Resilience Hub Multi Account

Multi-Account Resilience Hub v2 Setup

Overview

This SOP guides you through configuring Resilience Hub v2 to assess a service whose resources span multiple AWS accounts, using the per-service permission model (cross-account IAM roles assumed by an invoker role). Note: for organization-wide governance (centralized policies + visibility), Resilience Hub v2 also offers an AWS Organizations integration with a delegated administrator, configured from the management account via Organizations trusted access + the Resilience Hub console (not a resiliencehubv2 CLI operation). This SOP covers the per-service cross-account path; the two are complementary. Use when the customer has multiple AWS accounts and wants a central account to run assessments against workloads in member accounts.

Parameters

central_account_id (required): AWS account ID that runs assessments centrally member_account_id (optional): A member account ID hosting workloads. The Steps below configure a single member account; for each additional member account in scope, repeat Steps 3–4 and extend Step 2's sts:AssumeRole permissions policy so its Resource array lists the cross-account role ARN in every member account (the central invoker role needs assume permission for all of them, or discovery for the later accounts fails with AccessDenied). org_id (optional): AWS Organizations ID (e.g., "o-abc123") for trust policy conditions invoker_role_name (optional, default: "ResilienceHubAssessmentRole"): IAM role in the central account that Resilience Hub assumes cross_account_role_name (optional, default: "ResilienceHubAccess"): IAM role in member accounts external_id (optional): External ID for cross-account role assumption service_name (required for Step 4): Name for the service to register in Resilience Hub regions (required for Step 4): JSON array of the regions the service spans (e.g. '["us-east-1"]') service_arn (derived): The service ARN returned by create-service in Step 4 — capture it from that response for use in Step 5 (not supplied as an input)

Steps

1. Verify Dependencies

Check for required tools and warn the user if any are missing.

Constraints:

• You MUST verify that either the AWS CLI (e.g., aws --version) or the AWS MCP server's call_aws tool is available

• You MUST NOT run any AWS API calls or mutating commands during this verification — a lightweight availability check such as aws --version is acceptable, but do not invoke any resiliencehubv2 or iam operations

• You MUST inform the user about any missing tools with a clear message

• You MUST ask if the user wants to proceed anyway despite missing tools

2. Create the Invoker Role in the Central Account

Set up the IAM role Resilience Hub assumes in the central account.

Constraints:

• You MUST inform the customer that the central account needs an invoker IAM role that Resilience Hub assumes to perform assessments

• You MUST recommend the role trust the resiliencehub.amazonaws.com service principal

• You MUST inform the customer this role needs sts:AssumeRole permission for the member-account cross-account roles

• You MUST run the following AWS CLI command (use the AWS MCP server's call_aws tool when connected, otherwise the AWS CLI directly): aws iam create-role --role-name {invoker_role_name} --assume-role-policy-document '{"Version":"2012-10-17","Statement":[{"Effect":"Allow","Principal":{"Service":"resiliencehub.amazonaws.com"},"Action":"sts:AssumeRole","Condition":{"StringEquals":{"aws:SourceAccount":"{central_account_id}"}}}]}'

• The invoker role's trust policy MUST be emitted exactly as written in the create-role command above — do not reconstruct, summarize, or simplify it. The "Condition":{"StringEquals":{"aws:SourceAccount":"{central_account_id}"}} block is the confused-deputy guard and is REQUIRED: it MUST appear verbatim in the trust policy you submit, scoping trust so only the central account's Resilience Hub service principal can assume the role. Never drop the Condition block from the invoker role's trust policy, even when the user does not explicitly ask for hardening.

• The create-role command above only sets the trust policy (who may assume the invoker role). You MUST ALSO attach a permissions policy that lets the invoker role assume each cross-account role — without it, cross-account discovery fails with AccessDenied. The Resource array MUST list the cross-account role ARN for every member account in scope (add an entry per account; scope to the specific ARNs, never *) — a single-account Resource will cause AccessDenied for the other accounts. Run: aws iam put-role-policy --role-name {invoker_role_name} --policy-name AssumeCrossAccountResilienceRoles --policy-document '{"Version":"2012-10-17","Statement":[{"Effect":"Allow","Action":"sts:AssumeRole","Resource":["arn:aws:iam::{member_account_id}:role/{cross_account_role_name}"]}]}'

3. Configure Cross-Account IAM Roles in Member Accounts

Set up IAM roles in member accounts that the central invoker role can assume.

