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AWS cluster settings

Unless otherwise specified, new clusters on Astro are created with a set of default AWS resources that should be suitable for most use cases.

Read the following document for a reference of our default resources as well as supported cluster configurations.

Default cluster values

ResourceDescriptionQuantity/ Default SizeConfigurable
EKS ClusterAn EKS cluster is required to run the Astro data plane, which hosts the resources and data required to execute Airflow tasks.1x
Worker node poolA node pool of EC2 instances that hosts all workers with the default worker type for all Deployments in the cluster. The number of nodes in the pool auto-scales based on the demand for workers in your cluster. You can configure additional worker node pools to run tasks on different worker types.1x pool of m5.xlarge nodes✔️
Airflow node poolA node pool of EC2 instances that runs all core Airflow components, including the scheduler and webserver, for all Deployments in the cluster. This node pool is fully managed by Astronomer.1x pool of m5.xlarge nodes
Astro system node poolA node pool of EC2 instances that runs all other system components required in Astro. The availability zone determines how many nodes are created. This node pool is fully managed by Astronomer.1x pool of m5.xlarge nodes
RDS for PostgreSQL InstanceThe RDS instance is the primary database of the Astro data plane. It hosts a metadata database for each Deployment in the cluster.1x db.r5.large✔️
Elastic IPsRequired for connectivity with the Astro control plane and other public services.2x
SubnetsSubnets are provisioned in 2 different Availability Zones (AZs) for redundancy, with 1 public and 1 private subnet per AZ. Public subnets are required for the NAT and Internet gateways, while private subnets are required for EC2 nodes.2x /26 (public) and 1x /20 + 1x /21 (private)✔️
Internet GatewayRequired for connectivity with the control plane and other public services.1x
NAT GatewaysNAT Gateways translate outbound traffic from private subnets to public subnets.2x
RoutesRoutes are necessary to direct network traffic from the subnets and gateways.2x
Route TablesHome for the routes.2x
VPCVirtual network for launching and hosting AWS resources.1x /19✔️
Amazon S3Stores Airflow task logs.1x
Maximum Node CountThe maximum number of EC2 worker nodes that a particular worker node pool can scale to. This value applies to each worker node pool and does not apply to other node pools. When this limit is reached, your cluster can't auto-scale and worker Pods may fail to schedule.20✔️

Supported cluster configurations

You might need to modify configurations of a new or existing cluster on Astro. This section provides a reference for cluster configuration options.

To create a new cluster on Astro with a specified configuration, see Create a cluster. To request a change to an existing Cluster, see Modify a cluster. Astronomer is currently responsible for completing all cluster configuration changes.

Cluster regions

Depending on how you installed Astro, you can host Astro clusters in the following AWS regions:

CodeNameAstro - Bring Your Own CloudAstro - Hosted
af-south-1Africa (Cape Town)✔️
ap-east-1Asia Pacific (Hong Kong)✔️
ap-northeast-1Asia Pacific (Tokyo)✔️
ap-northeast-2Asia Pacific (Seoul)✔️
ap-northeast-3Asia Pacific (Osaka)✔️
ap-southeast-1Asia Pacific (Singapore)✔️
ap-southeast-2Asia Pacific (Sydney)✔️
ap-south-1Asia Pacific (Mumbai)✔️✔️
ca-central-1Canada (Central)✔️
eu-central-1Europe (Frankfurt)✔️✔️
eu-north-1Europe (Stockholm)✔️
eu-south-1Europe (Milan)✔️
eu-west-1Europe (Ireland)✔️✔️
eu-west-2Europe (London)✔️
eu-west-3Europe (Paris)✔️
me-south-1Middle East (Bahrain)✔️
sa-east-1South America (São Paulo)✔️
us-east-1US East (N. Virginia)✔️✔️
us-east-2US East (Ohio)✔️
us-west-1US West (N. California)✔️
us-west-2US West (Oregon)✔️✔️

Modifying the region of an existing cluster on Astro is not supported. If you're interested in an AWS region that isn't listed, contact Astronomer support.

RDS instance type

Every Astro cluster on AWS is created with and requires an RDS instance. RDS serves as a primary relational database for the data plane and powers the metadata database of all Astro Deployments within a single cluster. During the cluster creation process, you are asked to specify an RDS instance type according to your use case and expected workload, but it can be modified at any time.

Astro supports a variety of AWS RDS instance types. Each instance type has varying amounts of CPU, memory, storage, and networking capacity. For detailed information on each instance type, reference AWS documentation. If you're interested in an RDS instance type that is not on this list, reach out to Astronomer support.


  • db.r5.large (default)
  • db.r5.xlarge
  • db.r5.2xlarge
  • db.r5.4xlarge
  • db.r5.8xlarge
  • db.r5.12xlarge
  • db.r5.16xlarge
  • db.r5.24xlarge


  • db.m5.large
  • db.m5.xlarge
  • db.m5.2xlarge
  • db.m5.4xlarge
  • db.m5.8xlarge
  • db.m5.12xlarge
  • db.m5.16xlarge
  • db.m5.24xlarge

Worker node pools

A node pool is a group of nodes within a cluster that all have the same configuration. On Astro, worker nodes are responsible for running the Pods that execute Airflow tasks. Each worker node pool can be configured with a node instance type and a maximum node count. All Astro clusters have one worker node pool by default, but you can configure additional node pools to optimize resource use.

