Add springboot example demo
This commit is contained in:
Jingfang Liu
parent
26ddd1a3e5
commit
c1dfb506e6
|
|
@ -8,3 +8,6 @@ These demos are covered by presubmit tests.
|
|||
|
||||
* [mysql](mySql.md) - Create a mySql production
|
||||
configuration from scratch.
|
||||
|
||||
* [springboot](springboot.md) - Create a Spring Boot application production
|
||||
configuration from scratch.
|
||||
|
|
|
|||
|
|
@ -0,0 +1,350 @@
|
|||
# Demo: SpringBoot
|
||||
|
||||
In this tutorial, you will learn - how to use `kinflate` to customize a basic Spring Boot application's
|
||||
k8s configuration for production use cases.
|
||||
|
||||
In the production environment we want to customize the following:
|
||||
|
||||
- add application specific configuration for this Spring Boot application
|
||||
- configure prod DB access configuration
|
||||
- resource names to be prefixed by 'prod-'.
|
||||
- resources to have 'env: prod' labels.
|
||||
- JVM memory to be properly set.
|
||||
- health check and readiness check.
|
||||
|
||||
### Download resources
|
||||
|
||||
Download `deployment.yaml`, `service.yaml`. These are plain k8s resources files one
|
||||
could add to a k8s cluster to run sbdemo.
|
||||
|
||||
<!-- @makeSpringBootDir @test -->
|
||||
```
|
||||
DEMO_HOME=$(mktemp -d)
|
||||
cd $DEMO_HOME
|
||||
|
||||
# Get SpringBoot configs
|
||||
for f in service deployment; do \
|
||||
wget https://raw.githubusercontent.com/kinflate/example-springboot/master/$f.yaml ; \
|
||||
done
|
||||
```
|
||||
|
||||
### Initialize a manifest
|
||||
|
||||
A _manifest_ groups these resources together.
|
||||
|
||||
Create one:
|
||||
|
||||
<!-- @initApp @test -->
|
||||
```
|
||||
cd $DEMO_HOME
|
||||
kinflate init
|
||||
```
|
||||
|
||||
The above step will create a `kinflate` configuration file called `Kube-manifest.yaml` in current directory.
|
||||
|
||||
<!-- @catMan @test -->
|
||||
```
|
||||
cat $DEMO_HOME/Kube-manifest.yaml
|
||||
```
|
||||
|
||||
containing something like:
|
||||
|
||||
|
||||
> ```
|
||||
> apiVersion: manifest.k8s.io/v1alpha1
|
||||
> kind: Manifest
|
||||
> metadata:
|
||||
> name: helloworld
|
||||
> # description: helloworld does useful stuff.
|
||||
> namePrefix: some-prefix
|
||||
> # Labels to add to all objects and selectors.
|
||||
> # These labels would also be used to form the selector for apply --prune
|
||||
> # Named differently than “labels” to avoid confusion with metadata for this object
|
||||
> objectLabels:
|
||||
> app: helloworld
|
||||
> objectAnnotations:
|
||||
> note: This is a example annotation
|
||||
> resources:
|
||||
> - deployment.yaml
|
||||
> - service.yaml
|
||||
> # There could also be configmaps in Base, which would make these overlays
|
||||
> configMapGenerator: []
|
||||
> # There could be secrets in Base, if just using a fork/rebase workflow
|
||||
> secretGenerator: []
|
||||
> ```
|
||||
|
||||
|
||||
### Add the resources to the manifest
|
||||
|
||||
<!-- @addResources @test -->
|
||||
```
|
||||
cd $DEMO_HOME
|
||||
|
||||
kinflate edit add resource service.yaml
|
||||
kinflate edit add resource deployment.yaml
|
||||
|
||||
cat Kube-manifest.yaml
|
||||
```
|
||||
|
||||
`Kube-manifest.yaml`'s resources section should contain:
|
||||
|
||||
> ```
|
||||
> apiVersion: manifest.k8s.io/v1alpha1
|
||||
> ....
|
||||
> resources:
|
||||
> - service.yaml
|
||||
> - deployment.yaml
|
||||
> ```
|
||||
|
||||
### Add configmap to the manifest
|
||||
<!-- @addConfigMap @test -->
|
||||
```
|
||||
cd $DEMO_HOME
|
||||
wget https://raw.githubusercontent.com/kinflate/example-springboot/master/application.properties
|
||||
kinflate edit add configmap demo-configmap --from-file application.properties
|
||||
|
||||
cat Kube-manifest.yaml
|
||||
```
|
||||
`Kube-manifest.yaml`'s configMapGenerator section should contain:
|
||||
> ```
|
||||
> configMapGenerator:
|
||||
> - files:
|
||||
> - application.properties
|
||||
> name: demo-configmap
|
||||
> kind: Manifest
|
||||
> ```
|
||||
|
||||
### Customize configmap
|
||||
We want to add database credentials for the prod environment. In general, these credentials can be put into the file `application.properties`.
