Kubectl Fields Save
Kubernetes resources hierarchy parsing tool
Project README
kubectl-fields
Kubectl resources hierarchy parsing tool
Kubectl-fields is a cli tool to parse kubectl explain --recursive output to match given field and print its parental hierarchy in one-liner format.
Installation
Installing with krew
kubectl krew install fields
Installing with wget
wget https://github.com/rewanthtammana/kubectl-fields/releases/download/v1.2.0-beta/kubectl-fields-Linux-x86_64.tar.gz
sudo tar xvf kubectl-fields-Linux-x86_64.tar.gz -C /usr/bin/
Developer build
Build from Makefile
make build
Build only for Linux
make build-linux
Build with go
go get ./...
go build -o kubectl-fields main.go
mv kubectl-fields /usr/bin
Cross platform builds with go
go get ./...
GOOS=windows GOARCH=amd64 go build -o kubectl-fields.exe main.go
Usage
rewanth@ubuntu:~/go/src/kubectl-fields$ kubectl fields -h
kubectl-fields parses specified kubectl resources to match given pattern(s).
It prints matched fields parental hierarchy in one-liner format.
More info: https://github.com/rewanthtammana/kubectl-fields
Usage:
kubectl-fields [flags]
Examples:
Find resource field hierarchy:
$ kubectl fields svc affinity
spec.sessionAffinity
spec.sessionAffinityConfig
Find resource field hierarchy (case sensitive match):
$ kubectl fields po.spec.volumes -I Ver
downwardAPI.items.fieldRef.apiVersion
projected.sources.downwardAPI.items.fieldRef.apiVersion
Flags:
-I, --case-sensitive Case sensitive pattern match
-h, --help help for kubectl-fields
--no-color Do not print colored output
--stdin Expects input via pipes
Examples
Default match
Case sensitive match
Multi pattern match
Output on windows cmd
Pipeline
This application uses drone CI for building and running all test cases.
All the test cases are associated with kubectl. But as of now we cannot run kubectl inside containers. As a way around, all the kubectl data required for running test cases is pre-saved into text files. All the test cases are executed from pre-saved data against fresh built binary executable to check its robustness.
Why to use
CKA and CKAD are time-constrained exams. The default kubectl explain recursive command consumes lot of time to find the exact hierarchical order. This tool is built to ease the process of finding hierarchial structure for a given parameter.
It is difficult to lookup for exact hierarchical structure using kubectl explain recursive command. This tool solves this particular problem by printing the output in a easy readable one-liner format.
This tool has tremendous advantage over grep for this use case.
Problem statement
For ex, in CKA/CKAD exam you are asked to add SYS_ADMIN capabilities to a given pod. Finding the exact hierarchial order using kubectl explain command is time consuming and tiresome.
Current solution approach
Let's say you know that capabilities exist inside po.spec. You can apply recursive loop directly on po.spec instead of running it globally on po.
You can try to grep for string, "capabilities". The output is as follows:
rewanth@ubuntu:~/go/src/kubectl-fields$ kubectl explain --recursive po.spec | grep capabilities
capabilities <Object>
capabilities <Object>
In case if you need to find "version" attribute in services, then the below command is executed.
$ kubectl explain --recursive svc | grep -i version
VERSION: v1
apiVersion <string>
apiVersion <string>
resourceVersion <string>
apiVersion <string>
apiVersion <string>
resourceVersion <string>
But it doesn't show the hierarchial order of attribute. It just shows the matching lines. You can use advanced grep functions and try to find the parent hierarchy of capabilities attribute.
rewanth@ubuntu:~/go/src/kubectl-fields$ kubectl explain --recursive po.spec | grep capabilities -C 5
resources <Object>
limits <map[string]string>
requests <map[string]string>
securityContext <Object>
allowPrivilegeEscalation <boolean>
capabilities <Object>
add <[]string>
drop <[]string>
privileged <boolean>
procMount <string>
readOnlyRootFilesystem <boolean>
--
resources <Object>
limits <map[string]string>
requests <map[string]string>
securityContext <Object>
allowPrivilegeEscalation <boolean>
capabilities <Object>
add <[]string>
drop <[]string>
privileged <boolean>
procMount <string>
readOnlyRootFilesystem <boolean>
But still it doesn't show the complete parent hierarchy order. The full list need to be printed, scrolled and analyzed to find the exact hierarchical structure.
