Add: support for Ubuntu 16.04 LTS (Xenial).

Fix:
  1. OS-level packages `libffi-dev` and `libssl-dev`/`openssl-dev` should be installed explicitly since Ansible 2.0.2.0(???).
  2. Python package cffi should be installed explicitly since Ansible 2.0.2.0(???).
  3. add '--fix-missing' for apt.

@see boxcutter/ubuntu#62
@see pyca/cryptography#2280

.travis.yml

@@ -6,6 +6,7 @@ before_install:
     - docker info
     - docker version
 
+    - docker build  -t ansible_xenial           ubuntu16.04
     - docker build  -t ansible_trusty           ubuntu14.04
     - docker build  -t ansible_precise          ubuntu12.04
     - docker build  -t ansible_jessie           debian8
@@ -14,6 +15,7 @@ before_install:
     - docker build  -t ansible_centos6          centos6
     - docker build  -t ansible_alpine3          alpine3
 
+    - docker build  -t ansible_xenial_onbuild   ubuntu16.04-onbuild
     - docker build  -t ansible_trusty_onbuild   ubuntu14.04-onbuild
     - docker build  -t ansible_precise_onbuild  ubuntu12.04-onbuild
     - docker build  -t ansible_jessie_onbuild   debian8-onbuild
@@ -40,13 +42,15 @@ before_install:
     - docker build  -t ansible_1.9_alpine3_onbuild  1.9-alpine3-onbuild
 
 
+    - docker build  -t ansible_master_xenial           master-ubuntu16.04
     - docker build  -t ansible_master_trusty           master-ubuntu14.04
     - docker build  -t ansible_master_precise          master-ubuntu12.04
     - docker build  -t ansible_master_jessie           master-debian8
     - docker build  -t ansible_master_wheezy           master-debian7
     - docker build  -t ansible_master_centos7          master-centos7
     - docker build  -t ansible_master_centos6          master-centos6
 
+    - docker build  -t ansible_master_xenial_onbuild   master-ubuntu16.04-onbuild
     - docker build  -t ansible_master_trusty_onbuild   master-ubuntu14.04-onbuild
     - docker build  -t ansible_master_precise_onbuild  master-ubuntu12.04-onbuild
     - docker build  -t ansible_master_jessie_onbuild   master-debian8-onbuild
@@ -55,13 +59,15 @@ before_install:
     - docker build  -t ansible_master_centos6_onbuild  master-centos6-onbuild
 
 script:
+    - docker run -i ansible_xenial           > result-ubuntu16.04
     - docker run -i ansible_trusty           > result-ubuntu14.04
     - docker run -i ansible_precise          > result-ubuntu12.04
     - docker run -i ansible_jessie           > result-debian8
     - docker run -i ansible_wheezy           > result-debian7
     - docker run -i ansible_centos7          > result-centos7
     - docker run -i ansible_centos6          > result-centos6
     - docker run -i ansible_alpine3          > result-alpine3
+    - docker run -i ansible_xenial_onbuild   > result-ubuntu16.04-onbuild
     - docker run -i ansible_trusty_onbuild   > result-ubuntu14.04-onbuild
     - docker run -i ansible_precise_onbuild  > result-ubuntu12.04-onbuild
     - docker run -i ansible_jessie_onbuild   > result-debian8-onbuild
@@ -87,12 +93,14 @@ script:
     - docker run -i ansible_1.9_alpine3_onbuild  > result-1.9-alpine3-onbuild
 
 
+    - docker run -i ansible_master_xenial           > result-master-ubuntu16.04
     - docker run -i ansible_master_trusty           > result-master-ubuntu14.04
     - docker run -i ansible_master_precise          > result-master-ubuntu12.04
     - docker run -i ansible_master_jessie           > result-master-debian8
     - docker run -i ansible_master_wheezy           > result-master-debian7
     - docker run -i ansible_master_centos7          > result-master-centos7
     - docker run -i ansible_master_centos6          > result-master-centos6
+    - docker run -i ansible_master_xenial_onbuild   > result-master-ubuntu16.04-onbuild
     - docker run -i ansible_master_trusty_onbuild   > result-master-ubuntu14.04-onbuild
     - docker run -i ansible_master_precise_onbuild  > result-master-ubuntu12.04-onbuild
     - docker run -i ansible_master_jessie_onbuild   > result-master-debian8-onbuild
@@ -103,13 +111,15 @@ script:
 
