rtyler

A loose collection of notes from Puppet training

Last week, Kohsuke and I participated in a Puppet training and consulting event on behalf of the Jenkins project. Fortunately, or unfortunately depending on how you look at it, we both had some amount of Puppet knowledge going into the sessions, but neither of us had actually deployed a puppet master before, let alone used the Puppet Enterprise Console. I’ve written good bits of Puppet code, I’ve not made good use of Puppet though.

Below is a more or less unedited list of my notes taken during the entirety of the week.


Puppet Basics/Advanced Training

Installing Puppet Enterprise on Master

  • Install cloud provisioner
  • Puppet has its own CA built into it, don’t use upstream/certificate authority certificates for Puppet to Puppet communications
  • PostgreSQL is vendored by Puppet Enterprise

Installing the Puppet Enterprise on an Agent

  • Creating certificates can be done by the agent automatically, but the signing should be done on the master
  • Console can sign certs too through the UI
  • puppet --test will actually apply the changes, --noop is required to not actually enforce a catalog
  • tag on a resource or tag() to tag a class

Puppet Enterprise Console notes

  • 1-2 background tasks backed up and waiting means that something is probably broken.
  • Unresponsive node means that we likely have a dead node or that a node was not running a puppet agent
  • Live Management builds on top of MCollective

Node Classification

  • node classification uses the agent node’s name/certname (so use a FQDN)
  • node classification and our modules in the training VM, the modules we’ve built are the same “name” but are being deployed into different environment paths on the puppet master

Resources

  • puppet describe <resourcetype> for docs
  • should look into the puppetlabs/postgresql module for managing databases
  • exported resources, what order are those executed in relation to the collection?
  • Should look into nanliu/staging to making untars sane
Resource Relationships
  • Can use contains for containing class relationships instead of needing to use the anchor pattern
Language constructs
  • Scoping of variables in classes will generally be shared with include except for the params class pattern ,which is just about the only place to use inherit non-stupidly
  • catalog diff tool from zach smith would be useful for diffing ehether scope changes in old versus new puppet code
  • Using resource defaults in a class scope (such as File { owner => 'apache' } works well, but should be paired with a shared example to make sure things are enforced for subsequent file resources in the specs
  • For conditionals undef, '', false are falsey for the conditionals
  • Functions always execute on the master when the catalog is compiled
  • regsubst might be a good funciton to replace the puppet-jenkins use of inline_template

ERB Templates

  • <%= @foo -%> the -%> chomps the trailing newline
  • templates directory of the modules is where these should go.
  • template can take multiple files and concatenate them together

Defined types

  • Scope lookup inside defined types works such that: defined type scope -> calling class scope -> node scope -> global scope
  • Using purge => true on resources will make sure that we remove resources that are not managed. Good for making sure spurious configuration doesn’t find its way onto production machines

Hiera

  • Need to use hiera() in the manifests
  • Any facter fact that is available can be jammed into the hiera hierarchy
  • PuppetDB reporting/etc might include hiera-sourced secrets that were logged from a catalog run on a machine
  • hiera-based class parameters should be in the file as ntp::time_server
  • hiera_array interesting for pulling all matching values for a key down (e.g. a list of servers)
  • hiera_hash and create_resources make a lot of sense for how we should manage users

Relationships

  • subscribe and notify can be short-handed with <~ and ~>

Augues

  • augtool can be used from the command line to inspect the tree of a file on the file system before referring to it in Puppet with the augeas type
  • augeas.net

Troubleshooting

  • puppet agent --configprint vardir where lots of puppet agent/master state is stored
  • statedir contains all the information from the last run, etc.
  • last_run_report.yaml might contain secrets from the last run
  • Agent initiates connection to master, 443 and 8140 (console and agent traffic respectively) should be open on master, not on agents
  • puppet node deactivate will clean up exported resources from a dead machine. “unexport all exported resources”
  • /var/log/pe-*/*.log will have all the relevant logs on the master. /var/log/messages is likely going to be where logs are on agents

Rapid Deployment Support/Training

  • r10k deploy always runs on the puppet master, usually from a git post-receive hook
  • The r10k control repository can be a local file://git or git://git repo
  • profiles as a concept pull in modules with some business logic within them
  • profiles should probably be where the hiera lookups of data should occur
  • roles contain no logic at all
  • node classification with just assigning roles provides a simpler abstraction

Deployment pipeline iteration 0

  • feature branches created for jenkins-infra and then sending a pull request
  • staging branch should be PRed to, with the puppet master tooling running no-op deployments on all agents
  • merging to production should automatically deploy to puppet master and nodes

Secrets management

  • Private “keys repository” holding keys on github
  • hiera-eyaml as the default data provider for hiera on the puppetmaster
  • encrypted blobs can/should go into jenkins-infra.git/hieradata

Testing notes

  • rspec-puppet cannot be configured with an array as the module path

Misc notes

  • Setting up agent: ` curl -k https://puppet:8140/packages/current/install.bash bash`
  • The puppet master can also act as an apt repository for puppet packages