basalt-26.3: roachtest: ssh_problem failed

roachtest.ssh_problem [failed](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_Roachtests_VectorIndexingRoachtestNightlyGceBazel/21461590?buildTab=log) with [artifacts](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_Roachtests_VectorIndexingRoachtestNightlyGceBazel/21461590?buildTab=artifacts#/vecindex/random-s/nodes=1/prefix=0) on basalt-26.3 @ [014c5125e774a5b26ab5d7e140e6bfc3c8d1eb73](https://github.com/cockroachdb/cockroach/commits/014c5125e774a5b26ab5d7e140e6bfc3c8d1eb73):

```
test vecindex/random-s/nodes=1/prefix=0 failed: (test_runner.go:1017).func4: not all nodes booted successfully: timed out after 5m: TRANSIENT_ERROR(ssh_problem): exit status 255 [owner=test-eng]
```

Parameters:
- cloud=gce
- 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

- #173249 release-26.3.1-rc: roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.3.1-rc]
- #172584 release-26.3.0-rc: roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.3.0-rc]
- #172557 roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.4.14-rc]
- #172517 roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.2.22-rc]
- #172515 roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.1.8-rc]
- #172513 release-26.2.5-rc: roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.2.5-rc]
- #172364 release-26.3: roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.3]
- #172363 roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-master]
- #172359 roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-master]
- #171791 release-26.3: roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.3]

/cc @cockroachlabs/test-eng

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

Jira issue: CRDB-66638

Start with the roachtest README and the failure at test_runner.go:1017, then inspect the linked TeamCity log and artifacts for vecindex/random-s/nodes=1/prefix=0 on GCE. Compare the related ssh_problem failures listed across branches to identify the common cause; done means the failure is understood and the roachtest no longer reports this SSH timeout.

Written by the indexing model from the issue text.