59 lines
2.4 KiB
Markdown
59 lines
2.4 KiB
Markdown
|
---
|
||
|
|
title: Field Selectors
|
||
|
|
weight: 60
|
||
|
|
---
|
||
|
|
|
||
|
|
_Field selectors_ let you [select Kubernetes resources](/docs/concepts/overview/working-with-objects/kubernetes-objects) based on the value of one or more resource fields. Here are some example field selector queries:
|
||
|
|
|
||
|
|
* `metadata.name=my-service`
|
||
|
|
* `metadata.namespace!=default`
|
||
|
|
* `status.phase=Pending`
|
||
|
|
|
||
|
|
This `kubectl` command selects all Pods for which the value of the [`status.phase`](/docs/concepts/workloads/pods/pod-lifecycle/#pod-phase) field is `Running`:
|
||
|
|
|
||
|
|
```shell
|
||
|
|
$ kubectl get pods --field-selector status.phase=Running
|
||
|
|
```
|
||
|
|
|
||
|
|
{{< note >}}
|
||
|
|
Field selectors are essentially resource *filters*. By default, no selectors/filters are applied, meaning that all resources of the specified type are selected. This makes the following `kubectl` queries equivalent:
|
||
|
|
|
||
|
|
```shell
|
||
|
|
$ kubectl get pods
|
||
|
|
$ kubectl get pods --field-selector ""
|
||
|
|
```
|
||
|
|
{{< /note >}}
|
||
|
|
|
||
|
|
## Supported fields
|
||
|
|
|
||
|
|
Supported field selectors vary by Kubernetes resource type. All resource types support the `metadata.name` and `metadata.namespace` fields. Using unsupported field selectors produces an error. For example:
|
||
|
|
|
||
|
|
```shell
|
||
|
|
$ kubectl get ingress --field-selector foo.bar=baz
|
||
|
|
Error from server (BadRequest): Unable to find "ingresses" that match label selector "", field selector "foo.bar=baz": "foo.bar" is not a known field selector: only "metadata.name", "metadata.namespace"
|
||
|
|
```
|
||
|
|
|
||
|
|
## Supported operators
|
||
|
|
|
||
|
|
You can use the `=`, `==`, and `!=` operators with field selectors (`=` and `==` mean the same thing). This `kubectl` command, for example, selects all Kubernetes Services that aren't in the `default` namespace:
|
||
|
|
|
||
|
|
```shell
|
||
|
|
$ kubectl get services --field-selector metadata.namespace!=default
|
||
|
|
```
|
||
|
|
|
||
|
|
## Chained selectors
|
||
|
|
|
||
|
|
As with [label](/docs/concepts/overview/working-with-objects/labels) and other selectors, field selectors can be chained together as a comma-separated list. This `kubectl` command selects all Pods for which the `status.phase` does not equal `Running` and the `spec.restartPolicy` field equals `Always`:
|
||
|
|
|
||
|
|
```shell
|
||
|
|
$ kubectl get pods --field-selector=status.phase!=Running,spec.restartPolicy=Always
|
||
|
|
```
|
||
|
|
|
||
|
|
## Multiple resource types
|
||
|
|
|
||
|
|
You use field selectors across multiple resource types. This `kubectl` command selects all Statefulsets and Services that are not in the `default` namespace:
|
||
|
|
|
||
|
|
```shell
|
||
|
|
$ kubectl get statefulsets,services --field-selector metadata.namespace!=default
|
||
|
|
```
|