Add Ubuntu Bionic support to Pegleg

From community meeting on 04-June-2019 Ubuntu Xenial is the default
image for Airship projects, but a desire was voiced to also add support
for Ubuntu Bionic at the convenience of the contributors for each
project.

This patch:
1. Adds a new dockerfile specific to ubuntu:18.04 (bionic)
2. Updates gates to be specific about which ubuntu image is being
   checked.
3. Add to .zuul.yaml checks/gates/post jobs for bionic

Change-Id: Ib10641656f48baffec5b03ec48bf864d67209289

.zuul.yaml

@@ -23,16 +23,19 @@
     check:
       jobs:
         - openstack-tox-pep8
-        - airship-pegleg-docker-build-gate-ubuntu
+        - airship-pegleg-docker-build-gate-ubuntu_xenial
+        - airship-pegleg-docker-build-gate-ubuntu_bionic
         - airship-pegleg-docker-build-gate-opensuse
     gate:
       jobs:
         - openstack-tox-pep8
-        - airship-pegleg-docker-build-gate-ubuntu
+        - airship-pegleg-docker-build-gate-ubuntu_xenial
+        - airship-pegleg-docker-build-gate-ubuntu_bionic
         - airship-pegleg-docker-build-gate-opensuse
     post:
       jobs:
-        - airship-pegleg-docker-publish-ubuntu
+        - airship-pegleg-docker-publish-ubuntu_xenial
+        - airship-pegleg-docker-publish-ubuntu_bionic
         - airship-pegleg-docker-publish-opensuse
         - pegleg-upload-git-mirror
 
@@ -43,7 +46,7 @@
         label: ubuntu-xenial
 
 - job:
-    name: airship-pegleg-docker-build-gate-ubuntu
+    name: airship-pegleg-docker-build-gate-ubuntu_xenial
     timeout: 1800
     run: tools/gate/playbooks/docker-image-build.yaml
     nodeset: airship-pegleg-single-node
@@ -56,6 +59,20 @@
         dynamic:
           patch_set: true
 
+- job:
+    name: airship-pegleg-docker-build-gate-ubuntu_bionic
+    timeout: 1800
+    run: tools/gate/playbooks/docker-image-build.yaml
+    nodeset: airship-pegleg-single-node
+    irrelevant-files:
+      - '^doc/.*'
+    vars:
+      publish: false
+      distro: ubuntu_bionic
+      tags:
+        dynamic:
+          patch_set: true
+
 - job:
     name: airship-pegleg-docker-build-gate-opensuse
     timeout: 1800
@@ -71,7 +88,7 @@
           patch_set: true
 
 - job:
-    name: airship-pegleg-docker-publish-ubuntu
+    name: airship-pegleg-docker-publish-ubuntu_xenial
     timeout: 1800
     run: tools/gate/playbooks/docker-image-build.yaml
     nodeset: airship-pegleg-single-node
@@ -89,6 +106,25 @@
         static:
           - latest
 
+- job:
+    name: airship-pegleg-docker-publish-ubuntu_bionic
+    timeout: 1800
+    run: tools/gate/playbooks/docker-image-build.yaml
+    nodeset: airship-pegleg-single-node
+    secrets:
+      - airship_pegleg_quay_creds
+    irrelevant-files:
+      - '^doc/.*'
+    vars:
+      publish: true
+      distro: ubuntu_bionic
+      tags:
+        dynamic:
+          branch: true
+          commit: true
+        static:
+          - latest
+
 - job:
     name: airship-pegleg-docker-publish-opensuse
     timeout: 1800

images/pegleg/Dockerfile.ubuntu_bionic

@@ -0,0 +1,50 @@
+ARG FROM=ubuntu:18.04
+FROM ${FROM}
+ARG CFSSLURL=https://pkg.cfssl.org/R1.2/cfssl_linux-amd64
+
+LABEL org.opencontainers.image.authors='airship-discuss@lists.airshipit.org, irc://#airshipit@freenode'
+LABEL org.opencontainers.image.url='https://airshipit.org'
+LABEL org.opencontainers.image.documentation='https://airship-pegleg.readthedocs.org'
+LABEL org.opencontainers.image.source='https://opendev.org/airship/pegleg'
+LABEL org.opencontainers.image.vendor='The Airship Authors'
+LABEL org.opencontainers.image.licenses='Apache-2.0'
+
+ENV LANG=C.UTF-8
+ENV LC_ALL=C.UTF-8
+
+RUN set -ex \
+    && apt-get update -qq \
+    && apt-get install -y --no-install-recommends \
+         ca-certificates \
+         curl \
+         gcc \
+         git \
+         libssl-dev \
+         netbase \
+         openssh-client \
+         python3-dev \
+         python3-pip \
+         python3-setuptools \
+    && python3 -m pip install -U pip \
+    && apt-get autoremove -yqq --purge \
+    && apt-get clean \
+    && rm -rf \
+         /tmp/* \
+         /usr/share/doc \
+         /usr/share/doc-base \
+         /usr/share/man \
+         /var/lib/apt/lists/* \
+         /var/log/* \
+         /var/tmp/*
+
+VOLUME /var/pegleg
+WORKDIR /var/pegleg
+
+COPY requirements.txt /opt/pegleg/requirements.txt
+RUN pip3 install --no-cache-dir -r /opt/pegleg/requirements.txt
+
+COPY tools/install-cfssl.sh /opt/pegleg/tools/install-cfssl.sh
+RUN /opt/pegleg/tools/install-cfssl.sh ${CFSSLURL}
+
+COPY . /opt/pegleg
+RUN pip3 install -e /opt/pegleg