fix(dns): disable new dns client by default

changelog/unreleased/kong/refactor_dns_client.yml

@@ -1,5 +1,5 @@
 message: >
-  Starting from this version, a new DNS client library has been implemented and added into Kong. The new DNS client library has the following changes
+  Starting from this version, a new DNS client library has been implemented and added into Kong, which is disabled by default. The new DNS client library has the following changes
   - Introduced global caching for DNS records across workers, significantly reducing the query load on DNS servers.
   - Introduced observable statistics for the new DNS client, and a new Status API `/status/dns` to retrieve them.
   - Simplified the logic and make it more standardized

kong.conf.default

@@ -1542,7 +1542,7 @@
 # It provides observable statistics, you can retrieve them through the Admin API
 # `/status/dns`.
 
-#new_dns_client = on             # Enable the new DNS resolver
+#new_dns_client = off            # Enable or disable the new DNS resolver
 
 #resolver_address = <name servers parsed from resolv.conf>
                                  # Comma-separated list of nameservers, each

kong/templates/kong_defaults.lua

@@ -170,7 +170,7 @@ dns_not_found_ttl = 30
 dns_error_ttl = 1
 dns_no_sync = off
 
-new_dns_client = on
+new_dns_client = off
 
 resolver_address = NONE
 resolver_hosts_file = /etc/hosts