|
||||
However, for some cases, we want to keep the credentials in a different file and keep application specific configs in `application.properties`.
|
||||
With this clear separation, the credentials and application specific things can be managed and maintained flexibly by different teams.
|
||||
For example, application developers only tune the application configs in `application.properties` and operation teams or SREs
|
||||
only care about the credentials.
|
||||
|
||||
For Spring Boot application, we can set an active profile through the environment variable `spring.profiles.active`. Then
|
||||
the application will pick up an extra `application-<profile>.properties` file. With this, we can customize the configmap in two
|
||||
steps. Add an environment variable through the patch and add a file to the configmap.
|
||||
<!-- @customizeConfigMap @test -->
|
||||
```
|
||||
cat <<EOF >$DEMO_HOME/patch.yaml
|
||||
apiVersion: apps/v1beta2
|
||||
kind: Deployment
|
||||
metadata:
|
||||
name: sbdemo
|
||||
spec:
|
||||
template:
|
||||
spec:
|
||||
containers:
|
||||
- name: sbdemo
|
||||
env:
|
||||
- name: spring.profiles.active
|
||||
value: prod
|
||||
EOF
|
||||
|
||||
cat <<EOF >>$DEMO_HOME/Kube-manifest.yaml
|
||||
patches:
|
||||
- patch.yaml
|
||||
EOF
|
||||
|
||||
cat <<EOF >$DEMO_HOME/application-prod.properties
|
||||
spring.jpa.hibernate.ddl-auto=update
|
||||
spring.datasource.url=jdbc:mysql://<prod_database_host>:3306/db_example
|
||||
spring.datasource.username=root
|
||||
spring.datasource.password=admin
|
||||
EOF
|
||||
|
||||
kinflate edit add configmap demo-configmap --from-file application-prod.properties
|
||||
|
||||
cat Kube-manifest.yaml
|
||||
```
|
||||
`Kube-manifest.yaml`'s configMapGenerator section should contain:
|
||||
> ```
|
||||
> configMapGenerator:
|
||||
> - files:
|
||||
> - application.properties
|
||||
> - application-prod.properties
|
||||
> name: demo-configmap
|
||||
> kind: Manifest
|
||||
> ```
|
||||
|
||||
### Name Customization
|
||||
|
||||
Arrange for the resources to begin with prefix
|
||||
_prod-_ (since they are meant for the _production_
|
||||
environment):
|
||||
|
||||
<!-- @customizeLabel @test -->
|
||||
```
|
||||
cd $DEMO_HOME
|
||||
|
||||
kinflate edit set nameprefix 'prod-'
|
||||
|
||||
cat Kube-manifest.yaml
|
||||
```
|
||||
|
||||
`Kube-manifest.yaml` should have updated value of namePrefix field:
|
||||
|
||||
> ```
|
||||
> apiVersion: manifest.k8s.io/v1alpha1
|
||||
> ....
|
||||
> namePrefix: prod-
|
||||
> objectAnnotations:
|
||||
> note: This is a example annotation
|
||||
> ```
|
||||
|
||||
This `namePrefix` directive adds _prod-_ to all
|
||||
resource names.
|
||||
|
||||
<!-- @genNamePrefixConfig @test -->
|
||||
```
|
||||
kinflate build $DEMO_HOME
|
||||
```
|
||||
|
||||
The output should contain:
|
||||
> ```
|
||||
> apiVersion: v1
|
||||
> data:
|
||||
> ....
|
||||
> kind: ConfigMap
|
||||
> metadata:
|
||||
> ....
|
||||
> name: prod-demo-configmap-7746248cmc
|
||||
> ---
|
||||
> apiVersion: v1
|
||||
> kind: Service
|
||||
> metadata:
|
||||
> ....
|
||||
> name: prod-sbdemo
|
||||
> spec:
|
||||
> ....
|
||||
> ---
|
||||
> apiVersion: apps/v1beta2
|
||||
> kind: Deployment
|
||||
> metadata:
|
||||
> ....
|
||||
> name: prod-sbdemo
|
||||
> spec:
|
||||
> selector:
|
||||
> ....
|
||||
> ```
|
||||
|
||||
### Label Customization
|
||||
|
||||
We want resources in production environment to have
|
||||
certain labels so that we can query them by label
|
||||
selector.
|
||||
|
||||
`kinflate` does not have `edit set label` command to add
|
||||
label, but we can edit `Kube-manifest.yaml` file under
|
||||
`prod` directory and add the production labels under
|
||||
`objectLabels` fields as highlighted below.
