Getting started with AWS IoT Greengrass V2

To set up a Raspberry Pi for AWS IoT Greengrass V2

1. Enable SSH on your Raspberry Pi to remotely connect to it. For more information, see SSH (Secure shell) in the Raspberry Pi Documentation.

2. Find the IP address of your Raspberry Pi to connect to it with SSH. To do so, you can run the following command on your Raspberry Pi.

   hostname -I

3. Connect to your Raspberry Pi with SSH. On your development computer, run the following command. Replace username with the name of the user to sign in, and replace pi-ip-address with the IP address that you found in the previous step.

   ssh username@pi-ip-address

   The default Raspberry Pi user name and password are pi and raspberry, respectively.

   Important

   If your development computer uses an earlier version of Windows, you might not have the ssh command, or you might have ssh but can't connect to your Raspberry Pi. To connect to your Raspberry Pi, you can install and configure PuTTY, which is a no-cost, open source SSH client. Consult the PuTTY documentation to connect to your Raspberry Pi.

4. Install the Java runtime, which AWS IoT Greengrass Core software requires to run. On your Raspberry Pi, use the following commands to install Java 11.

   sudo apt install default-jdk

   When the installation completes, run the following command to verify that Java runs on your Raspberry Pi.

   java -version

   The command prints the version of Java that runs on the device. The output might look similar to the following example.

   openjdk version "11.0.9.1" 2020-11-04
   OpenJDK Runtime Environment (build 11.0.9.1+1-post-Debian-1deb10u2)
   OpenJDK 64-Bit Server VM (build 11.0.9.1+1-post-Debian-1deb10u2, mixed mode)

To install and configure the AWS IoT Greengrass Core software

1. On your AWS IoT Greengrass core device (your Raspberry Pi), run the following command to switch to the home directory.

   cd ~

2. Run the following command to download the AWS IoT Greengrass Core software.

   curl -s https://d2s8p88vqu9w66.cloudfront.net/releases/greengrass-nucleus-latest.zip > greengrass-nucleus-latest.zip

   By downloading this software, you agree to the Greengrass Core Software License Agreement.

3. Run the following command to unzip the software and remove the ZIP file. Replace GreengrassCore with the name of the destination folder.

   unzip greengrass-nucleus-latest.zip -d GreengrassCore && rm greengrass-nucleus-latest.zip

4. Provide your AWS credentials so that the installer can provision the AWS IoT and IAM resources for your core device. To increase security, you can get credentials for an IAM role that allows only the minimum permissions necessary to provision. For more information, see Minimal IAM policy for installer to provision resources.

   Do one of the following to retrieve credentials and provide them to the AWS IoT Greengrass Core software:

   • Use long-term credentials from an IAM user:

     1. Provide the access key ID and secret access key for your IAM user. For more information about how to retrieve long-term credentials, see Managing access keys for IAM users in the IAM User Guide.

     2. Run the following commands to provide the credentials to the AWS IoT Greengrass Core software.

        export AWS_ACCESS_KEY_ID=AKIAIOSFODNN7EXAMPLE
        export AWS_SECRET_ACCESS_KEY=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY

   • (Recommended) Use temporary security credentials from an IAM role:

     1. Provide the access key ID, secret access key, and session token from an IAM role that you assume. For more information about how to retrieve these credentials, see Using temporary security credentials with the AWS CLI in the IAM User Guide.

     2. Run the following commands to provide the credentials to the AWS IoT Greengrass Core software.

        export AWS_ACCESS_KEY_ID=AKIAIOSFODNN7EXAMPLE
        export AWS_SECRET_ACCESS_KEY=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
        export AWS_SESSION_TOKEN=AQoDYXdzEJr1K...o5OytwEXAMPLE=

   The AWS IoT Greengrass Core software doesn't save or store your credentials.

5. Run the following command to launch the AWS IoT Greengrass Core software installer. If your core device has systemd, this command installs the software as a system service that runs on boot. This command also specifies to use the ggc_user system user and ggc_group system group to run software components on the core device. The installer creates this default user and group for you. Replace argument values in your command as follows.

   1. /greengrass/v2: The path to the root folder to use to install the AWS IoT Greengrass Core software.

   2. GreengrassCore. The path to the folder where you unpacked the AWS IoT Greengrass Core software installer.

   3. region. The AWS Region in which to find or create resources.

   4. MyGreengrassCore. The name of the AWS IoT thing for your Greengrass core device. If the thing doesn't exist, the installer creates it. The installer downloads the certificates to authenticate as the AWS IoT thing. For more information, see Device authentication and authorization for AWS IoT Greengrass.

