# Fleet

Fleet for a reserved capacity CodeBuild project.

Fleets allow for process builds or tests to run immediately and reduces build durations,
by reserving compute resources for your projects.

You will be charged for the resources in the fleet, even if they are idle.

Extends: Construct › Resource › Fleet
Implements: IResource, IFleet, IConnectable, IGrantable, IEnvironmentAware, IFleetRef, IConstruct, IDependable

- CloudFormation: [`AWS::CodeBuild::Fleet`](https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/aws-resource-codebuild-fleet.html)
- L1 type: [`CfnFleet`](/cdk/api/v2/docs/aws-cdk-lib.aws_codebuild.CfnFleet.html)
- Source: [`aws-codebuild/lib/fleet.ts`](https://github.com/aws/aws-cdk/blob/v2.274.0/packages/aws-cdk-lib/aws-codebuild/lib/fleet.ts#L219)
- Type last changed: v2.234.0 · 8 Jan 2026

## Example

```ts
const fleet = new codebuild.Fleet(this, 'Fleet', {
    computeType: codebuild.FleetComputeType.MEDIUM,
    environmentType: codebuild.EnvironmentType.LINUX_CONTAINER,
    baseCapacity: 1,
});

new codebuild.Project(this, 'Project', {
  environment: {
    fleet,
    buildImage: codebuild.LinuxBuildImage.STANDARD_7_0,
  },
  // ...
})
```

## Initializer

```ts
new Fleet(scope: Construct, id: string, props: FleetProps)
```

## Construct Props

- `baseCapacity`: number (required) — The number of machines allocated to the compute fleet. Defines the number of builds that can run in parallel.

  Minimum value of 1.

- `computeConfiguration`: [ComputeConfiguration](/cdk/api/v2/docs/aws-cdk-lib.aws_codebuild.ComputeConfiguration.html) = do not specify compute configuration — The compute configuration of the compute fleet.

  This is only permitted if `computeType` is set to ATTRIBUTE_BASED or
  CUSTOM_INSTANCE_TYPE. In such cases, this is required.

  **Default:** do not specify compute configuration

- `computeType`: [FleetComputeType](/cdk/api/v2/docs/aws-cdk-lib.aws_codebuild.FleetComputeType.html) (required) — The instance type of the compute fleet.

- `environmentType`: [EnvironmentType](/cdk/api/v2/docs/aws-cdk-lib.aws_codebuild.EnvironmentType.html) (required) — The build environment (operating system/architecture/accelerator) type made available to projects using this fleet.

- `fleetName`: string = CloudFormation generated name — The name of the Fleet.

- `overflowBehavior`: [FleetOverflowBehavior](/cdk/api/v2/docs/aws-cdk-lib.aws_codebuild.FleetOverflowBehavior.html) = undefined - AWS CodeBuild default behavior is QUEUE — The compute fleet overflow behavior.

  For overflow behavior `QUEUE`, overflow builds need to wait on the existing fleet instances to become available.

  For overflow behavior `ON_DEMAND`, overflow builds run on CodeBuild on-demand.

  **Default:** undefined - AWS CodeBuild default behavior is QUEUE

- `role`: [IRole](/cdk/api/v2/docs/aws-cdk-lib.aws_iam.IRole.html) = A role will be created if any permissions are granted — Service Role assumed by Fleet instances.

  This Role is not used by Project builds running on Fleet instances; Project
  builds assume the `role` on Project instead.

  **Default:** A role will be created if any permissions are granted

- `securityGroups`: [ISecurityGroup](/cdk/api/v2/docs/aws-cdk-lib.aws_ec2.ISecurityGroup.html)[] = A security group will be automatically created. — What security groups to associate with the fleet's network interfaces. If none are provided, one will be created automatically.

  Only used if `vpc` is supplied.

  **Default:** A security group will be automatically created.

- `subnetSelection`: [SubnetSelection](/cdk/api/v2/docs/aws-cdk-lib.aws_ec2.SubnetSelection.html) = private subnets if available else public subnets — Where to place the network interfaces within the VPC.

  To access AWS services, your fleet needs to be in one of the following types of subnets:

  1. Subnets with access to the internet (of type PRIVATE_WITH_EGRESS).
  2. Private subnets unconnected to the internet, but with [VPC endpoints](https://docs.aws.amazon.com/codebuild/latest/userguide/use-vpc-endpoints-with-codebuild.html) for the necessary services.

  If you don't specify a subnet selection, the default behavior is to use PRIVATE_WITH_EGRESS subnets first if they exist,
  then PRIVATE_WITHOUT_EGRESS, and finally PUBLIC subnets. If your VPC doesn't have PRIVATE_WITH_EGRESS subnets but you need
  AWS service access, add VPC Endpoints to your private subnets.

