release-26.2.5-rc: roachtest: cluster_creation failed

roachtest.cluster_creation [failed](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_RoachtestNightlyAwsBazel/21422074?buildTab=log) with [artifacts](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_RoachtestNightlyAwsBazel/21422074?buildTab=artifacts#/cdc/frontier-persistence-benchmark/interval=10m/tables=100/ranges=100) on release-26.2.5-rc @ [aecc5c2a65078594fed36cb70bdbf2b0a0aaaf96](https://github.com/cockroachdb/cockroach/commits/aecc5c2a65078594fed36cb70bdbf2b0a0aaaf96):

```
test cdc/frontier-persistence-benchmark/interval=10m/tables=100/ranges=100 failed: (test_runner.go:1017).func4: in provider: aws: failed to create instance teamcity-21422074-1784031274-17-n4cpu16-0004: aws create failed due to capacity for machine type m7g.xlarge in zone(s) [us-east-2b]; suggested zone(s): [us-east-2a us-east-2c]: failed to run: aws ec2 run-instances --associate-public-ip-address --count 1 --instance-type m7g.xlarge --image-id ami-05983a09f7dc1c18f --key-name teamcity-runner--tRWNP6JdyiaKa7EqlCf0a_bVlM= --region us-east-2 --security-group-ids sg-04d72b57e29d671f1 --subnet-id subnet-0e3d146e87ebc5a2c --tag-specifications ResourceType=instance,Tags=[{Key=roachtest-branch,Value=release-26-2-5-rc},{Key=usage,Value=roachtest},{Key=spot,Value=true},{Key=roachprod,Value=true},{Key=cluster,Value=teamcity-21422074-1784031274-17-n4cpu16},{Key=lifetime,Value=12h0m0s},{Key=arch,Value=arm64},{Key=created,Value=2026-07-14T12:33:10Z},{Key=Name,Value=teamcity-21422074-1784031274-17-n4cpu16-0004},{Key=Cluster,Value=teamcity-21422074-1784031274-17-n4cpu16}] ResourceType=volume,Tags=[{Key=roachtest-branch,Value=release-26-2-5-rc},{Key=usage,Value=roachtest},{Key=spot,Value=true},{Key=roachprod,Value=true},{Key=cluster,Value=teamcity-21422074-1784031274-17-n4cpu16},{Key=lifetime,Value=12h0m0s},{Key=arch,Value=arm64},{Key=created,Value=2026-07-14T12:33:10Z},{Key=Name,Value=teamcity-21422074-1784031274-17-n4cpu16-0004},{Key=Cluster,Value=teamcity-21422074-1784031274-17-n4cpu16}] --user-data file:///tmp/aws-startup-script3094088372 --iam-instance-profile Name=roachprod-testing --block-device-mapping file:///tmp/aws-block-device-mapping2747071927 --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 m7g.xlarge capacity in the Availability Zone you requested (us-east-2b). Our system will be working on provisioning additional capacity. You can currently get m7g.xlarge capacity by not specifying an Availability Zone in your request or choosing us-east-2a, us-east-2c.: exit status 254 [owner=test-eng]
```

Parameters:
- cloud=aws
- coverageBuild=false
- cpu=16
- 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

- #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]
- #172191 roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.4]
- #172020 roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.2]
- #171764 release-26.3: roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.3]
- #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]
- #171588 release-26.2.3-rc: roachtest: cluster_creation failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.2.3-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-65757

Start with the linked TeamCity failure and the pkg/cmd/roachtest/README.md entry point. Trace cluster creation for AWS spot instances and determine how the reported InsufficientInstanceCapacity response and suggested zones should be handled. Done means the cluster_creation failure is no longer produced by this capacity condition, with relevant roachtest coverage or validation.

Written by the indexing model from the issue text.