Download and extract a tar.gz file Run the Greengrass device setup script Install from an APT repository Run AWS IoT Greengrass in a Docker container Run AWS IoT Greengrass in a snap Archive a core software installation

Install the AWS IoT Greengrass Core software

The AWS IoT Greengrass Core software extends AWS functionality onto an AWS IoT Greengrass core device, making it possible for local devices to act locally on the data they generate.

AWS IoT Greengrass provides several options for installing the AWS IoT Greengrass Core software:

Download and extract a tar.gz file.
Run the Greengrass Device Setup script.
Install from an APT repository.

AWS IoT Greengrass also provides containerized environments that run the AWS IoT Greengrass Core software.

Run AWS IoT Greengrass in a Docker container.
Run AWS IoT Greengrass in a snap.

Download and extract the AWS IoT Greengrass Core software package

Choose the AWS IoT Greengrass Core software for your platform to download as a tar.gz file and extract on your device. You can download recent versions of the software. For more information, see AWS IoT Greengrass Core software.

Run the Greengrass device setup script

Run Greengrass device setup to configure your device, install the latest AWS IoT Greengrass Core software version, and deploy a Hello World Lambda function in minutes. For more information, see Quick start: Greengrass device setup.

Install the AWS IoT Greengrass Core software from an APT repository

You can use the Advanced Package Tool (APT) package management system to install the latest version of the AWS IoT Greengrass Core software on your core device. The APT repository provided by AWS IoT Greengrass includes the following packages:

aws-iot-greengrass-core. Installs the AWS IoT Greengrass Core software.
aws-iot-greengrass-keyring. Installs the GnuPG (GPG) keys used to sign the AWS IoT Greengrass package repository.

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

You should be aware of the following considerations when you use the apt command to install the AWS IoT Greengrass Core software:

The AWS IoT Greengrass Core software is installed in the root directory.

The apt command installs the AWS IoT Greengrass Core software in a greengrass directory in the root file system. If /greengrass is already present, the command installs the new software version, but does not overwrite any group information or core configuration.

Over-the-air (OTA) updates are not supported.

You can use the apt installation option to upgrade the AWS IoT Greengrass Core software on your core device, but it doesn't support the safe update path provided by the AWS IoT Greengrass OTA update agent. The OTA update agent is a software component included with the AWS IoT Greengrass Core software package that's installed when you use the Download and extract a tar.gz file or Run the Greengrass device setup script installation options. The OTA update agent helps to guarantee that the core continues to function after an update by rolling back if the updates fails. For more information, see OTA updates of AWS IoT Greengrass Core software.

We recommend that you keep the keyring package updated.

Keeping the aws-iot-greengrass-keyring package updated allows you to receive updates for the GPG keys used to authenticate AWS IoT Greengrass APT repositories. It also allows you to upgrade the AWS IoT Greengrass Core software more easily. These trusted keys are installed in /etc/apt/trusted.gpg.d/. Public keys are valid for two years. If they expire, you must reconfigure the keyring package:


wget -O aws-iot-greengrass-keyring.deb https://d1onfpft10uf5o.cloudfront.net/greengrass-apt/downloads/aws-iot-greengrass-keyring.deb
sudo dpkg -i aws-iot-greengrass-keyring.deb

Important

In the unlikely event that the keys managed by AWS IoT Greengrass become compromised, you must update the aws-iot-greengrass-keyring package to replace the compromised keys with new keys. For more information, contact AWS Customer Support.

Requirements

The following requirements apply for using apt to install the AWS IoT Greengrass Core software:

Your device must be running one of the following platforms:

Architecture	OS	Distribution
Armv8 (AArch64)	Linux	Arch Linux
Armv7l	Linux	Raspbian Buster, 2019-07-10
x86_64	Linux	Ubuntu 18.04

You must have root access on the device.
To complete the steps in the following procedures, the following shell commands must be installed on the device: sudo, wget or curl, dpkg, echo, unzip, and tar.

Using apt to install the AWS IoT Greengrass Core software

You can use the APT package management system to install the AWS IoT Greengrass Core software on your device. Some core configuration steps might be required before you install the software.

