Quickstart: Use the Azure CLI to create a Batch account and run a job

This quickstart shows you how to get started with Azure Batch by using Azure CLI commands and scripts to create and manage Batch resources. You create a Batch account that has a pool of virtual machines, or compute nodes. You then create and run a job with tasks that run on the pool nodes.

After you complete this quickstart, you understand the key concepts of the Batch service and are ready to use Batch with more realistic, larger scale workloads.

Prerequisites

• If you don't have an Azure subscription, create an Azure free account before you begin.

• Azure Cloud Shell or Azure CLI.

  You can run the Azure CLI commands in this quickstart interactively in Azure Cloud Shell. To run the commands in the Cloud Shell, select Open Cloudshell at the upper-right corner of a code block. Select Copy to copy the code, and paste it into Cloud Shell to run it. You can also run Cloud Shell from within the Azure portal. Cloud Shell always uses the latest version of the Azure CLI.

  Alternatively, you can install Azure CLI locally to run the commands. The steps in this article require Azure CLI version 2.0.20 or later. Run az version to see your installed version and dependent libraries, and run az upgrade to upgrade. If you use a local installation, sign in to Azure by using the az login command.

Create a resource group

Run the following az group create command to create an Azure resource group named qsBatch in the eastus2 Azure region. The resource group is a logical container that holds the Azure resources for this quickstart.

az group create \
    --name qsBatch \
    --location eastus2

Create a storage account

Use the az storage account create command to create an Azure Storage account to link to your Batch account. Although this quickstart doesn't use the storage account, most real-world Batch workloads use a linked storage account to deploy applications and store input and output data.

Run the following command to create a Standard_LRS SKU storage account named mybatchstorage in your resource group:

az storage account create \
    --resource-group qsBatch \
    --name mybatchstorage \
    --location eastus2 \
    --sku Standard_LRS

Create a Batch account

Run the following az batch account create command to create a Batch account named mybatchaccount in your resource group and link it with the mybatchstorage storage account.

az batch account create \
    --name mybatchaccount \
    --storage-account mybatchstorage \
    --resource-group qsBatch \
    --location eastus2

Sign in to the new Batch account by running the az batch account login command. Once you authenticate your account with Batch, subsequent az batch commands in this session use this account context.

az batch account login \
    --name mybatchaccount \
    --resource-group qsBatch \
    --shared-key-auth

Create a pool of compute nodes

Run the az batch pool create command to create a pool of Linux compute nodes in your Batch account. The following example creates a pool named myPool that consists of two Standard_A1_v2 size VMs running Ubuntu 20.04 LTS OS. This node size offers a good balance of performance versus cost for this quickstart example.

az batch pool create \
    --id myPool \
    --image canonical:0001-com-ubuntu-server-focal:20_04-lts \
    --node-agent-sku-id "batch.node.ubuntu 20.04" \
    --target-dedicated-nodes 2 \
    --vm-size Standard_A1_v2

Batch creates the pool immediately, but takes a few minutes to allocate and start the compute nodes. To see the pool status, use the az batch pool show command. This command shows all the properties of the pool, and you can query for specific properties. The following command queries for the pool allocation state:

az batch pool show --pool-id myPool \
    --query "allocationState"

While Batch allocates and starts the nodes, the pool is in the resizing state. You can create a job and tasks while the pool state is still resizing. The pool is ready to run tasks when the allocation state is steady and all the nodes are running.

Create a job

Use the az batch job create command to create a Batch job to run on your pool. A Batch job is a logical group of one or more tasks. The job includes settings common to the tasks, such as the pool to run on. The following example creates a job called myJob on myPool that initially has no tasks.

az batch job create \
    --id myJob \
    --pool-id myPool

Create job tasks

Batch provides several ways to deploy apps and scripts to compute nodes. Use the az batch task create command to create tasks to run in the job. Each task has a command line that specifies an app or script.

The following Bash script creates four identical, parallel tasks called myTask1 through myTask4. The task command line displays the Batch environment variables on the compute node, and then waits 90 seconds.

for i in {1..4}
do
   az batch task create \
    --task-id myTask$i \
    --job-id myJob \
    --command-line "/bin/bash -c 'printenv | grep AZ_BATCH; sleep 90s'"
done

The command output shows the settings for each task. Batch distributes the tasks to the compute nodes.

