Switch package signing key

[Kentaro Hayashi]

Problem

Currently, we can't switch signing key yet.

Expected

Switch package signing key after releasing fluent-package v5 series.

Fluentd developers (Fluent Package Official Signing Key)
B40948B6A3B80E90F40E841F977D7A0943FA320E

Background

When releasing fluent-package v5.0.0, v5.0.1, we still use with old signing key because existing td-agent user can upgrade by
even though manually editing apt-line fluentd.sources.

https://github.com/fluent/fluent-package-builder/blob/master/fluent-package/manage-fluent-repositories.sh#L36

• If user install package via install script, new signing key is also installed.
  • deb: /usr/share/keyrings/fluent-archive-keyring.gpg
  • rpm: import via gpg --import (old and new key)

So switching signing key affects only existing td-agent users who manually point to fluent-package apt line.