 
     - echo "==> Validating the test results..."
+    - sh -c "[ -s result-ubuntu16.04         ]"
     - sh -c "[ -s result-ubuntu14.04         ]"
     - sh -c "[ -s result-ubuntu12.04         ]"
     - sh -c "[ -s result-debian8             ]"
     - sh -c "[ -s result-debian7             ]"
     - sh -c "[ -s result-centos7             ]"
     - sh -c "[ -s result-centos6             ]"
     - sh -c "[ -s result-alpine3             ]"
+    - sh -c "[ -s result-ubuntu16.04-onbuild ]"
     - sh -c "[ -s result-ubuntu14.04-onbuild ]"
     - sh -c "[ -s result-ubuntu12.04-onbuild ]"
     - sh -c "[ -s result-debian8-onbuild     ]"
@@ -133,12 +143,14 @@ script:
     - sh -c "[ -s result-1.9-centos6-onbuild     ]"
     - sh -c "[ -s result-1.9-alpine3-onbuild     ]"
 
+    - sh -c "[ -s result-master-ubuntu16.04         ]"
     - sh -c "[ -s result-master-ubuntu14.04         ]"
     - sh -c "[ -s result-master-ubuntu12.04         ]"
     - sh -c "[ -s result-master-debian8             ]"
     - sh -c "[ -s result-master-debian7             ]"
     - sh -c "[ -s result-master-centos7             ]"
     - sh -c "[ -s result-master-centos6             ]"
+    - sh -c "[ -s result-master-ubuntu16.04-onbuild ]"
     - sh -c "[ -s result-master-ubuntu14.04-onbuild ]"
     - sh -c "[ -s result-master-ubuntu12.04-onbuild ]"
     - sh -c "[ -s result-master-debian8-onbuild     ]"

1.9-alpine3-onbuild/Dockerfile

@@ -13,9 +13,10 @@ MAINTAINER William Yeh <[email protected]>
 
 
 RUN echo "===> Adding Python runtime..."  && \
-    apk --update add python py-pip openssl ca-certificates               && \
-    apk --update add --virtual build-dependencies python-dev build-base  && \
-    pip install --upgrade pip                                            && \
+    apk --update add python py-pip openssl ca-certificates    && \
+    apk --update add --virtual build-dependencies \
+                python-dev libffi-dev openssl-dev build-base  && \
+    pip install --upgrade pip cffi                            && \
     \
     \
     echo "===> Installing Ansible..."  && \

1.9-alpine3/Dockerfile

@@ -13,9 +13,10 @@ MAINTAINER William Yeh <[email protected]>
 
 
 RUN echo "===> Adding Python runtime..."  && \
-    apk --update add python py-pip openssl ca-certificates               && \
-    apk --update add --virtual build-dependencies python-dev build-base  && \
-    pip install --upgrade pip                                            && \
+    apk --update add python py-pip openssl ca-certificates    && \
+    apk --update add --virtual build-dependencies \
+                python-dev libffi-dev openssl-dev build-base  && \
+    pip install --upgrade pip cffi                            && \
     \
     \
     echo "===> Installing Ansible..."  && \

1.9-centos6-onbuild/Dockerfile

@@ -26,20 +26,22 @@ RUN echo "===> Installing EPEL..."        && \
     \
     \
     echo "===> Adding Ansible's prerequisites..."  && \
-    yum -y install gcc python-devel python-pip     && \
+    yum -y install gcc python-devel python-pip  \
+                       libffi-devel openssl-devel  && \
     pip install --upgrade pip                      && \                 
     \
     \
     echo "===> Installing Ansible..."     && \
-    pip install ansible==1.9.4            && \
+    pip install --upgrade ansible==1.9.4  && \
     \
     \
     echo "===> Disabling sudo 'requiretty' setting..."    && \
     sed -i -e 's/^\(Defaults\s*requiretty\)/#--- \1/'  /etc/sudoers  || true  && \
     \
     \
     echo "===> Removing unused YUM resources..."             && \
-    yum -y remove epel-release gcc python-devel python-pip   && \
+    yum -y remove epel-release gcc python-devel python-pip \
+                  libffi-devel openssl-devel  || true        && \
     yum clean all                                            && \
     \
     \