In the following procedures, run the commands in a terminal window on your device.

To configure your core

If you're setting up AWS IoT Greengrass for the first time, you must configure your core. If the adduser or addgroup command is not available, use useradd or groupadd instead.
1. Create the ggc_user and ggc_group system accounts.
```
sudo adduser --system ggc_user
sudo addgroup --system ggc_group
```
2. Set up your core device certificates and keys and your core configuration file.
  1. Follow the steps in Configure AWS IoT Greengrass on AWS IoT to create a Greengrass group and register your core. This process also generates a security resources package that you download. The package is a tar.gz file that contains a core device certificate, public-private keys, and the core configuration file. The name of the file starts with a 10-digit hash (for example, c6973960cc-setup.tar.gz) that's also used for the certificate and key file names.
    
    Skip step 11 where you download the AWS IoT Greengrass Core software.
  2. Transfer the package to your core device and run the following command to install the security resources. Replace hash with the 10-digit hash from your tar.gz file.
```
sudo mkdir -p /greengrass
sudo tar -xzvf hash-setup.tar.gz -C /greengrass
```
  3. Download a root CA certificate. For information about choosing the appropriate root CA certificate, see Server authentication in the AWS IoT Core Developer Guide.
    
    The following example downloads AmazonRootCA1.pem. To use curl, replace wget -O in the command with curl.
```
cd /greengrass/certs/
sudo wget -O root.ca.pem https://www.amazontrust.com/repository/AmazonRootCA1.pem
```
  These steps install the certificates and keys to /greengrass/certs and the configuration file to /greengrass/config. For more information, see AWS IoT Greengrass core configuration file.
Download and run the dependency checker for AWS IoT Greengrass. The dependency checker makes sure you have all of the required dependencies for the AWS IoT Greengrass Core software. You can skip this step if you're upgrading from one patch version to another patch version (for example, v1.9.3 to v1.9.4).
1. In the directory where you want to download the script, run the following command. To use curl, replace wget in the command with curl.
```
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
```
2. Where more appears, press the Spacebar key to page throught the output.
  - If stream manager is enabled in your Greengrass group, you must also install the Java 8 runtime before you deploy the group. This feature is enabled by default when you use the Default Group creation workflow in the AWS IoT Greengrass console to create a group.
  - You can install your target Lambda runtimes (for example, Python 3.8) and ignore the warnings about other missing optional runtime prerequisites.
  - You can ignore warnings about missing shell commands. These are required by the OTA update agent, which isn't included in this installation.

To install the AWS IoT Greengrass Core software

Install the AWS IoT Greengrass keyring package and add the repository. To use curl, replace wget -O in the command with curl.
```
wget -O aws-iot-greengrass-keyring.deb https://d1onfpft10uf5o.cloudfront.net/greengrass-apt/downloads/aws-iot-greengrass-keyring.deb
sudo dpkg -i aws-iot-greengrass-keyring.deb
echo "deb https://dnw9lb6lzp2d8.cloudfront.net stable main" | sudo tee /etc/apt/sources.list.d/greengrass.list
```
Note

If you keep the keyring package updated on your device, this step is required only the first time you install the AWS IoT Greengrass Core software from the APT repository.
Update your list of packages.
```
sudo apt update
```
Install the AWS IoT Greengrass Core software.
```
sudo apt install aws-iot-greengrass-core
```
Start the Greengrass daemon. The following commands use systemd scripts installed with the aws-iot-greengrass-core package.
```
systemctl start greengrass.service
systemctl status greengrass.service
```
If the output displays an Active state of active (running), the daemon started successfully.

To stop using the APT repository

If you want to stop using the APT repository for AWS IoT Greengrass, remove the packages and update your sources list.

Note

The remove command removes the packages, but not your configuration information. If you also want to permanently remove all configuration information (including device certificates, group information, and log files), replace remove in the following command with purge.


sudo apt remove aws-iot-greengrass-core aws-iot-greengrass-keyring
sudo rm /etc/apt/sources.list.d/greengrass.list
sudo apt update

Use systemd scripts to manage the Greengrass daemon lifecycle

The aws-iot-greengrass-core package also installs systemd scripts that you can use to manage the AWS IoT Greengrass Core software (daemon) lifecycle.

