Creating a job from images in a public registry

When you create a job, you can specify workload configuration information that is used each time that the job is run. You can create a job from the console or with the CLI.

Creating a job with the console

Create a Code Engine job by using the icr.io/codeengine/firstjob image. This job prints Hi from a batch job! My index is:.

Open Code Engine.
Select Let's go.
Select Job.
Enter a name for the job; for example, myjob.
Select a project from the list of available projects. You can also create a new one. Note that you must have a selected project to create a job.
Specify a container image for your job, for example, icr.io/codeengine/firstjob. If you have your own source code that you want to turn into a container image for the job, see building a container image. For more information about the code that is used for this example, see firstjob.
Modify any default values for environment variables or runtime settings. For more information about these options, see Options for creating and running a job.
Click Create.
From your job page, when your job is in ready status, click Submit job to submit a job based on the current configuration.
From the Submit job pane, accept all the default values, and click Submit job again to run your job.

From the Submit job pane, you can review and optionally change default configuration values such as instances, CPU, memory, number of job retries, and job timeout. You can specify either Array size or Array indices for the parallel job instances to run. For Array size, provide the number of instances to run in parallel for this job. For Array indices, provide a comma-separated list for your custom set of indices. For example, to run this job with a custom set of 5 indices, specify 3,12-14,25. You can also specify a custom value for the job array size, which updates the value of the automatically injected JOB_ARRAY_SIZE environment variable. After you submit this job, the system displays the status of the instances of your job on the Job details page. If you specify Array size instead of Array indices in the Submit job pane, from the Configuration section of the Job details page, this information is provided as Array indices.

You can find details about your job run on the Job status page.

Creating a job with the CLI

To create a job configuration with the CLI, use the job create command. This command requires a name and an image and also allows other optional arguments. For a complete listing of options, see the ibmcloud ce job create command.

Before you begin

Set up your Code Engine CLI environment.
Create and work with a project.

The following job create command creates a job configuration that is named myjob and uses the container image icr.io/codeengine/firstjob.

ibmcloud ce job create --name myjob  --image icr.io/codeengine/firstjob

Example output

Creating job 'myjob'...
OK

The following table summarizes the options that are used with the job create command in this example. For more information about the command and its options, see the ibmcloud ce job create command.

Table 1. Command options
Option	Description
`--image`	The name of the image that is used for runs of the job. This value is required. The format is `REGISTRY/NAMESPACE/REPOSITORY:TAG` where `REGISTRY` and `TAG` are optional. If `TAG` is not specified, the default is `latest`. For images in Docker Hub, you can specify the image with `NAMESPACE/REPOSITORY`, as the default for `REGISTRY` is `docker.io`. For other registries, use `REGISTRY/NAMESPACE/REPOSITORY` or `REGISTRY/NAMESPACE/REPOSITORY:TAG`.
`--name`	The name of the job. Use a name that is unique within the project. This value is required. The name must begin and end with a lowercase alphanumeric character. The name must be 63 characters or fewer and can contain lowercase letters, numbers, and hyphens (-).

Next steps

After you create your job, submit the job to run it. See Run a job. You can run your job multiple times.
After you run your job, to view details of your job and job runs, see access job details.
Now that your job is created, consider making your jobs event-driven. By using event subscriptions, you can trigger your jobs by periodic schedules or set your job to react to events like file uploads.
You can update your job and its referenced code in any of the following ways, independent of how you created or previously updated your job.
- If you have a container image, per the Open Container Initiative (OCI) standard, then you need to provide only a reference to the image, which points to the location of your container registry when you create (or update) your job. You can create (or update) your job from images in a public registry or private registry and then access the referenced image from your job run.
  
  If you created your job by using the job create command and you specified the --build-source option to build the container image from local or repository source, and you want to change your job to point to a different container image, you must first remove the association of the build from your job. For example, run ibmcloud ce job update -n JOB_NAME --build-clear. After you remove the association of the build from your job, you can update the job to reference a different image.
- If you are starting with source code that resides in a Git repository, you can choose to let Code Engine take care of building the image from your source and creating (or updating) the job with a single operation. In this scenario, Code Engine uploads your image to IBM Cloud® Container Registry. To learn more, see Creating a job from repository source code. If you want more control over the build of your image, then you can choose to build the image with Code Engine before you create (or update) your job and run the job.
- If you are starting with source code that resides on a local workstation, you can choose to let Code Engine take care of building the image from your source and creating the job with a single CLI command. In this scenario, Code Engine uploads your image to IBM Cloud® Container Registry. To learn more, see Creating your job from local source code with the CLI. If you want more control over the build of your image, then you can choose to build the image) with Code Engine before you create (or update) your job and run the job.
For example, you might choose to let Code Engine handle the build of your local source while you evolve the development of your source for the job. Then, after the image is matured, you can update the job to reference the specific image that you want. You can repeat this process as needed.

When you run your updated job, the latest version of your referenced container image is used for the job run, unless a tag is specified for the image. If a tag is specified for the image, then the tagged image is used for the job run.

Looking for more code examples? Check out the Samples for IBM Cloud Code Engine GitHub repo.