1.9-centos6/Dockerfile

@@ -26,20 +26,22 @@ RUN echo "===> Installing EPEL..."        && \
     \
     \
     echo "===> Adding Ansible's prerequisites..."  && \
-    yum -y install gcc python-devel python-pip     && \
+    yum -y install gcc python-devel python-pip  \
+                       libffi-devel openssl-devel  && \
     pip install --upgrade pip                      && \                 
     \
     \
     echo "===> Installing Ansible..."     && \
-    pip install ansible==1.9.4            && \
+    pip install --upgrade ansible==1.9.4  && \
     \
     \
     echo "===> Disabling sudo 'requiretty' setting..."    && \
     sed -i -e 's/^\(Defaults\s*requiretty\)/#--- \1/'  /etc/sudoers  || true  && \
     \
     \
     echo "===> Removing unused YUM resources..."             && \
-    yum -y remove epel-release gcc python-devel python-pip   && \
+    yum -y remove epel-release gcc python-devel python-pip \
+                  libffi-devel openssl-devel  || true        && \
     yum clean all                                            && \
     \
     \

1.9-centos7-onbuild/Dockerfile

@@ -41,20 +41,22 @@ RUN echo "===> Enabling systemd..."  && \
     \
     \
     echo "===> Adding Ansible's prerequisites..."  && \
-    yum -y install gcc python-devel python-pip     && \
+    yum -y install gcc python-devel python-pip  \
+                       libffi-devel openssl-devel  && \
     pip install --upgrade pip                      && \                 
     \
     \
     echo "===> Installing Ansible..."     && \
-    pip install ansible==1.9.4            && \
+    pip install --upgrade ansible==1.9.4  && \
     \
     \
     echo "===> Disabling sudo 'requiretty' setting..."    && \
     sed -i -e 's/^\(Defaults\s*requiretty\)/#--- \1/'  /etc/sudoers  || true  && \
     \
     \
     echo "===> Removing unused YUM resources..."             && \
-    yum -y remove epel-release gcc python-devel python-pip   && \
+    yum -y remove epel-release gcc python-devel python-pip \
+                  libffi-devel openssl-devel  || true        && \
     yum clean all                                            && \
     \
     \

1.9-centos7/Dockerfile

@@ -41,20 +41,22 @@ RUN echo "===> Enabling systemd..."  && \
     \
     \
     echo "===> Adding Ansible's prerequisites..."  && \
-    yum -y install gcc python-devel python-pip     && \
+    yum -y install gcc python-devel python-pip  \
+                       libffi-devel openssl-devel  && \
     pip install --upgrade pip                      && \                 
     \
     \
     echo "===> Installing Ansible..."     && \
-    pip install ansible==1.9.4            && \
+    pip install --upgrade ansible==1.9.4  && \
     \
     \
     echo "===> Disabling sudo 'requiretty' setting..."    && \
     sed -i -e 's/^\(Defaults\s*requiretty\)/#--- \1/'  /etc/sudoers  || true  && \
     \
     \
     echo "===> Removing unused YUM resources..."             && \
-    yum -y remove epel-release gcc python-devel python-pip   && \
+    yum -y remove epel-release gcc python-devel python-pip \
+                  libffi-devel openssl-devel  || true        && \
     yum clean all                                            && \
     \
     \