To start the Greengrass daemon during boot:
```
systemctl enable greengrass.service
```
To start the Greengrass daemon:
```
systemctl start greengrass.service
```
To stop the Greengrass daemon:
```
systemctl stop greengrass.service
```
To check the status of the Greengrass daemon:
```
systemctl status greengrass.service
```

Run AWS IoT Greengrass in a Docker container

AWS IoT Greengrass provides a Dockerfile and Docker images that make it easier for you to run the AWS IoT Greengrass Core software in a Docker container. For more information, see AWS IoT Greengrass Docker software.

Note

You can also run a Docker application on a Greengrass core device. To do so, use the Greengrass Docker application deployment connector.

Run AWS IoT Greengrass in a snap

AWS IoT Greengrass snap v1.11.0 enables you to run a limited version of AWS IoT Greengrass through convenient software packages with all necessary dependencies in a containerized environment.

Note

The AWS IoT Greengrass snap is available for AWS IoT Greengrass Core software v1.11.0 and later. Unsupported versions don't receive bug fixes or updates.

The AWS IoT Greengrass snap doesn't support connectors and machine learning (ML) inference.

Snap concepts

To help you understand how to use the AWS IoT Greengrass snap, here are essential snap concepts:

Channel

A snap component that defines which version of a snap is installed and tracked for updates. Snaps are automatically updated to the latest version of the current channel.

Interface

A snap component that grants access to resources, such as networks and user files.

To run the AWS IoT Greengrass snap, the following interfaces must be connected. Note that greengrass-support-no-container must be connected first and never disconnected.


      - greengrass-support-no-container
      - hardware-observe
      - home-for-hooks
      - hugepages-control
      - log-observe
      - mount-observe
      - network
      - network-bind
      - network-control
      - process-control
      - system-observe

The other interfaces are optional. If your Lambda functions require access to specific resources, you might need to connect to the appropriate interfaces.

Refresh

Snaps are automatically updated. The snapd daemon is the snap package manager that checks for updates four times a day by default. Each update check is called a refresh. When a refresh occurs, the daemon stops, the snap gets updated, and then the daemon restarts.

For more information, visit the Snapcraft website.

What's new with AWS IoT Greengrass snap v1.11.0

The following describes what's new and changed with the latest version of the AWS IoT Greengrass snap.

The latest version supports only the snap_daemon user, exposed as user ID (UID) and group (GID) 584788.
The latest version supports only noncontainerized Lambda functions.

Important

Because noncontainerized Lambda functions must share the same user (snap_daemon), the Lambda functions have no isolation from each other. For more information, see Controlling execution of Greengrass Lambda functions by using group-specific configuration.
The latest version supports C, C++, Java 8, Node.js 12.x, Python 2.7, Python 3.7, and Python 3.8 runtimes.

Note

To avoid redundant Python runtimes, Python 3.7 Lambda functions actually run the Python 3.8 runtime.

Getting started with AWS IoT Greengrass snap

The following procedure helps you install and configure the AWS IoT Greengrass snap on your device.

Requirements

The following requirements apply, when you run the AWS IoT Greengrass snap:

You must run the AWS IoT Greengrass snap on a supported Linux distribution, such as Ubuntu, Linux Mint, Debian, and Fedora.
You must install the snapd daemon on your device. The snapd daemon including the snap tool manages the snap environment on your device.

For the list of supported Linux distributions and installation instructions, see Installing snapd in the Snap documentation.

Install and configure the AWS IoT Greengrass snap

The following tutorial shows you how to install and configure the AWS IoT Greengrass snap on your device.

Note

Although this tutorial uses an Amazon EC2 instance (x86 t2.micro Ubuntu 20.04), you can run the AWS IoT Greengrass snap with physical hardware, such as a Raspberry Pi.
The snapd daemon is preinstalled on Ubuntu.