Constraints:

• You MUST inform the customer that each member account needs an IAM role with a trust policy allowing the central account's invoker role to assume it

• You MUST recommend using the aws:PrincipalOrgID condition to restrict access to the organization

• You MUST recommend an externalId condition for defense in depth

• You SHOULD recommend generating the externalId with a secure random generator (e.g. aws secretsmanager get-random-password --password-length 32 --exclude-punctuation) and storing it in AWS Secrets Manager / SSM Parameter Store, referenced dynamically at deploy time rather than hardcoded

• You MUST inform the customer that the cross-account role only needs READ-ONLY permissions for resource discovery (e.g. cloudformation:Describe*, ec2:Describe*, rds:Describe*); recommend it not include any write/mutate permissions

• You SHOULD recommend deploying the role via CloudFormation StackSets for consistency across accounts

• You MUST run the following AWS CLI command in each member account (use the AWS MCP server's call_aws tool when connected, otherwise the AWS CLI directly): aws iam create-role --role-name {cross_account_role_name} --assume-role-policy-document '{"Version":"2012-10-17","Statement":[{"Effect":"Allow","Principal":{"AWS":"arn:aws:iam::{central_account_id}:role/{invoker_role_name}"},"Action":"sts:AssumeRole","Condition":{"StringEquals":{"sts:ExternalId":"{external_id}","aws:PrincipalOrgID":"{org_id}"}}}]}', then attach an explicit least-privilege read-only discovery policy with aws iam put-role-policy (the AWS docs attach the broad ReadOnlyAccess managed policy for simplicity, but we recommend a tighter least-privilege policy instead — avoid ReadOnlyAccess): aws iam put-role-policy --role-name {cross_account_role_name} --policy-name ResilienceHubDiscovery --policy-document '{"Version":"2012-10-17","Statement":[{"Effect":"Allow","Action":["cloudformation:DescribeStacks","cloudformation:ListStackResources","ec2:DescribeInstances","rds:DescribeDBInstances","elasticloadbalancing:DescribeLoadBalancers"],"Resource":"*"}]}' (this action list is illustrative, not exhaustive — Resilience Hub's required discovery permissions grow as it adds support for new resource types, so consult the current Resilience Hub IAM permissions reference and extend the action list to cover the resource types actually in scope rather than treating the list above as complete)

• You MUST omit the sts:ExternalId condition key from the trust policy if external_id is not provided, and omit aws:PrincipalOrgID if org_id is not provided; if neither is provided, omit the Condition block entirely — leaving an empty "" placeholder makes the role unassumable. You SHOULD warn the customer that omitting both conditions removes the confused-deputy guard entirely (any principal the trust policy names could assume the role), and you SHOULD NOT proceed without at least one of aws:PrincipalOrgID or sts:ExternalId — treat supplying one as the secure default, and recommend both together for defense in depth.

4. Create Services with the Cross-Account Permission Model

Register services that span member accounts using the permission model.

Constraints:

• You MUST inform the customer that this is run from the central account

• You MUST run the following AWS CLI command (use the AWS MCP server's call_aws tool when connected, otherwise the AWS CLI directly): aws resiliencehubv2 create-service --name {service_name} --regions '{regions}' --permission-model '{"invokerRoleName":"{invoker_role_name}","crossAccountRoles":[{"crossAccountRoleArn":"arn:aws:iam::{member_account_id}:role/{cross_account_role_name}","externalId":"{external_id}"}]}'

• You MUST include the permission model with cross-account role ARNs for each member account

• You MUST omit the externalId field from each crossAccountRoles entry if external_id is not provided — this MUST match Step 3, where the trust policy omits the sts:ExternalId condition in that case. Passing a placeholder/empty externalId that the member-account trust policy does not expect will cause the cross-account AssumeRole to fail.

• You SHOULD recommend using an external ID for additional security

• You MUST NOT invent a register-delegated-administrator resiliencehubv2 CLI operation — there is none. Organization-wide delegated-administrator registration is done via AWS Organizations trusted access + the Resilience Hub console, separately from this per-service create-service flow (do not conflate the two)

• You MUST capture the serviceArn from the create-service response ({service_arn}) and reuse it in Step 5's verification commands

5. Verify Cross-Account Visibility

Confirm the central account can assess resources across accounts.

Constraints:

• You MUST run the following AWS CLI command (use the AWS MCP server's call_aws tool when connected, otherwise the AWS CLI directly): aws resiliencehubv2 list-services to verify the cross-account services were created

• You MUST run the following AWS CLI command (use the AWS MCP server's call_aws tool when connected, otherwise the AWS CLI directly): aws resiliencehubv2 list-input-sources --service-arn {service_arn} to confirm resources in member accounts were discovered

• You MUST inform the customer that if discovery fails, the most likely cause is the member-account IAM role trust policy or missing resource-discovery permissions

Security Considerations

See SKILL.md for the full Security Considerations. When executing only from this procedure, surface these controls to the customer:

• Scope cross-account trust narrowly: the cross-account role should trust only the specific central invoker-role ARN (not the whole account), gated with aws:PrincipalOrgID and an externalId condition, and grant read-only discovery permissions only — never write/mutate actions. For read-only Describe* discovery actions that do not support resource-level permissions, "Resource": "*" is acceptable (as in Step 3); for any actions that do support resource-level ARNs, scope Resource to the specific ARNs in scope rather than *.

• Rotate the externalId periodically: treat it as a shared secret — generate it randomly, store it in AWS Secrets Manager / SSM Parameter Store, reference it dynamically, rotate on a schedule, and never hardcode it or emit it in plaintext (CI/CD logs, IaC output).

• Avoid leaking the externalId to shell history: because it is a shared secret, avoid passing the externalId — or any policy document / permission-model payload containing it — where it is captured in shell history (~/.bash_history) and process listings. When using the AWS CLI directly, prefer a file://… payload reference (or --cli-input-json file://…), or disable history for the session (set +o history). When using the AWS MCP server's call_aws tool, pass the payload as inline JSON — the tool does not access the local filesystem, so file:// references do not apply — and source the externalId from a secret store (Secrets Manager / SSM SecureString) at call time rather than hardcoding it. Either way, do not commit or log the real secret.

• Monitor for unauthorized access: enable AWS CloudTrail in both the central and member accounts to log cross-account sts:AssumeRole calls, and alarm on failed or unexpected AssumeRole attempts against the cross-account roles.

Examples

# Create a cross-account service from the central account
aws resiliencehubv2 create-service --name "payment-api" --regions '["us-east-1"]' \
  --permission-model '{"invokerRoleName":"ResilienceHubAssessmentRole","crossAccountRoles":[{"crossAccountRoleArn":"arn:aws:iam::222222222222:role/ResilienceHubAccess","externalId":"{external_id}"}]}'

# The externalId is a shared secret that defends against confused-deputy attacks —
# generate a cryptographically random value and store it in Secrets Manager rather than
# hardcoding a static value, then reference the secret at deploy time:
#   aws secretsmanager create-secret --name resilience-hub/cross-account-external-id \
#     --generate-random-password --password-length 32

# Verify the service and its discovered resources
aws resiliencehubv2 list-services
aws resiliencehubv2 list-input-sources --service-arn {service_arn}

Troubleshooting

Cross-account assessment fails with AccessDenied The IAM role in the member account either doesn't exist, has an incorrect trust policy, or lacks resource discovery permissions. Verify: (1) the cross-account role ARN matches exactly, (2) the trust policy allows the central account's invoker role to assume it, (3) the externalId matches if configured.

No resources discovered in a member account Confirm the cross-account role has read permissions for the resource types in scope (CloudFormation, EC2, RDS, etc.) and that the input source points to valid resources in that account's region.

Looking for a delegated-administrator setup Resilience Hub v2 does support an AWS Organizations integration with a delegated administrator for organization-wide policy management and visibility — set it up from the management account via Organizations trusted access + the Resilience Hub console (create the service-linked role, then register the delegated administrator). It is not a resiliencehubv2 CLI operation. To assess a single service whose resources span accounts, use the per-service cross-account permission model in this SOP; the two are complementary.