If your cluster has multiple worker node pools with different worker node instance types, users in your organization can configure tasks to run on those worker types using worker queues. To enable a new worker type for your cluster, contact Astronomer support with a request to create a new node pool or modify an existing node pool.

Astronomer monitors your usage and the number of nodes deployed in your cluster. As your usage of Airflow increases, Astronomer support might contact you and provide recommendations for updating your node pools to optimize your infrastructure spend or increase the efficiency of your tasks.

For information about each available instance type, see the following resource reference and Amazon EC2 Instance Types.

Worker node resource reference

Each worker in a worker node pool runs a single worker Pod. A worker Pod's actual available size is equivalent to the total capacity of the instance type minus Astro’s system overhead.

The following table lists all available instance types for worker node pools, as well as the Pod size that is supported for each instance type. As the system requirements of Astro change, these values can increase or decrease.

Worker Node TypeCPUMemory
m5.xlarge3 CPUs13 GiB MEM
m5.2xlarge7 CPUs29 GiB MEM
m5.4xlarge15 CPUs61 GiB MEM
m5.8xlarge31 CPUs125 GiB MEM
m5.12xlarge47 CPUs189 GiB MEM
m5.16xlarge63 CPUs253 GiB MEM
m5.24xlarge95 CPUs381 GiB MEM
m5.metal95 CPUs381 GiB MEM
m5d.xlarge3 CPUs13 GiB MEM
m5d.2xlarge7 CPUs29 GiB MEM
m5d.4xlarge15 CPUs61 GiB MEM
m5d.8xlarge31 CPUs125 GiB MEM
m5d.12xlarge47 CPUs189 GiB MEM
m5d.16xlarge63 CPUs253 GiB MEM
m5d.24xlarge95 CPUs381 GiB MEM
m5d.metal95 CPUs381 GiB MEM
m6i.xlarge3 CPUs13 GiB MEM
m6i.2xlarge7 CPUs29 GiB MEM
m6i.4xlarge15 CPUs61 GiB MEM
m6i.8xlarge31 CPUs125 GiB MEM
m6i.12xlarge47 CPUs189 GiB MEM
m6i.16xlarge63 CPUs253 GiB MEM
m6i.24xlarge95 CPUs381 GiB MEM
m6i.metal95 CPUs381 GiB MEM
m6id.xlarge3 CPUs13 GiB MEM
m6id.2xlarge7 CPUs29 GiB MEM
m6id.4xlarge15 CPU61 GiB MEM
m6id.8xlarge31 CPU125 GiB MEM
m6id.12xlarge47 CPU189 GiB MEM
m6id.16xlarge63 CPU253 GiB MEM
m6id.24xlarge95 CPU381 GiB MEM
m6id.metal127 CPU509 GiB MEM
r6i.xlarge3 CPUs29 GiB MEM
r61.2xlarge7 CPUs61 GiB MEM
r6i.4xlarge15 CPUs125 GiB MEM
r6i.8xlarge31 CPUs253 GiB MEM
r6i.12xlarge47 CPUs381 GiB MEM
r6i.16xlarge63 CPUs509 GiB MEM
r6i.24xlarge95 CPUs765 GiB MEM
r6i.metal95 CPUs1021 GiB MEM
c6i.xlarge3 CPUs5 GiB MEM
c61.2xlarge7 CPUs13 GiB MEM
c6i.4xlarge15 CPUs29 GiB MEM
c6i.8xlarge31 CPUs61 GiB MEM
c6i.12xlarge47 CPUs93 GiB MEM
c6i.16xlarge63 CPUs125 GiB MEM
c6i.24xlarge95 CPUs189 GiB MEM
c6i.metal95 CPUs189 GiB MEM
t2.xlarge3 CPUs13 GiB MEM
t3.xlarge3 CPUs13 GiB MEM
t3.2xlarge7 CPUs29 GiB MEM

If your Organization is interested in using an instance type that supports a larger worker size, contact Astronomer support. For more information about configuring worker size on Astro, see Configure a Deployment.


Astronomer doesn’t recommend using t series instance types in standard mode for production workloads, because CPU utilization for t instance types in standard mode can be throttled.


With the exception of m5d and m6id nodes, all supported node types have a maximum of 20GB of storage per node for system use only. If you need locally attached storage for task execution, Astronomer recommends modifying your cluster to run m5d or m6id nodes, which Astronomer provisions with NVMe SSD volumes. To utilize the ephemeral storage on these node types, have your task write data to /ephemeral. If your task uses the KubernetesPodOperator, mount an emptyDir volume in your operator container spec instead. See Amazon EC2 M6i Instances and Amazon EC2 M5 Instances for the amount of available storage in each node type.

The ability to provision ephemeral storage for all node instance types is coming soon.

If you need to pass significant data between Airflow tasks, Astronomer recommends using an XCom backend such as AWS S3 or Google Cloud Storage (GCS). For more information and best practices, see the Airflow Guide on Passing Data Between Airflow Tasks.

Maximum node count

Each Astro cluster has a limit on how many nodes it can run at once. This maximum includes worker nodes as well as system nodes managed by Astronomer.

The default maximum node count for all nodes across your cluster is 20. A cluster's node count is most affected by the number of worker Pods that are executing Airflow tasks. See Worker autoscaling logic.

If the node count for your cluster reaches the maximum node count, new tasks might not run or get scheduled. Astronomer monitors maximum node count and is responsible for contacting your organization if it is reached. To check your cluster's current node count, contact Astronomer Support.