      Note

      The thing name can't contain colon (:) characters.

   5. MyGreengrassCoreGroup. The name of AWS IoT thing group for your Greengrass core device. If the thing group doesn't exist, the installer creates it and adds the thing to it. If the thing group exists and has an active deployment, the core device downloads and runs the software that the deployment specifies.

      Note

      The thing group name can't contain colon (:) characters.

   6. GreengrassV2TokenExchangeRole. The name of the IAM role that allows the Greengrass core device to get temporary AWS credentials. If the role doesn't exist, the installer creates it and creates and attaches a policy named GreengrassV2TokenExchangeRoleAccess. For more information, see Authorize core devices to interact with AWS services.

   7. GreengrassCoreTokenExchangeRoleAlias. The alias to the IAM role that allows the Greengrass core device to get temporary credentials later. If the role alias doesn't exist, the installer creates it and points it to the IAM role that you specify. For more information, see Authorize core devices to interact with AWS services.

   sudo -E java -Droot="/greengrass/v2" -Dlog.store=FILE \
     -jar ./GreengrassCore/lib/Greengrass.jar \
     --aws-region region \
     --thing-name MyGreengrassCore \
     --thing-group-name MyGreengrassCoreGroup \
     --tes-role-name GreengrassV2TokenExchangeRole \
     --tes-role-alias-name GreengrassCoreTokenExchangeRoleAlias \
     --component-default-user ggc_user:ggc_group \
     --provision true \
     --setup-system-service true \
     --deploy-dev-tools true

   Note

   If you are running AWS IoT Greengrass on a device with limited memory, you can control the amount of memory that AWS IoT Greengrass Core software uses. To control memory allocation, you can set JVM heap size options in the jvmOptions configuration parameter in your nucleus component. For more information, see Control memory allocation with JVM options.

   When you run this command, you should see the following messages to indicate that the installer succeeded.

   Successfully configured Nucleus with provisioned resource details!
   Configured Nucleus to deploy aws.greengrass.Cli component
   Successfully set up Nucleus as a system service

   Note

   If your system doesn't have systemd, the installer won't set up the software as a system service, and you won't see that success message.

6. The local development tools can take up to a minute to deploy. You can run the following command to check the status of the deployment. Replace MyGreengrassCore with the name of your core device.

   aws greengrassv2 list-effective-deployments --core-device-thing-name MyGreengrassCore

   The coreDeviceExecutionStatus indicates the status of the deployment to the core device. When the status is SUCCEEDED, run the following command to verify that the Greengrass CLI is installed and runs. Replace /greengrass/v2 with the path to the root folder.

   /greengrass/v2/bin/greengrass-cli help

   The command outputs help information for the Greengrass CLI. If the greengrass-cli isn't found, the deployment might have failed to install the Greengrass CLI. For more information, see Troubleshooting.

   You can also run the following command to manually deploy the AWS IoT Greengrass CLI to your device.

   • Replace region with the Region that you use.

   • Replace account-id with your AWS account ID.

   • Replace MyGreengrassCore with the name of your core device.

   Linux, macOS, or Unix

   aws greengrassv2 create-deployment \
     --target-arn "arn:aws:iot:region:account-id:thing/MyGreengrassCore" \
     --components '{
       "aws.greengrass.Cli": {
         "componentVersion": "2.1.0"
       }
     }'

   Windows (CMD)

   aws greengrassv2 create-deployment ^
     --target-arn "arn:aws:iot:region:account-id:thing/MyGreengrassCore" ^
     --components "{\"aws.greengrass.Cli\":{\"componentVersion\":\"2.1.0\"}}"

   Windows (PowerShell)

   aws greengrassv2 create-deployment `
     --target-arn "arn:aws:iot:region:account-id:thing/MyGreengrassCore" `
     --components '{\"aws.greengrass.Cli\":{\"componentVersion\":\"2.1.0\"}}'

   Tip

   You can add /greengrass/v2/bin to your PATH environment variable to run greengrass-cli without its absolute path.

7. If you installed the software as a system service, the installer runs the software for you. Otherwise, you must run the software. To see if the installer set up the software as a system service, look for the following line in the installer output.

   Successfully set up Nucleus as a system service

   If you don't see this message, do the following to run the software:

   1. Run the following command to run the software.

      sudo /greengrass/v2/alts/current/distro/bin/loader

      The software prints the following message if it launches successfully.

      Launched Nucleus successfully.

