Camel K plugin (deprecated)
This plugin is deprecated, and expected to be removed in the upcoming releases. |
Please make sure to meet these prerequisites for running Camel integrations on Kubernetes:
-
Connect to namespace on a Kubernetes cluster where you want to run the integration
-
Camel K operator must be installed on the Kubernetes cluster (either installed on the same namespace or as global operator for the whole cluster)
To set up a local Kubernetes cluster, you have several options. Camel K JBang is able to interact with all of these Kubernetes platforms.
-
Kind
-
Minikube
Of course, you may also connect to a remote Kubernetes cluster.
Running Camel routes on Kubernetes is quite simple with Camel JBang. In fact, you can develop and test your Camel route locally with Camel JBang and then promote the same source to running it as an integration on Kubernetes.
The Camel K JBang functionality is provided as a command plugin. This means you need to enable the camel-k
plugin first to use the subcommands in Camel JBang.
camel plugin add camel-k
You should see the camel-k
plugin listed as an installed plugin.
camel plugin get
NAME COMMAND DEPENDENCY DESCRIPTION
camel-k k org.apache.camel:camel-jbang-plugin-k Manage Camel integrations on Kubernetes
Now Camel JBang is able to run the subcommands offered by the plugin.
Run integrations
Simply run the integration using the k
subcommand in Camel JBang.
camel k run route.yaml
The command runs the Camel integration on Kubernetes. More precisely, it creates a Camel K Integration custom resource in the current namespace. The Camel K operator makes sure to create a proper runtime image and run the integration (usually as a Pod).
The Camel K operator will automatically manage and configure this integration. In particular, the operator takes care on exposing services, configuring health endpoints, providing metrics, updating image streams and much more.
By default, the run command will not wait for the integration to in state running. You need to add -w
or --wait
option in order to wait for the integration to become ready.
The --logs
option makes the command also print the integration output once the integration Pod is running.
The run command offers a lot more options that you may use to configure the Camel K integration.
Option | Description |
---|---|
| The integration name. Use this when the name should not get derived from the source file name. |
| An image built externally (for instance via CI/CD). Enabling it will skip the integration build phase. |
| The kit used to run the integration. |
| The trait profile to use for the deployment. |
| The service account used to run this Integration. |
| The path of the YAML file containing a PodSpec template to be used for the integration pods. |
| Operator id selected to manage this integration. (default=camel-k) |
| Adds dependency that should be included, use "camel:" prefix for a Camel component, "mvn:org.my:app:1.0" for a Maven dependency. |
| Add a runtime property or properties file from a path, a config map or a secret (syntax: |
| Add a build time property or properties file from a path, a config map or a secret (syntax: |
| Add a runtime configuration from a ConfigMap or a Secret (syntax: |
| Add a runtime resource from a Configmap or a Secret (syntax: |
| Add an OpenAPI spec (syntax: |
| Set an environment variable in the integration container, for instance |
| Mount a volume into the integration container, for instance |
| A Service that the integration should bind to, specified as |
| Add a source file to your integration, this is added to the list of files listed as arguments of the command. |
| Add a maven repository used to resolve dependencies. |
| Add an annotation to the integration. Use name values pairs like |
| Add a label to the integration. Use name values pairs like |
| Add a trait configuration to the integration. Use name values pairs like |
| Write YAML sources as Flow objects in the integration custom resource (default=true). |
| Enable storage of sources and resources as a compressed binary blobs. |
| Wait for the integration to become ready. |
| Print logs after integration has been started. |
| Just output the generated integration custom resource (supports: YAML or JSON or k8s). |
List integrations
You can list the available integration resources with the following command.
camel k get
NAME PHASE KIT READY
my-route Running kit-123456789 1/1
This looks for all integrations in the current namespace and lists their individual status.
Show integration logs
To inspect the log output of a running integration call:
camel k logs my-route
The command connects to the running integration Pod and prints the log output. Just terminate the process to stop printing the logs.
Delete integrations
Of course, you may also delete an integration resource from the cluster.
camel k delete my-route
To remove all available integrations on the current namespace use the --all
option.
camel k delete --all
Create integration pipes
In some contexts (for example, "serverless"), users often want to leverage the power of Apache Camel to be able to connect to various sources/sinks, with focus on connectivity to 3rd party technologies and services and less focus on doing complex processing (such as transformations or other enterprise integration patterns).
