Docker Support

I tested the patch for this issue before it was merged. When packages with a fix become available, the same test procedure should be viable. To test, I spun up a pair of VMs, with hostnames of:

• fedora-26-pulp-2-15-node1
• fedora-26-pulp-2-15-node2

I installed Pulp 2.15 on them with the Ansible playbooks in the pulp-ci repository. This playbook also installs and configures Crane. I applied the patch Ina sent me and restarted each host. I then executed the following on the first host:

pulp-admin docker repo create --repo-id=first --feed=https://registry-1.docker.io --upstream-name=busybox
pulp-admin docker repo sync run --repo-id=first
pulp-admin docker repo publish run --repo-id=first
systemctl restart httpd  # make crane re-read metadata from disk right away
tail --follow /var/log/httpd/access_log

I then executed the following on the second host:

pulp-admin docker repo create --repo-id=second --feed=http://fedora-26-pulp-2-15-node1:5000 --upstream-name=first --verify-feed-ssl=false
pulp-admin docker repo sync run --repo-id=second
pulp-admin docker repo list --repo-id=second --details

The sync succeeded, with plenty of entries appearing in the first host's httpd access log, and with repo list on the second host showing plenty of content.

Applied in changeset e734ef61352bb69fc7b75b6a9366fb52285c5d49.

@preethi This issue can be automated. However, understand that it'll be a bit difficult, as it requires the participation of multiple hosts. Basically, the test can be written, but it will only be able to be run at this time with hosts provided by an automation QE. Our Jenkins set-up can't provide multipple hosts for tests.