Apache Camel-K to run integration using kamel cli in Kind cluster

Camel-K

Apache Camel K is a lightweight cloud-integration platform that runs natively on Kubernetes.
In this blog will show how to install Camel-K operator in Kubernetes (KIND) cluster.
Have created a simple integration code (Java integration).
- The integration code expose a REST endpoint using Camel component.
- The message is passed as URL path variable.
- The message is routed to direct endpoint and transform with a constant string.

Pre-requisites

Docker Desktop (Docker daemon running).
Dockerhub account.
Kamel CLI installed.
KIND CLI installed.
Basic understanding on Kubernetes and Operator pattern.

Options to install Camel-K operator

There are different option to install Camel-K. Options are listed below,
- using Helm charts
- using OperatorHub
- using Kamel CLI
In this blog the Camel-K operator is installed with Kamel CLI in KIND cluster.

Note:- During Camel-K installation we need to configure the docker registry (docker.io). In this blog have used Dockerhub, we can use private registry as well.

Install KIND cluster and deploy Nginx Ingress controller

The ingress controller is used to access the REST endpoint from the host machine.
Below is the KIND cluster configuration file which includes patch configuration for ingress controller, save this as kamel-kind-cluster.yaml.

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  kubeadmConfigPatches:
  - |
    kind: InitConfiguration
    nodeRegistration:
      kubeletExtraArgs:
        node-labels: "ingress-ready=true"
  extraPortMappings:
  - containerPort: 80
    hostPort: 80
    protocol: TCP
  - containerPort: 443
    hostPort: 443
    protocol: TCP

We need to use the above configuration in Kind CLI to create the cluster, the command usage is listed below.

kind create cluster --config kamel-kind-cluster.yaml --name kamel-ingress

In order to apply the ingress controller configuration below command. Refer kind documentation for more info.

kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/main/deploy/static/provider/kind/deploy.yaml

Install Camel-K operator in KIND cluster

To install the Camel-K operator with Kamel CLI, we need to configure the docker registry (docker.io). For this first we need to create a secret in the cluster with the Docker credentials.

Note:-
Creating a secret with the $HOME/.docker/config.json file directly didn't work for me. When running the integration, the logs indicated unauthorized access.
Below is the command to create secret from docker config file.
kubectl create secret generic regcred \
 --from-file=.dockerconfigjson=$HOME/.docker/config.json \
 --type=kubernetes.io/dockerconfigjson

Install OLM in the cluster

This is optional step. By installing the OLM (Operator Lifecycle Management) we are not required to use the option --olm=false in Kamel CLI during installation.

To install the OLM, run below command from Gitbash.

curl -sL https://github.com/operator-framework/operator-lifecycle-manager/releases/download/v0.23.1/install.sh | bash -s v0.23.1

To create the secret with the Docker credentials use below commands
- Storing the Dockerhub credentials in the environment variable will help in case we need to automate the installation process.

# from powershell use below command, to accessing environment variable we use $env:<env-key>
kubectl -n default create secret docker-registry external-registry-secret --docker-username $env:DOCKER_USER --docker-password $env:DOCKER_PASS

# from shell (like git bash) use below command
kubectl -n default create secret docker-registry external-registry-secret --docker-username $DOCKER_USER --docker-password $DOCKER_PASS

Below command will install the Camel-K operator in default namespace.

# the secret created above is passed in --registry-secret in this command
kamel install -n default --registry docker.io --organization <organization-name> --registry-secret external-registry-secret --wait

If OLM is not installed in the cluster (as mentioned above), in this case then we need to use --olm=false in the command shown below.

kamel install -n default --olm=false --registry docker.io --organization <organization-name> --registry-secret external-registry-secret --wait

Info:

Camel-K operator installation takes sometime to install. Camel-K operator deploys as a pod, so to check the status of the pod in the default namespace use kubectl get pods.

Running a simple integration

We can use Kamel CLI to run integration code developed in Java, groovy, etc.
The Camel-K operator gets deployed to cluster as a pod, we can simply check the status of the pod and make sure it is in running state before creating an integration.
Below is a simple Java integration code, which uses Camel RouteBuilder and REST component to expose REST endpoint and routes the message.


import org.apache.camel.*;
import org.apache.camel.builder.RouteBuilder;

public class WelcomeRoute extends RouteBuilder {

   @Override
   public void configure() throws Exception {
      restConfiguration().bindingMode("auto");

        rest("/api")
            .get("/demo/{info}")
            .to("log:info")
            .to("direct:msg");
        from("direct:msg")
                .transform().simple("msg received - ${header.info}");
   }
}

During development we can run the integration using --dev option, the command to create and run the integration looks like below.

kamel run WelcomeRoute.java --dev

Using --dev will print the logs in console.
With this flag any changes to the Java file will reflect immediately in the integration real time.
Below is the console log output of successfully deployed integration.

