_port": 22,
                "ssh_timeout": "10000ms",
                "ssh_user": null,
                "switchover_on_low_disk_space": false,
                "switchover_timeout": "90000ms",
                "type": "monitor",
                "user": "maxuser",
                "verify_master_failure": true
            },
            "source": {
                "file": "/etc/maxscale.cnf",
                "type": "static"
            },
            "state": "Running",
            "ticks": 4
        },
        "id": "MariaDB-Monitor",
        "links": {
            "self": "http://localhost:8989/v1/monitors/MariaDB-Monitor/"
        },
        "relationships": {
            "servers": {
                "data": [
                    {
                        "id": "server1",
                        "type": "servers"
                    },
                    {
                        "id": "server2",
                        "type": "servers"
                    }
                ],
                "links": {
                    "related": "http://localhost:8989/v1/servers/",
                    "self": "http://localhost:8989/v1/monitors/MariaDB-Monitor/relationships/servers/"
                }
            },
            "services": {
                "data": [
                    {
                        "id": "RW-Split-Router",
                        "type": "services"
                    }
                ],
                "links": {
                    "related": "http://localhost:8989/v1/services/",
                    "self": "http://localhost:8989/v1/monitors/MariaDB-Monitor/relationships/services/"
                }
            }
        },
        "type": "monitors"
    },
    "links": {
        "self": "http://localhost:8989/v1/monitors/MariaDB-Monitor/"
    }
}

Get all monitors

GET /v1/monitors

Get all monitors.

Response

Status: 200 OK

{
    "data": [
        {
            "attributes": {
                "module": "mariadbmon",
                "monitor_diagnostics": {
                    "master": "server1",
                    "master_gtid_domain_id": 0,
                    "primary": null,
                    "server_info": [
                        {
                            "gtid_binlog_pos": "0-3000-5",
                            "gtid_current_pos": "0-3000-5",
                            "lock_held": null,
                            "master_group": null,
                            "name": "server1",
                            "read_only": false,
                            "server_id": 3000,
                            "slave_connections": [],
                            "state_details": null
                        },
                        {
                            "gtid_binlog_pos": "0-3000-5",
                            "gtid_current_pos": "0-3000-5",
                            "lock_held": null,
                            "master_group": null,
                            "name": "server2",
                            "read_only": false,
                            "server_id": 3001,
                            "slave_connections": [
                                {
                                    "connection_name": "",
                                    "gtid_io_pos": "",
                                    "last_io_error": "",
                                    "last_sql_error": "",
                                    "master_host": "127.0.0.1",
                                    "master_port": 3000,
                                    "master_server_id": 3000,
                                    "master_server_name": "server1",
                                    "seconds_behind_master": 0,
                                    "slave_io_running": "Yes",
                                    "slave_sql_running": "Yes"
                                }
                            ],
                            "state_details": null
                        }
                    ],
                    "state": "Idle"
                },
                "parameters": {
                    "assume_unique_hostnames": true,
                    "auto_failover": false,
                    "auto_rejoin": false,
                    "backend_connect_attempts": 1,
                    "backend_connect_timeout": "3000ms",
                    "backend_read_timeout": "3000ms",
                    "backend_write_timeout": "3000ms",
                    "cooperative_monitoring_locks": "none",
                    "cs_admin_api_key": null,
                    "cs_admin_base_path": "/cmapi/0.4.0",
                    "cs_admin_port": 8640,
                    "demotion_sql_file": null,
                    "disk_space_check_interval": "0ms",
                    "disk_space_threshold": null,
                    "enforce_read_only_slaves": false,
                    "enforce_simple_topology": false,
                    "enforce_writable_master": false,
                    "events": "all,master_down,master_up,slave_down,slave_up,server_down,server_up,synced_down,synced_up,donor_down,donor_up,lost_master,lost_slave,lost_synced,lost_donor,new_master,new_slave,new_synced,new_donor",
                    "failcount": 5,
                    "failover_timeout": "90000ms",
                    "handle_events": true,
                    "journal_max_age": "28800000ms",
                    "maintenance_on_low_disk_space": true,
                    "master_conditions": "primary_monitor_master",
                    "master_failure_timeout": "10000ms",
                    "module": "mariadbmon",
                    "monitor_interval": "5000ms",
                    "password": "*****",
                    "promotion_sql_file": null,
                    "rebuild_port": 4444,
                    "replication_master_ssl": false,
                    "replication_password": "*****",
                    "replication_user": "maxuser",
                    "script": null,
                    "script_max_replication_lag": -1,
                    "script_timeout": "90000ms",
                    "servers_no_promotion": null,
                    "slave_conditions": "",
                    "ssh_check_host_key": true,
                    "ssh_keyfile": null,
                    "ssh_port": 22,
                    "ssh_timeout": "10000ms",
                    "ssh_user": null,
                    "switchover_on_low_disk_space": false,
                    "switchover_timeout": "90000ms",
                    "type": "monitor",
                    "user": "maxuser",
                    "verify_master_failure": true
                },
                "source": {
                    "file": "/etc/maxscale.cnf",
                    "type": "static"
                },
                "state": "Running",
                "ticks": 4
            },
            "id": "MariaDB-Monitor",
            "links": {
                "self": "http://localhost:8989/v1/monitors/MariaDB-Monitor/"
            },
            "relationships": {
                "servers": {
                    "data": [
                        {
                            "id": "server1",
                            "type": "servers"
                        },
                        {
                            "id": "server2",
                            "type": "servers"
                        }
                    ],
                    "links": {
                        "related": "http://localhost:8989/v1/servers/",
                        "self": "http://localhost:8989/v1/monitors/MariaDB-Monitor/relationships/servers/"
                    }
                },
                "services": {
                    "data": [
                        {
                            "id": "RW-Split-Router",
                            "type": "services"
                        }
                    ],
                    "links": {
                        "related": "http://localhost:8989/v1/services/",
                        "self": "http://localhost:8989/v1/monitors/MariaDB-Monitor/relationships/services/"
                    }
                }
            },
            "type": "monitors"
        }
    ],
    "links": {
        "self": "http://localhost:8989/v1/monitors/"
    }
}

