Kubectl get JSONPath Support
External
Internal
Overview
kubectl get -o jsonpath='{<jsonpath-expression>}' ...
supports a JSONPath template, which consists in JSONPath expressions enclosed by curly braces.
kubectl get pod some-pod -o jsonpath='{.status.phase}'
More than one JSONPath expressions can be concatenated in a JSON template:
kubectl get pod some-pod -o jsonpath='the pod name {.metadata.name} and phase {.status.phase}'
The JSONPath expression are mainly used to:
- Filter the JSON content to only allow specific fields in the JSON object, using filter expressions.
- Format the output.
The result object is printed as its String() function.
In addition to the original JSONPath syntax, kubectl provides the following extensions:
- The possibility to use double quotes to quote text inside JSONPath expressions.
- The availability of the range and end operators to iterate lists.
Note that when the result of the kubectl query contains more than one item, it is returned as a "List" top-level JSON Object, where individual results are element of an ".items" array:
{
"apiVersion": "v1",
"kind": "List",
"metadata": {
"resourceVersion": "..."
...
}
"items": [
{
"apiVersion": "v1",
"kind": "Namespace",
...
},
...
]
}
The result should be processed as such:
kubectl get pods -o jsonpath="{.items[*]...}"
jsonpath and Queries that Return Arrays
⚠️ If the kubectl query returns an array, as when --selector
is used, ensure the JSONPath expression includes .items[*]
, otherwise the filter will not work correctly.
kubectl get pod --selector=app=someapp -o jsonpath='{.metadata.name}'
will return an empty string, even if there is a pod with a "app=someapp" selector. The correct query is:
kubectl get pod --selector=app=someapp -o jsonpath='{.items[*].metadata.name}'
Syntax
$
As in the generic case, the $ operator is optional, since the expression always starts from the root object by default. However, the leading dot is not optional. More details on $:
Element Selection
Object Fields Selection
Individual Fields
The value of a specified field can be obtained with the child operator:
kubectl get pod <pod-name> -o jsonpath="{.status.phase}"
kubectl get pod <pod-name> -o jsonpath="{['status']['phase']}"
When more than one resource is returned as result, the result is a JSON "List" Object with an .items field, which can be queried as such:
kubectl get pods -o jsonpath="{.items[*].status.phase}"
Field Recursive Descent
All values for a specific field can be obtained recursively with:
kubectl get pod <pod-name> -o jsonpath="{..name}"
More details:
Array Element Selection
Subscript operators:
- JSONPath [0-based-index]
- JSONPath [index1, index2, ...]
- JSONPath [start:end], [start:]
- JSONPath [:n]
- JSONPath [-n:]
Wildcard
Wildcard can be used to iterated over the elements of an Array:
kubectl get nodes -o jsonpath='{.items[*]}'
Iterate over the elements of an Array and display a specific key:
kubectl get pod <pod-name> -o jsonpath=".status.conditions[*].lastTransitionTime"
More details:
@
"@" represents the current object. For more details, see:
[,]
[,] is the union operator that allows combining and displaying side by side multiple fields of the same object:
kubectl get pod <pod-name> -o jsonpath="{.status.conditions[*]['status', 'type']}"
More details:
Filter Expressions
Filter expressions can be applied to Array elements or Object fields. Filter expressions can provide the same results, and are more flexible than the built-in kubectl get field selector.
To apply to Array elements:
[?(expression)]
kubectl get pods -o jsonpath='{.items[?(@.status.phase=="Running")].metadata.name}'
For syntactic details and various particular cases see:
Filter Expressions Examples
kubectl get pods -o jsonpath='{.items[?(@.metadata.labels.name=="web")].metadata.name}'
Filter by an element:
kubectl get nodes -o jsonpath='{.items[*].status.addresses[?(@.type=="InternalIP")]}'
Print the element "address"
kubectl get nodes -o jsonpath='{.items[*].status.addresses[?(@.type=="InternalIP")].address}'
JSONPath Extensions
range and end Operators
JSONPath and Regular Expression Support
JSONPath regular expressions are not supported by kubectl -o jsonpath. If you want to match using regular expressions, use jq:
kubectl get pods -o json | jq -r '.items[] | select(.metadata.name | test("test-")).spec.containers[].image'
Other Examples
Select and Combine Two or More Elements
kubectl get pod \
-o jsonpath='{.items[0].spec.volumes[?(@.name=="A")].hostPath.path}'+'{.items[0].spec.volumes[?(@.name=="B")].hostPath.path}'
returns "/some/path/a+/some/path/b"
Array Length
Selecting a Pod Based on the Value of an Annotation
Assuming the pod returns the following to kubectl get pod -o json
:
{
"apiVersion": "v1",
"items": [
{
"apiVersion": "v1",
"kind": "Pod",
"metadata": {
"annotations": {
"some.random.annotation": "some value",
...
then the following jsonpath selects the pod. Note that all dots in the annotation name must be escaped:
kubectl get pod -o=jsonpath='{.items[?(@.metadata.annotations.some\.random\.annotation=="some value")].metadata.name}'; echo ""