"SSL_read: unexpected eof while reading" in Ubuntu 22.04/openssl 3.0.2

[drbugfinder-work]

Hi,

with the switch from Ubuntu 20.04 to Ubuntu 22.04 (which includes the transition from openssl 1.1.1f to openssl 3.0.2), we are getting the following error message every few seconds with a Forward input (from Fluent Bit) with TLS/SSL encryption:

│ 2022-07-25 09:09:34 +0000 [warn]: #0 close socket due to unexpected ssl error: SSL_read: unexpected eof while reading
│ 2022-07-25 09:09:42 +0000 [warn]: #0 close socket due to unexpected ssl error: SSL_read: unexpected eof while reading

Maybe it is related to curl/curl#5138 (curl/curl#5138 (comment))

We cannot see any impact on message handling from Fluent Bit to td-agent. Setting TLS version (of td-agent) did not change the SSL EOF warnings.

We tried with td-agent 4.3.2 and the pre-release version of 4.4.0 and got the same warning.

[drbugfinder-work]

To me it looks like fluentd was not updated to use OpenSSL 3, like described here: openssl/openssl@0cd2ee6#diff-9a86c74704f3d66bc69ba9cf9dc3168eea957103bcc36f1c2e3a1f05b10188a1R166

[ashie]

I close the duplicate issue, let's continue at fluent/fluentd#3833