Environment setup for Greengrass

NoteOn platforms that require a reboot, your input values from the previous session, excluding credentials, are temporarily stored in the GreengrassDeviceSetup.config.info ﬁle.

When the setup is complete, the terminal displays a success status message that's similar to the following.

3. If you included the Hello World Lambda function, Greengrass device setup deploys the Greengrass group to your core device. To test the Lambda function, or for information about how to remove the Lambda function from the group, continue to the section called “Verify the Lambda function is running on the core device” (p. 150) in Module 3-1 of the Getting Started tutorial.

NoteMake sure that the AWS Region selected in the console is the same one that you used to conﬁgure your Greengrass environment. By default, the Region is US West (Oregon).

If you didn't include the Hello World Lambda function, you can create your own Lambda

function (p. 139) or try other Greengrass features. For example, you can add the Docker application deployment (p. 448) connector to your group and use it to deploy Docker containers to your core device.

Module 1: Environment setup for Greengrass

This module shows you how to get an out-of-the-box Raspberry Pi, Amazon EC2 instance, or other device ready to be used by AWS IoT Greengrass as your AWS IoT Greengrass core device.

TipOr, to use a script that sets up your core device for you, see the section called “Quick start:

Greengrass device setup” (p. 108).

This module should take less than 30 minutes to complete.

Before you begin, read the requirements (p. 107) for this tutorial. Then, follow the setup instructions in one of the following topics. Choose only the topic that applies to your core device type.

Topics

Setting up a Raspberry Pi

• Setting up a Raspberry Pi (p. 119)

• Setting up an Amazon EC2 instance (p. 125)

• Setting up other devices (p. 129)

Note

To learn how to use AWS IoT Greengrass running in a prebuilt Docker container, see the section called “Run AWS IoT Greengrass in a Docker container” (p. 251).

Setting up a Raspberry Pi

Follow the steps in this topic to set up a Raspberry Pi to use as your AWS IoT Greengrass core.

TipAWS IoT Greengrass also provides other options for installing the AWS IoT Greengrass Core software. For example, you can use Greengrass device setup (p. 108) to conﬁgure your environment and install the latest version of the AWS IoT Greengrass Core software. Or, on supported Debian platforms, you can use the APT package manager (p. 30) to install or upgrade the AWS IoT Greengrass Core software. For more information, see the section called “Install the AWS IoT Greengrass Core software” (p. 30).

If you are setting up a Raspberry Pi for the ﬁrst time, you must follow all of these steps. Otherwise, you can skip to step 9 (p. 123). However, we recommend that you re-image your Raspberry Pi with the operating system as recommended in step 2.

1. Download and install an SD card formatter such as SD Memory Card Formatter. Insert the SD card into your computer. Start the program and choose the drive where you have inserted your SD card.

You can perform a quick format of the SD card.

2. Download the Raspbian Buster operating system as a zip ﬁle.

3. Using an SD card-writing tool (such as Etcher), follow the tool's instructions to ﬂash the downloaded zip ﬁle onto the SD card. Because the operating system image is large, this step might take some time. Eject your SD card from your computer, and insert the microSD card into your Raspberry Pi.

4. For the ﬁrst boot, we recommend that you connect the Raspberry Pi to a monitor (through HDMI), a keyboard, and a mouse. Next, connect your Pi to a micro USB power source and the Raspbian operating system should start up.

5. You might want to conﬁgure the Pi's keyboard layout before you continue. To do so, choose the Raspberry icon in the upper-right, choose Preferences and then choose Mouse and Keyboard Settings. Next, on the Keyboard tab, choose Keyboard Layout, and then choose an appropriate keyboard variant.

6. Next, connect your Raspberry Pi to the internet through a Wi-Fi network or an Ethernet cable.

NoteConnect your Raspberry Pi to the same network that your computer is connected to, and be sure that both your computer and Raspberry Pi have internet access before you continue. If you're in a work environment or behind a ﬁrewall, you might need to connect your Pi and your computer to the guest network to get both devices on the same network. However, this approach might disconnect your computer from local network resources, such as your intranet. One solution is to connect the Pi to the guest Wi-Fi network and to connect your computer to the guest Wi-Fi network and your local network through an Ethernet cable. In this conﬁguration, your computer should be able to connect to the Raspberry Pi through the guest Wi-Fi network and your local network resources through the Ethernet cable.

