About the LogDNA Agent

Learn about LogDNA's agent-based log collection and monitoring features.

What is the LogDNA Agent?

The LogDNA Agent reads log files from the computer that it is installed on, and uploads the log data to your LogDNA account to view in the LogDNA web application.

The LogDNA Agent runs on Kubernetes, Openshift, Linux, Windows, and MaxOS.


Earlier versions of the LogDNA Agents

Note that this document addresses both our Node.js-based (which is sometimes referred to as Agent v1) and the Rust-based agent, formerly referred to as Agent v2.

How do I install the LogDNA Agent?

To install the LogDNA Agent follow the instructions in the documentation for each operating system or platform:

You can also log in to the LogDNA web application at https://app.LogDNA.com/ and follow the instructions in the product UI for adding log sources instructions. In the LogDNA app, click on the Help button (bottom left corner of the dashboard), then Logging Setup.

How do I tell the LogDNA Agent what to log?

By default, the LogDNA Agent automatically logs all .log and extensionless files located under /var/log/, but if you want to log other directories or files, you can use the following commands to in a host terminal to specify additional directories or files:

#For directories:
sudo logdna-agent -d "/path/to/my/logs"
#For files:
sudo logdna-agent -f "/path/to/my/logfile"

If you need more complex logic, you can also view and set specific logging paths (as well as use glob patterns by editing /etc/LogDNA.confor /etc/LogDNA.env`, depending on the agent version. For example:

Is the LogDNA agent open source?

Absolutely! You can view (and contribute to!) the source code on GitHub for both Agentv1 and Agent v2 and even build the agent yourself. If you have any questions or feedback, email us at [email protected]

We also love the open source community, so please feel welcome to submit PRs or report any issues you find. Check out our contributing guide for more info.

How do I use host tags?

Host tags allow you to group hosts automatically into dynamic host groups without having to explicitly assign a host to a group within the LogDNA web app. To use tags, ensure the agent is installed on your host and use the following command to add a tag or tags:

sudo logdna-agent -t mytag,myothertag,anothertag

You can also edit the LogDNA configuration file (/etc/logdna.conf or /etc/logdna.env`, depending on the agent version) and specify the tags there.

Keep in mind, even if your hostname or host machine changes, as long as the agent is running with the same tags configured, that host will automatically be added to the dynamic group located under the hosts filter.

How do I override the default hostname?

The LogDNA agent automatically uses the machine's default OS hostname. If you wish to use a different hostname, you can edit the LogDNA configuration file (/etc/LogDNA.conf or /etc/LogDNA.env`, depending on the agent version) and specify the hostname there.