Building a custom Amazon ParallelCluster AMI
When using the Amazon ParallelCluster command line interface (CLI) or API, you only pay for the Amazon resources that are created when you create or update Amazon ParallelCluster images and clusters. For more information, see Amazon services used by Amazon ParallelCluster.
The Amazon ParallelCluster UI is built on a serverless architecture and you can use it within the Amazon Free Tier category for most cases. For more information, see Amazon ParallelCluster UI costs.
Important
If you build a custom AMI, you must repeat the steps that you used to create your custom AMI with each new Amazon ParallelCluster release.
Before reading further, we recommend that you first review the Custom bootstrap actions section. Determine if the modifications that you want to make can be scripted and supported with future Amazon ParallelCluster releases.
Even though building a custom AMI in general isn't ideal, there are specific scenarios where building a custom AMI for Amazon ParallelCluster is necessary. This tutorial covers how to build a custom AMI for these scenarios.
Prerequisites
-
Amazon ParallelCluster is installed.
-
The Amazon CLI is installed and configured.
-
You have an Amazon EC2 key pair.
-
You have an IAM role with the permissions required to run the pcluster CLI and build images.
How to customize the Amazon ParallelCluster AMI
There are two ways to build a custom Amazon ParallelCluster AMI. One of these two methods is to build a new AMI using the Amazon ParallelCluster CLI. Another method requires that you to make manual modifications to build a new AMI that's available under your Amazon Web Services account.
Build a custom Amazon ParallelCluster AMI
If you have a customized AMI and software, you can apply the changes that are needed by Amazon ParallelCluster on top of it. Amazon ParallelCluster relies on the EC2 Image Builder service to build customized AMIs. For more information, see the Image Builder User Guide.
Key points:
-
The process takes about 1 hour. This time can vary if there are additional Build / Components to be installed at build time.
-
The AMI is tagged with the versions of the main components. These include the kernel, scheduler, and EFA driver. A subset of the component versions are also reported in the AMI description.
-
Starting from Amazon ParallelCluster 3.0.0, a new set of CLI commands can be used to manage the lifecycle of images. This includes build-image, list-images, describe-image, and delete-image.
-
This method is repeatable. You can re-run it to keep AMIs updated (for example, OS updates), and then use them when you update an existing cluster.
Note
If you use this method in the Amazon China Partition, you might get network errors. For example, you might see these errors from
the pcluster build-image
command when it downloads packages from GitHub or from an OS repository. If this happens, we recommend that
you use one of the following alternative methods:
-
Follow the Modify an Amazon ParallelCluster AMI approach that bypasses this command.
-
Build the image in another Partition and Region, such as
us-east-1
, and then store-restore it to move it to the China Region. For more information, see Store and restore an AMI using S3 in the Amazon EC2 User Guide.
Steps:
-
Configure your Amazon Web Services account credentials so that the Amazon ParallelCluster client can make calls to Amazon API operations on your behalf. For a list of the required permissions, see Amazon Identity and Access Management permissions in Amazon ParallelCluster.
-
Create a basic build image configuration file. To do this, specify the InstanceType to be used to build the image and the ParentImage. These are used as the starting point to create the AMI. For more information about optional build parameters, see Image Configuration.
Build: InstanceType:
<BUILD_INSTANCE_TYPE>
ParentImage:<BASE_AMI_ID>
-
Use the CLI command pcluster build-image to build an Amazon ParallelCluster AMI starting from the AMI that you provide as the base.
$
pcluster build-image --image-id
IMAGE_ID
--image-configurationIMAGE_CONFIG.yaml
--regionREGION
{ "image": { "imageId": "IMAGE_ID", "imageBuildStatus": "BUILD_IN_PROGRESS", "cloudformationStackStatus": "CREATE_IN_PROGRESS", "cloudformationStackArn": "arn:aws:cloudformation:us-east-1:123456789012:stack/IMAGE_ID/abcd1234-ef56-gh78-ij90-1234abcd5678", "region": "us-east-1", "version": "3.7.0" } }
Warning
pcluster build-image
uses the default VPC. If you delete the default VPC using Amazon Control Tower or Amazon Landing Zone, the subnet ID must be specified in the image configuration file. For more information, see SubnetId.For a list of other parameters, see the pcluster build-image command reference page. The results of the preceding command are as follows:
-
A CloudFormation stack is created based on the image configuration. The stack includes all of the EC2 Image Builder resources required for the build.
-
The created resources include the official Image Builder Amazon ParallelCluster components that custom Image Builder components can be added to. To learn how to create custom components, see the Custom AMIs examples
in the HPC for Public Sector Customers Workshop. -
EC2 Image Builder launches a build instance, applies the Amazon ParallelCluster cookbook, installs the Amazon ParallelCluster software stack, and performs necessary configuration tasks. The Amazon ParallelCluster cookbook is used to build and bootstrap Amazon ParallelCluster.
