Kor - Kubernetes Orphaned Resources Finder

Kor is a tool to discover unused Kubernetes resources. Currently, Kor can identify and list unused:

• ConfigMaps
• Secrets
• Services
• ServiceAccounts
• Deployments
• StatefulSets
• Roles
• HPAs
• PVCs
• Ingresses
• PDBs

Installation

Download the binary for your operating system from the releases page and add it to your system's PATH.

Homebrew

For macOS users, you can install Kor using Homebrew:

brew install kor

Build from source

Install the binary to your $GOBIN or $GOPATH/bin:

go install github.com/yonahd/kor@latest

Docker

Run a container with your kubeconfig mounted:

docker run --rm -i yonahdissen/kor

docker run --rm -i -v "/path/to/.kube/config:/root/.kube/config" yonahdissen/kor all

Helm

Run as a cronjob in your Cluster (with an option for sending slack updates)

helm upgrade -i kor \
    --namespace kor \
    --create-namespace \
    --set cronJob.enabled=true
    ./charts/kor

Run as a deployment in your Cluster exposing prometheus metrics

helm upgrade -i kor \
    --namespace kor \
    --create-namespace \
    ./charts/kor

For more information see in cluster usage

Usage

Kor provides various subcommands to identify and list unused resources. The available commands are:

• all - Gets all unused resources for the specified namespace or all namespaces.
• configmap - Gets unused ConfigMaps for the specified namespace or all namespaces.
• secret - Gets unused Secrets for the specified namespace or all namespaces.
• services - Gets unused Services for the specified namespace or all namespaces.
• serviceaccount - Gets unused ServiceAccounts for the specified namespace or all namespaces.
• deployments - Gets unused Deployments for the specified namespace or all namespaces.
• statefulsets - Gets unused StatefulSets for the specified namespace or all namespaces.
• role - Gets unused Roles for the specified namespace or all namespaces.
• hpa - Gets unused HPAs for the specified namespace or all namespaces.
• pvc - Gets unused PVCs for the specified namespace or all namespaces.
• ingress - Gets unused Ingresses for the specified namespace or all namespaces.
• pdb - Gets unused PDBs for the specified namespace or all namespaces.
• exporter - Export Prometheus metrics.

Supported Flags

-e, --exclude-namespaces string   Namespaces to be excluded, split by comma. Example: --exclude-namespace ns1,ns2,ns3. If --include-namespace is set, --exclude-namespaces will be ignored.
-h, --help                        help for kor
-n, --include-namespaces string   Namespaces to run on, split by comma. Example: --include-namespace ns1,ns2,ns3.
-k, --kubeconfig string           Path to kubeconfig file (optional)
    --output string               Output format (table or json) (default "table")
    --slack-auth-token string     Slack auth token to send notifications to. --slack-auth-token requires --slack-channel to be set.
    --slack-channel string        Slack channel to send notifications to. --slack-channel requires --slack-auth-token to be set.
    --slack-webhook-url string    Slack webhook URL to send notifications to

To use a specific subcommand, run kor [subcommand] [flags].

kor all --namespace my-namespace

For more information about each subcommand and its available flags, you can use the --help flag.

kor [subcommand] --help

Supported resources and limitations

Resource	What it looks for	Known False Positives ⚠️
ConfigMaps	ConfigMaps not used in the following places: - Pods - Containers - ConfigMaps used through Volumes - ConfigMaps used through environment variables	ConfigMaps used by resources which don't explicitly state them in the config. e.g Grafana dashboards loaded dynamically OPA policies fluentd configs
Secrets	Secrets not used in the following places: - Pods - Containers - Secrets used through volumes - Secrets used through environment variables - Secrets used by Ingress TLS - Secrets used by ServiceAccounts	Secrets used by resources which don't explicitly state them in the config
Services	Services with no endpoints
Deployments	Deployments with no Replicas
ServiceAccounts	ServiceAccounts unused by Pods ServiceAccounts unused by roleBinding or clusterRoleBinding
StatefulSets	Statefulsets with no Replicas
Roles	Roles not used in roleBinding
PVCs	PVCs not used in Pods
Ingresses	Ingresses not pointing at any Service
Hpas	HPAs not used in Deployments HPAs not used in StatefulSets
Pdbs	PDBs not used in Deployments PDBs not used in StatefulSets

Ignore Resources

The resources labeled with "kor/used = true" will be ignored by kor even if they are unused. You can add this label to resources you want to ignore.

Import Option

You can also use kor as a Go library to programmatically discover unused resources. By importing the github.com/yonahd/kor/pkg/kor package, you can call the relevant functions to retrieve unused resources. The library provides the option to get the results in JSON format by specifying the outputFormat parameter.

import (
    "github.com/yonahd/kor/pkg/kor"
)

func main() {
    myNamespaces := kor.IncludeExcludeLists{
        IncludeListStr: "my-namespace1, my-namespace2",
    }
    outputFormat := "json" // Set to "json" for JSON output

    if outputFormat == "json" {
        jsonResponse, err := kor.GetUnusedDeploymentsStructured(myNamespaces, kubeconfig, "json")
        if err != nil {
            // Handle error
        }
        // Process the JSON response
        // ...
    } else {
        kor.GetUnusedDeployments(namespace)
    }
}

In Cluster Usage

To use this tool inside the cluster running as a CronJob and sending the results to a Slack Webhook as raw text(has characters limits of 4000) or to a Slack channel by uploading a file(recommended), you can use the following commands:

# Send to a Slack webhook as raw text
helm upgrade -i kor \
    --namespace kor \
    --create-namespace \
    --set cronJob.slackWebhookUrl=<slack-webhook-url> \
    ./charts/kor

# Send to a Slack channel by uploading a file
helm upgrade -i kor \
    --namespace kor \
    --create-namespace \
    --set cronJob.slackChannel=<slack-channel> \
    --set cronJob.slackToken=<slack-token> \
    ./charts/kor

Note: To send it to Slack as a file it's required to set the slackToken and slackChannel values.

It's set to run every Monday at 1 a.m. by default. You can change the schedule by setting the cronJob.schedule value.

helm upgrade -i kor \
    --namespace kor \
    --create-namespace \
    --set cronJob.slackChannel=<slack-channel> \
    --set cronJob.slackToken=<slack-token> \
    --set cronJob.schedule="0 1 * * 1" \
    ./charts/kor

Contributing

Contributions are welcome! If you encounter any bugs or have suggestions for improvements, please open an issue in the issue tracker.

License

This open-source project is available under the MIT License. Feel free to use, modify, and distribute it as per the terms of the license.