Not only it will take so much time to scroll up and down to find parent of an element in terminal, the process is very tedious.
kubectl explain --recursive po.spec (click to expand 624 lines output)
rewanth@ubuntu:~/go/src/kubectl-fields$ kubectl explain --recursive po.spec
KIND: Pod
VERSION: v1
RESOURCE: spec <Object>
DESCRIPTION:
Specification of the desired behavior of the pod. More info:
https://git.k8s.io/community/contributors/devel/api-conventions.md#spec-and-status
PodSpec is a description of a pod.
FIELDS:
activeDeadlineSeconds <integer>
affinity <Object>
nodeAffinity <Object>
preferredDuringSchedulingIgnoredDuringExecution <[]Object>
preference <Object>
matchExpressions <[]Object>
key <string>
operator <string>
values <[]string>
matchFields <[]Object>
key <string>
operator <string>
values <[]string>
weight <integer>
requiredDuringSchedulingIgnoredDuringExecution <Object>
nodeSelectorTerms <[]Object>
matchExpressions <[]Object>
key <string>
operator <string>
values <[]string>
matchFields <[]Object>
key <string>
operator <string>
values <[]string>
podAffinity <Object>
preferredDuringSchedulingIgnoredDuringExecution <[]Object>
podAffinityTerm <Object>
labelSelector <Object>
matchExpressions <[]Object>
key <string>
operator <string>
values <[]string>
matchLabels <map[string]string>
namespaces <[]string>
topologyKey <string>
weight <integer>
requiredDuringSchedulingIgnoredDuringExecution <[]Object>
labelSelector <Object>
matchExpressions <[]Object>
key <string>
operator <string>
values <[]string>
matchLabels <map[string]string>
namespaces <[]string>
topologyKey <string>
podAntiAffinity <Object>
preferredDuringSchedulingIgnoredDuringExecution <[]Object>
podAffinityTerm <Object>
labelSelector <Object>
matchExpressions <[]Object>
key <string>
operator <string>
values <[]string>
matchLabels <map[string]string>
namespaces <[]string>
topologyKey <string>
weight <integer>
requiredDuringSchedulingIgnoredDuringExecution <[]Object>
labelSelector <Object>
matchExpressions <[]Object>
key <string>
operator <string>
values <[]string>
matchLabels <map[string]string>
namespaces <[]string>
topologyKey <string>
automountServiceAccountToken <boolean>
containers <[]Object>
args <[]string>
command <[]string>
env <[]Object>
name <string>
value <string>
valueFrom <Object>
configMapKeyRef <Object>
key <string>
name <string>
optional <boolean>
fieldRef <Object>
apiVersion <string>
fieldPath <string>
resourceFieldRef <Object>
containerName <string>
divisor <string>
resource <string>
secretKeyRef <Object>
key <string>
name <string>
optional <boolean>
envFrom <[]Object>
configMapRef <Object>
name <string>
optional <boolean>
prefix <string>
secretRef <Object>
name <string>
optional <boolean>
image <string>
imagePullPolicy <string>
lifecycle <Object>
postStart <Object>
exec <Object>
command <[]string>
httpGet <Object>
host <string>
httpHeaders <[]Object>
name <string>
value <string>
path <string>
port <string>
scheme <string>
tcpSocket <Object>
host <string>
port <string>
preStop <Object>
exec <Object>
command <[]string>
httpGet <Object>
host <string>
httpHeaders <[]Object>
name <string>
value <string>
path <string>
port <string>
scheme <string>
tcpSocket <Object>
host <string>
port <string>
livenessProbe <Object>
exec <Object>
command <[]string>
failureThreshold <integer>
httpGet <Object>
host <string>
httpHeaders <[]Object>
name <string>
value <string>
path <string>
port <string>
scheme <string>
initialDelaySeconds <integer>
periodSeconds <integer>
successThreshold <integer>