   2. You must leave the current terminal session open to keep the AWS IoT Greengrass Core software running. On your development computer, run the following command to open a second SSH session that you can use to run additional commands on the core device. Replace username with the name of the user to sign in, and replace pi-ip-address with the IP address of the device.

      ssh username@pi-ip-address

   For more information about how to interact with the Greengrass system service, see Configure AWS IoT Greengrass as a system service.

To create a Hello World component

1. On your Greengrass core device, run the following command to change to the AWS IoT Greengrass installation folder to use for local development. Replace ~/GreengrassCore with the path to the installation folder.

   cd ~/GreengrassCore

2. AWS IoT Greengrass expects that component recipes and artifacts are in separate folders.

   Run the following command to create a folder for the component recipe.

   mkdir recipes

3. Run the following command to create the recipe file and open it in a text editor.

   JSON

   nano recipes/com.example.HelloWorld-1.0.0.json

   YAML

   nano recipes/com.example.HelloWorld-1.0.0.yaml

   Paste the following recipe into the file.

   JSON

   {
     "RecipeFormatVersion": "2020-01-25",
     "ComponentName": "com.example.HelloWorld",
     "ComponentVersion": "1.0.0",
     "ComponentDescription": "My first AWS IoT Greengrass component.",
     "ComponentPublisher": "Amazon",
     "ComponentConfiguration": {
       "DefaultConfiguration": {
         "Message": "world"
       }
     },
     "Manifests": [
       {
         "Platform": {
           "os": "linux"
         },
         "Lifecycle": {
           "Run": "python3 -u {artifacts:path}/hello_world.py '{configuration:/Message}'"
         }
       }
     ]
   }

   YAML

   ---
   RecipeFormatVersion: 2020-01-25
   ComponentName: com.example.HelloWorld
   ComponentVersion: '1.0.0'
   ComponentDescription: My first AWS IoT Greengrass component.
   ComponentPublisher: Amazon
   ComponentConfiguration:
     DefaultConfiguration:
       Message: world
   Manifests:
     - Platform:
         os: linux
       Lifecycle:
         Run: |
           python3 -u {artifacts:path}/hello_world.py '{configuration:/Message}'

   This recipe's ComponentConfiguration section defines a parameter, Message, that defaults to world. The Manifests section defines a manifest, which is a set of lifecycle instructions and artifacts for a platform. You can define multiple manifests to specify different install instructions for various platforms, for example. In the manifest, the Lifecycle section instructs the Greengrass core device to run the Hello World script with the Message parameter value as an argument.

4. Run the following command to create a folder for the component artifacts.

   mkdir -p artifacts/com.example.HelloWorld/1.0.0

   Important

   You must use the following format for the artifact folder path. Include the component name and version that you specify in the recipe.

   artifacts/componentName/componentVersion/

5. Run the following command to create a Python script artifact file and open it in a text editor.

   nano artifacts/com.example.HelloWorld/1.0.0/hello_world.py

   Paste the following Python script into the file.

   import sys
   import datetime
   
   message = "Hello, %s! Current time: %s." % (sys.argv[1], datetime.datetime.now())
   
   # Print the message to stdout.
   print(message)
   
   # Append the message to the log file.
   with open('/tmp/Greengrass_HelloWorld.log', 'a') as f:
       print(message, file=f)

   This Python script logs a hello message and the current time to /tmp/Greengrass_HelloWorld.log.

6. Use the local AWS IoT Greengrass CLI to manage components on your Greengrass core device.

   Run the following command to deploy the component to the AWS IoT Greengrass core. Replace /greengrass/v2 with your AWS IoT Greengrass V2 root folder, and replace ~/GreengrassCore with your AWS IoT Greengrass V2 installation folder.

   sudo /greengrass/v2/bin/greengrass-cli deployment create \
     --recipeDir ~/GreengrassCore/recipes \
     --artifactDir ~/GreengrassCore/artifacts \
     --merge "com.example.HelloWorld=1.0.0"

   This command adds the component that uses the recipe in recipes and the Python script in artifacts. The --merge option adds or updates the component and version that you specify.

7. Run the following command to verify that the Hello World component runs and logs messages.

   tail -f /tmp/Greengrass_HelloWorld.log

   You should see messages similar to the following example.

   Hello, world! Current time: 2020-11-30 17:48:59.153933.

