Awesome
kubectl-neat
Remove clutter from Kubernetes manifests to make them more readable.
Demo
Here is a result of a kubectl get pod -o yaml
for a simple Pod. The lines marked in red are considered redundant and will be removed from the output by kubectl-neat.
Why
When you create a Kubernetes resource, let's say a Pod, Kubernetes adds a whole bunch of internal system information to the yaml or json that you originally authored. This includes:
- Metadata such as creation timestamp, or some internal IDs
- Fill in for missing attributes with default values
- Additional system attributes created by admission controllers, such as service account token
- Status information
If you try to kubectl get
resources you have created, they will no longer look like what you originally authored, and will be unreadably verbose.
kubectl-neat
cleans up that redundant information for you.
Installation
kubectl krew install neat
or just download the binary if you prefer.
When used as a kubectl plugin the command is kubectl neat
, and when used as a standalone executable it's kubectl-neat
.
Usage
There are two modes of operation that specify where to get the input document from: a local file or from Kubernetes.
Local - file or Stdin
This is the default mode if you run just kubectl neat
. This command accepts an optional flag -f/--file
which specifies the file to neat. It can be a path to a local file, or -
to read the file from stdin. If omitted, it will default to -
. The file must be a yaml or json file and a valid Kubernetes resource.
There's another optional optional flag, -o/--output
which specifies the format for the output. If omitted it will default to the same format of the input (auto-detected).
Examples:
kubectl get pod mypod -o yaml | kubectl neat
kubectl get pod mypod -oyaml | kubectl neat -o json
kubectl neat -f - <./my-pod.json
kubectl neat -f ./my-pod.json
kubectl neat -f ./my-pod.json --output yaml
Kubernetes - kubectl get wrapper
This mode is invoked by calling the get
subcommand, i.e kubectl neat get ...
. It is a convenience to run kubectl get
and then kubectl neat
the output in a single command. It accepts any argument that kubectl get
accepts and passes those arguments as is to kubectl get
. Since it executes kubectl
, it need to be able to find it in the path.
Examples:
kubectl neat get -- pod mypod -oyaml
kubectl neat get -- svc -n default myservice --output json
How it works
Besides general tidying for status, metadata, and empty fields, kubectl-neat primarily looks for two types of things: default values inserted by Kubernetes' object model, and common mutating controllers.
Kubernetes object model defaults
For de-defaulting Kubernetes' object model, we invoke the same code that Kubernetes would have, and see what default values were assigned. If these observed values look like the ones we have in the incoming spec, we conclude they are default. If they weren't, and the user manually set a field to it's default value, it's not a bad thing to remove it anyway.
Common mutating controllers
Here are the recommended admission controllers, and their relation to kubectl-neat:
controller | description | neat |
---|---|---|
NamespaceLifecycle | rejects operations on resources in namespaces being deleted | ignore |
LimitRanger | set default values for resource requests and limits | ignore |
ServiceAccount | set default service account and assign token | Remove default-token-* volumes. Remove deprecated spec.serviceAccount |
TaintNodesByCondition | automatically taint a node based on node conditions | TODO |
Priority | validate priority class and add it's value | ignore |
DefaultTolerationSeconds | configure pods to temporarily tolarate notready and unreachable taints | TODO |
DefaultStorageClass | validate and set default storage class for new pvc | ignore |
StorageObjectInUseProtection | prevent deletion of pvc/pv in use by adding a finalizer | ignore |
PersistentVolumeClaimResize | enforce pvc resizing only for enabled storage classes | ignore |
MutatingAdmissionWebhook | implement the mutating webhook feature | ignore |
ValidatingAdmissionWebhook | implement the validating webhook feature | ignore |
RuntimeClass | add pod overhead according to runtime class | TODO |
ResourceQuota | implement the resource qouta feature | ignore |
Kubernetes Scheduler | assign pods to nodes | Remove spec.nodeName |