Compute Templates

To create a new compute group:

• Choose "Create stack (with new

resources)" in CloudFormation

• Then in the "Prepare

template" section, choose "Template is ready" and proceed to specify template

You can update a template to do one or both of the following:

• Upgrade to a newer version of Datomic
• Modify template parameters

To update a compute group template:

• Select an existing compute group stack

in CloudFormation

• Then choose "Update stack"
• If you are upgrading Datomic, choose "Replace current template" and proceed to specify template below.
• If you are only modifying template parameters, choose "Use current template" and proceed to parameters below.

Deleting a compute group deletes all that group's resources: EC2 instances, application load balancer, and API gateways. It does not delete your Datomic system or any data, and you can recreate the compute group again later. To delete a Datomic compute group:

• Find your compute group stack in CloudFormation
• Right-click on your query group stack and select "Delete stack"

You will use the compute stack name to distinguish your compute group from other groups on the same system and from compute groups for other systems. A good choice is $(System)-(Role), where $(System) is your system name, and $(Role) is the role this group serves, e.g. "primary compute", an application name, or a particular task or load profile. For example, the inventory system might have "inventory-primary" for its primary compute group, and "inventory-analytics" for a query group serving analytics.

Datomic configuration is managed via CloudFormation parameters, minimizing the surface area of AWS you must engage to run a system. As your needs grow, you may revisit and adjust the parameters that control the amount of compute resources, i.e. Instance Type and the Auto Scaling Configuration.

Most other parameters are likely to be set once when starting a compute group and never revisited. That said, except where explicitly noted, you can change any of these parameters by performing a rolling stack update.

Each parameter is summarized in the table below and then described in detail. Compute stack parameters are named by a Label in the CloudFormation UI, and under the Parameters key in CloudFormation JSON.

• Instance type: type of EC2 instance for compute nodes. Check onstance sizes.
• AWS EC2 key pair: key pair for ssh access to nodes.
• Application name: ion CodeDeploy application name. This name cannot be changed later.
• Environment map: ion environment map.
• Preload database: all compute group instances will load this database when they start, before accepting requests.
• Metrics Level: level of metrics detail. Default sets metric level based on instance size, and should be suitable for most users.

• Auto scaling configuration: each of the auto scaling configuration settings allows you to set a specific number, or "Default" to choose a default based on your instance size.

  • Desired capacity: AWS Auto Scaling desired capacity or "default"
  • Minimum group instances: AWS Auto Scaling minimum size or "default".
  • Maximum group instances: AWS Auto Scaling maximum size or "default".
  • The minimum number of instances during update: the number of instances that must be in service within the AWS while AWS CloudFormation updates instances, should be at least 1 less than maximum. A number or "default".
• Client API: manage an AWS API gateway for Datomic Client API access. Most users should choose "yes". (If "no", you will have to configure VPC access for clients).
• Ions: manage an AWS API Gateway for ion web applications. Most users should choose "yes". (If "no", HTTP direct ions will be inaccessible).
• Existing IAM managed policy for instances: (Optional) Name of a IAM managed policy to assign to instance nodes.
• Support configuration: leave blank unless directed by Datomic support.