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Better multi-patch demo.

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This commit is contained in:
Jeffrey Regan
2020-04-06 16:16:33 -07:00
parent f08594cc22
commit 86bcb47b7d
2 changed files with 109 additions and 80 deletions
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16
examples/jsonpatch.md
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@@ -1,6 +1,10 @@
# Demo: applying a json patch # JSON Patching
A kustomization file supports customizing resources via [JSON patches](https://tools.ietf.org/html/rfc6902). [JSON patches]: https://tools.ietf.org/html/rfc6902
[JSON patch]: https://tools.ietf.org/html/rfc6902
A kustomization file supports customizing
resources via [JSON patches].
Make a place to work: Make a place to work:
@@ -140,9 +144,8 @@ Confirm they match:
diff $DEMO_HOME/out_actual.yaml $DEMO_HOME/out_expected.yaml diff $DEMO_HOME/out_actual.yaml $DEMO_HOME/out_expected.yaml
``` ```
Let's further edit the same `Ingress` object, If you prefer YAML to JSON, the patch can be expressed
but using a patch written in YAML instead of JSON. in YAML format (neverthless following [JSON patch] rules):
<!-- @writeYamlPatch @testAgainstLatestRelease --> <!-- @writeYamlPatch @testAgainstLatestRelease -->
``` ```
@@ -193,3 +196,6 @@ Try it:
kustomize build $DEMO_HOME | tail -n 8 |\ kustomize build $DEMO_HOME | tail -n 8 |\
diff $DEMO_HOME/out_expected.yaml - diff $DEMO_HOME/out_expected.yaml -
``` ```
To see how to apply one JSON patch to many resources,
see the [multi-patch](../patchMultipleObjects.md) demo.

173
examples/patchMultipleObjects.md
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@@ -1,43 +1,78 @@
[Strategic Merge Patch]: https://github.com/kubernetes/community/blob/master/contributors/devel/sig-api-machinery/strategic-merge-patch.md # Patching multiple resources at once.
[JSON patches]: https://tools.ietf.org/html/rfc6902
[label selector]: https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/#label-selectors kustomize supports patching via either a
[strategic merge patch] (wherein you
partially re-specify the thing you want to
modify, with in-place changes) or a
[JSON patch] (wherein you specify specific
operation/target/value tuples in a particular
syntax).
A kustomize file lets one specify many
patches. Each patch must be associated with
a _target selector_:
[strategic merge patch]: https://github.com/kubernetes/community/blob/master/contributors/devel/sig-api-machinery/strategic-merge-patch.md
[JSON patch]: ../jsonpatch.md
> ```yaml
> patches:
> - path: <relative path to file containing patch>
> target:
> group: <optional group>
> version: <optional version>
> kind: <optional kind>
> name: <optional name>
> namespace: <optional namespace>
> labelSelector: <optional label selector>
> annotationSelector: <optional annotation selector>
> ```
E.g. select resources with _name_ matching `foo*`:
> ```yaml
> target:
> name: foo*
> ```
Select all resources of _kind_ `Deployment`:
> ```yaml
> target:
> kind: Deployment
> ```
[label/annotation selector rules]: https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/#label-selectors
Using multiple fields just makes the target
more specific. The following selects only
Deployments that also have the _label_ `app=hello`
(full [label/annotation selector rules]):
> ```yaml
> target:
> kind: Deployment
> labelSelector: app=hello
> ```
### Demo
The example below shows how to inject a
sidecar container for multiple Deployment
resources.
# Demo: applying a patch to multiple resources Make a place to work:
A kustomization file supports customizing resources via both <!-- @demoHome @testAgainstLatestRelease -->
[Strategic Merge Patch] and [JSON patches]. Now one patch can be
applied to multiple resources.