Install the core18 snap by running the following command in your device's terminal:
```
sudo snap install core18
```
The core18 snap is a base snap that provides a runtime environment with commonly used libraries. This snap is built from Ubuntu 18.04 LTS.
Upgrade snapd by running the following command:
```
sudo snap install --channel=edge snapd; sudo snap refresh --channel=edge snapd
```
Note

snapd support for the AWS IoT Greengrass snap hasn't reached the stable channel. We recommend that you use --channel=edge instead of --channel=stable.

Run the snap list command to check if you have the AWS IoT Greengrass snap installed.

The following example response shows that snapd is installed, but aws-iot-greengrass isn't.


Name              Version               Rev    Tracking         Publisher   Notes
amazon-ssm-agent  3.0.161.0             2996   latest/stable/…  aws✓        classic
core              16-2.48               10444  latest/stable    canonical✓  core
core18            20200929              1932   latest/stable    canonical✓  base
lxd               4.0.4                 18150  4.0/stable/…     canonical✓  -
snapd             2.48+git548.g929ccfb  10526  latest/edge      canonical✓  snapd

Choose one of the following options to install AWS IoT Greengrass snap v1.11.0.

To install the AWS IoT Greengrass snap, run the following command:


sudo snap install aws-iot-greengrass

Example response:


aws-iot-greengrass 1.11.0 from Amazon Web Services (aws✓) installed

To migrate from v1.8 to v1.11 or update to the latest version, run the following command:
```
sudo snap refresh --channel=latest aws-iot-greengrass
```

Like other snaps, the AWS IoT Greengrass snap uses channels to manage minor versions. Snaps are automatically updated to the latest version of the current channel. For examples, if you specify --channel=1.8.x, your AWS IoT Greengrass snap is updated to v1.8.4. Currently, --channel=1.11.x is not supported.

You can run the snap info aws-iot-greengrass command to get the list of available channels for AWS IoT Greengrass.

Example response:


name:      aws-iot-greengrass
summary:   AWS supported software that extends cloud capabilities to local devices.
publisher: Amazon Web Services (aws✓)
store-url: https://snapcraft.io/aws-iot-greengrass
contact:   https://forums.aws.amazon.com/forum.jspa?forumID=254&start=0
license:   unset
description: |
  AWS IoT Greengrass seamlessly extends AWS onto edge devices so they can act locally on the data
  they generate, while still using the cloud for management, analytics, and durable storage.
  
  AWS IoT Greenrgass snap v1.11.0 enables you to run a limited version of AWS IoT Greengrass with
  all necessary dependencies in a containerized environment.
  
  The AWS IoT Greengrass snap doesn’t support connectors and machine learning (ML) inference.
  
  By downloading this software you agree to the Greengrass Core Software License Agreement
  (https://s3-us-west-2.amazonaws.com/greengrass-release-license/greengrass-license-v1.pdf).
  
  For more information, see Run AWS IoT Greengrass in a snap
  (https://docs.aws.amazon.com/greengrass/latest/developerguide/install-ggc.html#gg-snap-support) in
  the AWS IoT Greengrass Developer.
  
  If you need help, try the AWS IoT Greengrass forum
  (https://forums.aws.amazon.com/forum.jspa?forumID=254) or connect with an AWS IQ expert
  (https://iq.aws.amazon.com/services/aws/greengrass).
services:
  aws-iot-greengrass.greengrassd: forking, disabled, inactive
snap-id:      SRDuhPJGj4XPxFNNZQKOTvURAp0wxKnd
tracking:     latest/stable
refresh-date: today at 01:19 UTC
channels:
  latest/stable:    1.11.0 2020-12-04 (44) 111MB -
  latest/candidate: 1.11.0 2020-12-04 (44) 111MB -
  latest/beta:      1.11.0 2020-12-04 (44) 111MB -
  latest/edge:      1.11.0 2020-12-01 (44) 111MB -
  1.8.x/stable:     1.8.4  2020-12-01  (4)  98MB -
  1.8.x/candidate:  1.8.4  2020-12-01  (4)  98MB -
  1.8.x/beta:       ↑                            
  1.8.x/edge:       ↑                            
installed:          1.11.0            (44) 111MB -

To run the AWS IoT Greengrass snap, the following interfaces must be connected:

