add default to cloud

main.go

@@ -32,7 +32,7 @@ var (
 	disableSlowMetrics       = kingpin.Flag("disable-slow-metrics", "Disable slow metrics for performance reasons").Default("false").Bool()
 	disableDeprecatedMetrics = kingpin.Flag("disable-deprecated-metrics", "Disable deprecated metrics").Default("false").Bool()
 	disableCinderAgentUUID   = kingpin.Flag("disable-cinder-agent-uuid", "Disable UUID generation for Cinder agents").Default("false").Bool()
-	cloud                    = kingpin.Arg("cloud", "name or id of the cloud to gather metrics from").String()
+	cloud                    = kingpin.Arg("cloud", "name or id of the cloud to gather metrics from").Default("default").String()
 	multiCloud               = kingpin.Flag("multi-cloud", "Toggle the multiple cloud scraping mode under /probe?cloud=").Default("false").Bool()
 	domainID                 = kingpin.Flag("domain-id", "Gather metrics only for the given Domain ID (defaults to all domains)").String()
 )