K9s: The Ultimate Terminal UI for Kubernetes Management

Introduction

Managing Kubernetes clusters from the command line with kubectl can be tedious and time-consuming. Enter k9s - a powerful terminal-based UI that provides a real-time, interactive way to manage your Kubernetes clusters. Think of it as a “top” command for Kubernetes, but with superpowers.

K9s makes it easier to navigate, observe, and manage your applications running on Kubernetes. It continuously monitors cluster resources and provides a visual, menu-driven interface that significantly reduces the complexity of working with Kubernetes.

Why Use K9s?

Key Benefits

• Real-time Monitoring: Watch your cluster resources update live
• Faster Navigation: Navigate between namespaces and resources with simple key presses
• Resource Management: View logs, describe resources, edit manifests, and delete resources without complex kubectl commands
• Context Switching: Easily switch between different clusters and namespaces
• Visual Feedback: Color-coded status indicators make it easy to spot issues
• Reduced Typing: Execute common operations with single key commands
• Plugin Support: Extend functionality with custom plugins

Installation

macOS

# Using Homebrew brew install k9s # Using MacPorts sudo port install k9s

Linux

# Using snap sudo snap install k9s # Using pacman (Arch Linux) sudo pacman -S k9s # Using apt (Ubuntu/Debian) - from official releases curl -sL https://github.com/derailed/k9s/releases/latest/download/k9s_Linux_amd64.tar.gz | tar xvz -C /tmp sudo mv /tmp/k9s /usr/local/bin/

Windows

# Using Chocolatey choco install k9s # Using Scoop scoop install k9s

Using Go

go install github.com/derailed/k9s@latest

Getting Started

Simply run k9s in your terminal:

k9s

K9s will automatically use your current kubectl context. You can also specify a specific context:

k9s --context my-cluster-context

Essential Commands Reference

Navigation Commands

Command	Description
:	Enter command mode
/	Filter resources
Esc	Exit command/filter mode
?	Show keyboard shortcuts
Ctrl-a	Show all available resources
Ctrl-c	Quit k9s
:q	Quit k9s
0-9	Select namespace (from recent list)

Resource Navigation

Command	Description
:pods or :po	View pods
:deployments or :deploy	View deployments
:services or :svc	View services
:namespaces or :ns	View namespaces
:nodes or :no	View nodes
:configmaps or :cm	View config maps
:secrets	View secrets
:ingress or :ing	View ingresses
:jobs	View jobs
:cronjobs or :cj	View cron jobs
:statefulsets or :sts	View stateful sets
:daemonsets or :ds	View daemon sets
:persistentvolumes or :pv	View persistent volumes
:persistentvolumeclaims or :pvc	View persistent volume claims

Resource Actions

Command	Description
Enter	View resource details
d	Describe resource
v	View resource YAML
e	Edit resource
l	View logs (for pods)
Ctrl-l	Toggle auto-refresh logs
s	Shell into container
Ctrl-d	Delete resource
y	View resource as YAML
f	Port-forward (for services/pods)
z	Show last applied configuration
Ctrl-z	Suspend/Resume resource updates

Filtering and Sorting

Command	Description
/ + text	Filter by name
Ctrl-s	Save current filter
Ctrl-r	Toggle auto-refresh
Shift-f	Toggle fuzzy filter
Ctrl-f	Toggle full screen
Shift-a	Sort by age
Shift-n	Sort by name

Context and Namespace Management

Command	Description
:ctx	View and switch contexts
:ns	View and switch namespaces
Shift-0	View all namespaces
:contexts	List all available contexts

Log Viewing Commands

Command	Description
0	Show previous logs
1	Toggle auto-scroll
2	Toggle wrap
3	Toggle timestamps
4	Download logs
/	Filter logs
>	Next match
<	Previous match

Pro Tips and Tricks

1. Aliases for Quick Access

k9s supports kubectl-style aliases. You can type shortened versions:

:po → pods :svc → services :deploy → deployments :ns → namespaces :no → nodes :cm → configmaps

2. Regex Filtering

Use regex patterns when filtering resources:

/^app- # Find resources starting with "app-" /production$ # Find resources ending with "production" /nginx|apache # Find resources containing nginx OR apache

3. Custom Skins

Create a custom skin for k9s by editing ~/.config/k9s/skin.yml:

k9s: body: fgColor: dodgerblue prompt: fgColor: cadetblue info: fgColor: lightskyblue title: fgColor: aqua

4. Benchmarking Resources

Press Shift-b on a resource to run benchmarks and test performance.

5. Xray View

Press x on a pod to see an xray view showing all related resources (services, config maps, secrets, etc.).

6. Pulse View

Press p to see the pulse view - a real-time visualization of cluster metrics and resource utilization.