Pipe resources represent a special form of Camel integrations where a source gets bound to a sink. The operation to create such a Pipe resource is often related to as the process of binding a source to a sink.
You can use the Camel JBang subcommand bind
to create Pipe resources. The result of this Pipe resource being created on a Kubernetes cluster is a running Camel integration.
The Camel K bind command supports the following options:
Option | Description |
---|---|
| Operator id selected to manage this integration. (default=camel-k) |
| Source (from) such as a Kamelet or Camel endpoint uri that provides data. |
| Sink (to) such as a Kamelet or Camel endpoint uri where data should be sent to. |
| Add optional 1-n steps to the pipe processing. Each step represents a reference to a Kamelet of type action. |
| Add a pipe property in the form of |
| Add error handler (none,log,sink:<endpoint>). Sink endpoints are expected in the format |
| Add an annotation to the integration. Use name values pairs like |
| A Service that the integration should bind to, specified as |
| Add a trait configuration to the integration. Use name values pairs like |
| Wait for the integration to become ready. |
| Print logs after integration has been started. |
| Just output the generated pipe custom resource (supports: file, YAML or JSON). |
Sources and sinks in a pipe may be Camel endpoint URIs, a Kamelet or a references to a Kubernetes resource (e.g. Knative brokers, Kafka topics).
Binding Kamelets
In a typical use case, a Pipe connects Kamelets of type source and sink. Usually a Kamelet gets identified by its name (e.g. timer-source, log-sink).
camel k bind my-pipe --source timer-source --sink log-sink --property source.message="Camel rocks!" --property sink.showHeaders=true
The bind command receives the name of the pipe as a command argument and uses several options to specify the source and the sink. In addition to that, the user is able to specify properties on the individual source and sink (e.g., the message property on the timer-source Kamelet).
The result of this command is a Pipe custom resource that you can apply to a Kubernetes cluster.
apiVersion: camel.apache.org/v1
kind: Pipe
metadata:
name: my-pipe
annotations:
camel.apache.org/operator.id: camel-k
spec:
source: (1)
ref:
kind: Kamelet
apiVersion: camel.apache.org/v1
name: timer-source
properties:
message: "Camel rocks!"
sink: (2)
ref:
kind: Kamelet
apiVersion: camel.apache.org/v1
name: log-sink
properties:
showHeaders: true
1 | Reference to the source that provides data |
2 | Reference to the sink where data should be sent to |
Each Pipe resource uses an operator id annotation to specify which operator on the cluster should handle the resource.
The bind command is able to inspect the properties defined in the Kamelet specification in order to set default values. In case the Kamelet defines a required property that is not explicitly set by the user the bind command automatically creates a property placeholder with an example value. |
Add binding steps
You can specify 1-n additional steps that get executed between the source and sink.
camel k bind my-pipe --source timer-source --sink log-sink --step set-body-action --property step-1.value="Camel rocks!"
apiVersion: camel.apache.org/v1
kind: Pipe
metadata:
name: my-pipe
spec:
source:
# ...
steps:
- ref:
kind: Kamelet
apiVersion: camel.apache.org/v1
name: set-body-action
properties:
value: "Camel rocks!"
sink:
# ...
Each step should reverence a Kamelet of type action . The properties for a step can be set with the respective step-<n> prefix where n is the step number beginning with 1. |
Binding Camel endpoint URIs
Instead of referencing a Kamelet or Kubernetes resource you can also configure the source/sink to be an explicit Camel URI. For example, the following bind command is allowed:
camel k bind my-pipe --source timer:tick --sink https://mycompany.com/the-service --property source.period=5000
This will use the Camel endpoint URIs timer:tick
and log:info
as source and sink in the Pipe. The properties are set as endpoint parameters.
apiVersion: camel.apache.org/v1
kind: Pipe
metadata:
name: my-pipe
spec:
source:
uri: timer:tick (1)
properties:
period: 5000
sink:
uri: https://mycompany.com/the-service (2)
1 | Pipe with explicit Camel endpoint URI as source |
2 | Pipe with explicit Camel endpoint URI as sink where the data gets pushed to |
This Pipe explicitly defines Camel endpoint URIs that act as a source and sink.