   Note

   If the tail command tells you that the file doesn't exist, the local deployment may not be complete yet. If the file doesn't exist within 15 seconds, the deployment likely failed. This can occur if your recipe isn't valid, for example. Run the following command to view the AWS IoT Greengrass core log file. This file includes logs from the Greengrass core device's deployment service.

   sudo tail -f /greengrass/v2/logs/greengrass.log

   You can also view the log file for your Hello World component.

   sudo tail -f /greengrass/v2/logs/com.example.HelloWorld.log

   For more information, see Troubleshooting.

8. Modify the local component to iterate and test your code.

   Run the following command to edit hello_world.py.

   nano artifacts/com.example.HelloWorld/1.0.0/hello_world.py

9. Add the following code at line 5 to edit the message that the AWS IoT Greengrass core logs.

   message += " Greetings from your first Greengrass component."

   The hello_world.py script should now have the following contents.

   import sys
   import datetime
   
   message = "Hello, %s! Current time: %s." % (sys.argv[1], datetime.datetime.now())
   message += " Greetings from your first Greengrass component."
   # Print the message to stdout.
   print(message)
   
   # Append the message to the log file.
   with open('/tmp/Greengrass_HelloWorld.log', 'a') as f:
       print(message, file=f)

10. Run the following command to update the component with your changes.

    sudo /greengrass/v2/bin/greengrass-cli deployment create \
      --recipeDir ~/GreengrassCore/recipes \
      --artifactDir ~/GreengrassCore/artifacts \
      --merge "com.example.HelloWorld=1.0.0"

    This command applies the latest Hello World artifact to the AWS IoT Greengrass core runtime.

11. Run the following command to restart the component. When you restart a component, the core device uses the latest changes.

    sudo /greengrass/v2/bin/greengrass-cli component restart \
      --names "com.example.HelloWorld"

12. Check the log again to verify that the Hello World component outputs the new message.

    tail -f /tmp/Greengrass_HelloWorld.log

    You should see messages similar to the following example.

    Hello, world! Current time: 2020-11-30 17:48:59.153933. Greetings from your first Greengrass component.

13. You can update the component's configuration parameters to test different configurations. When you deploy a component, you can specify a configuration update, which defines how to modify the component's configuration on the core device. You can specify which configuration values to reset to default values and the new configuration values to merge onto the core device. For more information, see Update component configurations.

    Do the following:

    1. Create a file called hello-world-config-update.json to contain the configuration update.

       nano hello-world-config-update.json

    2. Copy the following JSON object into the file. This JSON object defines a configuration update that merges the value friend to the Message parameter to update its value. This configuration update doesn't specify any values to reset. You don't need to reset the Message parameter because the merge update replaces the existing value.

       {
         "com.example.HelloWorld": {
           "MERGE": {
             "Message": "friend"
           }
         }
       }

    3. Run the following command to deploy the configuration update to the Hello World component.

       sudo /greengrass/v2/bin/greengrass-cli deployment create \
         --merge "com.example.HelloWorld=1.0.0" \
         --update-config hello-world-config-update.json

    4. Check the log again to verify that the Hello World component outputs the new message.

       tail -f /tmp/Greengrass_HelloWorld.log

       You should see messages similar to the following example.

       Hello, friend! Current time: 2020-11-30 17:48:59.153933. Greetings from your first Greengrass component.

14. After you finish testing your component, remove it from your core device. This is required for you to deploy the component back to the core device after you upload it to AWS IoT Greengrass. Otherwise, the deployment fails with a version compatibility error because the local deployment specifies a different version of the component. Run the following command.

    sudo /greengrass/v2/bin/greengrass-cli deployment create --remove="com.example.HelloWorld"

To upload your Hello World component

1. Use an S3 bucket in your AWS account to host AWS IoT Greengrass component artifacts. When you deploy the component to a core device, the device downloads the component's artifacts from the bucket.

   You can use an existing S3 bucket, or run the following command to create a bucket. This command creates a bucket with your AWS account ID and AWS Region to form a unique bucket name. Replace 123456789012 with your AWS account ID and region with the AWS Region that you use for this tutorial.

   aws s3 mb s3://greengrass-component-artifacts-123456789012-region

   The command outputs the following information if the request succeeds.

   make_bucket: greengrass-component-artifacts-123456789012-region

2. Allow the core device to access component artifacts in the S3 bucket. Each core device has a core device IAM role that allows it to interact with AWS IoT and send logs to the AWS Cloud. This device role doesn't allow access to S3 buckets by default, so you must create and attach a policy that allows the core device to retrieve component artifacts from the S3 bucket.