tcpSocket <Object>
host <string>
port <string>
timeoutSeconds <integer>
name <string>
ports <[]Object>
containerPort <integer>
hostIP <string>
hostPort <integer>
name <string>
protocol <string>
readinessProbe <Object>
exec <Object>
command <[]string>
failureThreshold <integer>
httpGet <Object>
host <string>
httpHeaders <[]Object>
name <string>
value <string>
path <string>
port <string>
scheme <string>
initialDelaySeconds <integer>
periodSeconds <integer>
successThreshold <integer>
tcpSocket <Object>
host <string>
port <string>
timeoutSeconds <integer>
resources <Object>
limits <map[string]string>
requests <map[string]string>
securityContext <Object>
allowPrivilegeEscalation <boolean>
capabilities <Object>
add <[]string>
drop <[]string>
privileged <boolean>
procMount <string>
readOnlyRootFilesystem <boolean>
runAsGroup <integer>
runAsNonRoot <boolean>
runAsUser <integer>
seLinuxOptions <Object>
level <string>
role <string>
type <string>
user <string>
windowsOptions <Object>
gmsaCredentialSpec <string>
gmsaCredentialSpecName <string>
stdin <boolean>
stdinOnce <boolean>
terminationMessagePath <string>
terminationMessagePolicy <string>
tty <boolean>
volumeDevices <[]Object>
devicePath <string>
name <string>
volumeMounts <[]Object>
mountPath <string>
mountPropagation <string>
name <string>
readOnly <boolean>
subPath <string>
subPathExpr <string>
workingDir <string>
dnsConfig <Object>
nameservers <[]string>
options <[]Object>
name <string>
value <string>
searches <[]string>
dnsPolicy <string>
enableServiceLinks <boolean>
hostAliases <[]Object>
hostnames <[]string>
ip <string>
hostIPC <boolean>
hostNetwork <boolean>
hostPID <boolean>
hostname <string>
imagePullSecrets <[]Object>
name <string>
initContainers <[]Object>
args <[]string>
command <[]string>
env <[]Object>
name <string>
value <string>
valueFrom <Object>
configMapKeyRef <Object>
key <string>
name <string>
optional <boolean>
fieldRef <Object>
apiVersion <string>
fieldPath <string>
resourceFieldRef <Object>
containerName <string>
divisor <string>
resource <string>
secretKeyRef <Object>
key <string>
name <string>
optional <boolean>
envFrom <[]Object>
configMapRef <Object>
name <string>
optional <boolean>
prefix <string>
secretRef <Object>
name <string>
optional <boolean>
image <string>
imagePullPolicy <string>
lifecycle <Object>
postStart <Object>
exec <Object>
command <[]string>
httpGet <Object>
host <string>
httpHeaders <[]Object>
name <string>
value <string>
path <string>
port <string>
scheme <string>
tcpSocket <Object>
host <string>
port <string>
preStop <Object>
exec <Object>
command <[]string>
httpGet <Object>
host <string>
httpHeaders <[]Object>
name <string>
value <string>
path <string>
port <string>
scheme <string>
tcpSocket <Object>
host <string>
port <string>
livenessProbe <Object>
exec <Object>
command <[]string>
failureThreshold <integer>
httpGet <Object>
host <string>
httpHeaders <[]Object>
name <string>
value <string>
path <string>
port <string>
scheme <string>
initialDelaySeconds <integer>
periodSeconds <integer>
successThreshold <integer>
tcpSocket <Object>
host <string>
port <string>
timeoutSeconds <integer>
name <string>
ports <[]Object>
containerPort <integer>
hostIP <string>
hostPort <integer>
name <string>
protocol <string>
readinessProbe <Object>
exec <Object>
command <[]string>
failureThreshold <integer>
httpGet <Object>
host <string>
httpHeaders <[]Object>
name <string>
value <string>
path <string>
port <string>
scheme <string>
initialDelaySeconds <integer>
