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Copyright 2015 Hewlett-Packard Development Company, L.P.
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This work is licensed under a Creative Commons Attribution 3.0
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Unported License.
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http://creativecommons.org/licenses/by/3.0/legalcode
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====================
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Ansible Puppet Apply
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====================
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https://storyboard.openstack.org/#!/story/2000207
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Our current Config Management system consists of using ansible to orchestrate
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running puppet agent on each of our hosts, which then have to connect back
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to a puppetmaster to learn what they should apply. It's a highly coupled system
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that ultimately doesn't need to be that complex.
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Problem Description
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===================
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While the puppetmaster has served us well for quite some time, with the
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introduction of ansible for sequencing and orchestration, it's no longer
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needed. Having the puppetmaster introduces a few complexities, such as the
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need for certificate exchange and the certificate re-use dance when we're
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replacing servers. It's also a bootstrapping issue when spinning up a new
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infra, since you need the puppetmaster in place to get the puppetmaster in
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place.
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Finally, our friends from puppet sometimes like to release new versions of
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puppet that are backwards incompatible in ways that touch the wire protocol.
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If we're using puppet apply on each of the nodes, then rolling out a per-node
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upgrade is simple.
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Proposed Change
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===============
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Add a playbook that handles cloning system-config on all of the nodes and
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potentially running install_modules.sh on them. This should run before puppet
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is run. As an optimization, we could fetch on the master and rsync to all of
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the nodes, or do clarkb's trick of fetching the ref on the master and passing
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that to the remote git clone/update commands.
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Split the current hiera common.yaml into a set of files, a
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common.yaml file that contains things that should be available everywhere. A
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set of $group.yaml files, which map to a group of servers where every server
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in the group should have access to the values. And a set of $fqdn.yaml files
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that contain values that should only be accessed by one server.
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Group membership from the puppet perspective will be managed by a group variable
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set at the node level in site.pp. There should be an ansible group for every
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defined puppet group. For the purposes of this, that grouping will be managed
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manually, but as a follow on, we should find a better way to manage this
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mapping. Also, for the purposes of this, each node will only have one group
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from puppet/hiera perspective. Ansible supports multiple groups, as does the
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ansible openstack inventory module. For now, we'll avoid making use of that.
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In the ansible-puppet role, copy over the master's hieradata that is appropriate
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for that node to have. That is, the common.yaml file, any $group.yaml files
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for the node in question, and the $fqdn.yaml file. Then, have ansible run puppet
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apply pointing at the manifests/site.pp file on the host.
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We will need to populate the hiera files as part of node bootstrap. This will
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be simple once we have replaced launch_node.py with an ansible playbook using
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the openstack modules. However, that work actually wants this work first to
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simplify the exchange, so for now, we will want a patch to launch_node.py that
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calls the ansible puppet role instead of doing the ssh to the host to run
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puppet itself.
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To handle disabled nodes, we'll mark all of our ansible playbooks in run_all
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with ;!disabled - referencing an ansible node group called disabled that we
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can add and remove hosts from on the master.
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Since we will not have a puppetmaster, we'll need to coordinate puppet apply
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reporting to puppetdb. For this, we need to create a CA, a cert that the
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puppetdb server will have, and a cert that we will distribute to every host
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we run. The certs for the cattle and the puppetdb server can be installed via
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hiera secrets, with the cattle cert being an excellent target for common.yaml.
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Alternatives
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------------
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We could just keep using puppet agent.
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We could ditch puppet altogether and move completely to ansible.
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Implementation
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==============
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Assignee(s)
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-----------
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Primary assignee:
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- mordred
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- nibalizer
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Gerrit Topic
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------------
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Use Gerrit topic "puppet-apply" for all patches related to this spec.
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.. code-block:: bash
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git-review -t puppet-apply
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Work Items
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----------
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The description is kinda already written like work items.
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Repositories
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------------
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None
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Servers
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-------
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None
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DNS Entries
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-----------
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None
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Documentation
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-------------
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None
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Security
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--------
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Each server will be contacting puppetdb directly, rather than funneling
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through the puppetmaster.
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Secrets related to a particular server will be stored on that server. Of course,
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those secrets are all aready on that server in some form anyway.
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Testing
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-------
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We already have puppet apply tests, so that's awesome.
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Dependencies
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============
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None
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