Starting a custom host

This section explain how to customize the Accelerator host to run.

Overriding specific host parameters

Some hosts provides the ability to override some parameters of the lower level libraries used to run them.

For each host class, overriding parameters are represented by arguments of the dict type with a name that finish by kwargs.

The content of theses dict are specific to each case and their description can be found in the target library documentation.

Example with AWS EC2.

The AWS host provides some dict arguments to customize the boto3 client used to run AWS instances:

With this it is by example possible to change billing options when creating the instance. Example with the use of AWS spot instance:

import apyfal

 # Based on AWS documentation, create a dict containing arguments to pass
 # to the "create_instances" method.
 use_spot_instance = {
     'InstanceMarketOptions': {
         'MarketType': 'spot',
         'SpotOptions': {
             'SpotInstanceType': 'one-time',
             'InstanceInterruptionBehavior': 'terminate',
     'InstanceInitiatedShutdownBehavior': 'terminate',

# On Accelerator instantiation, pass the dict to the
# "boto3_create_instances_kwargs" argument.
with apyfal.Accelerator(
        accelerator='my_accelerator', host_type='AWS',
        boto3_create_instances_kwargs=use_spot_instance) as myaccel:

    # Continue the use of the accelerator as normal.

Starting host manually

The following explain how start an host without the use of Apyfal.

This is not the recommended way to instantiate an accelerator, but, this allow to use a more custom host configuration.

Getting host requirements

The host configuration differ depending the target host. It is possible to get the configuration to use with Apyfal.

import apyfal

# Load Apyfal "accelerator.conf" configuration file
config = apyfal.configuration.Configuration()

# Configuration file needs at least Accelize access keys, if not present in
# file, it is possible to add it programmatically:
config['accelize']['client_id'] = 'my_client_id'
config['accelize']['secret_id'] = 'my_secret_id'

# Get configuration from Accelize server
host_config = config.get_host_requirements(
    host_type='my_provider', accelerator='my_accelerator')

The host_config is a dictionary that contain all required information to configure the host. Depending the host_type, this dictionary may contain sub-dictionaries representing sub-categories like the CSP region.

Following values may be found inside it (Depending the host_type):

  • image: Host virtual machine image to use on CSP.
  • instancetype: The type/flavor of instance to use on CSP.
  • fpgaimage: The FPGA device bitstream image. This value may be ignored and will be configured automatically in following steps.

Instantiating host

The host can now be instantiated and started using previously retrieved parameters. This step is different for each host_type and will not be explained here. Read your host provider documentation for more information.

Configuring accelerator on host

Once the host is started and ready to use, connect to it using SSH:

ssh -Yt -i ~/.ssh/${key_pair}.pem centos@${host_ip}

Create the /home/centos/accelerator.conf file and complete it with at least:

  • client_id and secret_id in accelize section
  • host_type and region in host section.

Then, run Apyfal CLI to set initial configuration of the FPGA device:

apyfal create --accelerator my_accelerator
apyfal start

The Accelerator is now ready to use.