Kubernetes custom-columns select element from array
TLDR
for an element that is list use *
in square bracket.
So your query should look like this:
$ kubectl get service -n kube-system -o=custom-columns=NAME:.metadata.name,IP:.spec.clusterIP,PORT:.spec.ports[*].targetPort
NAME IP PORT
kube-dns 10.0.0.10 53,53
kubernetes-dashboard 10.0.0.250 9090
Notice the *
in PORT:.spec.ports[*].targetPort
.
Details:
So kubernetes is expecting a json-path-expr
after header
. The error I got when playing with expressions was following:
expected <header>:<json-path-expr>
So to iterate over all elements in a list instead of putting an index just use *
.
Various other json-path expressions can be found here.
You can use * for understanding which data in the json. For example:
kubectl get svc gdpr -o custom-columns=svc:*
As for me kubectl get svc -o custom-columns=svc:.metadata.name,IP:.metadata.annotations.domainName,PORT:.spec.ports[*].targetPort
was perfect (due external IP info) and looks like:
event site1.com 9000
gdpr site2.com 3333,8080
svcInt none 80
ui site6.com 80,6123,6124,6125,8081
p.s. About list external IP and hosts:
kubectl get nodes -o jsonpath='{range .items[*]}{.metadata.name} {.status.addresses[?(@.type=="ExternalIP")].address}{"\n"}'
ip-10-10-40-13.xxxxx.internal xx.xx.xx.175
ip-10-10-40-15.xxxxx.internal xx.xx.xx.236
ip-10-10-40-18.xxxxx.internal xx.xx.xx.207
kubectl get nodes -o jsonpath='{range .items[*]}{.status.addresses[?(@.type=="ExternalIP")].address}{"\n"}'
xx.xx.xx.175
xx.xx.xx.236
xx.xx.xx.207