Important

greengrass-support-no-container must be connected first and never disconnected.


sudo snap connect aws-iot-greengrass:greengrass-support-no-container
sudo snap connect aws-iot-greengrass:hardware-observe
sudo snap connect aws-iot-greengrass:home-for-hooks
sudo snap connect aws-iot-greengrass:hugepages-control
sudo snap connect aws-iot-greengrass:log-observe
sudo snap connect aws-iot-greengrass:mount-observe
sudo snap connect aws-iot-greengrass:network
sudo snap connect aws-iot-greengrass:network-bind
sudo snap connect aws-iot-greengrass:network-control
sudo snap connect aws-iot-greengrass:process-control
sudo snap connect aws-iot-greengrass:system-observe

To access specific resources that your Lambda functions need, you might connect to additional interfaces.

Run the following command to get the list of AWS IoT Greengrass snap supported interfaces:


snap connections aws-iot-greengrass

Example response:


Interface                Plug                                                Slot                 Notes
camera                   aws-iot-greengrass:camera                           -                    -
dvb                      aws-iot-greengrass:dvb                              -                    -
gpio                     aws-iot-greengrass:gpio                             -                    -
gpio-memory-control      aws-iot-greengrass:gpio-memory-control              -                    -
greengrass-support       aws-iot-greengrass:greengrass-support-no-container  :greengrass-support  -
hardware-observe         aws-iot-greengrass:hardware-observe                 :hardware-observe    manual
hardware-random-control  aws-iot-greengrass:hardware-random-control          -                    -
home                     aws-iot-greengrass:home-for-greengrassd             -                    -
home                     aws-iot-greengrass:home-for-hooks                   :home                manual
hugepages-control        aws-iot-greengrass:hugepages-control                :hugepages-control   manual
i2c                      aws-iot-greengrass:i2c                              -                    -
iio                      aws-iot-greengrass:iio                              -                    -
joystick                 aws-iot-greengrass:joystick                         -                    -
log-observe              aws-iot-greengrass:log-observe                      :log-observe         manual
mount-observe            aws-iot-greengrass:mount-observe                    :mount-observe       manual
network                  aws-iot-greengrass:network                          :network             -
network-bind             aws-iot-greengrass:network-bind                     :network-bind        -
network-control          aws-iot-greengrass:network-control                  :network-control     -
opengl                   aws-iot-greengrass:opengl                           :opengl              -
optical-drive            aws-iot-greengrass:optical-drive                    :optical-drive       -
process-control          aws-iot-greengrass:process-control                  :process-control     -
raw-usb                  aws-iot-greengrass:raw-usb                          -                    -
removable-media          aws-iot-greengrass:removable-media                  -                    -
serial-port              aws-iot-greengrass:serial-port                      -                    -
spi                      aws-iot-greengrass:spi                              -                    -
system-observe           aws-iot-greengrass:system-observe                   :system-observe      -

If you see a hyphen (-) in the Slot column, the corresponding interface isn't connected.

Follow Configure AWS IoT Greengrass on AWS IoT to create a Greengrass group and download the security resources and configuration file; for example, c6973960cc-setup.tar.gz.

This compressed file contains the core device certificate and cryptographic keys that enable secure communications between AWS IoT Core and the config.json file that contains configuration information specific to your Greengrass core. This information includes the location of certificate files and the AWS IoT Core endpoint.

Note

If you downloaded the file to a different device, follow the first two steps in Start AWS IoT Greengrass on the core device to transfer the files to the AWS IoT Greengrass core device.

For the AWS IoT Greengrass snap, make sure that you update the config.json file, as shown in the following:

Replace hash with the 10-digit hash number that is used for your security resources and configuration file names.
Run the tar -xzf hash-setup.tar.gz -C my-certs/ command to decompress the hash-setup.tar.gz file.


