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Component: spacelift/worker-pool

This component is responsible for provisioning Spacelift worker pools.

By default, workers are given pull access to the configured ECR, permission to assume the spacelift team role in the identity account (although you must also configure the spacelift team in the identity account to allow the workers to assume the role via trusted_role_arns), and have the following AWS managed IAM policies attached:

  • AmazonSSMManagedInstanceCore
  • AutoScalingReadOnlyAccess
  • AWSXRayDaemonWriteAccess
  • CloudWatchAgentServerPolicy

Among other things, this allows workers with SSM agent installed to be accessed via SSM Session Manager.

aws ssm start-session --target <instance-id>


Stack Level: Regional

Here's an example snippet for how to use this component.

# stacks/catalog/spacelift/worker-pool.yaml
administrative: true
space_name: root
enabled: true
spacelift_api_endpoint: https://<GITHUBORG>
spacelift_spaces_tenant_name: "acme"
spacelift_spaces_environment_name: "gbl"
spacelift_spaces_stage_name: "root"
account_map_tenant_name: core
ecr_environment_name: ue1
ecr_repo_name: infrastructure
ecr_stage_name: artifacts
ecr_tenant_name: core
# Set a low scaling threshold to ensure new workers are launched as soon as the current one(s) are busy
cpu_utilization_high_threshold_percent: 10
cpu_utilization_low_threshold_percent: 5
default_cooldown: 300
desired_capacity: null
health_check_grace_period: 300
health_check_type: EC2
infracost_enabled: true
instance_type: t3.small
max_size: 3
min_size: 1
name: spacelift-worker-pool
scale_down_cooldown_seconds: 2700
spacelift_agents_per_node: 1
wait_for_capacity_timeout: 5m
- device_name: "/dev/xvda"
no_device: null
virtual_name: null
delete_on_termination: null
encrypted: false
iops: null
kms_key_id: null
snapshot_id: null
volume_size: 100
volume_type: "gp2"

Impacts on billing

While scaling the workload for Spacelift, keep in mind that each agent connection counts against your quota of self-hosted workers. The number of EC2 instances you have running is not going to affect your Spacelift bill. As an example, if you had 3 EC2 instances in your Spacelift worker pool, and you configured spacelift_agents_per_node to be 3, you would see your Spacelift bill report 9 agents being run. Take care while configuring the worker pool for your Spacelift infrastructure.


Docker Image on ECR

Build and tag a Docker image for this repository and push to ECR. Ensure the account where this component is deployed has read-only access to the ECR repository.


Prior to deployment, the API key must exist in SSM. The key must have admin permissions.

To generate the key, please follow these instructions. Once generated, write the API key ID and secret to the SSM key store at the following locations within the same AWS account and region where the Spacelift worker pool will reside.

KeySSM PathType
API ID/spacelift/key_idSecureString
API Key/spacelift/key_secretSecureString

HINT: The API key ID is displayed as an upper-case, 16-character alphanumeric value next to the key name in the API key list.

Save the keys using chamber using the correct profile for where Spacelift worker pool is provisioned

AWS_PROFILE=acme-gbl-auto-admin chamber write spacelift key_id 1234567890123456
AWS_PROFILE=acme-gbl-auto-admin chamber write spacelift key_secret abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz

IAM configuration

After provisioning the component, you must give the created instance role permission to assume the Spacelift worker role. This is done by adding iam_role_arn from the output to the trusted_role_arns list for the spacelift role in aws-teams.


terraform>= 1.0.0
aws>= 4.9.0
cloudinit>= 2.2.0
spacelift>= 0.1.2


aws>= 4.9.0
cloudinit>= 2.2.0
spacelift>= 0.1.2




aws_ami.spaceliftdata source
aws_iam_policy_document.assume_role_policydata source
aws_iam_policy_document.defaultdata source
aws_partition.currentdata source
aws_ssm_parameter.spacelift_key_iddata source
aws_ssm_parameter.spacelift_key_secretdata source
cloudinit_config.configdata source


account_map_environment_nameThe name of the environment where account_map is provisionedstring"gbl"no
account_map_stage_nameThe name of the stage where account_map is provisionedstring"root"no
account_map_tenant_nameThe name of the tenant where account_map is provisioned.