|
||||
|
||||
<!-- @customizeLabels @test -->
|
||||
```
|
||||
sed -i 's/app: helloworld/app: prod/' \
|
||||
$DEMO_HOME/Kube-manifest.yaml
|
||||
```
|
||||
|
||||
At this point, running `kinflate build` will
|
||||
generate MySQL configs with name-prefix 'prod-' and
|
||||
labels `env:prod`.
|
||||
|
||||
|
||||
### Download Patch for JVM memory
|
||||
When a Spring Boot application is deployed in a k8s cluster, the JVM is running inside a container. We want to set memory limit for the container and make sure
|
||||
the JVM is aware of that limit. In K8s deployment, we can set the resource limits for containers and inject these limits to
|
||||
some environment variables by downward API. When the container starts to run, it can pick up the environment variables and
|
||||
set JVM options accordingly.
|
||||
|
||||
Download the patch `memorylimit_patch.yaml`. It contains the memory limits setup.
|
||||
<!-- @downloadPatch @test -->
|
||||
```
|
||||
cd $DEMO_HOME
|
||||
wget https://raw.githubusercontent.com/kinflate/example-springboot-instances/master/production/memorylimit_patch.yaml
|
||||
|
||||
cat memorylimit_patch.yaml
|
||||
```
|
||||
The output contains
|
||||
> ```
|
||||
> apiVersion: apps/v1beta2
|
||||
> kind: Deployment
|
||||
> metadata:
|
||||
> name: sbdemo
|
||||
> spec:
|
||||
> template:
|
||||
> spec:
|
||||
> containers:
|
||||
> - name: sbdemo
|
||||
> resources:
|
||||
> limits:
|
||||
> memory: 1250Mi
|
||||
> requests:
|
||||
> memory: 1250Mi
|
||||
> env:
|
||||
> - name: MEM_TOTAL_MB
|
||||
> valueFrom:
|
||||
> resourceFieldRef:
|
||||
> resource: limits.memory
|
||||
> ```
|
||||
|
||||
### Download Patch for health check
|
||||
We also want to add liveness check and readiness check in the production environment. Spring Boot application
|
||||
has end points such as `/actuator/health` for this. We can customize the k8s deployment resource to talk to Spring Boot end point.
|
||||
|
||||
Download the patch `healthcheck_patch.yaml`. It contains the liveness probes and readyness probes.
|
||||
<!-- @downloadPatch @test -->
|
||||
```
|
||||
cd $DEMO_HOME
|
||||
wget https://raw.githubusercontent.com/kinflate/example-springboot-instances/master/production/healthcheck_patch.yaml
|
||||
|
||||
cat healthcheck_patch.yaml
|
||||
```
|
||||
The output contains
|
||||
> ```
|
||||
> apiVersion: apps/v1beta2
|
||||
> kind: Deployment
|
||||
> metadata:
|
||||
> name: sbdemo
|
||||
> spec:
|
||||
> template:
|
||||
> spec:
|
||||
> containers:
|
||||
> - name: sbdemo
|
||||
> livenessProbe:
|
||||
> httpGet:
|
||||
> path: /actuator/health
|
||||
> port: 8080
|
||||
> initialDelaySeconds: 10
|
||||
> periodSeconds: 3
|
||||
> readinessProbe:
|
||||
> initialDelaySeconds: 20
|
||||
> periodSeconds: 10
|
||||
> httpGet:
|
||||
> path: /actuator/info
|
||||
> port: 8080
|
||||
> ```
|
||||
|
||||
### Add patch to Manifest
|
||||
Currently `kinflate` doesn't provide a command to add a file as a patch, but we can edit the file `Kube-manifest.yaml` to
|
||||
include this patch.
|
||||
<!-- @addPatch @test -->
|
||||
```
|
||||
mv $DEMO_HOME/Kube-manifest.yaml $DEMO_HOME/tmp.yaml
|
||||
sed '/patches:$/{N;s/- patch.yaml/- patch.yaml\n- memorylimit_patch.yaml\n- healthcheck_patch.yaml/}' $DEMO_HOME/tmp.yaml >& $DEMO_HOME/Kube-manifest.yaml
|
||||
```
|
||||
`Kube-manifest.yaml` should have patches field:
|
||||
> ```
|
||||
> patches
|
||||
> - patch.yaml
|
||||
> - memorylimit_patch.yaml
|
||||
> - healthcheck_patch.yaml
|
||||
> ```
|
||||
|
||||
The output of the following command can now be applied
|
||||
to the cluster (i.e. piped to `kubectl apply`) to
|
||||
create the production environment.
|
||||
|
||||
<!-- @finalBuild @test -->
|
||||
```
|
||||
kinflate build $DEMO_HOME # | kubectl apply -f -
|
||||
```
|
||||
Loading…
Reference in New Issue