Monitor resources on private networks

To monitor resources on private networks you can either:

Private Locations via Elastic Agent require only outbound connections from your network, while allowing Elastic’s global managed infrastructure to access a private endpoint requires inbound access, thus posing an additional risk that users must assess.

To give Elastic’s global managed infrastructure access to a private endpoint, use IP address filtering, HTTP authentication, or both.

To grant access via IP, use this list of egress IPs. The addresses and locations on this list may change, so automating updates to filtering rules is recommended. IP filtering alone will allow all users of Elastic’s global managed infrastructure access to your endpoints, if this is a concern consider adding additional protection via user/password authentication via a proxy like nginx.

Private Locations allow you to run monitors from your own premises. Before running a monitor on a Private Location, you’ll need to:

Start by setting up Fleet Server and Elastic Agent:

After setting up Fleet, you’ll connect Fleet to the Elastic Stack and enroll an Elastic Agent in Fleet.

Elastic provides Docker images that you can use to run Fleet and an Elastic Agent more easily. For monitors running on Private Locations, you must use the elastic-agent-complete Docker image to create a self-hosted Elastic Agent node. The standard Elastic Cloud or self-hosted Elastic Agent will not work.

To pull the Docker image run:

docker pull docker.elastic.co/elastic-agent/elastic-agent-complete:8.17.0

Then enroll and run an Elastic Agent. You’ll need an enrollment token and the URL of the Fleet Server. You can use the default enrollment token for your policy or create new policies and enrollment tokens as needed.

For more information on running Elastic Agent with Docker, refer to Run Elastic Agent in a container.

docker run \
  --env FLEET_ENROLL=1 \
  --env FLEET_URL={fleet-server-host-url} \
  --env FLEET_ENROLLMENT_TOKEN={enrollment-token} \
  --cap-add=NET_RAW \
  --cap-add=SETUID \
  --rm docker.elastic.co/elastic-agent/elastic-agent-complete:8.17.0

When the Elastic Agent is running you can add a new Private Location in Kibana:

By default Private Locations are configured to allow two simultaneous browser tests, and an unlimited number of lightweight checks. These limits can be set via the environment variables SYNTHETICS_LIMIT_{TYPE}, where {TYPE} is one of BROWSER, HTTP, TCP, and ICMP for the container running the Elastic Agent docker image.

It is critical to allocate enough memory and CPU capacity to handle configured limits. Start by allocating at least 2 GiB of memory and two cores per browser instance to ensure consistent performance and avoid out-of-memory errors. Then adjust as needed. Resource requirements will vary depending on workload. Much less memory is needed for lightweight monitors. Start by allocating at least 512MiB of memory and two cores for lightweight checks. Then increase allocated memory and CPU based on observed usage patterns.

These limits are for simultaneous tests, not total tests. For example, if 60 browser tests were scheduled to run once per hour and each took 1 minute to run, that would fully occupy one execution slot. However, it is a good practice to set up execution slots with extra capacity. A good starting point would be to over-allocate by a factor of 5. In the previous example that would mean allocating 5 slots.

Now you can add monitors to your Private Location in the Synthetics app or using the Elastic Synthetics library’s push method.