feat(inputs.kafka_consumer): Add resolve canonical bootstrap server option (#15368)

plugins/inputs/kafka_consumer/README.md

@@ -149,6 +149,11 @@ to use them.
   ## limit.
   # metadata_retry_max_duration = 0
 
+  ## When set to true, this turns each bootstrap broker address into a set of
+  ## IPs, then does a reverse lookup on each one to get its canonical hostname.
+  ## This list of hostnames then replaces the original address list.
+  ## resolve_canonical_bootstrap_servers_only = false
+
   ## Strategy for making connection to kafka brokers. Valid options: "startup",
   ## "defer". If set to "defer" the plugin is allowed to start before making a
   ## connection. This is useful if the broker may be down when telegraf is

plugins/inputs/kafka_consumer/kafka_consumer.go

@@ -49,9 +49,9 @@ type KafkaConsumer struct {
 	MsgHeaderAsMetricName                string          `toml:"msg_header_as_metric_name"`
 	ConsumerFetchDefault                 config.Size     `toml:"consumer_fetch_default"`
 	ConnectionStrategy                   string          `toml:"connection_strategy"`
+	ResolveCanonicalBootstrapServersOnly bool            `toml:"resolve_canonical_bootstrap_servers_only"`
 
 	kafka.ReadConfig
-
 	kafka.Logger
 
 	Log telegraf.Logger `toml:"-"`
@@ -150,6 +150,8 @@ func (k *KafkaConsumer) Init() error {
 		k.ConsumerCreator = &SaramaCreator{}
 	}
 
+	cfg.Net.ResolveCanonicalBootstrapServers = k.ResolveCanonicalBootstrapServersOnly
+
 	cfg.Consumer.MaxProcessingTime = time.Duration(k.MaxProcessingTime)
 
 	if k.ConsumerFetchDefault != 0 {

plugins/inputs/kafka_consumer/sample.conf

@@ -112,6 +112,11 @@
   ## limit.
   # metadata_retry_max_duration = 0
 
+  ## When set to true, this turns each bootstrap broker address into a set of
+  ## IPs, then does a reverse lookup on each one to get its canonical hostname.
+  ## This list of hostnames then replaces the original address list.
+  ## resolve_canonical_bootstrap_servers_only = false
+
   ## Strategy for making connection to kafka brokers. Valid options: "startup",
   ## "defer". If set to "defer" the plugin is allowed to start before making a
   ## connection. This is useful if the broker may be down when telegraf is