7. Custom Plugins

Create custom plugins in ~/.config/k9s/plugin.yml:

plugin: debug: shortCut: Shift-D description: Debug Pod scopes: - pods command: kubectl background: false args: - debug - -it - $NAME - -n - $NAMESPACE - --image=busybox

8. Popeye Integration

K9s can integrate with Popeye (a Kubernetes cluster sanitizer). Press Shift-p to run Popeye scans.

9. Resource Usage Monitoring

• Press Shift-t to toggle CPU/Memory graphs
• Use :top to see resource usage across nodes

10. Quick Shell Access

When viewing a pod:

1. Press Enter to view containers
2. Navigate to desired container
3. Press s to shell into it

Advanced Configuration

Config File Location

K9s stores its configuration in:

• macOS/Linux: ~/.config/k9s/config.yml
• Windows: %AppData%\k9s\config.yml

Sample Configuration

k9s: refreshRate: 2 maxConnRetry: 5 enableMouse: true headless: false logoless: false crumbsless: false readOnly: false noExitOnCtrlC: false skipLatestRevCheck: false screenDumpDir: /tmp/k9s-screens

Setting Default Namespace

Edit your config to set a default namespace:

k9s: clusters: my-cluster: namespace: active: production favorites: - default - kube-system - production - staging

Common Workflows

Debugging a Failing Pod

1. Launch k9s: k9s
2. Navigate to pods: :po
3. Filter for your pod: /your-pod-name
4. View logs: l
5. If needed, describe pod: Esc then d
6. Check events and conditions
7. Shell into pod if necessary: s

Updating a Deployment

1. Navigate to deployments: :deploy
2. Find your deployment
3. Edit it: e
4. Make changes in your editor
5. Save and exit
6. Watch the rollout: navigate to pods and observe new pods spinning up

Monitoring Resource Usage

1. View nodes: :no
2. Toggle metrics: Shift-t
3. Sort by CPU/Memory
4. Drill into specific node with Enter
5. View pods on that node

Port Forwarding for Local Testing

1. Navigate to service or pod: :svc or :po
2. Select target resource
3. Press f for port-forward
4. Specify local and remote ports
5. Access application on localhost

Troubleshooting

K9s Won’t Start

Check your kubeconfig:

kubectl cluster-info

Verify k9s can access the cluster:

k9s info

Performance Issues

Increase refresh rate in config:

refreshRate: 5 # Update every 5 seconds instead of 2

Missing Resources

Ensure your RBAC permissions allow viewing resources:

kubectl auth can-i list pods --all-namespaces

Keyboard Shortcuts Cheatsheet

Quick Reference Card

┌─────────────────────────────────────────────────┐ │ K9s Essential Shortcuts │ ├─────────────────────────────────────────────────┤ │ Navigation │ │ :resource → Go to resource type │ │ / → Filter current view │ │ Enter → View details │ │ Esc → Go back/Cancel │ │ ? → Help │ ├─────────────────────────────────────────────────┤ │ Actions │ │ d → Describe resource │ │ e → Edit resource │ │ l → View logs │ │ s → Shell into container │ │ y → View YAML │ │ Ctrl-d → Delete resource │ │ f → Port forward │ ├─────────────────────────────────────────────────┤ │ Views │ │ x → Xray view │ │ p → Pulse view │ │ Shift-t → Toggle metrics │ ├─────────────────────────────────────────────────┤ │ Context │ │ :ctx → Switch context │ │ :ns → Switch namespace │ │ Shift-0 → All namespaces │ ├─────────────────────────────────────────────────┤ │ System │ │ Ctrl-a → Show all resources │ │ Ctrl-r → Toggle auto-refresh │ │ Ctrl-c/:q → Quit │ └─────────────────────────────────────────────────┘

Comparison with kubectl

Task	kubectl	k9s
List pods	kubectl get pods	:po
View logs	kubectl logs pod-name	Navigate + l
Describe pod	kubectl describe pod pod-name	Navigate + d
Edit deployment	kubectl edit deploy deploy-name	:deploy + Navigate + e
Delete resource	kubectl delete pod pod-name	Navigate + Ctrl-d
Port forward	kubectl port-forward pod-name 8080:80	Navigate + f
Switch namespace	kubectl config set-context --current --namespace=ns	:ns + select

Conclusion

K9s is an indispensable tool for anyone working with Kubernetes regularly. It combines the power of kubectl with the convenience of a visual interface, all within your terminal. By mastering k9s commands and workflows, you can significantly speed up your Kubernetes management tasks and reduce errors.

The learning curve is minimal - start with basic navigation (:po, :svc, :deploy) and gradually incorporate more advanced features like filtering, xray views, and custom plugins. Before long, you’ll wonder how you ever managed Kubernetes without it.

Resources

• K9s GitHub Repository
• K9s Documentation
• K9s Plugins Repository
• Kubectl Command Reference

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Happy cluster managing! 🚀