Requirements

• Ruby 3.1.3 install with rbenv e.g. https://www.digitalocean.com/community/tutorials/how-to-install-ruby-on-rails-with-rbenv-on-ubuntu-22-04
• SSH access to relevant hosts
• For convenience a .ssh/config entry to make the hosts name accessible (e.g. map IP to hostname such as 'drax' or 'taspar')

Prerequisites

bundle install
berks install # lock cookbook dependencies
berks vendor  # install cookbook dependencies in berks-cookbooks

NOTE: you absolutely want to bundle exec all knife calls, knife-solo wants very specific versions.

How to Cook

# With hostname set up
knife solo cook --clean-up root@drax

# Without hostname set up (manual file definition)
knife solo cook --clean-up root@192.168.0.9 nodes/drax.json

# With verbosity
knife solo cook -V --clean-up root@drax

Secrets storage - aka Cupboard

Knife commands automatically will setup the `data_bags/cupboard/`` submodule, it includes encrypted secret blobs such as SSH keys. For more information see the cupboard README.

Note that 9/10 times problems with the cupboard are to do with gpg1 vs. gpg2 setup problems.

Solo vs. Zero

There's two knifes! knife-solo and then there's knife-zero. But why?! And which one do we use?

• How solo works: rsyncs the entire kitchen to the remote, then runs chef-solo on the remote to cook it.
• How zero works: starts chef-zero (lightweight server) on localhost, then creates an SSH tunnel to the remote, then runs chef-client on the remote to cook it, which in turn talks to the chef-zero on localhost through the tunnel to get cookbooks and other resources as needed.

I know, that doesn't tell you why, the why is that zero is architecturally how chef-server works. Which in turn means the kitchen needs to be in a chef-server compatible state for it to be usable with knife-zero. Conversely it means that by using knife-zero we can prepare for a potential move to chef-server in the future! It's also a tad faster because it does not have to rsync everything all the time.

All in all functionally there is not much difference though and knife-solo is easier to not cut yourself with. If you want you can still play around with zero though.

How to Cook with Zero

Firstly, zero and solo are not compatible as they want different versions of net-ssh. So, when using knife-zero you need to change the Gemfile entry from knife-solo, then run bundle update to get suitable versions installed.

Before one can knife a server it needs boostrapping.

knife zero bootstrap root@drax --node-name drax --no-converge

This bootstraps root@drax (install chef etc.) and assumes its node config is drax.json (by default the node name is the hostname which almost always is some stupid stuff for us, so best force a good one). Additionally we'll not converge the server right now, though you can if you want to.

Cooking/Converging needs a query. The reason for this is that you can converge multiple hosts at the same time based on the query. See zero docs for information on this. To only provision one node simply define its name as query. Additionally since we use bare bones json files for the nodes you'll need to define a suitable ssh user and hostname (you tell it which attribute is the hostname and that is the name). Note that as with knife-solo in order for this to work you need to have the hostname in your ssh config defined.

knife zero converge 'name:do-builder-001' --ssh-user root --attribute name