K9s – CLI Management Advanced Usage
Introduction
K9s for advanced usage, exploring, technical examples for experienced Kubernetes users.
provide by target-ops
Install K9s using Homebrew:
Alternatively, download the latest binary from the K9s releases page and add it to your PATH.
1. Custom Resource Views
K9s allows you to create custom views for specific Kubernetes resources.
Create a $HOME/.k9s/views.yml file:
views:
v1/pods:
columns:
– NAME
– READY
– STATUS
– RESTARTS
– CPU
– MEM
– AGE
– NODE
This configuration customizes the pod view to include CPU and memory usage.
2. Plugins
K9s supports plugins for extended functionality. Create a plugin in $HOME/.k9s/plugins.yml:
helm:
shortCut: Ctrl-H
description: Helm Charts
scopes:
– all
command: kubectl
background: false
args:
– get
– helmreleases
– –all-namespaces
This plugin allows quick access to Helm releases across all namespaces.
3. Resource Editing
built-in YAML editor for resources. To edit a resource:
Navigate to the resource
Press e to open the editor
Make changes and save
4. Port Forwarding
Easily set up port forwarding:
Navigate to a pod
Press Shift-F
Enter local and remote ports
CopyLocal Port: 8080
Remote Port: 80
This forwards local port 8080 to the pod’s port 80.
5. Log Streaming and Filtering
Stream logs from multiple pods simultaneously:
Select pods using the space bar
Press l to view logs Apply filters using the / key:
error|warning
This filters logs to show only lines containing “error” or “warning”.
7. CRD Management
Easily manage Custom Resource Definitions (CRDs):
Press :crd to list all CRDs
Navigate to a CRD and press enter to view instances
8. Context and Namespace Switching
Quickly switch between contexts and namespaces:
Press :ctx to list contexts Press :ns to list namespaces
9. Cluster Events Monitoring
Monitor cluster-wide events:
Press :events or ctrl-e
View real-time cluster events
Filter events: /NodeNotReady|FailedMount
10. Resource Utilization
View resource utilization across the cluster:
Press :pulses or ctrl-u
Monitor CPU, memory, and storage usage
11. YAML Diff
Compare resource YAML definitions:
Navigate to a resource
Press d to view YAML diff
Use j and k to navigate changes
This is useful for tracking changes over time or across environments.
Advanced Example: Automated Deployment Analysis
Let’s create a K9s plugin that analyzes deployments and reports potential issues.
Create a script analyze_deployments.sh:
kubectl get deployments -A -o json | jq -r ‘
.items[] |
select(.spec.replicas != .status.availableReplicas) |
“(.metadata.namespace),(.metadata.name),(.spec.replicas),(.status.availableReplicas)”
‘ | column -t -s, -N “Namespace,Deployment,Desired,Available”
Add the plugin to $HOME/.k9s/plugins.yml:
analyze-deployments:
shortCut: Ctrl-A
description: Analyze Deployments
scopes:
– deployments
command: /path/to/analyze_deployments.sh
background: false
In K9s, press Ctrl-A to run the analysis
This plugin quickly identifies deployments where the desired state doesn’t match the current state, helping troubleshoot scaling or health issues. Conclusion.
K9s offers a wealth of advanced features for managing Kubernetes clusters on macOS. By leveraging custom views, plugins, and built-in tools, you can significantly enhance your Kubernetes workflow. Experiment with these advanced techniques to streamline your cluster management and gain deeper insights into your Kubernetes environments.