7. You must set up SSH on your Pi to remotely connect to it. On your Raspberry Pi, open a terminal window and run the following command:

Setting up a Raspberry Pi

sudo raspi-config

You should see the following:

Scroll down and choose Interfacing Options and then choose P2 SSH. When prompted, choose Yes. (Use the Tab key followed by Enter). SSH should now be enabled. Choose OK. Use the Tab key to choose Finish and then press Enter. If the Raspberry Pi doesn't reboot automatically, run the following command:

sudo reboot

8. On your Raspberry Pi, run the following command in the terminal:

hostname -I

This returns the IP address of your Raspberry Pi.

NoteFor the following, if you receive an ECDSA key ﬁngerprint message (Are you sure you want to continue connecting (yes/no)?), enter yes. The default password for the Raspberry Pi is raspberry.

If you are using macOS, open a terminal window and enter the following:

ssh pi@IP-address

IP-address is the IP address of your Raspberry Pi that you obtained by using the hostname -I command.

If you are using Windows, you need to install and conﬁgure PuTTY. Expand Connection, choose Data, and make sure that Prompt is selected:

Setting up a Raspberry Pi

Next, choose Session, enter the IP address of the Raspberry Pi, and then choose Open using default settings.

Setting up a Raspberry Pi

If a PuTTY security alert is displayed, choose Yes.

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

Setting up a Raspberry Pi

NoteIf your computer is connected to a remote network using VPN, you might have diﬃculty connecting from the computer to the Raspberry Pi using SSH.

9. You are now ready to set up the Raspberry Pi for AWS IoT Greengrass. First, run the following commands from a local Raspberry Pi terminal window or an SSH terminal window:

sudo adduser --system ggc_user sudo addgroup --system ggc_group

10. To improve security on the Pi device, enable hardlink and softlink (symlink) protection on the operating system at startup.

a. Navigate to the 98-rpi.conf ﬁle.

cd /etc/sysctl.d ls

Note

If you don't see the 98-rpi.conf ﬁle, follow the instructions in the README.sysctl ﬁle.

b. Use a text editor (such as Leafpad, GNU nano, or vi) to add the following two lines to the end of the ﬁle. You might need to use the sudo command to edit as root (for example, sudo nano 98-rpi.conf).

fs.protected_hardlinks = 1 fs.protected_symlinks = 1 c. Reboot the Pi.

sudo reboot

After about a minute, connect to the Pi using SSH and then run the following command to conﬁrm the change:

sudo sysctl -a 2> /dev/null | grep fs.protected

You should see fs.protected_hardlinks = 1 and fs.protected_symlinks = 1.

11. Edit your command line boot ﬁle to enable and mount memory cgroups. This allows AWS IoT Greengrass to set the memory limit for Lambda functions. Cgroups are also required to run AWS IoT Greengrass in the default containerization (p. 242) mode.

a. Navigate to your boot directory.

cd /boot/

Setting up a Raspberry Pi

b. Use a text editor to open cmdline.txt. Append the following to the end of the existing line, not as a new line. You might need to use the sudo command to edit as root (for example, sudo nano cmdline.txt).

cgroup_enable=memory cgroup_memory=1 c. Now reboot the Pi.

sudo reboot

Your Raspberry Pi should now be ready for AWS IoT Greengrass.

12. Optional. Install the Java 8 runtime, which is required by stream manager (p. 343). This tutorial doesn't use stream manager, but it does use the Default Group creation workﬂow that enables stream manager by default. Use the following commands to install the Java 8 runtime on the core device, or disable stream manager before you deploy your group. Instructions for disabling stream manager are provided in Module 3.

sudo apt install openjdk-8-jdk

13. To make sure that you have all required dependencies, download and run the Greengrass

dependency checker from the AWS IoT Greengrass Samples repository on GitHub. These commands unzip and run the dependency checker script in the Downloads directory.

NoteThe dependency checker might fail if you are running version 5.4.51 of the Raspbian kernel.

This version does not mount memory cgroups correctly. This might cause Lambda functions running in container mode to fail.

