Merge pull request #3616 from hashicorp/b-hostname

Emit hostname as a label

Author: dadgar

CHANGELOG.md

@@ -4,6 +4,9 @@ __BACKWARDS INCOMPATIBILITIES:__
  * config: Nomad no longer parses Atlas configuration stanzas. Atlas has been
    deprecated since earlier this year. If you have an Atlas stanza in your
    config file it will have to be removed.
+ * telemetry: Hostname is now emitted via a tag rather than within the key name.
+   To maintain old behavior during an upgrade path specify
+   `backwards_compatible_metrics` in the telemetry configuration.
 
 IMPROVEMENTS:
  * core: Allow operators to reload TLS certificate and key files via SIGHUP
@@ -53,6 +56,7 @@ BUG FIXES:
  * sentinel: (Nomad Enterprise) Fix an issue that could cause an import error
    when multiple Sentinel policies are applied
  * telemetry: Do not emit metrics for non-running tasks [GH-3559]
+ * telemetry: Emit hostname as a tag rather than within the key name [GH-3616]
 
 ## 0.7.0 (November 1, 2017)
 

command/agent/command.go

@@ -654,6 +654,11 @@ func (c *Command) setupTelemetry(config *Config) (*metrics.InmemSink, error) {
 
 	metricsConf := metrics.DefaultConfig("nomad")
 	metricsConf.EnableHostname = !telConfig.DisableHostname
+
+	// Prefer the hostname as a label.
+	metricsConf.EnableHostnameLabel = !telConfig.DisableHostname &&
+		!telConfig.DisableTaggedMetrics && !telConfig.BackwardsCompatibleMetrics
+
 	if telConfig.UseNodeName {
 		metricsConf.HostName = config.NodeName
 		metricsConf.EnableHostname = true