release-26.2.6-rc: roachtest: cluster_creation failed

roachtest.cluster_creation [failed](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_RoachtestNightlyAwsBazel/21454409?buildTab=log) with [artifacts](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_RoachtestNightlyAwsBazel/21454409?buildTab=artifacts#/cdc/fine-grained-checkpointing) on release-26.2.6-rc @ [bb5598e3e59d65a515848129a9469d82627c3248](https://github.com/cockroachdb/cockroach/commits/bb5598e3e59d65a515848129a9469d82627c3248):

```
test cdc/fine-grained-checkpointing failed: (test_runner.go:1017).func4: in provider: aws: failed to create instance teamcity-21454409-1785997732-17-n4cpu4-0003: aws create failed due to capacity for machine type m6id.xlarge in zone(s) [us-east-2c]; suggested zone(s): [us-east-2a us-east-2b]: failed to run: aws ec2 run-instances --associate-public-ip-address --count 1 --instance-type m6id.xlarge --image-id ami-0e83be366243f524a --key-name teamcity-runner-x74YAqC7P7GVt38LmAgmq71cDB0= --region us-east-2 --security-group-ids sg-04d72b57e29d671f1 --subnet-id subnet-0e71591c1fe06645e --tag-specifications ResourceType=instance,Tags=[{Key=usage,Value=roachtest},{Key=roachtest-branch,Value=release-26-2-6-rc},{Key=spot,Value=true},{Key=roachprod,Value=true},{Key=cluster,Value=teamcity-21454409-1785997732-17-n4cpu4},{Key=lifetime,Value=12h0m0s},{Key=arch,Value=amd64},{Key=created,Value=2026-08-06T06:47:06Z},{Key=Name,Value=teamcity-21454409-1785997732-17-n4cpu4-0003},{Key=Cluster,Value=teamcity-21454409-1785997732-17-n4cpu4}] ResourceType=volume,Tags=[{Key=usage,Value=roachtest},{Key=roachtest-branch,Value=release-26-2-6-rc},{Key=spot,Value=true},{Key=roachprod,Value=true},{Key=cluster,Value=teamcity-21454409-1785997732-17-n4cpu4},{Key=lifetime,Value=12h0m0s},{Key=arch,Value=amd64},{Key=created,Value=2026-08-06T06:47:06Z},{Key=Name,Value=teamcity-21454409-1785997732-17-n4cpu4-0003},{Key=Cluster,Value=teamcity-21454409-1785997732-17-n4cpu4}] --user-data file:///tmp/aws-startup-script1307710609 --iam-instance-profile Name=roachprod-testing --block-device-mapping file:///tmp/aws-block-device-mapping171317509 --instance-market-options MarketType=spot,SpotOptions={SpotInstanceType=one-time,InstanceInterruptionBehavior=terminate} --output json: stderr:
An error occurred (InsufficientInstanceCapacity) when calling the RunInstances operation (reached max retries: 2): We currently do not have sufficient m6id.xlarge capacity in the Availability Zone you requested (us-east-2c). Our system will be working on provisioning additional capacity. You can currently get m6id.xlarge capacity by not specifying an Availability Zone in your request or choosing us-east-2a, us-east-2b.: exit status 254 [owner=test-eng]
```

Parameters:
- cloud=aws
- coverageBuild=false
- cpu=4
- diskCount=0
- runtimeAssertionsBuild=false
Help

See: [roachtest README](https://github.com/cockroachdb/cockroach/blob/master/pkg/cmd/roachtest/README.md)

See: [How To Investigate \(internal\)](https://cockroachlabs.atlassian.net/l/c/SSSBr8c7)

Same failure on other branches

- #173155 roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.4.15-rc]
- #173154 roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.2.23-rc]
- #172904 basalt-26.3: roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-basalt-26.3]
- #172635 release-26.2: roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.2]
- #172559 release-26.3.0-rc: roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.3.0-rc]
- #172510 roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.1.8-rc]
- #172509 release-26.2.5-rc: roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.2.5-rc]
- #172508 roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.1.8-rc]
- #172507 roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.4.14-rc]
- #172506 roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.2.22-rc]

/cc @cockroachlabs/test-eng

[This test on roachdash](https://roachdash.crdb.dev/?filter=status:open%20t:.*cluster_creation.*&sort=title+created&display=lastcommented+project) | [Improve this report!](https://github.com/cockroachdb/cockroach/tree/master/pkg/cmd/bazci/githubpost/issues)

Jira issue: CRDB-66482

Start with the linked cluster_creation failure log and the roachtest README, then review the related failures on other branches and the roachdash report. Investigate the AWS capacity error for m6id.xlarge in us-east-2c; done means the affected roachtest cluster creation no longer fails for this capacity condition.

Written by the indexing model from the issue text.