For more information on updating your kernel, see the Cgroups not loaded after kernel upgrade in the Raspberry Pi forums.

cd /home/pi/Downloads

mkdir greengrass-dependency-checker-GGCv1.11.x cd greengrass-dependency-checker-GGCv1.11.x

wget https://github.com/aws-samples/aws-greengrass-samples/raw/master/greengrass-dependency-checker-GGCv1.11.x.zip

unzip greengrass-dependency-checker-GGCv1.11.x.zip cd greengrass-dependency-checker-GGCv1.11.x sudo modprobe configs

sudo ./check_ggc_dependencies | more

Where more appears, press the Spacebar key to display another screen of text.

Important

This tutorial requires the Python 3.7 runtime to run local Lambda functions. When stream manager is enabled, it also requires the Java 8 runtime. If the check_ggc_dependencies script produces warnings about these missing runtime prerequisites, make sure to install them before you continue. You can ignore warnings about other missing optional runtime prerequisites.

For information about the modprobe command, run man modprobe in the terminal.

Your Raspberry Pi conﬁguration is complete. Continue to the section called “Module 2: Installing the AWS IoT Greengrass Core software” (p. 131).

Setting up an Amazon EC2 instance

Follow the steps in this topic to set up an Amazon EC2 instance to use as your AWS IoT Greengrass core.

TipOr, to use a script that sets up your environment and installs the AWS IoT Greengrass Core software for you, see the section called “Quick start: Greengrass device setup” (p. 108).

Although you can complete this tutorial using an Amazon EC2 instance, AWS IoT Greengrass should ideally be used with physical hardware. We recommend that you set up a Raspberry Pi (p. 119) instead of using an Amazon EC2 instance when possible. If you're using a Raspberry Pi, you do not need to follow the steps in this topic.

1. Sign in to the AWS Management Console and launch an Amazon EC2 instance using an Amazon Linux AMI. For information about Amazon EC2 instances, see the Amazon EC2 Getting Started Guide.

2. After your Amazon EC2 instance is running, enable port 8883 to allow incoming MQTT communications so that other devices can connect with the AWS IoT Greengrass core.

a. In the navigation pane of the Amazon EC2 console, choose Security Groups.

b. Select the security group for the instance that you just launched, and then choose the Inbound tab.

Setting up an Amazon EC2 instance

c. Choose Edit.

To enable port 8883, you add a custom TCP rule to the security group. For more information, see Adding rules to a security group in the Amazon EC2 User Guide for Linux Instances.

d. On the Edit inbound rules page, choose Add Rule, enter the following settings, and then choose Save.

• For Type, choose Custom TCP Rule.

• For Port Range, enter 8883.

• For Source, choose Anywhere.

• For Description, enter MQTT Communications.

3. Connect to your Amazon EC2 instance.

a. In the navigation pane, choose Instances, choose your instance, and then choose Connect.

b. Follow the instructions on the Connect To Your Instance page to connect to your instance by using SSH and your private key ﬁle.

Setting up an Amazon EC2 instance

You can use PuTTY for Windows or Terminal for macOS. For more information, see Connect to your Linux instance in the Amazon EC2 User Guide for Linux Instances.

You are now ready to set up your Amazon EC2 instance for AWS IoT Greengrass.

4. After you are connected to your Amazon EC2 instance, create the ggc_user and ggc_group accounts:

sudo adduser --system ggc_user sudo groupadd --system ggc_group

NoteIf the adduser command isn't available on your system, use the following command.

sudo useradd --system ggc_user

5. To improve security, make sure that hardlink and softlink (symlink) protections are enabled on the operating system of the Amazon EC2 instance at startup.

NoteThe steps for enabling hardlink and softlink protection vary by operating system. Consult the documentation for your distribution.

a. Run the following command to check if hardlink and softlink protections are enabled:

sudo sysctl -a | grep fs.protected

Setting up an Amazon EC2 instance

If hardlinks and softlinks are set to 1, your protections are enabled correctly. Proceed to step 6.

NoteSoftlinks are represented by fs.protected_symlinks.

b. If hardlinks and softlinks are not set to 1, enable these protections. Navigate to your system conﬁguration ﬁle.

cd /etc/sysctl.d ls

c. Using your favorite text editor (Leafpad, GNU nano, or vi), add the following two lines to the end of the system conﬁguration ﬁle. On Amazon Linux 1, this is the 00-defaults.conf ﬁle.