  **Default:** private subnets if available else public subnets

- `vpc`: [IVpc](/cdk/api/v2/docs/aws-cdk-lib.aws_ec2.IVpc.html) = No VPC is specified. — VPC network to place fleet instance network interfaces.

  Specify this if the fleet needs to access resources in a VPC.

## Properties

- `computeType`: [FleetComputeType](/cdk/api/v2/docs/aws-cdk-lib.aws_codebuild.FleetComputeType.html) (required) — The compute type of the fleet.

- `connections`: [Connections](/cdk/api/v2/docs/aws-cdk-lib.aws_ec2.Connections.html) (required) — The network connections associated with this Fleet's security group(s) in the configured VPC.

- `env`: [ResourceEnvironment](/cdk/api/v2/docs/aws-cdk-lib.interfaces.ResourceEnvironment.html) (required) — The environment this resource belongs to.

  For resources that are created and managed in a Stack (those created by
  creating new class instances like `new Role()`, `new Bucket()`, etc.), this
  is always the same as the environment of the stack they belong to.

  For referenced resources (those obtained from referencing methods like
  `Role.fromRoleArn()`, `Bucket.fromBucketName()`, etc.), they might be
  different than the stack they were imported into.

- `environmentType`: [EnvironmentType](/cdk/api/v2/docs/aws-cdk-lib.aws_codebuild.EnvironmentType.html) (required) — The build environment (operating system/architecture/accelerator) type made available to projects using this fleet.

- `fleetArn`: string (required) — The ARN of the fleet.

- `fleetName`: string (required) — The name of the fleet.

- `fleetRef`: [FleetReference](/cdk/api/v2/docs/aws-cdk-lib.interfaces.aws_codebuild.FleetReference.html) (required) — A reference to a Fleet resource.

- `grantPrincipal`: [IPrincipal](/cdk/api/v2/docs/aws-cdk-lib.aws_iam.IPrincipal.html) (required) — The grant principal for this Fleet's service role.

- `node`: [Node](/cdk/api/v2/docs/constructs.Node.html) (required) — The tree node.

- `PROPERTY_INJECTION_ID`: string (required) (static) — Uniquely identifies this class.

- `stack`: [Stack](/cdk/api/v2/docs/aws-cdk-lib.Stack.html) (required) — The stack in which this resource is defined.

## Methods

- `applyCrossStackReferenceStrength(strength: ReferenceStrength): void` — Override the cross-stack reference strength for this resource.

  When set, any cross-stack reference to this resource will use the specified
  mechanism instead of the global default determined by the
  `@aws-cdk/core:defaultCrossStackReferences` context key. This is useful for
  selectively weakening specific references to avoid the "deadly embrace" problem
  without changing the app-wide default.

  **Parameters**

  - `strength` — - The reference strength to use for this resource.

- `applyRemovalPolicy(policy: RemovalPolicy): void` — Apply the given removal policy to this resource.

  The Removal Policy controls what happens to this resource when it stops
  being managed by CloudFormation, either because you've removed it from the
  CDK application or because you've made a change that requires the resource
  to be replaced.

  The resource can be deleted (`RemovalPolicy.DESTROY`), or left in your AWS
  account for data recovery and cleanup later (`RemovalPolicy.RETAIN`).

- `fromFleetArn(scope: Construct, id: string, fleetArn: string): IFleet` (static) — Creates a Fleet construct that represents an external fleet.

  **Parameters**

  - `scope` — The scope creating construct (usually `this`).
  - `id` — The construct's id.
  - `fleetArn` — The ARN of the fleet.

- `isConstruct(x: any): boolean` (static) — Checks if `x` is a construct.

  Use this method instead of `instanceof` to properly detect `Construct`
  instances, even when the construct library is symlinked.

  Explanation: in JavaScript, multiple copies of the `constructs` library on
  disk are seen as independent, completely different libraries. As a
  consequence, the class `Construct` in each copy of the `constructs` library
  is seen as a different class, and an instance of one class will not test as
  `instanceof` the other class. `npm install` will not create installations
  like this, but users may manually symlink construct libraries together or
  use a monorepo tool: in those cases, multiple copies of the `constructs`
  library can be accidentally installed, and `instanceof` will behave
  unpredictably. It is safest to avoid using `instanceof`, and using
  this type-testing method instead.

  **Parameters**

  - `x` — Any object.

  **Returns:** true if `x` is an object created from a class which extends `Construct`.

- `isOwnedResource(construct: IConstruct): boolean` (static) — Returns true if the construct was created by CDK, and false otherwise.

- `isResource(construct: IConstruct): boolean` (static) — Check whether the given construct is a Resource.

- `toString(): string` — Returns a string representation of this construct.

- `with(...mixins: IMixin[]): IConstruct` — Applies one or more mixins to this construct.

  Mixins are applied in order. The list of constructs is captured at the
  start of the call, so constructs added by a mixin will not be visited.
  Use multiple `with()` calls if subsequent mixins should apply to added
  constructs.