disable DNS caching in order to get cluster bootstrap in docker swarm

Signed-off-by: Thomas Jaeckle <thomas.jaeckle@bosch-si.com>

services/base/src/main/resources/ditto-akka-config.conf

@@ -10,15 +10,9 @@ akka {
 
   io.dns {
 
-    resolver = "async-dns"
-    #resolver = "inet-address"
+    resolver = "inet-address"
 
-    # To-be-deprecated DNS resolver implementation which uses the Java InetAddress to resolve DNS records.
-    # To be replaced by `akka.io.dns.async` which implements the DNS protocol natively and without blocking (which InetAddress does)
     inet-address {
-      # Must implement akka.io.DnsProvider
-      provider-object = "akka.io.InetAddressDnsProvider"
-
       # To set the time to cache name resolutions
       # Possible values:
       # default: sun.net.InetAddressCachePolicy.get() and getNegative()
@@ -27,10 +21,6 @@ akka {
       # n [time unit]: positive timeout with unit, for example "30 s"
       positive-ttl = never
       negative-ttl = never
-
-      # How often to sweep out expired cache entries.
-      # Note that this interval has nothing to do with TTLs
-      cache-cleanup-interval = 120s
     }
   }