RFR: 8265690: Use the latest Ubuntu base image version in Docker testing [v2]

[Mikhailo Seledtsov]

On Thu, 22 Apr 2021 12:37:43 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Use latest Ubuntu base image to get latest glibc, so that host-built JDK has a higher chance to pass. Current "oraclelinux:7.6" image apparently has glibc 2.27. Please see the bug for more discussion.
>> 
>> Additional testing:
>>  - [x] `hotspot_containers` tests on Ubuntu 20.04 (glibc 2.31) -- used to fail, now passes
>>  - [x] `hotspot_containers` tests on Debian 9 (glibc 2.24) -- continues to pass
>>  - [x] `hotspot_containers` tests on Centos 7 (glibc 2.17) -- continues to pass
>
> Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains one additional commit since the last revision:
> 
>   8265690: Use latest Ubuntu base image version in Docker testing

As Igor has pointed out, we at Oracle explicitly use jdk.test.docker.image.(name|version) to specify base image+version for container test execution. Hence, in principle I have no objection to this change. Couple of notes though:

- this change might potentially affect other parties to OpenJDK that may rely on default base image being OracleLinux, who are not currently using -Ddk.test.docker.image
- one of recommended container best practices is to use an explicit version rather than "latest", for more deterministic outcomes

-------------

PR: https://git.openjdk.java.net/jdk/pull/3605