command/agent: Lowercase DC. Fixes #761

CHANGELOG.md

@@ -4,6 +4,10 @@ FEATURES:
 
  * Ability to configure minimum session TTL. [GH-821]
 
+BUG FIXES:
+
+ * Datacenter is lowercased, fixes DNS lookups [GH-761]
+
 IMPROVEMENTS:
 
  * Raft uses BoltDB as the backend store. [GH-857]

command/agent/command.go

@@ -179,6 +179,10 @@ func (c *Command) readConfig() *Config {
 		}
 	}
 
+	// Ensure the datacenter is always lowercased. The DNS endpoints automatically
+	// lowercase all queries, and internally we expect DC1 and dc1 to be the same.
+	config.Datacenter = strings.ToLower(config.Datacenter)
+
 	// Verify datacenter is valid
 	if !validDatacenter.MatchString(config.Datacenter) {
 		c.Ui.Error("Datacenter must be alpha-numeric with underscores and hypens only")