This can be done by specifying a patch and a target selector as follows:
```
patches:
- path: <PatchFile>
target:
group: <Group>
version: <Version>
kind: <Kind>
name: <Name>
namespace: <Namespace>
labelSelector: <LabelSelector>
annotationSelector: <AnnotationSelector>
```
Both `labelSelector` and `annotationSelector` should follow the convention in [label selector].
Kustomize selects the targets which match all the fields in `target` to apply the patch.
The example below shows how to inject a sidecar container for all deployment resources.
Make a `kustomization` containing a Deployment resource.
<!-- @createDeployment @testAgainstLatestRelease -->
``` ```
DEMO_HOME=$(mktemp -d) DEMO_HOME=$(mktemp -d)
```
cat <<EOF >$DEMO_HOME/kustomization.yaml Make a file describing two Deployments:
resources:
- deployments.yaml
EOF
<!-- @createDeployments @testAgainstLatestRelease -->
```
cat <<EOF >$DEMO_HOME/deployments.yaml cat <<EOF >$DEMO_HOME/deployments.yaml
apiVersion: apps/v1 apiVersion: apps/v1
kind: Deployment kind: Deployment
@@ -72,9 +107,10 @@ spec:
EOF EOF
``` ```
Declare a Strategic Merge Patch file to inject a sidecar container: Declare a [strategic merge patch] file
to inject a sidecar container:
<!-- @addPatch @testAgainstLatestRelease --> <!-- @definePatch @testAgainstLatestRelease -->
``` ```
cat <<EOF >$DEMO_HOME/patch.yaml cat <<EOF >$DEMO_HOME/patch.yaml
apiVersion: apps/v1 apiVersion: apps/v1
@@ -93,11 +129,16 @@ spec:
EOF EOF
``` ```
Apply the patch by adding _patches_ field in kustomization.yaml Finally, define a kustomization file
that specifies both a `patches` and `resources`
entry:
<!-- @applyPatch @testAgainstLatestRelease --> <!-- @createKustomization @testAgainstLatestRelease -->
``` ```
cat <<EOF >>$DEMO_HOME/kustomization.yaml cat <<EOF >$DEMO_HOME/kustomization.yaml
resources:
- deployments.yaml
patches: patches:
- path: patch.yaml - path: patch.yaml
target: target:
@@ -105,18 +146,11 @@ patches:
EOF EOF
``` ```
Running `kustomize build $DEMO_HOME`, in the output confirm that both Deployment resources are patched correctly. The expected result is:
<!-- @confirmPatch @testAgainstLatestRelease --> <!-- @definedExpectedOutput @testAgainstLatestRelease -->
``` ```
test 2 == \ cat <<EOF >$DEMO_HOME/out_expected.yaml
$(kustomize build $DEMO_HOME | grep "image: docker.io/istio/proxyv2" | wc -l); \
echo $?
```
The output is as follows:
```yaml
apiVersion: apps/v1 apiVersion: apps/v1
kind: Deployment kind: Deployment
metadata: metadata:
@@ -157,32 +191,21 @@ spec:
name: istio-proxy name: istio-proxy
- image: busybox - image: busybox
name: busybox name: busybox
EOF
``` ```
## Target selector Run the build:
- Select resources with name matching `name*` <!-- @runIt @testAgainstLatestRelease -->
```yaml ```
target: kustomize build $DEMO_HOME >$DEMO_HOME/out_actual.yaml
name: name* ```
```
- Select all Deployment resources Confirm expectations:
```yaml
target: <!-- @diffShouldExitZero @testAgainstLatestRelease -->
kind: Deployment ```
``` diff $DEMO_HOME/out_actual.yaml $DEMO_HOME/out_expected.yaml
- Select resources matching label `app=hello` ```
```yaml
target: To see how to do this with JSON patches,
labelSelector: app=hello try the [JSON patch] demo.
```
- Select resources matching annotation `app=hello`
```yaml
target:
annotationSelector: app=hello
```
- Select all Deployment resources matching label `app=hello`
```yaml
target:
kind: Deployment
labelSelector: app=hello
```