Introduce proper init system (/bin/tini) to Docker container

[mieciu]

What does this PR do?

🚧 Work in progress, there's probably more to come

This PR introduces init system (tini - ref: https://github.com/krallin/tini) for reaping zombie processes and proper signal forwarding. It also enables running processes with non-default UID/GID.

Why is it important?

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

Author's Checklist

• [ ]

How to test this PR locally

• Check that docker images can start, to be tested with default and ubi images.
• Check that audit module of auditbeat continues working (it needs to be run in the host pid namespace, so tini will be started without pid 1) https://www.elastic.co/guide/en/beats/auditbeat/7.x/running-on-docker.html

Related issues

Use cases

Screenshots

Logs

[elasticmachine]

💚 Build Succeeded

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Build stats

• Build Cause: Pull request #22137 updated

• Start Time: 2020-12-07T15:35:58.815+0000

• Duration: 79 min 22 sec

Test stats 🧪

Test	Results
Failed	0
Passed	17337
Skipped	1373
Total	18710

💚 Flaky test report

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Test stats 🧪

Test	Results
Failed	0
Passed	17337
Skipped	1373
Total	18710

[kuisathaverat]

I can backport the change when it is merged, we use backport

backport --pr 22137 --branch 7.x --branch 7.10 --branch 7.9

[jsoriano]

/package

[jsoriano]

/package

[jsoriano]

@mieciu package tests are failing, with this error:

[2020-12-07T10:21:50.602Z] >> Testing package contents
[2020-12-07T10:22:02.839Z] --- FAIL: TestDocker (3.70s)
[2020-12-07T10:22:02.839Z]     --- FAIL: TestDocker/auditbeat-oss-8.0.0-SNAPSHOT-linux-amd64.docker.tar.gz_entrypoint (0.00s)
[2020-12-07T10:22:02.839Z]         package_test.go:412: bin/tini entrypoint not found in docker
[2020-12-07T10:22:02.839Z] FAIL
[2020-12-07T10:22:02.839Z] FAIL	command-line-arguments	9.065s
[2020-12-07T10:22:02.839Z] FAIL

I think this is happening because /bin is a link to /usr/bin, so tini is actually in /usr/bin/tini in the docker layer.

Could you please replace appearances of /bin/tini path with /usr/bin/tini?

Thanks!

(Another solution could be to make tests aware of symlinks, but not sure how hard this would be as we are reading the layers as tar files).

[mieciu]

/package

[elasticmachine]

Pinging @elastic/integrations (Team:Integrations)

[jsoriano]

/package

[jsoriano]

LGTM, but lets wait for a last CI run. Thanks @mieciu!

[jsoriano]

Ignoring failure in E2E tests by now, they are passing in master, but they are failing in other PRs too, like in this one: #22879.

@mdelapenya could be something wrong with E2E tests for PRs? Master and nightly builds seem to be working fine.

[jsoriano]

I am backporting this to 7.x so it will be in 7.11 (#22982).

@kuisathaverat I see you also added labels for 7.10 and 7.9. Is this change needed in these versions? I would prefer not to make this change on versions already released.

[jsoriano]

I forgot adding a changelog, adding it here: #22983