AWS Elastic Compute Cloud (EC2)

The AWS EC2 client of Lithops can provide a truely serverless user experience on top of EC2 where Lithops creates new Virtual Machines (VMs) dynamically in runtime and scale Lithops jobs against them. Alternatively Lithops can start and stop an existing VM instances.

Note that AWS EC2 is a standalone backend, and as such, you can configure extra parameters in the ‘standalone’ section of the configuration:

Group	Key	Default	Mandatory	Additional info
standalone	runtime	python3	no	Runtime name to run the functions. Can be a Docker image name
standalone	auto_dismantle	True	no	If False then the VM is not stopped automatically.
standalone	soft_dismantle_timeout	300	no	Time in seconds to stop the VM instance after a job completed its execution
standalone	hard_dismantle_timeout	3600	no	Time in seconds to stop the VM instance after a job started its execution
standalone	exec_mode	consume	no	One of: consume, create or reuse. If set to create, Lithops will automatically create new VMs for each map() call based on the number of elements in iterdata. If set to reuse will try to reuse running workers if exist
standalone	pull_runtime	False	no	If set to True, Lithops will execute the command docker pull <runtime_name> in each VM before executing the a job (in case of using a docker runtime)

AWS

The assumption that you already familiar with AWS, and you have AUTH credentials to your account (HMAC Credentials).

Choose an operating system image for the VM

Any Virtual Machine (VM) need to define the instance’s operating system and version. Lithops support both standard operating system choices provided by the VPC or using pre-defined custom images that already contains all dependencies required by Lithops.

• Option 1: By default, Lithops uses an Ubuntu 20.04 image. In this case, no further action is required and you can continue to the next step. Lithops will install all required dependencies in the VM by itself. Notice this can consume about 3 min to complete all installations.

• Option 2: Alternatively, you can use a pre-built custom image that will greatly improve VM creation time for Lithops jobs. To benefit from this approach, navigate to runtime/aws_ec2, and follow the instructions.

Summary of configuration keys for AWS

Group	Key	Default	Mandatory	Additional info
aws	access_key_id		yes	Account access key to AWS services. To find them, navigate to My Security Credentials and click Create Access Key if you don’t already have one.
aws	secret_access_key		yes	Account secret access key to AWS services. To find them, navigate to My Security Credentials and click Create Access Key if you don’t already have one.
aws	session_token		no	Session token for temporary AWS credentials
aws	account_id		no	*This field will be used if present to retrieve the account ID instead of using AWS STS. The account ID is used to format full image names for container runtimes.

Lithops and the VM consume mode

In this mode, Lithops can start and stop an existing VM, and deploy an entire job to that VM. The partition logic in this scenario is different from the create/reuse mode, since entire job executed in the same VM.

Lithops configuration for the consume mode

Edit your lithops config and add the relevant keys:

lithops:
    backend: aws_ec2

aws:
    access_key_id: <AWS_ACCESS_KEY_ID>
    secret_access_key: <AWS_SECRET_ACCESS_KEY>
    #session_token: <AWS_SESSION_TOKEN>  # Optional

aws_ec2:
    region_name : <REGION_NAME>
    instance_id : <INSTANCE ID OF THE VM>

Summary of the configuration keys for the consume mode

Group	Key	Default	Mandatory	Additional info
aws_ec2	region_name		yes	Endpoint of your subnet region
aws_ec2	instance_id		yes	virtual server instance ID
aws_ec2	public_ip		no	Static Public IP address attached to your VM instance. By default public IPs are dynamic
aws_ec2	ssh_username	ubuntu	no	Username to access the VM
aws_ec2	ssh_key_filename		no	Path to the ssh key file provided to create the VM. It will use the default path if not provided
aws_ec2	worker_processes	2	no	Number of Lithops processes within a given worker. This can be used to parallelize function activations within a worker. It is recommendable to set this value to the same number of CPUs of the VM.

Lithops and the VM auto create|reuse mode

In this mode, Lithops will automatically create new worker VM instances in runtime, scale Lithops job against generated VMs, and automatically delete the VMs when the job is completed. Alternatively, you can set the reuse mode to keep running the started worker VMs, and reuse them for further executions. In the reuse mode, Lithops checks all the available worker VMs and start new workers if necessary.

Lithops configuration for the auto create mode

Edit your lithops config and add the relevant keys:

lithops:
    backend: aws_ec2

standalone:
    exec_mode: create|reuse

aws:
    access_key_id: <AWS_ACCESS_KEY_ID>
    secret_access_key: <AWS_SECRET_ACCESS_KEY>
    #session_token: <AWS_SESSION_TOKEN>  # Optional

aws_ec2:
    region_name: <REGION_NAME>
    vpc_id: <VPC_ID>
    iam_role: <IAM_ROLE>
    key_name: <SSH_KEY_NAME>
    security_group_id: <SECURITY_GROUP_ID>

Important information

1. The first time you use Lithops with specific runtime, Lithops will try generate and obtain runtime metadata. For this purpose Lithops will create a VM, extract specific metadata and delete VM. All further executions against same runtime will skip this step as runtime metadata will be cached both locally and in AWS S3.

2. In certain cases where ssh access details are wrong, Lithops might fail to ssh into created VM from the previous step. In this case, fix the ssh access credentials, navigate into the dashboard and manually delete the VMs.

3. The first time you deploy Lithops job in the create|reuse mode it is advised to navigate to the dashboard and verify that VM is being created and deleted.

Summary of the configuration keys for the create mode

Group	Key	Default	Mandatory	Additional info
aws_ec2	region_name		yes	Region name, for example: eu-west-1
aws_ec2	vpc_id		yes	VPC id. You can find all the available VPCs in the VPC Console page
aws_ec2	iam_role		yes	IAM EC2 role name. You can find it in the IAM Console page. Create a new EC2 role if it does not exist
aws_ec2	key_name		yes	SSH Key name. You can find the available keys in the EC2 console page. Create a new one or upload your own key if it does not exist
aws_ec2	security_group_id		yes	Security group ID. You can find the available security groups in the EC2 console page. The security group must have ports 22 and 8080 open
aws_ec2	ssh_username	ubuntu	no	Username to access the VM
aws_ec2	ssh_password		no	Password for accessing the worker VMs. If not provided, it is created randomly
aws_ec2	ssh_key_filename		no	Path to the ssh key file provided to access the VPC. It will use the default path if not provided
aws_ec2	request_spot_instances	True	no	Request spot instance for worker VMs
aws_ec2	target_ami		no	Virtual machine image id. Default is Ubuntu Server 20.04
aws_ec2	master_instance_type	t2.micro	no	Profile name for the master VM
aws_ec2	worker_instance_type	t2.medium	no	Profile name for the worker VMs
aws_ec2	delete_on_dismantle	True	no	Delete the worker VMs when they are stopped. Master VM is never deleted when stopped
aws_ec2	max_workers	100	no	Max number of workers per FunctionExecutor()
aws_ec2	worker_processes	2	no	Number of Lithops processes within a given worker. This can be used to parallelize function activations within a worker. It is recommendable to set this value to the same number of CPUs of a worker VM.

Test Lithops

Once you have your compute and storage backends configured, you can run a hello world function with:

lithops test -b aws_ec2 -s aws_s3

Viewing the execution logs

You can view the function executions logs in your local machine using the lithops client:

lithops logs poll

The master and worker VMs contains the Lithops service logs in /tmp/lithops/service.log

You can login to the master VM and get a live ssh connection with:

lithops attach -b aws_ec2