Host group reconfiguration is now easier than ever (Preview)

Host groups are a helpful Dynatrace feature, especially in larger and growing environments. The primary value of host groups is that they allow for the grouping of hosts into manageable sets. Host groups are currently in a Beta release phase, but they’ve already proven useful to many customers.

Imagine a situation where you have 1,000 hosts to monitor. Regardless of how awesome the default settings are, at some stage, you’ll want to change the configuration of some of the hosts. For example, you might decide to change the auto-update or anomaly-detection settings of your deployed OneAgents. Or you might want Dynatrace to treat a group of hosts in a load-balancer environment as a single virtual host. All of this is possible with the improved host groups feature, through simple yet powerful mechanisms.

You’ll find lots more information about this on the Host groups help page.

Host group reconfiguration without OneAgent reinstallation

One of the known limitations of our past approach is the fact that host groups can only be defined during initial OneAgent installation on hosts. This is particularly cumbersome in cases where the growth of an environment requires that you configure host groups only following the deployment of several OneAgents. Therefore, we’ve removed the requirement that you must reinstall each OneAgent in order to configure host groups.

Beginning with OneAgent version 1.161, we’re introducing a Preview for an improvement of this functionality. Preview participants can change host group assignments even following OneAgent deployment. The Preview solution is fully functional, however, in the coming weeks, until the solution is labeled GA (General Availability), we reserve the right to perform changes that may not be backward compatible. Such changes may affect the naming and location of related binaries.

Here’s how it works. You must invoke a command-line tool called oneagentutil, which is located at: <INSTALL_PATH>/agent/tools/lib[64]/oneagentutil.

On Windows, this binary can be found at:
C:\Program Files (x86)\dynatrace\oneagent\agent\tools\lib64 or C:\Program Files (x86)\dynatrace\oneagent\agent\tools\lib

On Linux and AIX, you’ll find this tool at:
/opt/dynatrace/oneagent/agent/tools/lib64 or /opt/dynatrace/oneagent/agent/tools/lib, depending on your architecture.

The tool accepts the following parameter for host group assignment:

$ oneagentutil --set-host-group <host group name>

The value of the<host group name> parameter is the host group that the OneAgent is to be associated with. Following invocation of the command, the OneAgent will be assigned to this host group. The specified name can’t exceed 100 characters and can only consist of alphanumeric characters, hyphens, underscores, and dot characters. Host groups names can’t begin with the string .dt.

To remove OneAgent from a host group, provide an empty string as the parameter value.

All host group changes require that you first stop OneAgent. Read the following Dynatrace Help topics to understand how to stop OneAgent operation on Linux, Windows, or AIX.

Once you’ve invoked the oneagentutil command and changed the settings, you’ll be informed about the next required steps, specifically the need to restart OneAgent.

Note: Changing host group assignments results in recalculation of process group IDs, which impacts data aggregation. To read more about the impact of host group changes on process group detection, see host groups in Dynatrace Help.

Other functions of the oneagentutil command

The oneagentutil command can also retrieve the host group name and return it to standard output. This allows for a certain amount of scripting and automation to be built on top of this feature.

$ oneagentutil --get-host-group

How to enroll in the Preview

To participate in the Preview, complete the following form. The list of current and past Preview and Early Access Release features can be found on the Preview and Early Adopter Releases page.

What’s next

Note that we’ve identified other areas of potential improvement related to the host groups feature. We will address these issues in upcoming Dynatrace releases.

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