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>