1.9-debian7-onbuild/Dockerfile

@@ -13,19 +13,21 @@ MAINTAINER William Yeh <[email protected]>
 
 
 RUN echo "===> Installing python, sudo, and supporting tools..."  && \
-    apt-get update  && \
+    apt-get update -y  &&  apt-get install --fix-missing          && \
     DEBIAN_FRONTEND=noninteractive         \
     apt-get install -y                     \
         python python-yaml sudo            \
-        curl gcc python-pip python-dev  && \
+        curl gcc python-pip python-dev libffi-dev libssl-dev  && \
+    pip install --upgrade cffi                     && \
     \
     \
     echo "===> Installing Ansible..."   && \
     pip install ansible==1.9.4          && \
     \
     \
     echo "===> Removing unused APT resources..."                  && \
-    apt-get -f -y --auto-remove remove gcc python-pip python-dev  && \
+    apt-get -f -y --auto-remove remove \
+                 gcc python-pip python-dev libffi-dev libssl-dev  && \
     apt-get clean                                                 && \
     rm -rf /var/lib/apt/lists/*  /tmp/*                           && \
     \

1.9-debian7/Dockerfile

@@ -13,19 +13,21 @@ MAINTAINER William Yeh <[email protected]>
 
 
 RUN echo "===> Installing python, sudo, and supporting tools..."  && \
-    apt-get update  && \
+    apt-get update -y  &&  apt-get install --fix-missing          && \
     DEBIAN_FRONTEND=noninteractive         \
     apt-get install -y                     \
         python python-yaml sudo            \
-        curl gcc python-pip python-dev  && \
+        curl gcc python-pip python-dev libffi-dev libssl-dev  && \
+    pip install --upgrade cffi                     && \
     \
     \
     echo "===> Installing Ansible..."   && \
     pip install ansible==1.9.4          && \
     \
     \
     echo "===> Removing unused APT resources..."                  && \
-    apt-get -f -y --auto-remove remove gcc python-pip python-dev  && \
+    apt-get -f -y --auto-remove remove \
+                 gcc python-pip python-dev libffi-dev libssl-dev  && \
     apt-get clean                                                 && \
     rm -rf /var/lib/apt/lists/*  /tmp/*                           && \
     \

1.9-debian8-onbuild/Dockerfile

@@ -13,19 +13,22 @@ MAINTAINER William Yeh <[email protected]>
 
 
 RUN echo "===> Installing python, sudo, and supporting tools..."  && \
-    apt-get update  && \
+    apt-get update -y  &&  apt-get install --fix-missing          && \
     DEBIAN_FRONTEND=noninteractive         \
     apt-get install -y                     \
         python python-yaml sudo            \
-        curl gcc python-pip python-dev  && \
+        curl gcc python-pip python-dev libffi-dev libssl-dev  && \
+    apt-get -y --purge remove python-cffi          && \
+    pip install --upgrade cffi                     && \
     \
     \
     echo "===> Installing Ansible..."   && \
     pip install ansible==1.9.4          && \
     \
     \
     echo "===> Removing unused APT resources..."                  && \
-    apt-get -f -y --auto-remove remove gcc python-pip python-dev  && \
+    apt-get -f -y --auto-remove remove \
+                 gcc python-pip python-dev libffi-dev libssl-dev  && \
     apt-get clean                                                 && \
     rm -rf /var/lib/apt/lists/*  /tmp/*                           && \
     \

1.9-debian8/Dockerfile

@@ -13,19 +13,22 @@ MAINTAINER William Yeh <[email protected]>
 
 
 RUN echo "===> Installing python, sudo, and supporting tools..."  && \
-    apt-get update  && \
+    apt-get update -y  &&  apt-get install --fix-missing          && \
     DEBIAN_FRONTEND=noninteractive         \
     apt-get install -y                     \
         python python-yaml sudo            \
-        curl gcc python-pip python-dev  && \
+        curl gcc python-pip python-dev libffi-dev libssl-dev  && \
+    apt-get -y --purge remove python-cffi          && \
+    pip install --upgrade cffi                     && \
     \
     \
     echo "===> Installing Ansible..."   && \
     pip install ansible==1.9.4          && \
     \
     \
     echo "===> Removing unused APT resources..."                  && \
-    apt-get -f -y --auto-remove remove gcc python-pip python-dev  && \
+    apt-get -f -y --auto-remove remove \
+                 gcc python-pip python-dev libffi-dev libssl-dev  && \
     apt-get clean                                                 && \
     rm -rf /var/lib/apt/lists/*  /tmp/*                           && \
     \