You can monitor multiple MySQL servers (either on the same machine, or across different machines) using two different methods:
By using a single agent instance to monitor multiple MySQL servers. You can use this method if you want to monitor multiple servers, but do not want or need to support Query Analysis on the additional servers.
By using multiple copies of the MySQL Enterprise Agent to monitor each server individually. Using this method requires additional overhead to monitor each server, while also allowing you to supply Query Analyzer data.
Using a Single Agent Instance
Do not use the single agent instance method if you want to use Query Analyzer. If you set your application to use the proxy port provided by the single instance then the queries may not be directed to the correct server. Using Query Analyzer, the proxy, and the single agent instance method is not supported.
When using the single agent instance method, the agent will attempt to determine the right information about the backend server that it is monitoring in order to use the information when applying rule and advisor information. Currently, this operation is performed for only one of the servers in the list of configured servers. If the servers being monitoring are using different MySQL versions then the rules applied to the servers may be incorrect, and you could get wrong or misleading advice about issues or problems on a given server.
To use a single agent to monitor multiple instances, you can
create additional directories and configuration files within the
instances directory for the agent. For
example, you can see the default structure of the agent
configuration directory:
./init.d ./init.d/mysql-monitor-agent ./instances ./instances/agent ./instances/agent/agent-instance.ini ./mysql-monitor-agent.ini
Within the instances directory, you can add
further directories, one for each monitored server. Each
additional directory must have a suitable
agent-instance.ini file containing the
connection information for the new MySQL server instance. For
example, the following structure demonstrates an agent monitoring
four MySQL servers:
./init.d ./init.d/mysql-monitor-agent ./instances ./instances/agent ./instances/agent/agent-instance.ini ./instances/mysql2 ./instances/mysql2/agent-instance.ini ./instances/mysql-rep ./instances/mysql-rep/agent-instance.ini ./instances/mysql-backup ./instances/mysql-backup/agent-instance.ini ./mysql-monitor-agent.ini
To add another MySQL monitored server, follow these steps:
Make sure that the MySQL instance that you want to monitor has a suitable user to use for connecting to the server. For more information, see Section 15.6.3.1, “Creating a MySQL User Account for the Monitor Agent”.
Copy an existing configuration directory and configuration files to the new directory:
shell> cp -R etc/instances/agent etc/instances/
mysql2Edit the configuration file within the new directory, for example
mysql2/agent-instance.ini, and set theuser,passwordand either thehostnameandport, orsocketparameters.Restart the agent:
shell> mysql-monitor-agent restart
Using Multiple Agent Instances
To use multiple agents to monitor multiple MySQL servers you need to create a new configuration structure for both the agent and the MySQL server instances you need to monitor, including the binaries and configuration files, and then update the configuration to set the corresponding parameters to monitor the new server. Using this method lets you enable query analysis by redirecting requests to the target server using the built-in proxy service within the agent.
For example, the directory structure below shows the configuration directory for two agents monitoring a single MySQL server each:
./init.d ./init.d/mysql-monitor-agent ./instances ./instances/agent ./instances/agent/agent-instance.ini ./instances-second/agent ./instances-second/agent/agent-instance.ini ./mysql-monitor-agent.ini ./mysql-second-agent.ini
The mysql-monitor-agent.ini file contains the
configuration for the first agent, with the MySQL servers
monitored defined within the instances
directory. The mysql-second-agent.ini file
contains the configuration information for the second agent, with
the MySQL servers monitor defined within the
instances-second directory.
To set up multiple agents:
Make sure that the MySQL instance that you want to monitor has a suitable user to use for connecting to the server. For more information, see Section 15.6.3.1, “Creating a MySQL User Account for the Monitor Agent”.
You need to generate a new UUID for the new agent:
shell> /opt/mysql/enterprise/agent/bin/mysql-proxy --plugins-agent --agent-generate-uuid ee9296d7-f7cd-4fee-8b26-ead884ebf398 2009-03-05 11:49:37: (critical) shutting down normally
Keep a record of the UUID to update the configuration file.
Note, the agent should not be running when the UUID is generated.
Copy the main agent configuration file, which is by default in
/opt/mysql/enterprise/agent/etc/mysql-monitor-agent.ini:shell> cp mysql-monitor-agent.ini
mysql-second-agent.iniEdit the new configuration file, changing the following settings:
Change the
mysqld-instance-dirto the new directory that will contain the individual MySQL server configuration files.Change the
proxy-addressto a different value than the first agent configuration.Change the
proxy-backend-addressesto specify the IP address and MySQL port number for the MySQL server.Change the
agent-uuidto the new value obtained in an earlier step.Change the
log-fileparameter to specify a different file to use when logging errors and problems. You cannot log to the same file from two different agents.Change the
pid-fileparameter to specify the file that will be used to store the process ID of the agent.
Copy an existing configuration directory and configuration files to the new directory:
shell> cp -R etc/instances etc/
instances-secondEdit the configuration file,
instances/second/agent/agent-instance.iniwithin the new directory, and set theuser,passwordand either thehostnameandport, orsocketparameters.With multiple instances, you must start each agent individually, specifying the location of the main configuration file. For example, to start the original (default) service:
shell> /opt/mysql/enterprise/agent/etc/init.d/mysql-monitor-agent start /opt/mysql/monitor/agent/etc/mysql-monitor-agent.ini
To start the second instance:
shell> /opt/mysql/enterprise/agent/etc/init.d/mysql-monitor-agent start /opt/mysql/monitor/agent/etc/mysql-second-agent.ini