Getting kubectl to output jsonpath results on separate lines is something that I have to Google every time. 😖
For example, the following command extracts the podIP for every running Pod across all namespaces.
kubectl get pods -A -o jsonpath='{.items[*].status.podIP}'
It returns something like the following:
10.244.0.11 10.244.0.8 10.244.0.14 10.244.0.10 10.244.0.6 10.244.0.12 10.244.0.13 10.244.0.15 10.244.0.7 10.244.0.9 10.244.0.3 10.244.0.2 10.244.0.5 172.18.0.2 172.18.0.2 172.18.0.2 172.18.0.2 172.18.0.2 172.18.0.2 10.244.0.4
That’s not the friendliest output to work with, that’s for sure. 🙅♀️
Adding New Lines
You can use the jsonpath range function to iterate over the list and tack on a new line after each element with {\n}.
kubectl get pods -A -o jsonpath='{range .items[*]}{.status.podIP}{"\n"}{end}'
This outputs:
10.244.0.11
10.244.0.8
10.244.0.14
10.244.0.10
10.244.0.6
10.244.0.12
10.244.0.13
10.244.0.15
10.244.0.7
10.244.0.9
10.244.0.3
10.244.0.2
10.244.0.5
172.18.0.2
172.18.0.2
172.18.0.2
172.18.0.2
172.18.0.2
172.18.0.2
10.244.0.4
Awesome! Now we can work with the output using all sorts of standard UNIX utilities that operate on new line (e.g. sort, xargs, uniq, etc.).
Bonus
You can use other whitespace characters too. So imagine we wanted to print the Pod namespaces/names along with their IPs and separate them by a comma.
$ kubectl get pods -A -o jsonpath='{range .items[*]}{.metadata.namespace}{"/"}{.metadata.name}{","}{.status.podIP}{"\n"}{end}'
default/fah-cpu-7c66fc7948-582sr,10.244.0.11
default/fah-cpu-7c66fc7948-c9xb5,10.244.0.8
default/fah-cpu-7c66fc7948-dlm5z,10.244.0.14
default/fah-cpu-7c66fc7948-g25cb,10.244.0.10
default/fah-cpu-7c66fc7948-g2svf,10.244.0.6
default/fah-cpu-7c66fc7948-hxmfn,10.244.0.12
default/fah-cpu-7c66fc7948-jxkp8,10.244.0.13
default/fah-cpu-7c66fc7948-n7rvt,10.244.0.15
default/fah-cpu-7c66fc7948-txvpg,10.244.0.7
default/fah-cpu-7c66fc7948-vzpbz,10.244.0.9
default/mando-57fff9d5f5-rdxrx,10.244.0.3
kube-system/coredns-66bff467f8-r9g25,10.244.0.2
kube-system/coredns-66bff467f8-xfd5k,10.244.0.5
kube-system/etcd-kind-control-plane,172.18.0.2
kube-system/kindnet-g6jvd,172.18.0.2
kube-system/kube-apiserver-kind-control-plane,172.18.0.2
kube-system/kube-controller-manager-kind-control-plane,172.18.0.2
kube-system/kube-proxy-9t7tt,172.18.0.2
kube-system/kube-scheduler-kind-control-plane,172.18.0.2
local-path-storage/local-path-provisioner-bd4bb6b75-zdv22,10.244.0.4
Outputting in jsonpath can be pretty handy!
Though I’ll still have to look up how to do it everytime. 😌