kubestronaut

This is my working directory for completing the CNCF Kubestronaut certification package.

Sources and Commit History

This is not a pretty portfolio, it's getting things done dirty.

sources and inspirations include, but are not limited to:

• https://github.com/talbotfoundry/k8s-kvm
• https://github.com/boxcutter/kvm/
• https://github.com/chef/bento

When snippets are pulled from repo issues, they are commented inline with references.

Branches are squashed, because save scumming is not a sin.

Environment

created and ran on x86_64 Debian Linux.

virtual machines are x86_64 Ubuntu 24.04.1 Linux.

SSH

Vagrant is configured to copy ~/.ssh/id_rsa.pub to the virtual machine's root user's authorized keys. The vagrant makefile target will drop ssh configuration snippets into ~/.ssh/vagrant.d/.

Host vagrant-*
    User root
    RequestTTY yes
    IdentityFile ~/.ssh/id_rsa.pub

Include vagrant.d/*

$ ssh vagrant-control-01 -- kubectl apply -f - < manifests/pod.yaml
pod/box created

 $ scp vagrant-control-01:.kube/config ~/.kube/
 $ kubectl get nodes
NAME                 STATUS   ROLES           AGE   VERSION
vagrant-control-01   Ready    control-plane   67m   v1.32.1
vagrant-control-02   Ready    control-plane   67m   v1.32.1
[...]

Building

make python

installs local python / pyenv runtime. ansible, etc.

make packer

builds base images and imports to vagrant.

must be explicitly ran first. not included in default build targets / dependencies, as it is quite a heavy operation.

ubuntu24.pkr.hcl: packer configuration file scripts/packer.sh: base box provision script

make vagrant

creates a 1 control node, 3 worker node k8s cluster by default.

export VAGRANT_K8S_PROFILE='full' will create a 3 control node, 5 worker node cluster.

CNCF Certification Notes

Blanket bullet points

• killer.sh exam simulators included are invaluable for finding weak spots
• foo?
• Time and resource management.
  • spend time wisely. if a question is taking a lot of digging through docs, flag and come back to it.
  • Know key search terms for boilerplate in k8s official docs.
  • vimrc
    • add set si for smartindent
  • env
    • export d="--dry-run=client -o yaml"

KCNA - K8s and Cloud Native Associate

• The CNCF Landscape is very intimidating.
  • take time to become familiar with graduated projects.

CKA - k8s Administrator

• cluster upgrade apply takes a very long time.

  • tmux and detach. flag the task, and come back after a few minutes.

• Time management:

  • 30% troubleshooting
  • 25% arch, install, configuration
  • both are quick work if you know where to look.

CKAD - k8s Application Developer

• considerable overlap from CKA.
• time management - topics are more even in weighting.

Security Associate - KCSA

• another large subject overlap with CKA, but multiple choice!

Security Specialist - CKS

• Required a pretty massive shift in local vagrant configuration.
  • Stuff that realistically should have been done for CKA.
  • Admin users and etcd encryption forced it.