-
The instance is stopped and a new AMI is created from it.
-
Another instance is launched from the newly created AMI. During the test phase, EC2 Image Builder runs tests that are defined in the Image Builder components.
-
If the build is successful, the stack is deleted. If the build fails, the stack is retained and available for inspection.
-
-
You can monitor the status of the build process by running the following command. After the build completes, you can run it to retrieve the AMI ID given in the response.
$
pcluster describe-image --image-id
IMAGE_ID
--regionREGION
# BEFORE COMPLETE { "imageConfiguration": { "url": "https://parallelcluster-1234abcd5678efgh-v1-do-not-delete.s3.amazonaws.com/parallelcluster/3.7.0/images/IMAGE_ID-abcd1234efgh5678/configs/image-config.yaml?...", }, "imageId": "IMAGE_ID", "imagebuilderImageStatus": "BUILDING", "imageBuildStatus": "BUILD_IN_PROGRESS", "cloudformationStackStatus": "CREATE_IN_PROGRESS", "cloudformationStackArn": "arn:aws:cloudformation:us-east-1:123456789012:stack/IMAGE_ID/abcd1234-ef56-gh78-ij90-1234abcd5678", "region": "us-east-1", "version": "3.7.0", "cloudformationStackTags": [ { "value": "3.7.0", "key": "parallelcluster:version" }, { "value": "IMAGE_ID", "key": "parallelcluster:image_name" }, ... ], "imageBuildLogsArn": "arn:aws:logs:us-east-1:123456789012:log-group:/aws/imagebuilder/ParallelClusterImage-IMAGE_ID", "cloudformationStackCreationTime": "2022-04-05T21:36:26.176Z" }
# AFTER COMPLETE { "imageConfiguration": { "url": "https://parallelcluster-1234abcd5678efgh-v1-do-not-delete.s3.us-east-1.amazonaws.com/parallelcluster/3.7.0/images/IMAGE_ID-abcd1234efgh5678/configs/image-config.yaml?Signature=..." }, "imageId": "IMAGE_ID", "imageBuildStatus": "BUILD_COMPLETE", "region": "us-east-1", "ec2AmiInfo": { "amiName": "IMAGE_ID 2022-04-05T21-39-24.020Z", "amiId": "ami-1234stuv5678wxyz", "description": "Amazon ParallelCluster AMI for alinux2, kernel-4.14.238-182.422.amzn2.x86_64, lustre-2.10.8-5.amzn2.x86_64, efa-1.13.0-1.amzn2.x86_64, dcv-2021.1.10598-1.el7.x86_64, slurm-20-11-8-1", "state": "AVAILABLE", "tags": [ { "value": "2021.3.11591-1.el7.x86_64", "key": "parallelcluster:dcv_version" }, ... ], "architecture": "x86_64" }, "version": "3.7.0" }
-
To create your cluster, enter the AMI ID in the CustomAmi field in your cluster configuration.
Troubleshooting and monitoring AMI creation process
Image creation completes in about an hour. You can monitor the process by running the pcluster describe-image command or log retrieval commands.
$
pcluster describe-image --image-id
IMAGE_ID
--regionREGION
The build-image command creates a CloudFormation stack with all the Amazon EC2 resources that are required to build the image, and launches the EC2 Image Builder process.
After running the build-image command, it's possible to retrieve CloudFormation stack events by using pcluster get-image-stack-events. You can filter results with the
--query
parameter to see the latest events. For more information, see Filtering Amazon CLI output in the Amazon Command Line Interface User Guide.
$
pcluster get-image-stack-events --image-id
IMAGE_ID
--regionREGION
--query "events[0]"{ "eventId": "ParallelClusterImage-CREATE_IN_PROGRESS-2022-04-05T21:39:24.725Z", "physicalResourceId": "arn:aws:imagebuilder:us-east-1:123456789012:image/parallelclusterimage-IMAGE_ID/3.7.0/1", "resourceStatus": "CREATE_IN_PROGRESS", "resourceStatusReason": "Resource creation Initiated", "resourceProperties": "{\"InfrastructureConfigurationArn\":\"arn:aws:imagebuilder:us-east-1:123456789012:infrastructure-configuration/parallelclusterimage-abcd1234-ef56-gh78-ij90-1234abcd5678\",\"ImageRecipeArn\":\"arn:aws:imagebuilder:us-east-1:123456789012:image-recipe/parallelclusterimage-IMAGE_ID/3.7.0\",\"DistributionConfigurationArn\":\"arn:aws:imagebuilder:us-east-1:123456789012:distribution-configuration/parallelclusterimage-abcd1234-ef56-gh78-ij90-1234abcd5678\",\"Tags\":{\"parallelcluster:image_name\":\"IMAGE_ID\",\"parallelcluster:image_id\":\"IMAGE_ID\"}}", "stackId": "arn:aws:cloudformation:us-east-1:123456789012:stack/IMAGE_ID/abcd1234-ef56-gh78-ij90-1234abcd5678", "stackName": "IMAGE_ID", "logicalResourceId": "ParallelClusterImage", "resourceType": "AWS::ImageBuilder::Image", "timestamp": "2022-04-05T21:39:24.725Z" }
After about 15 minutes, the stack events appear in the log event entry related to Image Builder creation. You can now list image log streams and monitor the Image Builder steps by using pcluster list-image-log-streams and pcluster get-image-log-events commands.