View task status

After you create the task, Batch queues the task to run on the pool. Once a node is available, the task runs on the node.

Use the az batch task show command to view the status of Batch tasks. The following example shows details about the status of myTask1:

az batch task show \
    --job-id myJob \
    --task-id myTask1

The command output includes many details. For example, an exitCode of 0 indicates that the task command completed successfully. The nodeId shows the name of the pool node that ran the task.

View task output

Use the az batch task file list command to list the files a task created on a node. The following command lists the files that myTask1 created:

az batch task file list \
    --job-id myJob \
    --task-id myTask1 \
    --output table

Results are similar to the following output:

Name        URL                                                                                       Is Directory    Content Length
----------  ----------------------------------------------------------------------------------------  --------------  ----------------
stdout.txt  https://mybatchaccount.eastus2.batch.azure.com/jobs/myJob/tasks/myTask1/files/stdout.txt  False                  695
certs       https://mybatchaccount.eastus2.batch.azure.com/jobs/myJob/tasks/myTask1/files/certs       True
wd          https://mybatchaccount.eastus2.batch.azure.com/jobs/myJob/tasks/myTask1/files/wd          True
stderr.txt  https://mybatchaccount.eastus2.batch.azure.com/jobs/myJob/tasks/myTask1/files/stderr.txt  False                    0

The az batch task file download command downloads output files to a local directory. Run the following example to download the stdout.txt file:

az batch task file download \
    --job-id myJob \
    --task-id myTask1 \
    --file-path stdout.txt \
    --destination ./stdout.txt

You can view the contents of the standard output file in a text editor. The following example shows a typical stdout.txt file. The standard output from this task shows the Azure Batch environment variables that are set on the node. You can refer to these environment variables in your Batch job task command lines, and in the apps and scripts the command lines run.

AZ_BATCH_TASK_DIR=/mnt/batch/tasks/workitems/myJob/job-1/myTask1
AZ_BATCH_NODE_STARTUP_DIR=/mnt/batch/tasks/startup
AZ_BATCH_CERTIFICATES_DIR=/mnt/batch/tasks/workitems/myJob/job-1/myTask1/certs
AZ_BATCH_ACCOUNT_URL=https://mybatchaccount.eastus2.batch.azure.com/
AZ_BATCH_TASK_WORKING_DIR=/mnt/batch/tasks/workitems/myJob/job-1/myTask1/wd
AZ_BATCH_NODE_SHARED_DIR=/mnt/batch/tasks/shared
AZ_BATCH_TASK_USER=_azbatch
AZ_BATCH_NODE_ROOT_DIR=/mnt/batch/tasks
AZ_BATCH_JOB_ID=myJobl
AZ_BATCH_NODE_IS_DEDICATED=true
AZ_BATCH_NODE_ID=tvm-257509324_2-20180703t215033z
AZ_BATCH_POOL_ID=myPool
AZ_BATCH_TASK_ID=myTask1
AZ_BATCH_ACCOUNT_NAME=mybatchaccount
AZ_BATCH_TASK_USER_IDENTITY=PoolNonAdmin

Clean up resources

If you want to continue with Batch tutorials and samples, you can use the Batch account and linked storage account that you created in this quickstart. There's no charge for the Batch account itself.

Pools and nodes incur charges while the nodes are running, even if they aren't running jobs. When you no longer need a pool, use the az batch pool delete command to delete it. Deleting a pool deletes all task output on the nodes, and the nodes themselves.

az batch pool delete --pool-id myPool

When you no longer need any of the resources you created for this quickstart, you can use the az group delete command to delete the resource group and all its resources. To delete the resource group and the storage account, Batch account, node pools, and all related resources, run the following command:

az group delete --name qsBatch

Next steps

In this quickstart, you created a Batch account and pool, created and ran a Batch job and tasks, and viewed task output from the nodes. Now that you understand the key concepts of the Batch service, you're ready to use Batch with more realistic, larger scale workloads. To learn more about Azure Batch, continue to the Azure Batch tutorials.