You can also specify endpoint parameters directly on the source/sink like --source timer:tick?period=5000 |
Binding to Knative broker
You can reference Knative eventing resources as source or sink in a Pipe resource. The reference to the Knative resource is identified by the apiVersion, kind and resource name. Users may add properties to the object reference as usual.
apiVersion: camel.apache.org/v1
kind: Pipe
metadata:
name: my-pipe
annotations:
camel.apache.org/operator.id: camel-k
spec:
source: (1)
ref:
kind: Kamelet
apiVersion: camel.apache.org/v1
name: timer-source
properties:
message: "Camel rocks!"
sink: (2)
ref:
kind: Broker
apiVersion: eventing.knative.dev/v1
name: default
properties:
type: org.apache.camel.event.my-event (3)
1 | Reference to the source that provides data |
2 | Reference to the Knative broker where data should be sent to |
3 | The CloudEvents event type that is used for the events |
Knative eventing uses CloudEvents data format by default. Camel provides the concept of data types that is able to transform from many different component data formats to CloudEvents data type. The data type transformation will set proper event properties such as ce-type, ce-source or ce-subject. |
When referencing a Knative broker as a source the type
property is mandatory in order to filter the event stream.
apiVersion: camel.apache.org/v1
kind: Pipe
metadata:
name: my-pipe
annotations:
camel.apache.org/operator.id: camel-k
spec:
source: (1)
ref:
kind: Broker
apiVersion: eventing.knative.dev/v1
name: default
properties:
type: org.apache.camel.event.my-event (2)
sink:
ref:
kind: Kamelet
apiVersion: camel.apache.org/v1
name: log-sink
1 | Reference to the source Knative broker that provides the events |
2 | Filter the event stream for events with the given CloudEvents event type |
Binding to Knative channels
Knative eventing provides the channel resource for a subscription consumer model. Camel K is able to automatically manage the subscription when referencing Knative eventing channels as a source or sink in a Pipe.
apiVersion: camel.apache.org/v1
kind: Pipe
metadata:
name: my-pipe
annotations:
camel.apache.org/operator.id: camel-k
spec:
source:
ref:
kind: Kamelet
apiVersion: camel.apache.org/v1
name: timer-source
properties:
message: "Camel rocks!"
sink: (1)
ref:
kind: InMemoryChannel
apiVersion: messaging.knative.dev/v1
name: my-messages
1 | Reference to the Knative message channel that receives the events |
The same approach can be used to subscribe to a message chanel as a consumer to act as a source in a Pipe.
apiVersion: camel.apache.org/v1
kind: Pipe
metadata:
name: my-pipe
annotations:
camel.apache.org/operator.id: camel-k
spec:
source: (1)
ref:
kind: InMemoryChannel
apiVersion: messaging.knative.dev/v1
name: my-messages
sink:
ref:
kind: Kamelet
apiVersion: camel.apache.org/v1
name: log-sink
1 | Reference to the source Knative message channel that provides the events |
Binding to Kafka topics
Kafka topic resources may act as a source or sink in a Pipe. Strimzi provides KafkaTopic resources that you can reference in your Pipe.
The reference to the Strimzi resource is identified by the apiVersion, kind and resource name. Users may add properties to the object reference such as the brokers bootstrap URI.
apiVersion: camel.apache.org/v1
kind: Pipe
metadata:
name: my-pipe
annotations:
camel.apache.org/operator.id: camel-k
spec:
source: (1)
ref:
kind: Kamelet
apiVersion: camel.apache.org/v1
name: timer-source
properties:
message: "Camel rocks!"
sink: (2)
ref:
kind: KafkaTopic
apiVersion: kafka.strimzi.io/v1beta2
name: my-topic
properties:
brokers: "my-cluster-kafka-bootstrap:9092" (3)
1 | Reference to the source that provides data |
2 | Reference to the Strimzi Kafka topic where data should be sent to |
3 | The Kafka brokers bootstrap URI |
Camel K is able to auto resolve the Kafka broker bootstrap URI by resolving the Strimzi Kafka resources in the same namespace. The operator may perform a lookup of the bootstrap URI and inject this as a property to the Camel component at runtime. |
You can set the brokers
property to explicitly point to the Strimzi Kafka broker.
