OCI Kube Prompt

This project is a small Bash script that displays the Kubernetes cluster actively set in the environment via the Bash prompt. This is currently geared toward Oracle Container Engine Kubernetes clusters, but could be easily extended to support other vendors.

As many people who operate Kubernetes-based systems have experienced, it's all too easy to accidentally point to the wrong Kubernetes cluster (like dev instead of prod) and get yourself into trouble. Displaying the name of the active cluster at all times reduces the chances of making a mistake.

This was originally inspired by this blog post. However, for many vendors, like OCI, the real human-readable details of the cluster (like its name) are not directly available within the KUBECONFIG file. It requires a bit of extra work to fetch those details.

Usage

Config File

Create a config file containing your OCI tenancy/user details, as described in the OCI docs. Ensure that this user is authorized to list compartments and clusters. For example:

[DEFAULT]
user=ocid1.user.oc1..aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
tenancy=ocid1.tenancy.oc1..aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
key_file=/tmp/my_api_key.pem
fingerprint=aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa

Add kube-prompt.sh to .bashrc or .bash_profile

Copy the oci-kube-prompt.sh file into the ~/.oci directory, then add to your .bashrc:

source ~/.oci/oci-kube-prompt.sh

Fetch OCI Clusters

We don't want to reach out to OCI on every shell command, so this is a one time step (or however frequently you want to refresh your cluster list) to fetch the current OCI clusters in the tenancy.

fetch_oci_clusters

This will create a directory ~/.oci/clusters containing mappings of cluster OCIDs to human readable cluster names. This can take a minute, depending on how many compartments and clusters you have.

Update Your Prompt

Finally, add a call to the __oci_cluster_name function into the PS1 variable within your .bashrc or .bash_profile. For example:

export PS1="\W\[\e[1;33m\]\$(__oci_cluster_name)\[\033[00m\] \$ "

Enjoy

At this point, whenever your KUBECONFIG is pointed to an OCI cluster, you'll see the region/name of the cluster in your Bash prompt, like:

tmp(uk-london-1/dan-dev) $ kubectl get pod --all-namespaces
kube-system   kube-dns-79744689dc-lhqzm                                         3/3       Running             0          19d
kube-system   kube-dns-79744689dc-ltkrx                                         3/3       Running             0          19d
kube-system   kube-flannel-ds-g5jsm                                             1/1       Running             0          19d
kube-system   kube-flannel-ds-qsrsn                                             1/1       Running             0          19d

Further Customizations

• If you'd like the prompt to show a different format for all clusters (say, without the region shown), just modify the fetch_oci_clusters() function in oci-fetch-prompt.sh and re-fetch your clusters.
• If you'd like to customize how a single cluster appears in your prompt, you can modify the ~/.oci/clusters/<ocid> for the cluster in question to display it however you want.

Contributions

Pull requests welcome!