   If your device's role already allows access to the S3 bucket, you can skip this step. Otherwise, create an IAM policy that allows access and attach it to the role, as follows:

   1. Create a file called component-artifact-policy.json and copy the following JSON into the file. This policy allows access to all files in the S3 bucket that you created in the previous step. Replace DOC-EXAMPLE-BUCKET with the name of the bucket to use.

      {
        "Version": "2012-10-17",
        "Statement": [
          {
            "Effect": "Allow",
            "Action": [
              "s3:GetObject"
            ],
            "Resource": "arn:aws:s3:::DOC-EXAMPLE-BUCKET/*"
          }
        ]
      }

   2. Run the following command to create the policy from the policy document in component-artifact-policy.json.

      aws iam create-policy \
        --policy-name MyGreengrassV2ComponentArtifactPolicy \
        --policy-document file://component-artifact-policy.json

      Copy the policy Amazon Resource Name (ARN) from the policy metadata in the output. You use this ARN to attach this policy to the core device role in the next step.

   3. Run the following command to attach the policy to the core device role. Replace GreengrassV2TokenExchangeRole with the name of the role that you specified when you ran the AWS IoT Greengrass Core software. Replace the policy ARN with the ARN from the previous step.

      aws iam attach-role-policy \
        --role-name GreengrassV2TokenExchangeRole \
        --policy-arn arn:aws:iam::123456789012:policy/MyGreengrassV2ComponentArtifactPolicy

      If the command has no output, it succeeded, and your core device can access artifacts that you upload to this S3 bucket.

3. Upload the Hello World Python script artifact to the S3 bucket. Run the following command to upload the script to the same path in the bucket where the script exists on your AWS IoT Greengrass core. Replace DOC-EXAMPLE-BUCKET with the name of the S3 bucket.

   aws s3 cp \
     artifacts/com.example.HelloWorld/1.0.0/hello_world.py \
     s3://DOC-EXAMPLE-BUCKET/artifacts/com.example.HelloWorld/1.0.0/hello_world.py

   The command outputs a line that starts with upload: if the request succeeds.

4. Add the artifact's Amazon S3 URI to the component recipe. The Amazon S3 URI is composed of the bucket name and the path to the artifact object in the bucket. Your script artifact's Amazon S3 URI is the URI that you upload the artifact to in the previous step. This URI should look similar to the following example. Replace DOC-EXAMPLE-BUCKET with the name of the S3 bucket.

   s3://DOC-EXAMPLE-BUCKET/artifacts/com.example.HelloWorld/1.0.0/hello_world.py

   To add the artifact to the recipe, add a list of Artifacts that contains a structure with the Amazon S3 URI.

   JSON

   "Artifacts": [
     {
       "URI": "s3://DOC-EXAMPLE-BUCKET/artifacts/com.example.HelloWorld/1.0.0/hello_world.py"
     }
   ]

   Run the following command to open the recipe file.

   nano recipes/com.example.HelloWorld-1.0.0.json

   Add the artifact to the recipe. Your recipe file should look similar to the following example.

   {
     "RecipeFormatVersion": "2020-01-25",
     "ComponentName": "com.example.HelloWorld",
     "ComponentVersion": "1.0.0",
     "ComponentDescription": "My first Greengrass component.",
     "ComponentPublisher": "Amazon",
     "ComponentConfiguration": {
       "DefaultConfiguration": {
         "Message": "world"
       }
     },
     "Manifests": [
       {
         "Platform": {
           "os": "linux"
         },
         "Lifecycle": {
           "Run": "python3 -u {artifacts:path}/hello_world.py '{configuration:/Message}'"
         },
         "Artifacts": [
           {
             "URI": "s3://DOC-EXAMPLE-BUCKET/artifacts/com.example.HelloWorld/1.0.0/hello_world.py"
           }
         ]
       }
     ]
   }

   YAML

   Artifacts:
     - URI: s3://DOC-EXAMPLE-BUCKET/artifacts/com.example.HelloWorld/1.0.0/hello_world.py

   Run the following command to open the recipe file.

   nano recipes/com.example.HelloWorld-1.0.0.yaml

   Add the artifact to the recipe. Your recipe file should look similar to the following example.

   ---
   RecipeFormatVersion: 2020-01-25
   ComponentName: com.example.HelloWorld
   ComponentVersion: '1.0.0'
   ComponentDescription: My first AWS IoT Greengrass component.
   ComponentPublisher: Amazon
   ComponentConfiguration:
     DefaultConfiguration:
       Message: world
   Manifests:
     - Platform:
         os: linux
       Lifecycle:
         Run: |
           python3 -u {artifacts:path}/hello_world.py '{configuration:/Message}'
       Artifacts:
         - URI: s3://DOC-EXAMPLE-BUCKET/artifacts/com.example.HelloWorld/1.0.0/hello_world.py

5. Create a component resource in AWS IoT Greengrass from the recipe. Run the following command to create the component from the recipe, which you provide as a binary file.