periodSeconds <integer>
successThreshold <integer>
tcpSocket <Object>
host <string>
port <string>
timeoutSeconds <integer>
resources <Object>
limits <map[string]string>
requests <map[string]string>
securityContext <Object>
allowPrivilegeEscalation <boolean>
capabilities <Object>
add <[]string>
drop <[]string>
privileged <boolean>
procMount <string>
readOnlyRootFilesystem <boolean>
runAsGroup <integer>
runAsNonRoot <boolean>
runAsUser <integer>
seLinuxOptions <Object>
level <string>
role <string>
type <string>
user <string>
windowsOptions <Object>
gmsaCredentialSpec <string>
gmsaCredentialSpecName <string>
stdin <boolean>
stdinOnce <boolean>
terminationMessagePath <string>
terminationMessagePolicy <string>
tty <boolean>
volumeDevices <[]Object>
devicePath <string>
name <string>
volumeMounts <[]Object>
mountPath <string>
mountPropagation <string>
name <string>
readOnly <boolean>
subPath <string>
subPathExpr <string>
workingDir <string>
nodeName <string>
nodeSelector <map[string]string>
preemptionPolicy <string>
priority <integer>
priorityClassName <string>
readinessGates <[]Object>
conditionType <string>
restartPolicy <string>
runtimeClassName <string>
schedulerName <string>
securityContext <Object>
fsGroup <integer>
runAsGroup <integer>
runAsNonRoot <boolean>
runAsUser <integer>
seLinuxOptions <Object>
level <string>
role <string>
type <string>
user <string>
supplementalGroups <[]integer>
sysctls <[]Object>
name <string>
value <string>
windowsOptions <Object>
gmsaCredentialSpec <string>
gmsaCredentialSpecName <string>
serviceAccount <string>
serviceAccountName <string>
shareProcessNamespace <boolean>
subdomain <string>
terminationGracePeriodSeconds <integer>
tolerations <[]Object>
effect <string>
key <string>
operator <string>
tolerationSeconds <integer>
value <string>
volumes <[]Object>
awsElasticBlockStore <Object>
fsType <string>
partition <integer>
readOnly <boolean>
volumeID <string>
azureDisk <Object>
cachingMode <string>
diskName <string>
diskURI <string>
fsType <string>
kind <string>
readOnly <boolean>
azureFile <Object>
readOnly <boolean>
secretName <string>
shareName <string>
cephfs <Object>
monitors <[]string>
path <string>
readOnly <boolean>
secretFile <string>
secretRef <Object>
name <string>
user <string>
cinder <Object>
fsType <string>
readOnly <boolean>
secretRef <Object>
name <string>
volumeID <string>
configMap <Object>
defaultMode <integer>
items <[]Object>
key <string>
mode <integer>
path <string>
name <string>
optional <boolean>
csi <Object>
driver <string>
fsType <string>
nodePublishSecretRef <Object>
name <string>
readOnly <boolean>
volumeAttributes <map[string]string>
downwardAPI <Object>
defaultMode <integer>
items <[]Object>
fieldRef <Object>
apiVersion <string>
fieldPath <string>
mode <integer>
path <string>
resourceFieldRef <Object>
containerName <string>
divisor <string>
resource <string>
emptyDir <Object>
medium <string>
sizeLimit <string>
fc <Object>
fsType <string>
lun <integer>
readOnly <boolean>
targetWWNs <[]string>
wwids <[]string>
flexVolume <Object>
driver <string>
fsType <string>
options <map[string]string>
readOnly <boolean>
secretRef <Object>
name <string>
flocker <Object>
datasetName <string>
datasetUUID <string>
gcePersistentDisk <Object>
fsType <string>
partition <integer>
pdName <string>
readOnly <boolean>
gitRepo <Object>
directory <string>
repository <string>
revision <string>
glusterfs <Object>
endpoints <string>
path <string>
readOnly <boolean>
hostPath <Object>
path <string>
type <string>