On Amazon Linux 2, this is the 99-amazon.conf ﬁle. You might need to change permissions (using the chmod command) to write to the ﬁle, or use the sudo command to edit as root (for example, sudo nano 00-defaults.conf).

fs.protected_hardlinks = 1 fs.protected_symlinks = 1 d. Reboot the Amazon EC2 instance.

sudo reboot

After a few minutes, connect to your instance using SSH and then run the following command to conﬁrm the change.

sudo sysctl -a | grep fs.protected

You should see that hardlinks and softlinks are set to 1.

6. Extract and run the following script to mount Linux control groups (cgroups). This allows AWS IoT Greengrass to set the memory limit for Lambda functions. Cgroups are also required to run AWS IoT Greengrass in the default containerization (p. 242) mode.

curl

https://raw.githubusercontent.com/tianon/cgroupfs-mount/951c38ee8d802330454bdede20d85ec1c0f8d312/cgroupfs-mount > cgroupfs-mount.sh chmod +x cgroupfs-mount.sh

sudo bash ./cgroupfs-mount.sh

Your Amazon EC2 instance should now be ready for AWS IoT Greengrass.

7. Optional. Install the Java 8 runtime, which is required by stream manager (p. 343). This tutorial doesn't use stream manager, but it does use the Default Group creation workﬂow that enables stream manager by default. Use the following commands to install the Java 8 runtime on the core device, or disable stream manager before you deploy your group. Instructions for disabling stream manager are provided in Module 3.

• For Debian-based distributions:

sudo apt install openjdk-8-jdk

• For Red Hat-based distributions:

sudo yum install java-1.8.0-openjdk

Setting up other devices

8. To make sure that you have all required dependencies, download and run the Greengrass

dependency checker from the AWS IoT Greengrass Samples repository on GitHub. These commands download, unzip, and run the dependency checker script in your Amazon EC2 instance.

mkdir greengrass-dependency-checker-GGCv1.11.x cd greengrass-dependency-checker-GGCv1.11.x

wget https://github.com/aws-samples/aws-greengrass-samples/raw/master/greengrass-dependency-checker-GGCv1.11.x.zip

unzip greengrass-dependency-checker-GGCv1.11.x.zip cd greengrass-dependency-checker-GGCv1.11.x sudo ./check_ggc_dependencies | more

Important

Your Amazon EC2 instance conﬁguration is complete. Continue to the section called “Module 2: Installing the AWS IoT Greengrass Core software” (p. 131).

Setting up other devices

Follow the steps in this topic to set up a device (other than a Raspberry Pi) to use as your AWS IoT Greengrass core.

TipOr, to use a script that sets up your environment and installs the AWS IoT Greengrass Core software for you, see the section called “Quick start: Greengrass device setup” (p. 108).

If you're new to AWS IoT Greengrass, we recommend that you use a Raspberry Pi or an Amazon EC2 instance as your core device, and follow the setup steps (p. 118) appropriate for your device.

If you plan to build a custom Linux-based system using the Yocto Project, you can use the AWS IoT Greengrass Bitbake Recipe from the meta-aws project. This recipe also helps you develop a software platform that supports AWS edge software for embedded applications. The Bitbake build installs, conﬁgures, and automatically runs the AWS IoT Greengrass Core software on your device.

Yocto Project

An open source collaboration project that helps you build custom Linux-based systems for embedded applications regardless hardware architecture. For more information, see the Yocto Project.

meta-aws

An AWS managed project that provides Yocto recipes. You can use the recipes to develop AWS edge sofware in Linux-based systems built with OpenEmbedded and Yocto Project. For more information about this community supported capability, see the meta-awsproject on GitHub.

meta-aws-demos

An AWS managed project that contains demonstrations for the meta-aws project. For more examples about the integration process, see the meta-aws-demos project on GitHub.

To use a diﬀerent device or supported platform (p. 13), follow the steps in this topic.

Setting up other devices

1. If your core device is an NVIDIA Jetson device, you must ﬁrst ﬂash the ﬁrmware with the JetPack 4.3 installer. If you're conﬁguring a diﬀerent device, skip to step 2.

NoteThe JetPack installer version that you use is based on your target CUDA Toolkit version.

The following instructions use JetPack 4.3 and CUDA Toolkit 10.0. For information about using the versions appropriate for your device, see How to Install Jetpack in the NVIDIA

在文檔中 AWS IoT Greengrass (頁 132-145)