Hosts¶

On this page

The Hosts Table
Agents

The “Hosts” section is the primary location for monitoring information in the MMS console. This tabbed interface provides access to all of your monitored objects. The tabs you see depend on the types of processes in your deployment. The tab:

“Hosts” displays all non-arbiter mongod instances.
“Mongos” displays all mongos instances.
“Configs” displays all database configuration servers.
“Arbiters” lists the mongod processes functioning as arbiters in replica sets.
“Monitoring Agents” lists the Monitoring agents attached to this MMS account.

For more information, see “Monitoring Agents.”

The remaining “Host” section tabs contain information about the monitoring process and environment. The tab:

“Monitoring Agent Log” displays a log of the Monitoring agent’s activity.
“Pings” provides access to the raw JSON document of the last 20 pings sent to MMS by the agent.

“Host Aliases” shows the mapping between system hostnames and the names provided by the monitored process (e.g. mongod and mongos.) In most cases, hosts are automatically aliased during auto-discovery. If needed, you may modify and configure the alias mapping in the “Settings” section of the console in the “Preferred Hostnames” section. For more information about creating host aliases, see “Creating Host Aliases”.

Note

When you add or update a “Preferred Hostname” value, this action resets all previous hostname aliases.
“CommandLine” shows the run time configuration options set in the configuration file and on the command line for each host.

All of these interfaces, except for the Command Line, provide a search field in the upper right corner to filter the lists in real time.

Note

If you see a hostname in displayed in orange on the host page, this means that:

On Prem MMS Monitoring has detected startup warnings for this host. You can see the warning in the last ping for the host.
On Prem MMS Monitoring suspects that the host has a low ulimit setting that is less than 1024. On Prem MMS Monitoring infers the host’s ulimit setting using the total number of available and current connections.

On Prem MMS Monitoring flags deactivated hosts with an amber yield sign on the host page. If you have deactivated hosts, On Prem MMS Monitoring will add a warning icon (the amber “yield” sign) at the top of the “Hosts” page.

Important

If you have deactivated hosts, review all deactivated hosts to ensure that they are still in use, and remove all hosts that are not active. Then click on the warning icon and select “Reactive ALL hosts”.

The Hosts Table¶

Host Groups¶

From the Hosts page, you can display groups of hosts in one view. By following a link from the “Cluster” or “Repl Set” columns, you can see a side-by-side comparison of charts from all hosts in a given cluster or replica set.

Host Labels¶

“Host Labels” provide a method to narrow the list of hosts in the MMS display. This is particularly crucial if you monitor a large number of hosts and want to access a more limited set of hosts.

A pencil icon on the “Hosts” tab itself opens a dialogue where you may create a new host label. After adding the first label, a drop down box appears where you can narrow the view by selecting a group.

To add hosts to a label or labels, click on the “Edit Host,” button (a pencil) in the rightmost column in the host table. In the dialogue box that returns, the third tab allows you to select or remove labels from this host.

Hosts may belong to none, one, or multiple labels.

Create Host Aliases¶

“Host Aliases” enables you to create host aliases for the hosts you monitor with MMS. These aliases are arbitrary, and are useful if your machines have existing hostnames that do not sufficiently describe the system in the context of MMS.

To set an alias for a host, click on the “Edit Host” button (a pencil) in the far right column of the hosts table. Port numbers are not appended to host aliases.

Remove Hosts¶

MMS cannot ignore any hosts added in the discovery process. You can always manually delete a host from the MMS dashboard by clicking on the trash icon on the far right of the host entry in the hosts table. If you want to add monitoring for a host that you have deleted from MMS, you must add this host manually using the “+ ADD HOST” button at the top of the “Hosts” page. For more about monitoring hosts, see “Monitoring Hosts with MMS”.

DB Profiling¶

On Prem MMS Monitoring can collect data from MongoDB’s profiler to provide statistics about performance and database operations.

This data can include sensitive information, including the content of database queries. Ensure that exposing this to On Prem MMS Monitoring is consistent with your information security practices. Additionally, be aware that the profiler can consume resources which may adversely affect MongoDB performance. Consider the implications before enabling profiling.

To allow On Prem MMS Monitoring to collect profile data for a specific host, click the “Enable profile data transmission,” button (the clock icon), in the far right column of the hosts table. It is the middle of the three icons. This raises a dialogue box that describes the implications of DB profiling and allows you to enable the transmission of the profiling data to On Prem MMS Monitoring.

Note

The Monitoring agent attempts to minimize its effect on the monitored systems. If resource intensive operations, like polling profile data, begins to impact the performance of the database, On Prem MMS Monitoring will throttle the frequency that it collects data. See “How does MMS gather database statistics?”for more information about the agent’s throttling process.

When enabled, On Prem MMS Monitoring samples profiling data from monitored instances: the agent only sends the most recent 20 entries from last minute.

When you select “Enable Profile Info Transmission,” the Monitoring agent will begin sending profile data to On Prem MMS Monitoring. All configuration changes made in the MMS console can take up to 2 minutes to propagate to the agent and another minute before profiling data appears in the MMS interface.

However, to begin collecting profile data, you need to modify the value of setProfilingLevel on the database itself. See the database profiler documentation for instructions for using the profiler. There is a link at the bottom of the Host Statistics page that displays the profile levels.

If you have profiling data, and wish to delete it from the system, there is a button on the bottom of the “Profile Data” tab, that says “Delete Profile Data.” When you click on this button, the MMS Console raises a confirmation dialogue. When you confirm, On Prem MMS Monitoring will begin removing stored profile data from this server’s record.

Note

If On Prem MMS Monitoring is storing a large amount of profile data for your instance, the removal process will not be instantaneous.

Agents¶

The “Agents” tab of the “Hosts” section contains information about the deployed Monitoring agents, and has the following fields:

Hostname: the name of the host running the agent.
Address: the IP address of the address running the agent.
Hosts: the number of MongoDB instances this agent monitors.
Ping Count: the number of pings (i.e. data payloads) sent by the agent since midnight GMT. Typically agents send pings every minute.
Conf Count: the number of configuration requests sent by the agent since midnight GMT. Typically agents request configuration updates every two minutes.
Version: the version of the agent software running on this agent instance.
Last Ping: the last time this agent sent a ping to the MMS servers.
Last Conf: the last time the agent made a configuration request of the MMS servers.

Note

If your Monitoring agent is out of date, it will be highlighted in red on the Monitoring Agents tab of the Hosts page.

Remember, if you have more than one Monitoring agent, only one agent actively monitors MongoDB instances at once. See “Monitoring Architecture” for more information.

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