Create a monitor

POST /v1/monitors

Create a new monitor. The request body must define at least the following fields.

  • data.id

  • Name of the monitor

  • data.type

  • Type of the object, must be monitors

  • data.attributes.module

  • The monitor module to use

  • data.attributes.parameters.user

  • The user to use

  • data.attributes.parameters.password

  • The password to use

All monitor parameters can be defined at creation time.

The following example defines a request body which creates a new monitor and assigns two servers to be monitored by it. It also defines a custom value for the monitor_interval parameter.

{
    data: {
        "id": "test-monitor", // Name of the monitor
        "type": "monitors",
        "attributes": {
            "module": "mariadbmon", // The monitor uses the mariadbmon module
            "parameters": { // Monitor parameters
                "monitor_interval": 1000,
                "user": "maxuser,
                "password": "maxpwd"
            }
        },
        "relationships": { // List of server relationships that this monitor uses
            "servers": {
                "data": [ // This monitor uses two servers
                    {
                        "id": "server1",
                        "type": "servers"
                    },
                    {
                        "id": "server2",
                        "type": "servers"
                    }
                ]
            }
        }
    }
}

Response

Monitor is created:

Status: 204 No Content

Update a monitor

PATCH /v1/monitors/:name

The request body must be a valid JSON document representing the modified monitor.

Modifiable Fields

The following standard server parameter can be modified.

In addition to these standard parameters, the monitor specific parameters can also be modified. Refer to the monitor module documentation for details on these parameters.

Response

Monitor is modified:

Status: 204 No Content

Invalid request body:

Status: 400 Bad Request

Update monitor relationships

PATCH /v1/monitors/:name/relationships/servers

The request body must be a JSON object that defines only the data field. The value of the data field must be an array of relationship objects that define the id and type fields of the relationship. This object will replace the existing relationships of the monitor.

The following is an example request and request body that defines a single server relationship for a monitor.

PATCH /v1/monitors/my-monitor/relationships/servers

{
    data: [
          { "id": "my-server", "type": "servers" }
    ]
}

All relationships for a monitor can be deleted by sending an empty array as the data field value. The following example removes all servers from a monitor.

PATCH /v1/monitors/my-monitor/relationships/servers

{
    data: []
}

Response

Monitor relationships modified:

Status: 204 No Content

Invalid JSON body:

Status: 400 Bad Request

Destroy a monitor

DELETE /v1/monitors/:name

Destroy a created monitor. The monitor must not have relationships to any servers in order to be destroyed.

This endpoint also supports the force=yes parameter that will unconditionally delete the monitor by first unlinking it from all servers that it uses.

Response

Monitor is deleted:

Status: 204 No Content

Monitor could not be deleted:

Status: 400 Bad Request

Stop a monitor

PUT /v1/monitors/:name/stop

Stops a started monitor.

Response

Monitor is stopped:

Status: 204 No Content

Start a monitor

PUT /v1/monitors/:name/start

Starts a stopped monitor.

Response

Monitor is started:

Status: 204 No Content

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