iscsi <Object>
chapAuthDiscovery <boolean>
chapAuthSession <boolean>
fsType <string>
initiatorName <string>
iqn <string>
iscsiInterface <string>
lun <integer>
portals <[]string>
readOnly <boolean>
secretRef <Object>
name <string>
targetPortal <string>
name <string>
nfs <Object>
path <string>
readOnly <boolean>
server <string>
persistentVolumeClaim <Object>
claimName <string>
readOnly <boolean>
photonPersistentDisk <Object>
fsType <string>
pdID <string>
portworxVolume <Object>
fsType <string>
readOnly <boolean>
volumeID <string>
projected <Object>
defaultMode <integer>
sources <[]Object>
configMap <Object>
items <[]Object>
key <string>
mode <integer>
path <string>
name <string>
optional <boolean>
downwardAPI <Object>
items <[]Object>
fieldRef <Object>
apiVersion <string>
fieldPath <string>
mode <integer>
path <string>
resourceFieldRef <Object>
containerName <string>
divisor <string>
resource <string>
secret <Object>
items <[]Object>
key <string>
mode <integer>
path <string>
name <string>
optional <boolean>
serviceAccountToken <Object>
audience <string>
expirationSeconds <integer>
path <string>
quobyte <Object>
group <string>
readOnly <boolean>
registry <string>
tenant <string>
user <string>
volume <string>
rbd <Object>
fsType <string>
image <string>
keyring <string>
monitors <[]string>
pool <string>
readOnly <boolean>
secretRef <Object>
name <string>
user <string>
scaleIO <Object>
fsType <string>
gateway <string>
protectionDomain <string>
readOnly <boolean>
secretRef <Object>
name <string>
sslEnabled <boolean>
storageMode <string>
storagePool <string>
system <string>
volumeName <string>
secret <Object>
defaultMode <integer>
items <[]Object>
key <string>
mode <integer>
path <string>
optional <boolean>
secretName <string>
storageos <Object>
fsType <string>
readOnly <boolean>
secretRef <Object>
name <string>
volumeName <string>
volumeNamespace <string>
vsphereVolume <Object>
fsType <string>
storagePolicyID <string>
storagePolicyName <string>
volumePath <string>
Proposed solution approach
kubectl-fields is the solution. This tool fixes the problem by parsing the kubectl explain --recursive output and returns a one-liner hierarchial structure instead of tree type hierarchy. This makes it easier for developers/users to analyze the resources hierarchy.
To find capabilities order in po.spec resources, the following command can be executed.
rewanth@ubuntu:~/go/src/kubectl-fields$ kubectl fields po.spec capabilities
containers.securityContext.capabilities
initContainers.securityContext.capabilities
Similarly to find "version" attribute structure in services resource, the below command can be executed.
rewanth@ubuntu:~/go/src/kubectl-fields$ kubectl fields svc -i version
apiVersion
metadata.initializers.result.apiVersion
metadata.initializers.result.metadata.resourceVersion
metadata.managedFields.apiVersion
metadata.ownerReferences.apiVersion
metadata.resourceVersion
Author
Todo
- Document the basic usage for README
- Build pipeline to run testcases
- Release the tool as krew package
- Write documentation according to godoc standards
- Release the tool as golang package
- Release the tool as a debian package
Contribution and support
Ways to contribute
- Suggest a feature
- Report a bug
- Fix something and open a pull request
- Fix documentation
- Spread the word
- Like this tool? Star and fork
Open Source Agenda is not affiliated with "Kubectl Fields" Project. README Source: rewanthtammana/kubectl-fields
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