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Cheatsheet - k9s

PreFlight Checks

  • K9s uses 256 colors terminal mode. On `Nix system make sure TERM is set accordingly.

    export TERM=xterm-256color

  • In order to issue resource edit commands make sure your EDITOR and KUBE_EDITOR env vars are set.

    # Kubectl edit command will use this env var.
export KUBE_EDITOR=my_fav_editor

  • K9s prefers recent kubernetes versions ie 1.28+

K8S Compatibility Matrix

k9s k8s client
>= v0.27.0 1.26.1
v0.26.7 - v0.26.6 1.25.3
v0.26.5 - v0.26.4 1.25.1
v0.26.3 - v0.26.1 1.24.3
v0.26.0 - v0.25.19 1.24.2
v0.25.18 - v0.25.3 1.22.3
v0.25.2 - v0.25.0 1.22.0
<= v0.24 1.21.3

Start k9s

# Use default kubeconfig
$ k9s

# Use non-default kubeconfig
$ k9s --kubeconfig /path/to/kubeconfig

# Use non-default context
$ k9s --context fooctx

# Readonly
$ k9s --readonly

## Check info (locations for configuration, logs, screen dumps)
$ k9s info

Using k9s

List Resources

List a specific resource:

:<resource>: list Resources, e.g. :pod to list all pods. :<resource> <namespace>: list Resources in a given namespace. List all available resources / apis:

:aliases or Ctrl-a: list all available aliases and resources. :crd: list all CRDs. :apiservices: list all API Serv

Filter

  • /<filter>: regex filter.
  • /!<filter>: inverse regex filter.
  • /-l <label>: filter by labels.
  • /-f <filter>: fuzzy match.

Choose namespace

Type :namespace, select the desired namespace by up or down key, press Enter to select.

Choose context

  • :ctx: list ctx, then select from the list.
  • :ctx <context>: switch to the specified context.

Show Decrypted Secrets

Type :secrets to list the secrets, then

  • x to decrypt the secret.
  • Esc to leave the decrypted display.

Key mapping

  • move up and down without moving your right hand:
  • j: down.
  • k: up.
  • h: left
  • l: right
  • SPACE: select multiple lines (e.g. then Ctrl-d to delete)
  • y: yaml.
  • d: describe.
  • v: view.
  • e: edit.
  • l: logs.
  • w: wrap.
  • r: auto-refresh.
  • s:
  • Deployment screen: scale the number of replicas.
  • Pod or Containers screen: shell
  • x: decode a Secret.
  • f: fullscreen. Tip: enter fullscreen mode before copying, to avoid | in copied text. cCtrl-d`: delete.
  • Ctrl-k: kill (no confirmation).
  • Ctrl-w: toggle wide columns. (Equivalent to kubectl ... -o wide)
  • Ctrl-z: toggle error state
  • Ctrl-e: hide header.
  • Ctrl-s: save output (e.g. the YAML) to disk.
  • Ctrl-l: rollback.

Sort by Column

  • Shift-c: sorts by CPU.
  • Shift-m: sorts by MEMORY.
  • Shift-s: sorts by STATUS.
  • Shift-p: sorts by namespace.
  • Shift-n: sorts by name.
  • Shift-o: sorts by node.
  • Shift-i: sorts by IP address.
  • Shift-a: sorts by container age.
  • Shift-t: sorts by number of restarts.
  • Shift-r: sorts by pod readiness.

Helm

  • :helm: show helm releases.
  • :helm NAMESPACE: show releases in a specific namespace.

User

There's no "user" object but in k9s you can see all the users by :users. Press Enter to see a list of Policies.

XRay View

  • :xray RESOURCE, e.g. :xray deploy.

Pulse View

  • :pulse: displays general information about the Kubernetes cluster.

Popeye View

  • :popeye or pop: checks all resources for conformity with the correctness criteria and displays the resulting "rating" with explanations. https://popeyecli.io

Show Disk Files

  • :dir /path E.g. :dir /tmp will show your /tmp folder on local disk. One common use case: Ctrl-s to save a yaml, then find it in :dir /tmp/k9s-screens-root, find the file, press e to edit and a to apply.

Quit

  • Esc: Bails out of view/command/filter mode. c:qorCtrl-c`: quit k9s.

Meaning of the Headers

Most of the headers are easy to understand; some of the special ones:

  • %CPU/R: Percentage of requested CPU
  • %CPU/L: Percentage of limited CPU
  • %MEM/R: Percentage of requested memory
  • %MEM/L: Percentage of limited memory
  • CPU/A: allocatable CPU

Pods:

  • pf: PortForward

Containers:

  • PROBES(L:R): Liveness and Readiness probes

FAQ

How to change among clusters?

