Upgrade to Vert.x 3.9.1 which depends on version of Netty which allow…

…s backported ALPN in JDK 1.8.0_252 to be used, and provide warning if openSSL is not installed

ksqldb-rest-app/src/main/java/io/confluent/ksql/api/server/Server.java

@@ -28,6 +28,7 @@
 import io.confluent.ksql.security.KsqlSecurityExtension;
 import io.confluent.ksql.util.KsqlException;
 import io.confluent.ksql.util.VertxCompletableFuture;
+import io.netty.handler.ssl.OpenSsl;
 import io.vertx.core.Vertx;
 import io.vertx.core.WorkerExecutor;
 import io.vertx.core.http.ClientAuth;
@@ -92,6 +93,10 @@ public Server(final Vertx vertx, final KsqlRestConfig config, final Endpoints en
     this.authenticationPlugin = Objects.requireNonNull(authenticationPlugin);
     this.serverState = Objects.requireNonNull(serverState);
     this.maxPushQueryCount = config.getInt(KsqlRestConfig.MAX_PUSH_QUERIES);
+    if (!OpenSsl.isAvailable()) {
+      log.warn("OpenSSL does not appear to be installed. ksqlDB will fall back to using the JDK "
+          + "TLS implementation. OpenSSL is recommended for better performance.");
+    }
   }
 
   public synchronized void start() {

pom.xml

@@ -121,7 +121,7 @@
         <wiremock.version>2.24.0</wiremock.version>
         <clearspring-analytics.version>2.9.5</clearspring-analytics.version>
         <icu.version>67.1</icu.version>
-        <vertx.version>3.9.0</vertx.version>
+        <vertx.version>3.9.1</vertx.version>
         <reactive-streams.version>1.0.3</reactive-streams.version>
         <skip.docker.build>true</skip.docker.build>
         <skip.docker.test>true</skip.docker.test>