Issue #61: Looks like CentOS 6 will be a no-go.

.travis.yml

@@ -1,14 +1,6 @@
 sudo: required
 
 env:
-  # CentOS 6.
-  - distribution: centos
-    version: 6
-    container_id: $(mktemp)
-    dockerfile: Dockerfile.centos-6
-    init: /sbin/init
-    run_opts: "--privileged --volume=/sys/fs/cgroup:/sys/fs/cgroup:ro"
-
   # CentOS 7.
   - distribution: centos
     version: 7

tests/Dockerfile.centos-6

@@ -1,10 +0,0 @@
-FROM centos:6
-
-# Install Ansible
-RUN rpm -Uvh http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
-RUN yum install -y ansible
-
-# Install Ansible inventory file
-RUN echo -e '[local]\nlocalhost ansible_connection=local' > /etc/ansible/hosts
-
-CMD ["/sbin/init"]