If the tenant label is not used, leave this as null.
additional_tag_mapAdditional key-value pairs to add to each map in tags_as_list_of_maps. Not added to tags or id.
This is for some rare cases where resources want additional configuration of tags
and therefore take a list of maps with tag key, value, and additional configuration.
architectureOS architecture of the EC2 instance AMIlist(string)
attributesID element. Additional attributes (e.g. workers or cluster) to add to id,
in the order they appear in the list. New attributes are appended to the
end of the list. The elements of the list are joined by the delimiter
and treated as a single ID element.
aws_config_fileThe AWS_CONFIG_FILE used by the worker. Can be overridden by /.spacelift/config.yml.string"/etc/aws-config/aws-config-spacelift"no
aws_profileThe AWS_PROFILE used by the worker. If not specified, "${var.namespace}-identity" will be used.
Can be overridden by /.spacelift/config.yml.
block_device_mappingsSpecify volumes to attach to the instance besides the volumes specified by the AMI
device_name = string
no_device = bool
virtual_name = string
ebs = object({
delete_on_termination = bool
encrypted = bool
iops = number
kms_key_id = string
snapshot_id = string
volume_size = number
volume_type = string
contextSingle object for setting entire context at once.
See description of individual variables for details.
Leave string and numeric variables as null to use default value.
Individual variable settings (non-null) override settings in context object,
except for attributes, tags, and additional_tag_map, which are merged.
"additional_tag_map": {},
"attributes": [],
"delimiter": null,
"descriptor_formats": {},
"enabled": true,
"environment": null,
"id_length_limit": null,
"label_key_case": null,
"label_order": [],
"label_value_case": null,
"labels_as_tags": [
"name": null,
"namespace": null,
"regex_replace_chars": null,
"stage": null,
"tags": {},
"tenant": null
cpu_utilization_high_threshold_percentCPU utilization high thresholdnumbern/ayes
cpu_utilization_low_threshold_percentCPU utilization low thresholdnumbern/ayes
custom_spacelift_amiCustom spacelift AMIboolfalseno
default_cooldownThe amount of time, in seconds, after a scaling activity completes before another scaling activity can startnumber300no
delimiterDelimiter to be used between ID elements.
Defaults to - (hyphen). Set to "" to use no delimiter at all.
descriptor_formatsDescribe additional descriptors to be output in the descriptors output map.
Map of maps. Keys are names of descriptors. Values are maps of the form
{<br/> format = string<br/> labels = list(string)<br/>}
(Type is any so the map values can later be enhanced to provide additional options.)
format is a Terraform format string to be passed to the format() function.
labels is a list of labels, in order, to pass to format() function.
Label values will be normalized before being passed to format() so they will be
identical to how they appear in id.
Default is {} (descriptors output will be empty).
desired_capacityThe number of Amazon EC2 instances that should be running in the group, if not set will use min_size as valuenumbernullno
ebs_optimizedIf true, the launched EC2 instance will be EBS-optimizedboolfalseno
ecr_environment_nameThe name of the environment where ecr is provisionedstring""no
ecr_regionAWS region that contains the ECR infrastructure repostring""no
ecr_repo_nameECR repository namestringn/ayes
ecr_stage_nameThe name of the stage where ecr is provisionedstring"artifacts"no
ecr_tenant_nameThe name of the tenant where ecr is provisioned.

