# Use host labels to organize systems, metrics, and alarms When you use Netdata to monitor and troubleshoot an entire infrastructure, whether that's dozens or hundreds of systems, you need sophisticated ways of keeping everything organized. You need alarms that adapt to the system's purpose, or whether the parent or child in a streaming setup. You need properly-labeled metrics archiving so you can sort, correlate, and mash-up your data to your heart's content. You need to keep tabs on ephemeral Docker containers in a Kubernetes cluster. You need **host labels**: a powerful new way of organizing your Netdata-monitored systems. We introduced host labels in [v1.20 of Netdata](https://blog.netdata.cloud/posts/release-1.20/), and they come pre-configured out of the box. Let's take a peek into how to create host labels and apply them across a few of Netdata's features to give you more organization power over your infrastructure. ## Create unique host labels Host labels are defined in `netdata.conf`. To create host labels, open that file using `edit-config`. ```bash cd /etc/netdata # Replace this path with your Netdata config directory, if different sudo ./edit-config netdata.conf ``` Create a new `[host labels]` section defining a new host label and its value for the system in question. Make sure not to violate any of the [host label naming rules](/docs/configure/common-changes.md#organize-nodes-with-host-labels). ```conf [host labels] type = webserver location = us-seattle installed = 20200218 ``` Once you've written a few host labels, you need to enable them. Instead of restarting the entire Netdata service, you can reload labels using the helpful `netdatacli` tool: ```bash netdatacli reload-labels ``` Your host labels will now be enabled. You can double-check these by using `curl http://HOST-IP:19999/api/v1/info` to read the status of your agent. For example, from a VPS system running Debian 10: ```json { ... "host_labels": { "_is_k8s_node": "false", "_is_parent": "false", "_virt_detection": "systemd-detect-virt", "_container_detection": "none", "_container": "unknown", "_virtualization": "kvm", "_architecture": "x86_64", "_kernel_version": "4.19.0-6-amd64", "_os_version": "10 (buster)", "_os_name": "Debian GNU/Linux", "type": "webserver", "location": "seattle", "installed": "20200218" }, ... } ``` You may have noticed a handful of labels that begin with an underscore (`_`). These are automatic labels. ### Automatic labels When Netdata starts, it captures relevant information about the system and converts them into automatically-generated host labels. You can use these to logically organize your systems via health entities, exporting metrics, parent-child status, and more. They capture the following: - Kernel version - Operating system name and version - CPU architecture, system cores, CPU frequency, RAM, and disk space - Whether Netdata is running inside of a container, and if so, the OS and hardware details about the container's host - Whether Netdata is running inside K8s node - What virtualization layer the system runs on top of, if any - Whether the system is a streaming parent or child If you want to organize your systems without manually creating host tags, try the automatic labels in some of the features below. ## Host labels in streaming You may have noticed the `_is_parent` and `_is_child` automatic labels from above. Host labels are also now streamed from a child to its parent node, which concentrates an entire infrastructure's OS, hardware, container, and virtualization information in one place: the parent. Now, if you'd like to remind yourself of how much RAM a certain child node has, you can access `http://localhost:19999/host/CHILD_HOSTNAME/api/v1/info` and reference the automatically-generated host labels from the child system. It's a vastly simplified way of accessing critical information about your infrastructure. > ⚠️ Because automatic labels for child nodes are accessible via API calls, and contain sensitive information like > kernel and operating system versions, you should secure streaming connections with SSL. See the [streaming > documentation](/streaming/README.md#securing-streaming-communications) for details. You may also want to use > [access lists](/web/server/README.md#access-lists) or [expose the API only to LAN/localhost > connections](/docs/netdata-security.md#expose-netdata-only-in-a-private-lan). You can also use `_is_parent`, `_is_child`, and any other host labels in both health entities and metrics exporting. Speaking of which... ## Host labels in health entities You can use host labels to logically organize your systems by their type, purpose, or location, and then apply specific alarms to them. For example, let's use configuration example from earlier: ```conf [host labels] type = webserver location = us-seattle installed = 20200218 ``` You could now create a new health entity (checking if disk space will run out soon) that applies only to any host labeled `webserver`: ```yaml template: disk_fill_rate on: disk.space lookup: max -1s at -30m unaligned of avail calc: ($this - $avail) / (30 * 60) every: 15s host labels: type = webserver ``` Or, by using one of the automatic labels, for only webserver systems running a specific OS: ```yaml host labels: _os_name = Debian* ``` In a streaming configuration where a parent node is triggering alarms for its child nodes, you could create health entities that apply only to child nodes: ```yaml host labels: _is_child = true ``` Or when ephemeral Docker nodes are involved: ```yaml host labels: _container = docker ``` Of course, there are many more possibilities for intuitively organizing your systems with host labels. See the [health documentation](/health/REFERENCE.md#alarm-line-host-labels) for more details, and then get creative! ## Host labels in metrics exporting If you have enabled any metrics exporting via our experimental [exporters](/exporting/README.md), any new host labels you created manually are sent to the destination database alongside metrics. You can change this behavior by editing `exporting.conf`, and you can even send automatically-generated labels on with exported metrics. ```conf [exporting:global] enabled = yes send configured labels = yes send automatic labels = no ``` You can also change this behavior per exporting connection: ```conf [opentsdb:my_instance3] enabled = yes destination = localhost:4242 data source = sum update every = 10 send charts matching = system.cpu send configured labels = no send automatic labels = yes ``` By applying labels to exported metrics, you can more easily parse historical metrics with the labels applied. To learn more about exporting, read the [documentation](/exporting/README.md). ## What's next? Host labels are a brand-new feature to Netdata, and yet they've already propagated deeply into some of its core functionality. We're just getting started with labels, and will keep the community apprised of additional functionality as it's made available. You can also track [issue #6503](https://github.com/netdata/netdata/issues/6503), which is where the Netdata team first kicked off this work. It should be noted that while the Netdata dashboard does not expose either user-configured or automatic host labels, API queries _do_ showcase this information. As always, we recommend you secure Netdata - [Expose Netdata only in a private LAN](/docs/netdata-security.md#expose-netdata-only-in-a-private-lan) - [Enable TLS/SSL for web/API requests](/web/server/README.md#enabling-tls-support) - Put Netdata behind a proxy - [Use an authenticating web server in proxy mode](/docs/netdata-security.md#use-an-authenticating-web-server-in-proxy-mode) - [Nginx proxy](/docs/Running-behind-nginx.md) - [Apache proxy](/docs/Running-behind-apache.md) - [Lighttpd](/docs/Running-behind-lighttpd.md) - [Caddy](/docs/Running-behind-caddy.md) If you have issues or questions around using host labels, don't hesitate to [file an issue](https://github.com/netdata/netdata/issues/new?labels=bug%2C+needs+triage&template=bug_report.md) on GitHub. We're excited to make host labels even more valuable to our users, which we can only do with your input. [](<>)