Autocomplete and Alias for kubectl

When you have to manage one or several Kubernetes clusters it is very likely that you'll spend a good amount of time typing kubectl commands. Kubectl has a lot of commands and each command can have many flags and options so, apart from the three or four most used commands, it's going to be impossible to work with kubectl without a cheatsheet. Also, the more specific you are with your command the longer your command will be.

To help us with this, there are a couple of features that we can enable in our shell sessions to work more efficiently with kubectl: 

• Autocomplete - Bash autocomplete, also known as tab completion, is a feature of the Bash shell that helps users quickly complete commands, file names, directories, and other entities by pressing the Tab key. When you type part of a command or file name and press Tab, Bash will either complete the command if it's unambiguous or provide a list of possible commands if there are multiple matches.

• Alias - The alias feature in Bash allows you to create shortcuts or alternative names for commands or series of commands. This can be useful for shortening frequently used commands, simplifying complex command sequences, or even creating custom command behaviors. 

Before diving into these two features, ensure your kubectl can connect to your cluster(s). For that, make sure you’ve set up correctly your kubeconfig file(s). Check out this post if you want to know more how to manage your kubeconfig.

Autocomplete for kubectl

Follow the next steps:

• Check if bash-completion is installed

type _init_completion

• If you get an output like the picture above that means bash_completion is installed. If not, install it with the following command

apt-get install bash-completion 

• After that, to enable autocomplete for kubectl commands in your bash shell, run the following command

kubectl completion bash | sudo tee /etc/bash_completion.d/kubectl > /dev/null

• Next you need to reload your bash shell. For that you can close your current session and open a new one or run the command

source ~/.bashrc

• Then try again typing kubectl get and press tab (twice). You should now get a list of the possible options to autocomplete

Setting up an alias for kubectl

• To create an alias, you use the alias command followed by the name of the alias and the command it should execute. The basic syntax is:

alias alias_name='command'

• For kubectl, the alias that many K8s use is k for kubectl. To create the alias for k=kubectl , run the command: 

echo 'alias k=kubectl' >>~/.bashrc

• After that, we need to reload the bash shell. So, close your terminal session and open a new one or run the command below for the changes to take effect. 

source ~/.bashrc

• Then try with the command:

k get nodes

• You should see your alias is now replacing kubectl

Enable autocompletion for your kubectl alias

• Lastly, if you noticed, when you set up your kubectl alias, autocomplete does not work. That’s because we need to tell our Operating System that we want to use automcomplete also for our alias.
• To do that, run the following

echo 'complete -o default -F __start_kubectl k' >>~/.bashrc

• And again, reload your bash shell. Log out and log back in to apply changes and verify that now autocomplete works for kubectl and k alias

More alias for kubectl

As we mentioned above, an alias can be a shortcut for a command but also for more complex expressions. In our case, with kubectl, this means we can set up an alias for a kubectl command followed by options and flags which would reduce a lot those long specific commands when we want to get something specific. 

There are no standards for this, every K8s admin has their particular preferences. In my case this is the list of alias I like to use that reduce a lot my work with kubectl

alias k=kubectl
alias kg='kubectl get'
alias kd='kubectl describe'
alias kgn='k get nodes'
alias kgp='k get pods'
alias kgpa='kgp -A'
alias nano='KUBE_EDITOR=nano'
alias dr='--dry-run=client -o yaml'
alias kaf='k apply -f'