If the tenant label is not used, leave this as null.
enabledSet to false to prevent the module from creating any resourcesboolnullno
environmentID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT'stringnullno
github_netrc_enabledWhether to create a GitHub .netrc file so Spacelift can clone private GitHub repositories.boolfalseno
github_netrc_ssm_path_tokenIf github_netrc is enabled, this is the SSM path to retrieve the GitHub token.string"/github/token"no
github_netrc_ssm_path_userIf github_netrc is enabled, this is the SSM path to retrieve the GitHub userstring"/github/user"no
health_check_grace_periodTime (in seconds) after instance comes into service before checking healthnumber300no
health_check_typeControls how health checking is done. Valid values are EC2 or ELBstring"EC2"no
iam_attributesAdditional attributes to add to the IDs of the IAM role and policylist(string)[]no
id_length_limitLimit id to this many characters (minimum 6).
Set to 0 for unlimited length.
Set to null for keep the existing setting, which defaults to 0.
Does not affect id_full.
infracost_api_token_ssm_pathThis is the SSM path to retrieve and set the INFRACOST_API_TOKEN environment variablestring"/infracost/token"no
infracost_cli_argsThese are the CLI args passed to infracoststring""no
infracost_enabledWhether to enable infracost for Spacelift stacksboolfalseno
infracost_warn_on_failureA failure executing Infracost, or a non-zero exit code being returned from the command will cause runs to fail. If this is true, this will only warn instead of failing the stack.booltrueno
instance_lifetimeNumber of seconds after which the instance will be terminated. The default is set to 14 days.number1209600no
instance_refreshThe instance refresh definition. If this block is configured, an Instance Refresh will be started when the Auto Scaling Group is updated
strategy = string
preferences = object({
instance_warmup = optional(number, null)
min_healthy_percentage = optional(number, null)
skip_matching = optional(bool, null)
auto_rollback = optional(bool, null)
triggers = optional(list(string), [])
instance_typeEC2 instance type to use for workersstring"r5n.large"no
label_key_caseControls the letter case of the tags keys (label names) for tags generated by this module.
Does not affect keys of tags passed in via the tags input.
Possible values: lower, title, upper.
Default value: title.
label_orderThe order in which the labels (ID elements) appear in the id.
Defaults to ["namespace", "environment", "stage", "name", "attributes"].
You can omit any of the 6 labels ("tenant" is the 6th), but at least one must be present.
label_value_caseControls the letter case of ID elements (labels) as included in id,
set as tag values, and output by this module individually.
Does not affect values of tags passed in via the tags input.
Possible values: lower, title, upper and none (no transformation).
Set this to title and set delimiter to "" to yield Pascal Case IDs.
Default value: lower.
labels_as_tagsSet of labels (ID elements) to include as tags in the tags output.
Default is to include all labels.
Tags with empty values will not be included in the tags output.
Set to [] to suppress all generated tags.
The value of the name tag, if included, will be the id, not the name.
Unlike other null-label inputs, the initial setting of labels_as_tags cannot be
changed in later chained modules. Attempts to change it will be silently ignored.
launch_template_versionLaunch template version to use for workers. Note that instance refresh settings are IGNORED unless template version is emptystring"$Latest"no
max_sizeThe maximum size of the autoscale groupnumbern/ayes
min_sizeThe minimum size of the autoscale groupnumbern/ayes
mixed_instances_policyPolicy to use a mixed group of on-demand/spot of different types. Launch template is automatically generated.
instances_distribution = object({
on_demand_allocation_strategy = string
on_demand_base_capacity = number
on_demand_percentage_above_base_capacity = number
spot_allocation_strategy = string
spot_instance_pools = number
spot_max_price = string
override = list(object({
instance_type = string
weighted_capacity = number
nameID element. Usually the component or solution name, e.g. 'app' or 'jenkins'.
This is the only ID element not also included as a tag.
The "name" tag is set to the full id string. There is no tag with the value of the name input.
namespaceID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally uniquestringnullno
regex_replace_charsTerraform regular expression (regex) string.
Characters matching the regex will be removed from the ID elements.
If not set, "/[^a-zA-Z0-9-]/" is used to remove all characters other than hyphens, letters and digits.
regionAWS Regionstringn/ayes
scale_down_cooldown_secondsThe amount of time, in seconds, after a scaling activity completes and before the next scaling activity can startnumber300no
space_nameThe name of the Space to create the worker pool instring"root"no
spacelift_agents_per_nodeNumber of Spacelift agents to run on one worker node. NOTE: This affects billable units. Spacelift charges per agent.number1no
spacelift_ami_idAMI ID of Spacelift worker pool imagestringnullno
spacelift_api_endpointThe Spacelift API endpoint URL (e.g.
spacelift_aws_account_idAWS Account ID owned by Spaceliftstring"643313122712"no
spacelift_domain_nameTop-level domain name to use for pulling the launcher binarystring""no
spacelift_runner_imageURL of ECR image to use for Spaceliftstring""no
spacelift_spaces_component_nameThe name of the spacelift spaces componentstring"spacelift/spaces"no
spacelift_spaces_environment_nameThe environment name of the spacelift spaces componentstringnullno
spacelift_spaces_stage_nameThe stage name of the spacelift spaces componentstringnullno
spacelift_spaces_tenant_nameThe tenant name of the spacelift spaces componentstringnullno
stageID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release'stringnullno
tagsAdditional tags (e.g. {'BusinessUnit': 'XYZ'}).
Neither the tag keys nor the tag values will be modified by this module.
tenantID element _(Rarely used, not included by default)_. A customer identifier, indicating who this instance of a resource is forstringnullno
termination_policiesA list of policies to decide how the instances in the auto scale group should be terminated. The allowed values are OldestInstance, NewestInstance, OldestLaunchConfiguration, ClosestToNextInstanceHour, Defaultlist(string)
wait_for_capacity_timeoutA maximum duration that Terraform should wait for ASG instances to be healthy before timing out. (See also Waiting for Capacity below.) Setting this to '0' causes Terraform to skip all Capacity Waiting behaviorstringn/ayes


autoscaling_group_arnThe ARN for this AutoScaling Group
autoscaling_group_default_cooldownTime between a scaling activity and the succeeding scaling activity
autoscaling_group_health_check_grace_periodTime after instance comes into service before checking health
autoscaling_group_health_check_typeEC2 or ELB. Controls how health checking is done
autoscaling_group_idThe autoscaling group id
autoscaling_group_max_sizeThe maximum size of the autoscale group
autoscaling_group_min_sizeThe minimum size of the autoscale group
autoscaling_group_nameThe autoscaling group name
iam_role_arnSpacelift IAM Role ARN
iam_role_idSpacelift IAM Role ID
iam_role_nameSpacelift IAM Role name
launch_template_arnThe ARN of the launch template
launch_template_idThe ID of the launch template
security_group_arnSpacelift Security Group ARN
security_group_idSpacelift Security Group ID
security_group_nameSpacelift Security Group Name
worker_pool_idSpacelift worker pool ID
worker_pool_nameSpacelift worker pool name