Add ubuntu focal image for tempest

Change-Id: I386a98cf88b26cce4c3c7ac7f03eaa22575c822c

tempest/Dockerfile.ubuntu_focal

@@ -0,0 +1,27 @@
+ARG FROM=ubuntu:20.04
+FROM ${FROM}
+
+RUN set -ex ;\
+    export DEBIAN_FRONTEND=noninteractive ;\
+    apt-get update ;\
+    apt-get upgrade -y ;\
+    apt-get install netbase -y ;\
+    apt-get install --no-install-recommends -y \
+        python3-dev \
+        build-essential \
+        python3-pip \
+        libssl-dev \
+        git ;\
+    pip3 install -U pip ;\
+    git clone https://git.openstack.org/openstack/tempest ;\
+    git clone https://git.openstack.org/openstack/cinder-tempest-plugin ;\
+    git clone https://git.openstack.org/openstack/heat-tempest-plugin ;\
+    git clone https://git.openstack.org/openstack/keystone-tempest-plugin ;\
+    git clone https://git.openstack.org/openstack/neutron-tempest-plugin ;\
+    pip3 install -U setuptools==58.0.0 ;\
+    pip3 install wheel ;\
+    pip3 install -e tempest/ \
+                    cinder-tempest-plugin/ \
+                    heat-tempest-plugin/ \
+                    keystone-tempest-plugin/ \
+                    neutron-tempest-plugin/ ;\

zuul.d/tempest.yaml

@@ -40,12 +40,12 @@
           tags:
             - latest-ubuntu_bionic
             - "ubuntu_bionic-{{ currentdate }}"
-        #- context: tempest
-        #  repository: openstackhelm/tempest
-        #  dockerfile: Dockerfile.opensuse_15
-        #  tags:
-        #    - latest-opensuse_15
-        #    - "opensuse_15-{{ currentdate }}"
+        - context: tempest
+          repository: openstackhelm/tempest
+          dockerfile: Dockerfile.ubuntu_focal
+          tags:
+            - latest-ubuntu_focal
+            - "ubuntu_focal-{{ currentdate }}"
     files: &tempest_files
       - tempest/.*
       - zuul.d/tempest.yaml