FAQ: Monitoring and Alerts
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This addresses common questions about Ops Manager and how it monitors MongoDB instances and alerts you of issues with those deployments.
Host Configuration
How do I add a new host or server?
See Add Existing MongoDB Processes to Ops Manager.
Can Ops Manager monitor itself?
Yes. You can use Ops Manager to monitor the backing MongoDB instances that hold data for Ops Manager and the Backup Daemon. Create a separate project for the backing instances.
You cannot, however, use Ops Manager to backup or automate the backing instances.
Ops Manager also provides built-in basic monitoring of all backing databases through system alerts.
Can I monitor Kerberos-enabled instances?
Yes. Ops Manager does support monitoring for Kerberos-enabled MongoDB instances. To learn how this works, see Configure the MongoDB Agent for Kerberos.
Monitoring
Do I need an agent for every MongoDB instance?
No. In your Ops Manager project, a single agent connects to all MongoDB databases. Configure firewalls to allow the agent to connect across data centers and servers.
Beginning with agent version 5.0.0, you can activate Monitoring with multiple agents to distribute monitoring assignments and provide failover. Ops Manager distributes monitoring assignments among up to 100 running agents. If you run more than 100 agents, the additional agents behave as "standby" agents. For details, see Manage Monitoring Function.
Where should I run the agent?
The amount of resources the agent requires varies depending
on infrastructure size, the number of servers and the databases it is
monitoring. Run the agent on an existing machine with additional
capacity that does not run a mongod instance. You may
also run the agent on a smaller dedicated instance.
The agent load scales with the number of monitored mongod
plus mongos processes and the number of databases in your MongoDB
environment.
For production environments, it is recommended to install the
agent on a dedicated server, and not on the
the same host as a data bearing mongod instance. This
allows you to perform maintenance on the mongod and its
host without affecting the monitoring for your deployment.
Additionally, an agent may contend for resources with the
mongod.
You can install the agent on the same system as an
arbiter, a mongos, or an application server depending on the
requirements of these services and available resources.
Can I run the agent on an AWS micro server?
If you monitor five or fewer mongod instances, you can use an AWS
micro server.
Why can't the agent connect to my host?
The most common problem is that the agent is unable to resolve the
hostname of the host. Check DNS and the /etc/hosts file.
The second most common problem is that there are firewall rules in place that prohibit access to the host from the agent.
To test the connection, login to the host running the agent and try
to connect using mongosh:
mongosh <hostname>:<port>/test
Note
Ops Manager does not support port forwarding.
Why does the agent connect with hostnames instead of IP addresses?
By default, the agent resolves hostnames to connect. If the agent cannot connect by resolving a hostname, you can force the agent to prefer an IP address over its corresponding hostname for a specific IP address. Preferred hostnames also allow you to specify the hostname to use for servers with multiple aliases. This prevents servers from appearing multiple times under different names in the Ops Manager interface.
To create a preferred hostname, go to Project Settings and add a Preferred Hostnames entry. For details, see Edit Project Settings
How do I setup and configure the agent?
See the README file included in the agent download.
How do I disable Monitoring in Ops Manager?
Data Presentation
What are all those vertical bars in my charts?
A red bar indicates a server restart.
A orange bar indicates the server is now a primary.
A brown bar indicates the server is now a secondary.
Data Retention
What is the data retention policy for Ops Manager?
Ops Manager retains two distinct types of data: metrics, which describe usage; and snapshots, which back up your data.
Ops Manager preserves:
Ops Manager preserves metric data according to Ops Manager's Monitoring Data Retention settings. Ops Manager administrators can modify the settings by selecting Admin, then General, then Ops Manager Config, then the Miscellaneous tab, and then scrolling to Default Monitoring Data Retention.
Snapshots according to their retention policy.
Alerts
What do the alert conditions mean?
For a reference on the alert conditions, see Review Alert Conditions.
What alerts are configured by default?
See Configure Alert Settings for the default alert configurations as well as steps to add new alerts or modify existing alerts, including modifying the alert frequency.