{
  ...
  "crypto" : {
    "principals" : {
      "SecretsManager" : {
        "privateKeyPath" : "file:///snap/aws-iot-greengrass/current/greengrass/certs/hash.private.key"
      },
      "IoTCertificate" : {
        "privateKeyPath" : "file:///snap/aws-iot-greengrass/current/greengrass/certs/hash.private.key",
        "certificatePath" : "file:///snap/aws-iot-greengrass/current/greengrass/certs/hash.cert.pem"
      }
    },
    "caPath" : "file:///snap/aws-iot-greengrass/current/greengrass/certs/root.ca.pem"
  },
  "writeDirectory": "/var/snap/aws-iot-greengrass/current/ggc-write-directory",
  "pidFileDirectory": "/var/snap/aws-iot-greengrass/current/pidFileDirectory"
}

Run the following command to add your AWS IoT Greengrass certificate and configuration files:
```
sudo snap set aws-iot-greengrass gg-certs=/home/ubuntu/my-certs
```

Deploying a Lambda function

This section shows you how to deploy a customer managed Lambda function on the AWS IoT Greengrass snap.

Important

AWS IoT Greengrass snap v1.11 only supports noncontainerized Lambda functions.

Run the following command to start the AWS IoT Greengrass daemon:
```
sudo snap start aws-iot-greengrass
```
Example response:
```
Started.
```
Note

If you get an error, you can use the snap run command for a detailed error message. For more troubleshooting information, see error: cannot perform the following tasks: - Run service command "start" for services ["greengrassd"] of snap "aws-iot-greengrass" ([start snap.aws-iot-greengrass.greengrassd.service] failed with exit status 1: Job for snap.aws-iot-greengrass.greengrassd.service failed because the control process exited with error code. See "systemctl status snap.aws-iot-greengrass.greengrassd.service" and "journalctl -xe" for details.).

Run the following command to confirm that the daemon is running:


snap services aws-iot-greengrass.greengrassd

Example response:


Service                         Startup   Current  Notes
aws-iot-greengrass.greengrassd  disabled  active   -

Follow Module 3 (part 1): Lambda functions on AWS IoT Greengrass to create and deploy a Hello World Lambda function. However, before you deploy the Lambda function, complete the next step.
Make sure that your Lambda function run as the snap_daemon user and in the no container mode. To update the settings of your Greengrass group, do the following in the AWS IoT Greengrass console:
1. Sign in to the AWS IoT Greengrass console.
2. In the navigation pane, under Greengrass, choose Groups.
3. Under Greengrass groups, choose the target group.
4. On the group configuration page, in the navigation pane, choose Settings.
5. Under Lambda runtime environment, do the following:
  1. For Default Lambda function user ID/ group ID, choose Another user ID/group ID, and then enter 584788 for both UID (number) and GID (number).
  2. For Default Lambda function containerization, choose No container.

Stopping the AWS IoT Greengrass daemon

You can use the snap stop command to stop a service.

To stop the AWS IoT Greengrass daemon, run the following command:


sudo snap stop aws-iot-greengrass

The command should return Stopped..

To check if you successfully stopped the snap, run the following command:


snap services aws-iot-greengrass.greengrassd

Example response:


Service                         Startup   Current   Notes
aws-iot-greengrass.greengrassd  disabled  inactive  -

Uninstalling the AWS IoT Greengrass snap

To uninstall the AWS IoT Greengrass snap, run the following command:


sudo snap remove aws-iot-greengrass

Example response:


aws-iot-greengrass removed

Troubleshooting the AWS IoT Greengrass snap

Use the following information to help troubleshoot issues with the AWS IoT Greengrass snap.

Got permission denied errors.

Solution: Permission denied errors are often because of missing interfaces. For the list of missing interfaces and detailed troubleshooting information, you can use the snappy-debug tool.

Run the following command to install the tool.


sudo snap install snappy-debug

Example response:


snappy-debug 0.36-snapd2.45.1 from Canonical✓ installed

Run the sudo snappy-debug command in a separate terminal session. The operation continues until a permission denied error occurs.

