kubectl & jq tips & tricks

pod

• wait for specific pod to be ready using labels - good for scripting
  $ kubectl wait --for=condition-ready pod -l foo-bar

• list pod status
  $ kubectl -n <namespace> get pods -ojson | jq '.items[].status'

• list pods that are not ready
  $ kubectl -n <namespace> get pods -ojson | jq '.items[].status.containerStatuses | select(.[].ready == false) | .metadata.name'

• List pods and the nodes that they run on
  $ kubectl get pod -o=custom-colums=NODE:.spec.nodeName,NAME:.metadata.name

• List pods sorted by memory usage
  $ kubectl top pods --all-namespaces --sort-by="memory"

• List pods that have specific label value
  $ kubectl get pods -l 'label in (foo,bar)'

• number of pods running in specific namespace
  $ kubectl -n <namespace> get pods -ojson | jq '. | length'

• pod logs from last restart
  $ kubectl logs <name> --previous

• pod logs from pods with specific label
  $ kubectl logs -l foo=bar

• copy a file from pod to local (can work visa versa)
  $ kubectl cp <namespace>/<pod name>:<file path> <local file path>

• delete pod NOW
  $ kubectl delete pod <name> --now

service

secrets

• copy a secret from one namespace to another
  $ kubectl get secrets -o json --namespace | \ jq '.items[].metadata.namespace = ""' | \ kubectl create-f -

deployment

• create the default yaml to customize for your deployment
  $ kubectl run test -- image=grafana/grafana --dry-run -o yaml

patching

• edit a resource and get the patch
  $ kubectl edit <resource>/<name> --output-pathch

• Apply the patch
  $ kubectl patch --patch=<output file from previous>

port-fowrard

• forward a port from a service to a local port
  $ kubectl port-foward svc/<name> <local-port>:<remote-port>

environment vars

• list env vars for a resource
  $ kubectl set env <resource>/<name> --list

selector

• Get all resources that match a selector
  $ kubectl get deployment,replicasets,pods,services --selector=foo=bar

events

• list events sorted by lastTimestamp
  $ kubectl get events --sort-by=".lastTimestamp"

• watch warnings across all namespaces
  $ kubeclt get events -w --field-selector=type=Warning --all-namespaces

• add event column to the list of watched pods
  $ kubectl get pods -w --output-watch-events

autoscale

• load-based horizontal pod autoscaling
  $ kubectl autoscale deployment <deployment name> --min=3 --max=12

annotation

• add annotation
  $ kubectl annotate <resource>/<name> foo=bar
• remove annotation
  $ kubectl annotate <resource>/<name> foo-
• list annotations
  $ kubectl get <resource>/<name> -o jsonpath='{.metadata.annotations}'
  OR
  $ kubectl get <resource>/<name> -o=json | jq -r '.metadata.annotations'

job & cronjob

• Create a new job from a cronjob
  $ kubectl create job --from=cronjob/<name of cronjob> <name of this job>