Add all kubeconfig paths to $KUBECONFIG, then start k9s:

$ export KUBECONFIG=/path/to/kubeconfig1:/path/to/kubeconfig2:~/.kube/config:$KUBECONFIG

$ k9s

Inside k9s, type :ctx, then select the context to change to a different cluster.

How to scale up or scale down a deployment?

Go to the Deployments page, and press s, then enter a number for the desired num of ReplicaSet.

How to force delete a pod?

Ctrl-d, move cursor to Force, press space to select, click OK.

What is the plus (+) next to the namespace?

In k9s, some namespace foo may appear as foo+, the + denotes a favorite namespace, i.e. it will appear on the header with a number to quickly select the namespace, e.g. 0 to select all namespaces.

To add + to the namespace: select namespace in the list, press u (for "Use").

The * indicate the default namespace.

How to monitor resource usage?

Check CPU and MEM usage on the top left corner of the screen;

Check usage in Node and Pod page;

This is equivalent to:

$ kubectl top nodes
$ kubectl top pods

$ kubectl top node <node_name>

Where are the k9s config files?

Note that all YAML files in the .k9s directory must have the .yml extension (.yaml doesn’t work).

  • $HOME/.k9s/views.yml: customize the column view for resource lists.
  • $HOME/.k9s/plugin.yml: manage plugins.
  • $XDG_CONFIG_HOME/k9s/config.yml: k9s config.
  • $XDG_CONFIG_HOME/k9s/alias.yml: define your own alias.
  • $XDG_CONFIG_HOME/k9s/hotkey.yml: define your own hotkeys.
  • $XDG_CONFIG_HOME/k9s/plugin.yml: manage plugins.

How to Check Objects with the Same Name in Different API Groups

e.g. Cluster may be found in different api groups, like cluster.x-k8s.io or clusterregistry.k8s.io or baremetal.cluster.gke.io.

apiVersion: cluster.x-k8s.io/v1alpha3
kind: Cluster

apiVersion: clusterregistry.k8s.io/v1alpha1
kind: Cluster

apiVersion: baremetal.cluster.gke.io/v1
kind: Cluster

Use apiVersion/kind (i.e. Group/Version/kind) instead of just kind to check the API of a specific group.

  • :cluster.x-k8s.io/v1alpha3/clusters
  • :clusterregistry.k8s.io/v1alpha1/clusters
  • :baremetal.cluster.gke.io/v1/clusters Or go to the CRDs page (:crd), move to the correct row, press enter.

How to change log setting

Change ~/.config/k9s/config.yml:

logger:
  tail: 500
  buffer: 5000
  sinceSeconds: -1

How to monitor what's going on:

  • :event (or :ev): see the stream of events.
  • :pod: see the list of pods Shift-a to sort by age.
  • :job: see the list of jobs, ordered by time by default.

What if editing a yaml in k9s is reverted back?

Find the controller that manages the CR, scale it down for deletion.

# Scale down the controllers:
$ kubectl scale --replicas=0 deployment/CONTROLLER_MANAGER_NAME -n NAMESPACE

# Edit the manifest, e.g. changing a field `foo` to true
$ kubectl patch KIND NAME -n NAMESPACE --type=json -p="[{'op': 'replace', 'path': '/spec/foo', 'value': true}]"

# Scale up the controllers:
$ kubectl scale --replicas=1 deployment/CONTROLLER_MANAGER_NAME -n NAMESPACE

Where to find k9s logs?

$ k9s info | grep Logs
Logs:              /root/.local/state/k9s/k9s.log

Benchmark

k9s includes a basic HTTP load generator.

To enable it, you have to configure port forwarding in the pod. Select the pod and press SHIFT + f, go to the port-forward menu (using the pf alias).

After selecting the port and hitting CTRL + b, the benchmark would start. Its results are saved in /tmp for subsequent analysis.

To change the configuration of the benchmark, create the $HOME/.k9s/bench-<my_context>.yml file (unique for each cluster).

Plugins

https://github.com/derailed/k9s/tree/master/plugins

Install

# Go
$ go install github.com/derailed/k9s@latest

# Homebrew / LinuxBrew
$ brew install derailed/k9s/k9s

# MacPort
sudo port install k9s

# Snap
sudo snap install k9s

# PacMan
pacman -S k9s

# Windows: scoop
scoop install k9s

# Windows: chocolatey
choco install k9s

Official Website

https://k9scli.io/