Pod Trait

The pod trait allows the customization of the Integration pods. It applies the PodSpecTemplate struct contained in the Integration .spec.podTemplate field, into the Integration deployment Pods template, using strategic merge patch.

This can be used to customize the container where Camel routes execute, by using the integration container name.

This trait is available in the following profiles: Kubernetes, Knative, OpenShift.

Note 1: In the current implementation, template options override the configuration options defined via CLI, for example in:

$ kamel run integration.yaml --pod-template template.yaml --env TEST_VARIABLE=will_be_overriden --env ANOTHER_VARIABLE=Im_There

The value from the template overwrites the TEST_VARIABLE environment variable, while ANOTHER_VARIABLE stays unchanged.

Note 2: Changes to the integration container entrypoint aren’t applied due to current trait execution order.

Configuration

Trait properties can be specified when running any integration with the CLI:

$ kamel run --trait pod.[key]=[value] integration.yaml

The following configuration options are available:

Property Type Description

pod.enabled

bool

Can be used to enable or disable a trait. All traits share this common property.

Sidecar containers

With the following Integration, that reads files from a directory:

pod-trait-route.yaml
- from:
    uri: "file:///var/log"
    steps:
      - setBody:
          simple: "${body}: {{TEST_VARIABLE}}"
      - to: "log:info"

Plus the following Pod template, that adds a sidecar container to the Integration Pod, generating some data into the directory, and mounts it into the integration container:

pod-trait-template.yaml
containers:
  - name: integration
    env:
      - name: TEST_VARIABLE
        value: "hello from the template"
    volumeMounts:
      - name: var-logs
        mountPath: /var/log
  - name: sidecar
    image: busybox
    command: [ "/bin/sh" , "-c", "while true; do echo $(date -u) 'Content from the sidecar container' > /var/log/file.txt; sleep 1;done" ]
    volumeMounts:
      - name: var-logs
        mountPath: /var/log
volumes:
  - name: var-logs
    emptyDir: { }

The Integration route logs the content of the file generated by the sidecar container, e.g.:

kamel run pod-trait-route.yaml --pod-template pod-trait-template.yaml
...
Condition "Ready" is "True" for Integration pod-trait-route: 1/1 ready replicas
Integration "pod-trait-route" in phase "Running"
[1] 2024-05-15 11:32:30,562 INFO  [info] (Camel (camel-1) thread #1 - file:///var/log) Exchange[ExchangePattern: InOnly, BodyType: String, Body: Wed May 15 11:32:30 UTC 2024 Content from the sidecar container: hello from the template]
[1] 2024-05-15 11:32:31,574 INFO  [info] (Camel (camel-1) thread #1 - file:///var/log) Exchange[ExchangePattern: InOnly, BodyType: String, Body: Wed May 15 11:32:31 UTC 2024 Content from the sidecar container: hello from the template]
[1] 2024-05-15 11:32:32,583 INFO  [info] (Camel (camel-1) thread #1 - file:///var/log) Exchange[ExchangePattern: InOnly, BodyType: String, Body: Wed May 15 11:32:32 UTC 2024 Content from the sidecar container: hello from the template]

Init containers

With this trait you will be also able to run initContainers. There is a little caveat though, as you will need to include at least one container in the template spec, you will need to provide the configuration for the default container, which is integration. Here a simple example:

template.yaml
containers:
  - name: integration
initContainers:
  - name: init
    image: busybox
    command: [ "/bin/sh" , "-c", "echo 'hello'!" ]

The integration container will be overwritten by the container running the route, and the initContainer will run before the route as expected.

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