I'm newbie to Kubernetes. I wonder how to launch a container programmatically in Java (or Scala), and feed the input stream of the process with some binary data. Probably I need a job. I've found how to launch a job, but I have no control over its input stream.

I can use any convenient Kubernetes client library.

I need it to launch a kaniko container and feed its input stream with a .tar.gz file generated on the fly (via the --context tar://stdin option).

I could do an exec over an existing kaniko container, but don't know to launch the container appropriately for this purpose, because the container doesn't include any shell.

CodePudding user response：

You can use kubectl run to create a pod and connect its stdin with option -i. Your container should termiate gracefully when the work is done.

Example:

echo "echo foo" | kubectl run -i busybox --image=busybox --restart=Never 

Reference:

https://jamesdefabia.github.io/docs/user-guide/kubectl/kubectl_run/

CodePudding user response：

Programmatically with the fabric8 Java client library, it can be done in this way:

https://github.com/fabric8io/kubernetes-client/blob/master/doc/CHEATSHEET.md#running-a-pod

try (KubernetesClient client = new KubernetesClientBuilder().build()) {
    client.run().inNamespace("default")
            .withName("kaniko")
            .withImage("gcr.io/kaniko-project/executor:latest")
            .done();
}

It is quite handy to set env. variables or add arguments.

Now I have to research, how to feed the standard input.