How can I obtain the kubeconfig file for my LKE cluster using the API or linode-cli?

I totally appreciate how these several factors can appear disorienting. To provide an effective explanation here, I will organize the points you've raised into a few sections.

Kubeconfig output from API/CLI

The most important detail to mention first is that our API and Linode CLI provide the Kubeconfig file as a string encoded in Base64 format. Since both our API and Kubeconfig are formatted in JSON, encoding the Kubeconfig file as a Base64 value helps to avoid presenting the file with a complicated JSON-in-JSON nesting structure.

This will have effects on how to process this Kubeconfig data, which I will explain in a later section.

Linode CLI and Kubeconfig output

Our Linode CLI uses "box formatting" characters to provide elegant output. This usually yields clean-looking results, but due to the length of the Base64 string (several thousand characters), this has the the unforunate effect of significantly elongating the box borders when retrieving a Kubeconfig file. You will likely see output like this as a result:

$ linode-cli lke kubeconfig-view $clusterID
┌───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

(this is significantly shortened from the actual output)

The Base64 Kubeconfig file will still be located in this output, but it may not be immediately intuitive, and it will definitely be difficult to effectively interact with it.

Fortunately, alleviating this is as simple as using the --json flag with Linode CLI, which suppresses the usual Linode CLI "box formatting" to provide JSON output:

linode-cli --json lke kubeconfig-view $clusterID

At this point, the Linode CLI will output data in largely the same manner as the API.

Decoding the Base64 into a usable Kubeconfig file

In order to be usable as a Kubeconfig file, the Base64 output from Linode CLI or API must be decoded back to its usable JSON format. The base64 application is standard on many systems, and it has a -d option for decoding Base64 strings.

However, for greater utility, I like using the jq utility for its additional JSON-parsing capabilities. jq additionally contains a built-in Base64 decoder, allowing you to obtain a usable Kubeconfig file with just a single command.

Due to slight discrepancies in the output format between the Linode CLI's JSON mode and the Linode API, the jq command you use will be slightly different depending on the source of your Kubeconfig Base64 data. As of this writing, I had success with the following command formats.

For the API:

curl -sH "Authorization: Bearer $TOKEN" https://api.linode.com/v4/lke/clusters/89/kubeconfig | jq -r '.[] | @base64d'

For the Linode CLI:

linode-cli --json lke kubeconfig-view 89 | jq -r '.[].kubeconfig | @base64d'

The main difference between these is the jq selection filters used to extract the Base64 data out of the CLI/API JSON structures. You may read more about jq's options by running man jq on your system or by reading the online jq manual. (Be sure to choose the correct manual for your version. As of this writing, there are links at the top of the page for jq's versions. You can run jq --version to determine your version of jq.)

Regardless of these differences, both outputs will ultimately filter their results through the built-in @base64d format of jq, which decodes Base64 strings into their original text. As a result, you will see your Kubeconfig file when you run this command.

Saving the decoded Kubeconfig file

The final step to implement here is to save this Kubeconfig file to your disk. You can use the > and >> shell operators to save this output to a file. Each of these operators differs very important in their functionality: > will overwrite the file in question, while >> will append to that file.

Either one of these options will have an effect on the file, so to ensure the proper operation of your services, I recommend determining whether your target file exists before running this command. This will help ensure that it does not either get overwritten or appended with unexpected data.

These examples adapted from earlier will overwrite or append the Kubeconfig output to the specified file names:

curl -sH "Authorization: Bearer $TOKEN" https://api.linode.com/v4/lke/clusters/89/kubeconfig | jq -r '.[] | @base64d' > ~/.kube/overwritten_kubeconfig.yaml
curl -sH "Authorization: Bearer $TOKEN" https://api.linode.com/v4/lke/clusters/89/kubeconfig | jq -r '.[] | @base64d' >> ~/.kube/appended_kubeconfig.yaml
linode-cli --json lke kubeconfig-view 89 | jq -r '.[].kubeconfig | @base64d' > ~/.kube/overwritten_kubeconfig.yaml
linode-cli --json lke kubeconfig-view 89 | jq -r '.[].kubeconfig | @base64d' >> ~/.kube/appended_kubeconfig.yaml

You can then use these files with kubectl in multiple ways:

1. Export the KUBECONFIG variable before running kubectl:

export KUBECONFIG=~/.kube/overwritten_kubeconfig.yaml
kubectl get pods
export KUBECONFIG=~/.kube/appended_kubeconfig.yaml
kubectl get svc

1. Set the KUBECONFIG variable while running kubectl:

KUBECONFIG=~/.kube/overwritten_kubeconfig.yaml kubectl get pods
KUBECONFIG=~/.kube/appended_kubeconfig.yaml kubectl get svc

1. Set the --kubeconfig= option in kubectl:

kubectl --kubeconfig=$HOME/.kube/overwritten_kubeconfig.yaml get pods
kubectl --kubeconfig=$HOME/.kube/appended_kubeconfig.yaml get svc

This may not work with the ~ shorthand used in Linux systems for the home directory, so you may need to use $HOME instead.

Conclusion

The Linode API and CLI are excellent options for working with your Linode services, including your LKE services. It does take some extra work to understand the way the API and CLI present Kubeconfig files and to convert this data into a format usable with kubectl. With the proper understanding and tools, though, these hurdles are very easy to clear. This will allow you to enjoy both the automatation and scalability benefits of API/CLI along with as the availability and orchestration benefits of our Kubernetes offerings.