Error handling
You can configure an error handler in order to specify what to do when some event ends up with failure. Pipes offer a mechanism to specify an error policy to adopt in case an event processing fails.
In case of an exception thrown during the pipe processing, the respective error handler will perform its actions.
The Pipe knows different types of error handlers none
, log
and sink
:
-
none → Explicit
noErrorHandler
is set and the error is ignored. -
log → Errors get logged to the output.
-
sink → Errors get pushed to a specified endpoint in the form of dead letter queue.
The error handler may be configured with special properties that allow you to define the error handling behavior such as redelivery or delay policy.
No error handler
There may be certain cases where you want to just ignore any failure happening in your integration. In this situation use a none
error handler.
camel k bind my-pipe --source timer-source --sink log-sink --error-handler none
This results in following error handler configuration on the pipe:
apiVersion: camel.apache.org/v1
kind: Pipe
metadata:
name: my-pipe
spec:
source:
# ...
sink:
# ...
errorHandler:
none: {}
Log error handler
Apache Camel offers a default behavior for handling failure: log to standard output. However, you can use the log
error handler to specify other behaviors such as redelivery or delay policy.
camel k bind my-pipe --source timer-source --sink log-sink --error-handler log --property error-handler.maximumRedeliveries=3 --property error-handler.redeliveryDelay=2000
This results in the error handler configuration on the Pipe:
apiVersion: camel.apache.org/v1
kind: Pipe
metadata:
name: my-pipe
spec:
source:
# ...
sink:
# ...
errorHandler:
log:
parameters: (1)
redeliveryDelay: 2000
maximumRedeliveries: 3
1 | Parameters belonging to the log error handler type |
Sink error handler
The sink
error handler is probably the most interesting error handler type as it allows you to redirect failing events to other components, such as a third party URI, a queue or topic or even another Kamelet
which will be performing certain logic with the failing event.
The sink error handler expects a proper endpoint URI, which may be a reference to another Kamelet, a fully qualified custom resource reference or an arbitrary Camel endpoint URI.
camel k bind my-pipe --source timer-source --sink log-sink --error-handler sink:my-error-handler --property error-handler.sink.message=ERROR! --property error-handler.maximumRedeliveries=1
apiVersion: camel.apache.org/v1
kind: Pipe
metadata:
name: my-pipe
spec:
source:
# ...
sink:
# ...
errorHandler:
sink:
endpoint:
ref: (1)
kind: Kamelet
apiVersion: camel.apache.org/v1
name: my-error-handler
properties:
message: "ERROR!" (2)
# ...
parameters:
maximumRedeliveries: 1 (3)
# ...
1 | You can use ref or uri . ref will be interpreted by the operator according the kind , apiVersion and name . You can use any Kamelet , KafkaTopic channel or Knative destination. |
2 | Properties targeting the sink endpoint (in this example, a property on the Kamelet named my-error-handler ). Properties targeting the sink endpoint need to use the error-handler.sink.* prefix. |
3 | Parameters for the error handler (such as redelivery or delay policy). Error handler parameters need to use the error-handler.* prefix. |
The error handler properties are divided into properties that target the error handler sink endpoint and properties that should be set on the Camel error handler component, (e.g., maximumRedeliveries). You need to specify the respective property prefix (error-handler. or error-handler.sink. ) to decide where the property should be set. |
As an alternative to referencing a Kamelet as an error handler sink, you may also use an arbitrary Camel endpoint URI.
camel k bind my-pipe --source timer-source --sink log-sink --error-handler sink:log:error --property error-handler.sink.showHeaders=true
It creates the error handler specification as follows:
apiVersion: camel.apache.org/v1
kind: Pipe
metadata:
name: my-pipe
spec:
source:
# ...
sink:
# ...
errorHandler:
sink:
endpoint:
uri: log:error
properties:
showHeaders: true