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https://issues.apache.org/jira/browse/GEODE-9824?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Dale Emery reassigned GEODE-9824:
---------------------------------
Assignee: Dale Emery
> AvailablePortHelper configures itself poorly in a test JVM
> ----------------------------------------------------------
>
> Key: GEODE-9824
> URL: https://issues.apache.org/jira/browse/GEODE-9824
> Project: Geode
> Issue Type: Bug
> Components: tests
> Affects Versions: 1.15.0
> Reporter: Dale Emery
> Assignee: Dale Emery
> Priority: Major
>
> In the test JVM, `AvailablePortHelper` initializes its "next port to check"
> to a randomly selected port. That randomly selected port might be one of the
> ones that a child VM will check early.
> # Here's a problematic sequence of events:
> In the test JVM, `AvailablePortHelper` learns that the range of ports
> available to it is (say) 23750–24166. It randomly selects one of those as its
> "next port to check." Let's suppose it randomly picks 23854 as its starting
> port.
> # The test starts vm0. In vm0 `AvailablePortHelper` initializes its "next
> port to check" by computing it based on its VM number. For the given
> available port range (23750–24166), vm0 will *always* start at 23854.
> # At this point, both the test JVM and child vm0 have the exact same "next
> port to check." Trouble is looming.
> # The test requests a port in the test JVM, and gets the randomly selected
> one: 23854. It doesn't bind to this port yet. Later it will try to start a
> server on this port in vm1. Trouble is fast approaching.
> # The test invokes `AvailablePortHelper` in vm0, and gets vm0's starting
> port: 23854. The test then starts a server, which binds to that port.
> # At this point, the test JVM thinks it has reserved the port, but vm0 has
> bound to it. Trouble is imminent.
> # The test tries to start a server in vm1, using the port it believes it
> reserved. Trouble has arrived. The operation fails because the port is
> already in use.
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