diff --git a/app/src/main/scala/hstream/server/KafkaBroker.scala b/app/src/main/scala/hstream/server/KafkaBroker.scala
index 9a3f625..27d1a5b 100644
--- a/app/src/main/scala/hstream/server/KafkaBroker.scala
+++ b/app/src/main/scala/hstream/server/KafkaBroker.scala
@@ -7,6 +7,9 @@ import java.nio.file.{Files, Paths}
 import kafka.utils.Logging
 import kafka.network.SocketServer
 
+import scala.concurrent._
+import ExecutionContext.Implicits.global
+import scala.concurrent.duration._
 import scala.sys.process._
 import scala.util.Random
 
@@ -52,18 +55,11 @@ class KafkaBroker(
           val image = config.testingConfig
             .getOrElse("image", throw new IllegalArgumentException("image is required"))
             .asInstanceOf[String]
-          val rmArg =
-            if (
-              config.testingConfig
-                .getOrElse("container_remove", throw new IllegalArgumentException("container_remove is required"))
-                .asInstanceOf[Boolean]
-            ) "--rm"
-            else ""
           val storeDir = config.testingConfig
             .getOrElse("store_dir", throw new IllegalArgumentException("store_dir is required"))
             .asInstanceOf[String]
           val dockerCmd =
-            s"docker run $rmArg -d --network host --name $containerName -v $storeDir:/data/store $image $command"
+            s"docker run -d --network host --name $containerName -v $storeDir:/data/store $image $command"
           info(s"=> Start hserver by: $dockerCmd")
           dockerCmd.run()
         } else {
@@ -71,6 +67,8 @@ class KafkaBroker(
         }
       }
     }
+
+    awaitStartup()
   }
 
   // TODO: TMP_FOR_HSTREAM
@@ -145,4 +143,28 @@ class KafkaBroker(
     }
   }
 
+  // --------------------------------------------------------------------------
+  // For hstream
+
+  private def awaitStartup(retries: Int = 20): Unit = {
+    if (retries <= 0) {
+      s"docker logs $containerName".!
+      throw new RuntimeException("Failed to start hstream!")
+    }
+    val port = config.port
+    val f = Future {
+      try {
+        val socket = new java.net.Socket("127.0.0.1", port)
+        socket.close()
+        info("=> The server port is open at " + port)
+      } catch {
+        case e: java.net.ConnectException =>
+          info("=> Retry to connect to the server port " + port)
+          Thread.sleep(1000)
+          awaitStartup(retries - 1)
+      }
+    }
+    Await.result(f, 60.second)
+  }
+
 }
diff --git a/app/src/test/scala/utils/kafka/utils/TestUtils.scala b/app/src/test/scala/utils/kafka/utils/TestUtils.scala
index e897061..443c202 100644
--- a/app/src/test/scala/utils/kafka/utils/TestUtils.scala
+++ b/app/src/test/scala/utils/kafka/utils/TestUtils.scala
@@ -2767,21 +2767,38 @@ object TestUtils extends Logging {
       endingIdNumber: Int,
       testName: String
   ): Seq[Properties] = {
-    val brokerConfig = brokerContainer.get("config").asInstanceOf[java.util.Map[String, Object]]
+    val brokerConfig = brokerContainer.get("config").asInstanceOf[java.util.Map[String, Object]].asScala
     // NOTE: Since this has side effect, do NOT move it inside the following loop (startingIdNumber to endingIdNumber)
-    val basePort = brokerConfig.remove("base_port").asInstanceOf[Int]
-    val advertisedAddress = brokerConfig.get("advertised.address").asInstanceOf[String]
+    val basePort = brokerConfig.remove("base_port").asInstanceOf[Option[Int]]
+    val advertisedAddress = brokerConfig
+      .getOrElse(
+        "advertised.address",
+        throw new IllegalArgumentException("advertised.address is required in broker_container")
+      )
+      .asInstanceOf[String]
+
+    // FIXME: we use a fixed port (the first gossipPort) for seed node, this is a temporary solution
+    var fstGossipPort: Int = -1
 
     // generate
     val props = (startingIdNumber to endingIdNumber).zipWithIndex.map { case (nodeId, idx) =>
       val prop = new Properties
-      val port = basePort + idx * 2
-      val gossipPort = basePort + idx * 2 + 1
+      val port = basePort match {
+        case None    => getUnusedPort()
+        case Some(p) => p + idx * 2
+      }
+      val gossipPort = basePort match {
+        case None    => getUnusedPort()
+        case Some(p) => p + idx * 2 + 1
+      }
+      if (idx == 0) {
+        fstGossipPort = gossipPort
+      }
       // broker config
       prop.put("broker.id", nodeId.toString)
       prop.put("port", port.toString)
       prop.put("gossip.port", gossipPort.toString)
-      brokerConfig.asScala.foreach { case (k, v) => prop.put(k, v.toString) }
+      brokerConfig.foreach { case (k, v) => prop.put(k, v.toString) }
       // testing config
       val testingConfig: collection.mutable.Map[String, Object] =
         brokerContainer
@@ -2799,10 +2816,10 @@ object TestUtils extends Logging {
       val metastorePort = testingConfig
         .getOrElse("metastore_port", throw new IllegalArgumentException("metastore_port is required in testing_config"))
         .asInstanceOf[Int]
-      // FIXME: we use a fixed port `basePort + 1` for seed node, this is a temporary solution
+      // FIXME: we use a fixed port (the first gossipPort) for seed node, this is a temporary solution
       val args = s"""--server-id $nodeId
                 --port $port --gossip-port $gossipPort
-                --seed-nodes 127.0.0.1:${basePort + 1}
+                --seed-nodes 127.0.0.1:$fstGossipPort
                 --advertised-address $advertisedAddress
                 --metastore-uri zk://127.0.0.1:$metastorePort
                 --store-config /data/store/logdevice.conf
diff --git a/script/config.yaml.tmpl b/script/config.yaml.tmpl
index df8bc28..59ef57e 100644
--- a/script/config.yaml.tmpl
+++ b/script/config.yaml.tmpl
@@ -2,7 +2,9 @@ use: broker_container
 
 broker_container:
   config:
-    base_port: ${base_port}
+    # Optional. If no base_port, all ports will be random.
+    #
+    #base_port: ${base_port}
     advertised.address: 127.0.0.1
 
   testing_config:
@@ -15,7 +17,7 @@ broker_container:
       hstream-server kafka
         --bind-address 0.0.0.0
         --metrics-port 0
-        --log-level debug1
+        --log-level debug
         --log-with-color
         --log-flush-immediately
         --store-log-level error
diff --git a/script/run_test.sh b/script/run_test.sh
index e911852..5789b36 100755
--- a/script/run_test.sh
+++ b/script/run_test.sh
@@ -17,7 +17,7 @@ generate_config() {
     if [ -f $env_file ]; then
         store_admin_port=$(cat $env_file | grep STORE_ADMIN_LOCAL_PORT | cut -d'=' -f2)
         zookeeper_port=$(cat $env_file | grep ZOOKEEPER_LOCAL_PORT | cut -d'=' -f2)
-        base_port=$(find_freeport)
+        base_port=$(find_freeport)  # Optional
         sed -e "s/\${base_port}/$base_port/g" \
             -e "s#\${image}#$hstream_image#g" \
             -e "s/\${metastore_port}/$zookeeper_port/g" \