I cleared the CKA a few days back, and here are some tips from my experiences that might help you in the exam:
1. Set Up Your Environment Before Starting the Exam#
Edit the
~/.bashrc: Enable vim keybindings for bash. Also set force_color_prompt to yes. This is required if you want to have a colourful prompt in your Bash shell while using Tmux.Edit
~/.tmux.conf: Enable vi copy mode in Tmux. This becomes very helpful for copying stuff from the terminal/man pages to the output.
echo "set -o vi" >> ~/.bashrc
echo "force_color_promp=yes" >> ~/.bashrc
echo "setw -g mode-keys vi" >> ~/.tmux.conf
The vim-edit (activated by pressing v, in vi mode) can be very helpful while copy pasting long command that need to be edited. ex: While performing a kubeadm node upgrade.
2. Store Values in a Variable for Long Commands#
- A good example is doing an etcd backup. The command for this is usually quite long.
- Unless the keys and certs are part of the question, you can get the values by running
kubectl describe -n kube-system etcd | grep "/etcd/"in most cases. - Store these paths as environment variables, like this:
end=https://localhost:2379/
cert=/etc/kubernetes/pki/etcd/server.crt
key=/etc/kubernetes/pki/etcd/server.key
cacert=/etc/kubernetes/pki/etcd/ca.crt
Now, the etcd backup command can be done easily as follows.:
ETCDCTL_API=3 etcdctl --endpoints=$end --cert=$cert --key=$key --cacert=$cacert snapshot save /path/save.db
This will also be helpful, in ensuring you’re doing the thing right in the first go as well!
3. Get Familiar with journalctl and Directories/Files Inside /var/log#
- Troubleshooting is a key part of the exam, so getting comfortable with logging tools in linux can be very helpful. Getting familiar with troubleshooting the kubelet is essential. I would suggest practising Kim’s Killercoda scenarios, they can be accommodating in this regard.
4. Use man Pages Efficiently Using grep#
- Full credit to this goes to Rio. If you want to look at examples of how the command is run with
kubectl, use it the following way:
$ kubectl create ingress -h | grep "kubectl create"
kubectl create ingress simple --rule="foo.com/bar=svc1:8080,tls=my-cert"
kubectl create ingress catch-all --class=otheringress --rule="/path=svc:port"
kubectl create ingress annotated --class=default --rule="foo.com/bar=svc:port" \
kubectl create ingress multipath --class=default \
kubectl create ingress ingress1 --class=default \
kubectl create ingress ingtls --class=default \
kubectl create ingress ingsecret --class=default \
kubectl create ingress ingdefault --class=default \
kubectl create ingress NAME --rule=host/path=service:port[,tls[=secret]] [options]
Similarly, you can do this for other resources as well.
kubectl auth can-i -h | grep "kubectl auth"
I hope these tips help you prepare. Have a great day and good luck with your exam!
Har Har Mahadev 🙏