BIGTOP-3492. Add Ubuntu 20.04 support to the Docker provisioner. (#747)

diff --git a/provisioner/docker/config_ubuntu-20.04.yaml b/provisioner/docker/config_ubuntu-20.04.yaml
new file mode 100644
index 0000000..0b772cb
--- /dev/null
+++ b/provisioner/docker/config_ubuntu-20.04.yaml
@@ -0,0 +1,24 @@
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+docker:
+        memory_limit: "4g"
+        image:  "bigtop/puppet:trunk-ubuntu-20.04"
+
+repo: "http://repos.bigtop.apache.org/releases/3.0.0/ubuntu/20.04/$(ARCH)"
+distro: debian
+components: [hdfs, yarn, mapreduce]
+enable_local_repo: false
+smoke_test_components: [hdfs, yarn, mapreduce]