roachtest: cluster_creation failed

roachtest.cluster_creation [failed](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_RoachtestNightlyAwsBazel/21402186?buildTab=log) with [artifacts](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_RoachtestNightlyAwsBazel/21402186?buildTab=artifacts#/restore/tpce/15GB/aws/nodes=4/cpus=8) on release-25.2 @ [b29b38600438cd4ac63e5be0aba7bf9da5ddbfa9](https://github.com/cockroachdb/cockroach/commits/b29b38600438cd4ac63e5be0aba7bf9da5ddbfa9):

```
test restore/tpce/15GB/aws/nodes=4/cpus=8 failed: (test_runner.go:840).func4: in provider: aws: failed to run: aws ec2 run-instances --associate-public-ip-address --count 1 --instance-type m6i.2xlarge --image-id ami-0e83be366243f524a --key-name teamcity-runner-UkVSIXbA8bQzQ4eF9VuaJRE8a9E= --region us-east-2 --security-group-ids sg-04d72b57e29d671f1 --subnet-id subnet-0258dc9d1b6473d84 --tag-specifications ResourceType=instance,Tags=[{Key=roachtest-branch,Value=release-25-2},{Key=usage,Value=roachtest},{Key=Name,Value=teamcity-21402186-1782452470-53-n4cpu8-0001},{Key=Cluster,Value=teamcity-21402186-1782452470-53-n4cpu8},{Key=spot,Value=true},{Key=roachprod,Value=true},{Key=cluster,Value=teamcity-21402186-1782452470-53-n4cpu8},{Key=lifetime,Value=12h0m0s},{Key=arch,Value=amd64},{Key=created,Value=2026-06-26T06:47:16Z}] ResourceType=volume,Tags=[{Key=roachtest-branch,Value=release-25-2},{Key=usage,Value=roachtest},{Key=Name,Value=teamcity-21402186-1782452470-53-n4cpu8-0001},{Key=Cluster,Value=teamcity-21402186-1782452470-53-n4cpu8},{Key=spot,Value=true},{Key=roachprod,Value=true},{Key=cluster,Value=teamcity-21402186-1782452470-53-n4cpu8},{Key=lifetime,Value=12h0m0s},{Key=arch,Value=amd64},{Key=created,Value=2026-06-26T06:47:16Z}] --user-data file:///tmp/aws-startup-script2302958256 --iam-instance-profile Name=roachprod-testing --block-device-mapping file:///tmp/aws-block-device-mapping4234666871 --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 m6i.2xlarge capacity in the Availability Zone you requested (us-east-2a). Our system will be working on provisioning additional capacity. You can currently get m6i.2xlarge capacity by not specifying an Availability Zone in your request or choosing us-east-2b, us-east-2c.: exit status 254 [owner=test-eng]
```

Parameters:
- cloud=aws
- coverageBuild=false
- cpu=8
- 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

- #171624 roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.1.6-rc]
- #171623 roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.4.12-rc]
- #171620 roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.2.20-rc]
- #171526 roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-24.1.30-rc]
- #171104 roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.1]
- #170429 roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.1.5-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-65158

Start with the roachtest README and the linked TeamCity log and artifacts for the AWS cluster_creation failure. Trace how the reported m6i.2xlarge request selects us-east-2a; done means the recurring InsufficientInstanceCapacity failure is handled or prevented across the affected branches.

Written by the indexing model from the issue text.