What is KubeLinter? How to use it?

What is KubeLinter?

The KubeLinter is an open-source command-line tool to check the quality of Kubernetes objects’ configurations. It also detects any misconfigurations on Kubernetes YAML files and Helm charts. KubeLinter can be integrated into CI/CD pipelines and checks YAML files before deployment. KubeLinter has about 20 built-in rules and provides the feature to create new ones based on the environment’s needs.

How to use it?

KubeLinter does not require too many resources and can be used by running commands in different OS command lines.

Microsoft Windows

• Command Prompt
• PowerShell

Unix-like systems

• Bash
• Zsh
• Tcsh

How to install KubeLinter?

Using Brew

It is pretty simple if you have HomeBrew for macOS or LinuxBrew. KubeLinter can be installed by using the following command:

brew install kube-linter

Using the Latest Binary

You can find and download the latest binaries from the following repo. You can use these binaries in docker containers or CI pipelines.

Releases · stackrox/kube-linter

Here’s how to download and install KubeLinter on Linux.

wget https://github.com/stackrox/kube-linter/releases/download/0.2.5/kube-linter-linux.tar.gz
tar -xvf kube-linter-linux.tar.gz
mv kube-linter /usr/local/bin/

How to use KubeLinter?

After we have done with the installation phase, we can simply type kube-linter and see the available commands. KubeLinter has five main commands:

1. checks 2. help 3. lint 4. templates 5. version

The 2nd and 5th commands already define itself 😄

The kube-linter check list command lists built-in policies provided by KubeLinter.

Output for checks list

Now, we can focus on the most important command to check our yaml files. lint command allows you to check single file or multiple files in a directory. To check single file:

kube-linter lint path/to/kubelinter-example.yaml

To check multiple files in a directory:

kube-linter lint path/to/example-yaml-files/

Also, to check a single file with a specific rule:

kube-linter lint path/to/kubelinter-example.yaml --include privileged-ports

Check yaml file with all built-in rules:

kube-linter lint path/to/kubelinter-example.yaml --add-all-built-in

Example use of KubeLinter

To see the output of KubeLinter I have created a simple yaml file.

An example of yaml file

I have simply typed the following commands.

kube-linter lint kubelinter-pod.yaml

Here is the output:

Output for yaml check

All in all, taking advantage of KubeLinter, you can create secure and best practice applied yaml files for your production environment.

Documentations

You can find the official GitHub repo and other useful links below.

GitHub - stackrox/kube-linter: KubeLinter is a static analysis tool that checks Kubernetes YAML…

KubeLinter