v0.12 branch retire

[cosmo0920]

Problem

Fluentd v1 had been shipped and Fluentd core team recommends to use Fluentd v1 stable version.
Fluentd v0.12 is still maintained but it is not actively.

Steps to replicate

What should we announce for this?

• Just stop maintain?
• Send stop maintaining announce into Fluentd Mailing List?
• or ...?

Expected Behavior or What you need to ask

We want to know how many people use this plugin which is v1 or older.

Using Fluentd and ES plugin versions

• OS version
• Fluentd v0.12 series
• ES plugin 1.x.y
• ES version (optional)

/Cc: @jcantrill @ewolinetz @nhosoi @richm

[cosmo0920]

Currently, heavily traffic environment is affected this bug: fluent/fluentd#1941

After this bug is solved, we should decide v0.12 branch handling.

[richm]

We are desperately trying to use fluentd 1.x - the problem is that we have use a ruby25 SCL image, and for Red Hat release purposes, convert about 90+ rpm packages to use the ruby 2.5 SCL, and it is a very long and tedious process. Worst case, we will probably maintain our own 0.12 branch at https://github.com/ViaQ/fluent-plugin-elasticsearch

[cosmo0920]

Yep, I know it.
This is not immediately work, but future work. (perhaps until RHEL 9 or 10)