title: Jenkins mesosphere/jenkins-dind:0.3.1 and proxy
body: <p>All,
  I am using DCOS and the associated Jenkins.
  My company is having a proxy for any external traffic.
  Jenkins is running properly and can access the internal network as well as any external network.
  I can get jobs to curl a URL on internet if I set the HTTP proxy. I can pass this proxy to mesosphere/jenkins-dind:0.3.1 container as environment variable however, I can't run any docker pull or docker run while being in docker in docker mode.</p>
  
  <p>I managed to reproduce the issue on one of the agent box.</p>
  
  <p>sudo docker run hello-world</p>
  
  <p>Hello from Docker!</p>
  
  <p>This works!!
  However, sudo docker run --privileged mesosphere/jenkins-dind:0.3.1   wrapper.sh "docker run hello-world" will fail with 
  docker: Error while pulling image: Get <a href="https://index.docker.io/v1/repositories/library/hello-world/images" rel="nofollow noreferrer">https://index.docker.io/v1/repositories/library/hello-world/images</a>: x509: certificate is valid for FG3K6C3A13800607, not index.docker.io.</p>
  
  <p>This is typically showing that the docker daemon is not having access to the proxy.</p>
  
  <p>Do you know how to ensure that the dind is getting access to the proxy settings?
  Antoine</p>