Condition "Ready" is "True" for Integration welcome-route: 1/1 ready replicas
[1] 2023-02-09 02:36:48,267 INFO  [org.apa.cam.k.Runtime] (main) Apache Camel K Runtime 1.16.0
[1] 2023-02-09 02:36:48,325 INFO  [org.apa.cam.qua.cor.CamelBootstrapRecorder] (main) Bootstrap runtime: org.apache.camel.quarkus.main.CamelMainRuntime
[1] 2023-02-09 02:36:48,334 INFO  [org.apa.cam.mai.MainSupport] (main) Apache Camel (Main) 3.19.0 is starting
[1] 2023-02-09 02:36:48,517 INFO  [org.apa.cam.k.lis.SourcesConfigurer] (main) Loading routes from: SourceDefinition{language='java', type='source', location='file:/etc/camel/sources/.\WelcomeRoute.java', }
[1] 2023-02-09 02:36:55,022 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main) Apache Camel 3.19.0 (camel-1) is starting
[1] 2023-02-09 02:36:55,161 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main) Routes startup (started:2)
[1] 2023-02-09 02:36:55,162 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main)     Started route1 (direct://msg)
[1] 2023-02-09 02:36:55,162 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main)     Started route2 (rest://get:/api:/demo/%7Binfo%7D)
[1] 2023-02-09 02:36:55,163 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main) Apache Camel 3.19.0 (camel-1) started in 732ms (build:0ms init:605ms start:127ms)
[1] 2023-02-09 02:36:55,874 INFO  [io.quarkus] (main) camel-k-integration 1.11.1 on JVM (powered by Quarkus 2.14.0.Final) started in 18.400s. Listening on: http://0.0.0.0:8080
[1] 2023-02-09 02:36:55,879 INFO  [io.quarkus] (main) Profile prod activated.
[1] 2023-02-09 02:36:55,889 INFO  [io.quarkus] (main) Installed features: [camel-attachments, camel-bean, camel-core, camel-direct, camel-java-joor-dsl, camel-k-core, camel-k-runtime, camel-kubernetes, camel-log, camel-platform-http, camel-rest, cdi, kubernetes-client, security, smallrye-context-propagation, vertx]

Kamel CLI can be used to check the status of integration, use below command.

kamel get

If the integration is running on a specific namespace we can use kame get -n <namespace-name>.

By default Camel-K creates a ClusterIP service for this integration.

The endpoints exposed can be checked using the command kubectl get endpoint

By default the Camel-K operator creates service as ClusterIP. In case if we want to expose the service as NodePort or LoadBalancer, we can use Service Traits to configure. The command looks like below.
- There are different traits supported by Camel-K, refer the Camel-K traits documentation.

kamel run --trait service.enabled=true --trait service.node-port=true --trait service.type=NodePort -n <namespace> <file.java> --dev

Apply ingress rule to access the endpoint

To access the REST endpoint from the host machine, we use Nginx Ingress control already deployed in cluster.
We need a ingress rule configuration to route traffic to access the service.
The ingress rule configuration manifest content is listed below save this in a file named ingress-rule.yaml.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: kamel-welcome-route
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /$2
spec:
  rules:
  - http:
      paths:
      - pathType: Prefix
        path: /(/|$)(.*)
        backend:
          service:
            name: welcome-route
            port:
              number: 80

To apply the ingress rule use kubectl apply -f ingress-rule.yaml command.
To check the ingress status use kubectl get ingress command.

Access the REST endpoint and output

Once the integration is deployed successfully and in running state, we can use wget to get access the endpoint. Below is the complete command.

wget -q -O - localhost/api/demo/hello

Below is the operator and integration pod running in cluster, have used Lens to connect to the kind cluster.

Passing properties to the integration code

For a simple groovy script, where the my.message is fetched from the properties. Save the below content to a file Message.groovy.

from('timer:props?period=1000')
    .log('{{my.message}}')

To pass the property values, since we are not using --dev, the integration will be created

kamel run --property my.message="Example-From-Property" Message.groovy

Output looks like below

[1] 2023-02-09 03:46:30,116 INFO  [route1] (Camel (camel-1) thread #1 - timer://props) Example-From-Property
[1] 2023-02-09 03:46:31,090 INFO  [route1] (Camel (camel-1) thread #1 - timer://props) Example-From-Property

Delete an integration using Kamel CLI

Kamel CLI command kamel get can be used to list the integration status.
To delete the integration, we need to use below command

kamel delete <name-of-integration>

Additional information

We can use ConfigMap with the configuration or properties file and pass it in runtime using Kamel CLI to the integration code. Refer the Camel-K runtime configuration documentation
Promoting the integration to different environment, we can do it as well refer the Camel-K promoting documentation

Run Integration in Apache Camel-K

Table of contents

Camel-K

Pre-requisites

Options to install Camel-K operator

Install KIND cluster and deploy Nginx Ingress controller

Install Camel-K operator in KIND cluster

Install OLM in the cluster

Running a simple integration

Apply ingress rule to access the endpoint

Access the REST endpoint and output

Passing properties to the integration code

Delete an integration using Kamel CLI

Additional information