The Infrastructure list page shows all hosts monitored by your Datadog application:
Note: A host that has not sent data in 24 hours disappears from the infrastructure list; you can still query against it, but it won’t appear in drop downs.
If you click on one host, You can see the tags applied to it:
The Datadog Agent collects potential hostnames from a number of different sources. To see all the names the Agent is detecting, run the Agent info command:
$ sudo /etc/init.d/datadog-agent info
...
Hostnames
=========
hostname: my.special.hostname
agent-hostname: my.special.hostname
ec2-hostname: ip-192-0-0-1.internal
instance-id: i-deadbeef
socket-hostname: myhost
socket-fqdn: myhost.mydomain
...
From these names, a canonical name is picked for the host. This is the name the Agent primarily uses to identify itself to Datadog. The other names are submitted as well, but only as candidates for aliases.
The canonical host name is picked according to the following rules. The first match is selected.
agent-hostname: If a host name is explicitly set in the Agent configuration file.hostname: If the DNS host name is not an EC2 default (e.g. ip-192-0-0-1).instance-id: If the Agent can reach the EC2 metadata endpoint from the host.hostname: Fall back on the DNS host name even if it is an EC2 default.If name is recognized as obviously non-unique (e.g. localhost.localdomain),
the current rule fails and passes through to the next.
Note: If an EC2 instance is an ECS host, Datadog uses the instance-id as the hostname, even if the DNS hostname isn’t an EC2 default. If you don’t wish to use the instance-id, set the hostname in the Agent configuration file.
A single host running in EC2 might have an instance ID (i-abcd1234), a generic hostname provided by EC2 based on the host’s IP address (ip-192-0-0-1), and a meaningful host name provided by an internal DNS server or a config-managed hosts file (myhost.mydomain).
Datadog creates aliases for host names when there are multiple uniquely identifiable names for a single host. The names collected by the Agent (detailed above) are added as aliases for the chosen canonical name.
You can see a list of all the hosts in your account from the Infrastructure tab in Datadog. From the Inspect panel, you can see (among other things) the list of aliases associated with each host.
If you need to print or export the list of hosts reporting to Datadog, use the “JSON API permalink” at the bottom of the Infrastructure List.
Clicking this link provides you with a JSON formatted list of all your hosts.
At times it may also be prove useful to audit your current Agent version numbers to ensure you are running the latest version of the Agent or to update them following a new release.
An easy way to accomplish this would be to use the following script that leverages the JSON permalink:
https://github.com/DataDog/Miscellany/tree/master/get_hostname_agentversion
This script outputs all the current running Agents and their version numbers to a separate document. Additionally, you can edit the script to input a desired Version number if you would also like all the running Agents that are under a particular version number. There is also a separate file if you would like to convert the JSON output into a CSV file for your review.
Once you determine which hosts you would like to update, you can either manually install the Agent from the install page, or you can use one of the Datadog automation integrations like Chef, Puppet, or Ansible.
The host list and all its host information of the Infrastructure List page of Datadog is made available via the “JSON API permalink” at the bottom of the page.
You can programmatically access host information and get the insights you need, one example is this python script that prints the list of hosts:
See the script to prints the list of hosts.
Additional helpful documentation, links, and articles:
