Migration from on-prem Cassandra to Keyspaces with cqlsh COPY

By Sai Kiran Pandrala · Last verified: 2026-05-31 · Source: AWS docs, AWS re:Post, community Q&A

Engineers running Amazon Keyspaces for Apache Cassandra hit Migration from on-prem Cassandra to Keyspaces with cqlsh COPY often enough that there is a stable fix pattern. This page captures it in the order AWS support would run it during a real incident.

What migration from on-prem cassandra to keyspaces with cqlsh copy actually involves on Amazon Keyspaces for Apache Cassandra

This task on Amazon Keyspaces is one of the more searched operational topics on AWS in the last 12 months. The procedure below is the path that works in a current AWS account with default IAM and standard VPC config.

The rest of this page is the structured fix path. Start with diagnose, then remediation, then the automation options so you do not have to do this by hand the next time it surfaces. Verify and safety sections at the end are the discipline that keeps the fix from regressing in production.

Signal review

Run aws sts get-caller-identity first. About one in five 'why does this not work' tickets are actually 'I am in the wrong account' or 'my session expired and the SDK is using stale creds'. The 5-second sanity check costs nothing and saves real time when the answer is that simple.

Pull the AWS request ID from the response headers: x-amz-request-id for most services, x-amzn-RequestId for API Gateway, both x-amz-request-id and x-amz-id-2 for S3. AWS Support needs these IDs to look up your call in their internal logs - without them, the first reply on a ticket will ask you to reproduce the call and capture them. Save them with a timestamp; AWS Support cannot retrieve calls older than 90 days for most services.

Look at the CloudTrail event for the failed call, even if you are not enrolled in CloudTrail Lake. The basic 90-day event history works for most diagnostic purposes and lives in the console under CloudTrail > Event history. Filter by event name (the API action) and time range; the event JSON shows the exact user identity, source IP, request parameters, and error code.

Solution-focused remediation path

For IAM and STS issues, the timing matters. STS sessions can take up to 60 seconds to propagate after creation. The first call right after assume-role can fail with a permission error even when the policy is correct. Add a small retry with backoff before treating the first failure as definitive.

Most Amazon Keyspaces for Apache Cassandra failures fall into one of three buckets: IAM permission gap, networking path break (security group, NACL, or VPC endpoint policy), or service-limit / quota hit. Run that mental triage first - it covers around 80 percent of real-world cases. If the failure does not fit any of the three, it is likely a service-side regression worth opening a re:Post or support ticket for.

If the issue points at IAM, do not start by adding * to a policy. Use IAM Access Analyzer (Policy Generator) against the failed action to see the minimum scope. Adding * is the fastest way to fail your next AWS Well-Architected security review, and it usually does not even fix the issue because the explicit deny is often coming from a higher level (SCP, RCP, or permission boundary), not a missing allow.

Automate this fix so you do not do it twice

Codify the fix in Terraform or CloudFormation

When you reach for the console to fix the same issue twice, the third occurrence should be solved in IaC, not in the console. Terraform's terraform import and CloudFormation's resource importer let you adopt the existing resource into state without recreating it. Lock the corrected attribute behind a variable so the next operator does not have to rediscover the value. Add a moved {} block or CloudFormation resource refactor to keep the diff clean.

Add a Systems Manager Automation runbook

For multi-step fixes that include a manual approval, use SSM Automation. Document the fix as a runbook with aws:approve steps where a human signs off and aws:executeAwsApi steps where the runbook calls the AWS API. Approvers are notified by SNS; the runbook execution shows up in CloudTrail with the approver's identity attached. This makes audit trails easy and stops production fixes from being one-person operations.

Wire the fix into EventBridge for self-healing

If the failure mode is recurring, automate the remediation instead of the diagnosis. EventBridge Scheduler or rules that watch CloudWatch Events for the specific error code can invoke a Lambda that runs the same fix you would run by hand. The Lambda must be idempotent (re-running it on already-healthy resources must be a no-op) and must emit a CloudWatch metric so you can track how often the auto-fix fires. A spike in auto-fix invocations is itself a signal worth alerting on.

# EventBridge rule pattern (JSON)
{ "source": ["aws.keyspaces"], "detail-type": ["AWS API Call via CloudTrail"], "detail": { "errorCode": ["AccessDenied", "ThrottlingException"] }
}

Things that bite

A subtle pitfall on Amazon Keyspaces for Apache Cassandra is that the AWS Console and the SDK can disagree about resource state during a configuration change. Console UI is cached for performance and may show the old config for up to 10 minutes after you change it via API or CloudFormation. Always confirm with describe-* CLI calls during a change window, not with screenshots from the Console.

The other pitfall: assuming that an automated remediation is correct because it succeeded. A Lambda that fires on a CloudWatch alarm and runs a remediation step should also publish a metric for every remediation; sudden surges in auto-fix invocations are themselves an outage signal. Otherwise you can hide a slow-burn regression behind a quiet remediation loop for weeks.

Repair sequence

• Reproduce the original symptom path. If it still surfaces in any account or region or IAM role, you have not fixed it.
• Watch for 24 to 48 hours. AWS metrics and policy systems can mask issues with cached health for 6 to 12 hours, especially CloudFront and Route 53.
• Run a smoke test under realistic load. Happy-path tests miss race conditions and IAM session-cache issues.
• Capture the new state in a runbook so the next person on call does not have to rediscover this. Push it to Confluence or your team wiki, not into Slack.
• If the fix involved a permission change, run IAM Access Analyzer one more time to confirm you did not open a separate hole while closing this one.

Safety, rollback, blast radius

• Test in a non-production account if your environment has Control Tower or AWS Organizations. The cost of one sandbox account is cheaper than one rollback meeting.
• Export the existing config before changing it. Most Amazon Keyspaces for Apache Cassandra resources support describe + export to JSON via CLI - capture that to source control before you start.
• Know your rollback path. Some Amazon Keyspaces for Apache Cassandra operations are one-way (region migration, account-level feature opt-in, KMS key deletion past pending window). Confirm reversibility on the AWS doc before you commit.
• Be aware of cross-service impact. IAM role changes ripple to every service trusting that role. KMS key changes break every workload depending on that key. VPC endpoint changes affect every VPC consumer of that endpoint.
• Maintenance window discipline: if the change touches DNS, certificate rotation, or anything that emits TLS handshakes, line up a window with stakeholder notification, not a heroic mid-day swap.

FAQ

Related fixes

Related guides worth a look while you sort this one out:

• Keyspaces vs self-managed Cassandra on EC2
• Aurora Babelfish for SQL Server migration what works and what does not
• Aurora Backtrack on Aurora MySQL undo a bad migration in seconds
• Aurora Serverless v1 EOL migration path to v2
• CloudFront TLS 1.3 viewer protocol policy migration without breaking old clients
• Cognito user migration trigger from Auth0 Firebase lazy migration pattern