Select Telegraf plugins with labels and selectors

Labels and selectors let you enable or disable plugin instances at startup without editing the configuration file: add labels to plugins in the configuration, then pass selectors on the command line. Inspired by Kubernetes labels, this is useful when many Telegraf instances share one configuration source, such as a configuration managed with Telegraf Controller, and each instance should run only a subset of the configured plugins.

Add labels to plugins

Add an optional labels table to any input, output, processor, or aggregator plugin:

[[inputs.cpu]]
  [inputs.cpu.labels]
    app = "payments"
    region = "us-east"
    env = "prod"

Label keys and values are plain strings that can contain alphanumeric characters, dots (.), dashes (-), and underscores (_). Neither keys nor values can contain wildcard characters.

Select plugins at startup

Pass one or more --select flags when starting Telegraf. Each --select value is a semicolon-separated list of key-value pairs:

<key>=<value>[;<key>=<value>]

• Pairs within a single --select value combine with logical AND: all must match.
• Multiple --select flags combine with logical OR: a plugin is enabled if it matches any selector set.
• Selector values support glob patterns: * matches any number of characters and ? matches a single character (for example, region=us-*). Selector keys don’t support wildcards.
• Repeating the same key within a single --select value causes an error at startup. Using the same key in different --select flags is allowed.

telegraf --config config.conf --config-directory directory/ \
  --select="app=payments;region=us-*" \
  --select="env=prod"

Matching behavior

Telegraf matches selectors against each plugin’s labels to decide whether the plugin instance is enabled:

A selector matches when every key-value pair in it matches a label on the plugin. Labels the selector doesn’t mention are ignored.