   JSON

   aws greengrassv2 create-component-version \
     --inline-recipe fileb://recipes/com.example.HelloWorld-1.0.0.json

   YAML

   aws greengrassv2 create-component-version \
     --inline-recipe fileb://recipes/com.example.HelloWorld-1.0.0.yaml

   The response looks similar to the following example if the request succeeds.

   {
     "arn": "arn:aws:greengrass:region:123456789012:components:com.example.HelloWorld:versions:1.0.0",
     "componentName": "com.example.HelloWorld",
     "componentVersion": "1.0.0",
     "creationTimestamp": "Mon Nov 30 09:04:05 UTC 2020",
     "status": {
       "componentState": "REQUESTED",
       "message": "NONE",
       "errors": {}
     }
   }

   Copy the arn from the output to check the state of the component in the next step.

   Note

   You can also see your Hello World component in the AWS IoT Greengrass console on the Components page.

6. Verify that the component creates and is ready to be deployed. When you create a component, its state is REQUESTED. Then, AWS IoT Greengrass validates that the component is deployable. You can run the following command to query the component status and verify that your component is deployable. Replace the arn with the ARN from the previous step.

   aws greengrassv2 describe-component \
     --arn "arn:aws:greengrass:region:123456789012:components:com.example.HelloWorld:versions:1.0.0"

   If the component validates, the response indicates that the component state is DEPLOYABLE.

   {
     "arn": "arn:aws:greengrass:region:123456789012:components:com.example.HelloWorld:versions:1.0.0",
     "componentName": "com.example.HelloWorld",
     "componentVersion": "1.0.0",
     "creationTimestamp": "2020-11-30T18:04:05.823Z",
     "publisher": "Amazon",
     "description": "My first Greengrass component.",
     "status": {
       "componentState": "DEPLOYABLE",
       "message": "NONE",
       "errors": {}
     },
     "platforms": [
       {
         "os": "linux",
         "architecture": "all"
       }
     ]
   }

To deploy your Hello World component

1. On your development computer, create a file called hello-world-deployment.json and copy the following JSON into the file. This file defines the components and configurations to deploy.

   {
     "components": {
       "com.example.HelloWorld": {
         "componentVersion": "1.0.0",
         "configurationUpdate": {
           "merge": "{\"Message\":\"universe\"}"
         }
       }
     }
   }

   This configuration file specifies to deploy version 1.0.0 of the Hello World component that you developed and published in the previous procedure. The configurationUpdate specifies to merge the component configuration in a JSON-encoded string. This configuration update sets the Hello World Message parameter to universe for the device in this deployment.

2. Run the following command to deploy the component to your Greengrass core device. You can deploy to things, which are individual devices, or thing groups, which are groups of devices. Replace MyGreengrassCore with the name of the AWS IoT thing for your core device.

   aws greengrassv2 create-deployment \
     --target-arn "arn:aws:iot:region:account-id:thing/MyGreengrassCore" \
     --cli-input-json file://hello-world-deployment.json

   The command outputs a response similar to the following example.

   {
     "deploymentId": "deb69c37-314a-4369-a6a1-3dff9fce73a9",
     "iotJobId": "b5d92151-6348-4941-8603-bdbfb3e02b75",
     "iotJobArn": "arn:aws:iot:region:account-id:job/b5d92151-6348-4941-8603-bdbfb3e02b75"
   }

3. Verify that the deployment completes successfully. The deployment can take several minutes to complete. Check the Hello World log to verify the change. Run the following command on your Greengrass core device.

   tail -f /tmp/Greengrass_HelloWorld.log

   You should see messages similar to the following example.

   Hello, universe! Current time: 2020-11-30 18:18:59.153933. Greetings from your first Greengrass component.

   Note

   If the log messages don't change, the deployment failed or didn't reach the core device. This can occur if your core device isn't connected to the internet or doesn't have permissions to retrieve artifacts from your S3 bucket. Run the following command on your core device to view the AWS IoT Greengrass Core software log file. This file includes logs from the Greengrass core device's deployment service.

   sudo tail -f /greengrass/v2/logs/greengrass.log

   For more information, see Troubleshooting.