For example, if your Lambda function tries to read a file in the $HOME directory, you may get the following response:


INFO: Following '/var/log/syslog'. If have dropped messages, use:
INFO: $ sudo journalctl --output=short --follow --all | sudo snappy-debug
kernel.printk_ratelimit = 0
= AppArmor =
Time: Dec  6 04:48:26
Log: apparmor="DENIED" operation="mknod" profile="snap.aws-iot-greengrass.greengrassd" name="/home/ubuntu/my-file.txt" pid=12345 comm="touch" requested_mask="c" denied_mask="c" fsuid=0 ouid=0
File: /home/ubuntu/my-file.txt (write)
Suggestion:
* add 'home' to 'plugs'

This example shows that creating the /home/ubuntu/my-file.txt file caused the permission error. It also suggests that you add home to plugs. However, this sugguestion is not applicable. The home-for-greengrassd and home-for-hooks plugs are only given the read-only access.

For more information, see The snappy-debug snap in the Snap documentation.

error: cannot perform the following tasks: - Run service command "start" for services ["greengrassd"] of snap "aws-iot-greengrass" ([start snap.aws-iot-greengrass.greengrassd.service] failed with exit status 1: Job for snap.aws-iot-greengrass.greengrassd.service failed because the control process exited with error code. See "systemctl status snap.aws-iot-greengrass.greengrassd.service" and "journalctl -xe" for details.)

Solution: You might see this error when the snap start aws-iot-greengrass command fails to start the AWS IoT Greengrass Core software.

For more troubleshooting information, run the following command:


sudo snap run aws-iot-greengrass.greengrassd

Example response:


Couldn't find /snap/aws-iot-greengrass/44/greengrass/config/config.json.

This examples shows that AWS IoT Greengrass couldn't find the config.json file. You might check the configuration and certificate files.

/var/snap/aws-iot-greengrass/current/ggc-write-directory/packages/1.11.0/rootfs/merged is not an absolute path or is a symlink.

Solution: The AWS IoT Greengrass snap supports only noncontainerized Lambda functions. Make sure that you run your Lambda functions in the no container mode. For more information, see Considerations when choosing Lambda function containerization in the AWS IoT Greengrass Developer Guide.

The snapd daemon failed to restart after you ran the sudo snap refresh snapd command.

Solution: Follow steps 6 through 8 in Install and configure the AWS IoT Greengrass snap to add the AWS IoT Greengrass certificate and configuration files to the AWS IoT Greengrass snap.

Archive an AWS IoT Greengrass Core software installation

When you upgrade to a new version of the AWS IoT Greengrass Core software, you can archive the currently installed version. This preserves your current installation environment so you can test a new software version on the same hardware. This also makes it easy to roll back to your archived version for any reason.

To archive the current installation and install a new version

Download the AWS IoT Greengrass Core software installation package that you want to upgrade to.
Copy the package to the destination core device. For instructions that show how to transfer files, see this step.

Note

You copy your current certificates, keys, and configuration file to the new installation later.

Run the commands in the following steps in your core device terminal.
Make sure that the Greengrass daemon is stopped on the core device.
1. To check whether the daemon is running:
```
ps aux | grep -E 'greengrass.*daemon'
```
  If the output contains a root entry for /greengrass/ggc/packages/ggc-version/bin/daemon, then the daemon is running.
  
  Note
  
  This procedure is written with the assumption that the AWS IoT Greengrass Core software is installed in the /greengrass directory.
2. To stop the daemon:
```
cd /greengrass/ggc/core/
sudo ./greengrassd stop
```
Move the current Greengrass root directory to a different directory.
```
sudo mv /greengrass /greengrass_backup
```
Untar the new software on the core device. Replace the os-architecture and version placeholders in the command.
```
sudo tar –zxvf greengrass-os-architecture-version.tar.gz –C /
```

Copy the archived certificates, keys, and configuration file to the new installation.


sudo cp /greengrass_backup/certs/* /greengrass/certs
sudo cp /greengrass_backup/config/* /greengrass/config

Start the daemon:


cd /greengrass/ggc/core/
sudo ./greengrassd start

Now, you can make a group deployment to test the new installation. If something fails, you can restore the archived installation.

To restore the archived installation

Stop the daemon.
Delete the new /greengrass directory.
Move the /greengrass_backup directory back to /greengrass.
Start the daemon.

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What is AWS IoT Greengrass?

Configure the AWS IoT Greengrass core