BIGTOP-3523. Drop Ubuntu 16.04 support. (#768)

diff --git a/bigtop_toolchain/bin/puppetize.sh b/bigtop_toolchain/bin/puppetize.sh
index 0259d6b..0d2907a 100755
--- a/bigtop_toolchain/bin/puppetize.sh
+++ b/bigtop_toolchain/bin/puppetize.sh
@@ -30,10 +30,6 @@
         # So we install that module in the same way as CentOS 7.
         puppet module install puppetlabs-stdlib --version 4.12.0
         ;;
-    ubuntu-16.04)
-        apt-get update
-        apt-get -y install wget curl sudo unzip puppet software-properties-common puppet-module-puppetlabs-apt puppet-module-puppetlabs-stdlib
-        ;;
     ubuntu-18.04|ubuntu-20.04)
         apt-get update
         apt-get -y install wget curl sudo unzip puppet software-properties-common puppet-module-puppetlabs-apt puppet-module-puppetlabs-stdlib systemd-sysv
diff --git a/provisioner/docker/config_ubuntu-16.04.yaml b/provisioner/docker/config_ubuntu-16.04.yaml
deleted file mode 100644
index e087a78..0000000
--- a/provisioner/docker/config_ubuntu-16.04.yaml
+++ /dev/null
@@ -1,24 +0,0 @@
-# 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-16.04"
-
-repo: "http://repos.bigtop.apache.org/releases/1.4.0/ubuntu/16.04/$(ARCH)"
-distro: debian
-components: [hdfs, yarn, mapreduce]
-enable_local_repo: false
-smoke_test_components: [hdfs, yarn, mapreduce]