Now that we know how to properly create an application, containarize it and deploy it to Kubernetes it’s time for us to extend it. If we want to iterate over our app the manual way we have to go, execute jib, then kubectl apply again and so on. We are going to introduce a couple of tools to help us with that.
Automatically detects changes, compile your application and deploys it for you. The tool integrates with well jib and the IntelliJ Cloud Code plugin which makes it key for a great developer experience.
In order to use it we need to add a new file called skaffold.yml and move our Deployment and Service YAML files to a folder called k8s.
apiVersion: skaffold/v1beta15
kind: Config
build:
artifacts:
- image: albertoimpl/myapp-jib
jib: {}With that configured we can run it from the command line or through the IDE. You can even debug and add a breakpoint to your code:
Now that we have the ability to iterate over our app, we are going to show how to customize it for different environments: Kustomize lets you customize raw, template-free YAML files for multiple purposes, leaving the original YAML untouched and usable as is.
touch kustomization.yaml
kustomize edit add resource service.yaml
kustomize edit add resource deployment.yamlwill generate:
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
- k8s/deployment.yaml
- k8s/service.yamlYou can have profiles within Skaffold but we found that using Kustomize to represent them was a better approach that we can reuse to generate our real production deployment by using variants and overlays.
A variant is the outcome, in a cluster, of applying an overlay to a base.
For that, we have to change our file structure a bit. We will have our original deployment and service, altogether with a new kustomization.yaml file:
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
- deployment.yaml
- service.yamlThen, we are going to create overlays for development and for production:
resources:
- ../../base
patchesStrategicMerge:
- replicas.yaml
namePrefix: development-We will decrease the number of replicas to 1 in our development environment:
apiVersion: apps/v1
kind: Deployment
metadata:
namespace: default
name: myapp
spec:
replicas: 1And increase it to 5 in our production one:
apiVersion: apps/v1
kind: Deployment
metadata:
namespace: default
name: myapp
spec:
replicas: 5This is the final structure:
~/app-kustomize
├── base
│ ├── deployment.yaml
│ ├── service.yaml
│ └── kustomization.yaml
└── overlays
├── development
│ ├── kustomization.yaml
│ ├── profiles.yaml
│ └── replicas.yaml
└── production
├── kustomization.yaml
├── profiles.yaml
└── replicas.yamlWith overlays we can also provide different configurations depending on the environment.
For us get our development overlay:
kustomize build overlays/developmentAnd for production just:
kustomize build overlays/productionWe can commit and version those files or just apply them as part of the deployment process:
kustomize build overlays/production | kubectl apply -f -The is my typical workflow, but I found a tool recently that looks very interesting to test some cases. It is called Okteto and it helps us with the automatic hot reloads of the project.
By adding spring-boot-devtools to our app:
compile 'org.springframework.boot:spring-boot-devtools' k apply -f k8s/deployment.yaml
deployment.apps/myapp configured curl https://get.okteto.com -sSfL | sh
> Installing /usr/local/bin/okteto
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 143 0 143 0 0 117 0 --:--:-- 0:00:01 --:--:-- 118
100 611 0 611 0 0 349 0 --:--:-- 0:00:01 --:--:-- 349
100 46.9M 100 46.9M 0 0 1079k 0 0:00:44 0:00:44 --:--:-- 1213k
> Okteto successfully installed!okteto init
Recommended image for development with Java: okteto/gradle:latest
Which docker image do you want to use for your development environment? [okteto/gradle:latest]: okteto/gradle:latest
✓ Okteto manifest (okteto.yml) createdNote that this has to be done in a real cluster, KIND is not supported yet.
okteto up
Deployment app-okteto doesn't exist in namespace default. Do you want to create a new one? [y/n]: y
✓ Development environment activated
✓ Files synchronized
Namespace: default
Name: app-okteto
Forward: 8080 -> 8080
8088 -> 8088
root@app-okteto-7468b9849b-rdsl5:/okteto#It creates an environment with our current working directory
root@app-okteto-7468b9849b-rdsl5:/okteto# ls
build.gradle deployment.yaml gradle gradlew gradlew.bat HELP.md okteto.yml service.yaml settings.gradle srck get all
NAME READY STATUS RESTARTS AGE
pod/app-okteto-7468b9849b-rdsl5 1/1 Running 0 2m15s
pod/myapp-5855864f54-6d75k 1/1 Running 0 2m42s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/app-okteto ClusterIP 10.118.5.98 <none> 8080/TCP 2m16s
service/kubernetes ClusterIP 10.118.0.1 <none> 443/TCP 11m
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/app-okteto 1/1 1 1 2m16s
deployment.apps/myapp 1/1 1 1 2m43s
NAME DESIRED CURRENT READY AGE
replicaset.apps/app-okteto-7468b9849b 1 1 1 2m16s
replicaset.apps/myapp-5855864f54 1 1 1 2m43sroot@app-okteto-56b998d9f6-m76p5:/okteto# gradle bootRun
Listening for transport dt_socket at address: 8088
> Task :bootRun
> :compileJava > Resolve dependencies of :compileClasspath > Resolve files of :detachedConfiguration6
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.1.8.RELEASE)
2019-10-29 09:07:47.642 INFO 257 --- [ restartedMain] c.a.d.containers.ContainersApplication : Starting ContainersApplication on app-okteto-56b998d9f6-m76p5 with PID 257 (/okteto/build/classes/java/main started by root in /okteto)
2019-10-29 09:07:47.655 INFO 257 --- [ restartedMain] c.a.d.containers.ContainersApplication : No active profile set, falling back to default profiles: default
2019-10-29 09:07:47.839 INFO 257 --- [ restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : Devtools property defaults active! Set 'spring.devtools.add-properties' to 'false' to disable
2019-10-29 09:07:47.840 INFO 257 --- [ restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : For additional web related logging consider setting the 'logging.level.web' property to 'DEBUG'
2019-10-29 09:07:51.737 INFO 257 --- [ restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2019-10-29 09:07:51.819 INFO 257 --- [ restartedMain] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2019-10-29 09:07:51.829 INFO 257 --- [ restartedMain] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.24]
2019-10-29 09:07:52.052 INFO 257 --- [ restartedMain] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2019-10-29 09:07:52.056 INFO 257 --- [ restartedMain] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 4216 ms
2019-10-29 09:07:53.471 INFO 257 --- [ restartedMain] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'
2019-10-29 09:07:54.142 INFO 257 --- [ restartedMain] o.s.b.d.a.OptionalLiveReloadServer : LiveReload server is running on port 35729
2019-10-29 09:07:54.161 INFO 257 --- [ restartedMain] o.s.b.a.e.web.EndpointLinksResolver : Exposing 2 endpoint(s) beneath base path '/actuator'
2019-10-29 09:07:54.359 INFO 257 --- [ restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2019-10-29 09:07:54.373 INFO 257 --- [ restartedMain] c.a.d.containers.ContainersApplication : Started ContainersApplication in 7.742 seconds (JVM running for 8.586)Note the:
LiveReload server is running on port 35729curl localhost:8080/hello
Hello, world@RequestMapping("/hello")
public String hello() {
return "Hello, live!";
}curl localhost:8080/hello
Hello, live