# Example cluster with custom bootstrap actions
<a name="custom-bootstrap-actions-example-cluster-v3"></a>

The following steps create a simple script to be executed after the node is configured, that installs the `R,` `curl` and `wget` packages in the nodes of the cluster.

1. Create a script.

   ```
   #!/bin/bash
     echo "The script has $# arguments"
     for arg in "$@"
     do
         echo "arg: ${arg}"
     done
     yum -y install "${@:1}"
   ```

1. Upload the script with the correct permissions to Amazon S3. If public read permissions aren't appropriate for you, use [`HeadNode`](HeadNode-v3.md) / [`Iam`](HeadNode-v3.md#HeadNode-v3-Iam) / [`S3Access`](HeadNode-v3.md#yaml-HeadNode-Iam-S3Access) and [`Scheduling`](Scheduling-v3.md) / [`SlurmQueues`](Scheduling-v3.md#Scheduling-v3-SlurmQueues) configuration sections. For more information, see [Working with Amazon S3](s3_resources-v3.md).

   ```
   $ aws s3 cp --acl public-read /path/to/myscript.sh s3://amzn-s3-demo-bucket/myscript.sh
   ```
**Important**  
If the script was edited on Windows, line endings must be changed from CRLF to LF before the script is uploaded to Amazon S3.

1. Update the AWS ParallelCluster configuration to include the new `OnNodeConfigured` action.

   ```
   CustomActions:
     OnNodeConfigured:
       Script: https://<amzn-s3-demo-bucket>.s3.<region>.amazonaws.com/myscript.sh
       Args:
         - "R"
         - "curl"
         - "wget"
   ```

   If the bucket doesn't have public-read permission, use `s3` as the URL protocol.

   ```
   CustomActions:
     OnNodeConfigured:
       Script: s3://amzn-s3-demo-bucket/myscript.sh
       Args:
         - "R"
         - "curl"
         - "wget"
   ```

1. Launch the cluster.

   ```
   $ pcluster create-cluster --cluster-name mycluster \
     --region <region> --cluster-configuration config-file.yaml
   ```

1. Verify the output.
   + If you added custom actions to the `HeadNode` configuration, log in to the head node and check the `cfn-init.log` file located at `/var/log/cfn-init.log` by running the following command:

     ```
     $ less /var/log/cfn-init.log
       2021-09-03 10:43:54,588 [DEBUG] Command run
       postinstall output: The script has 3 arguments
       arg: R
       arg: curl
       arg: wget
       Loaded plugins: dkms-build-requires, priorities, update-motd, upgrade-helper
       Package R-3.4.1-1.52.amzn1.x86_64 already installed and latest version
       Package curl-7.61.1-7.91.amzn1.x86_64 already installed and latest version
       Package wget-1.18-4.29.amzn1.x86_64 already installed and latest version
       Nothing to do
     ```
   + If you added custom actions to the `SlurmQueues` setting, check the `cloud-init.log` located at `/var/log/cloud-init.log` in a compute node. Use CloudWatch to view these logs.

   You can view both of these logs in the Amazon CloudWatch console. For more information, see [Integration with Amazon CloudWatch Logs](cloudwatch-logs-v3.md).