$
pcluster list-image-log-streams --image-id
"3.7.0/1" ]IMAGE_ID
--regionREGION
\ --query 'logStreams[*].logStreamName'$
pcluster get-image-log-events --image-id
IMAGE_ID
--regionREGION
\ --log-stream-name 3.7.0/1 --limit 3{ "nextToken": "f/36295977202298886557255241372854078762600452615936671762", "prevToken": "b/36295977196879805474012299949460899222346900769983430672", "events": [ { "message": "ExecuteBash: FINISHED EXECUTION", "timestamp": "2022-04-05T22:13:26.633Z" }, { "message": "Document arn:aws:imagebuilder:us-east-1:123456789012:component/parallelclusterimage-test-abcd1234-ef56-gh78-ij90-1234abcd5678/3.7.0/1", "timestamp": "2022-04-05T22:13:26.741Z" }, { "message": "TOE has completed execution successfully", "timestamp": "2022-04-05T22:13:26.819Z" } ] }
Continue to check with the describe-image command until you see the BUILD_COMPLETE
status.
$
pcluster describe-image --image-id
IMAGE_ID
--regionREGION
{ "imageConfiguration": { "url": "https://parallelcluster-1234abcd5678efgh-v1-do-not-delete.s3.us-east-1.amazonaws.com/parallelcluster/3.7.0/images/IMAGE_ID-abcd1234efgh5678/configs/image-config.yaml?Signature=..." }, "imageId": "IMAGE_ID", "imageBuildStatus": "BUILD_COMPLETE", "region": "us-east-1", "ec2AmiInfo": { "amiName": "IMAGE_ID 2022-04-05T21-39-24.020Z", "amiId": "ami-1234stuv5678wxyz", "description": "Amazon ParallelCluster AMI for alinux2, kernel-4.14.238-182.422.amzn2.x86_64, lustre-2.10.8-5.amzn2.x86_64, efa-1.13.0-1.amzn2.x86_64, dcv-2021.1.10598-1.el7.x86_64, slurm-20-11-8-1", "state": "AVAILABLE", "tags": [ { "value": "2021.3.11591-1.el7.x86_64", "key": "parallelcluster:dcv_version" }, ... ], "architecture": "x86_64" }, "version": "3.7.0" }
If you need to troubleshoot a custom AMI creation issue, create an archive of the image logs as described in following steps.
It's possible to archive the logs in an Amazon S3 bucket or in a local file, depending on the --output
parameter.
$
pcluster export-image-logs --image-id
IMAGE_ID
--regionREGION
\ --bucketBUCKET_NAME
--bucket-prefixBUCKET_FOLDER
{ "url": "https://BUCKET_NAME.s3.us-east-1.amazonaws.com/BUCKET-FOLDER/IMAGE_ID-logs-202209071136.tar.gz?AWSAccessKeyId=..." }
$
pcluster export-image-logs --image-id
IMAGE_ID
\ --regionREGION
--bucketBUCKET_NAME
--bucket-prefixBUCKET_FOLDER
--output-file /tmp/archive.tar.gz{ "path": "/tmp/archive.tar.gz" }
The archive contains the CloudWatch Logs Streams related to the Image Builder process and Amazon CloudFormation stack events. The command might take several minutes to run.
Managing Custom AMIs
Starting from Amazon ParallelCluster 3.0.0, a new set of commands has been added in the CLI to build, monitor, and manage the image lifecycle. For more information about the commands, see pcluster commands.
Modify an Amazon ParallelCluster AMI
This method consists of modifying an official Amazon ParallelCluster AMI by adding customization on top of it. The base Amazon ParallelCluster AMIs are updated with new releases. These AMIs have all of the components that are required for Amazon ParallelCluster to function when it's installed and configured. You can start with one of these as your base.
Key points:
-
This method is faster than the build-image command. However, it's a manual process and not automatically repeatable.
-
With this method, you don't have access to the log retrieval and image lifecycle management commands that are available through the CLI.
Steps: