ERROR Failed to create client to verify connection (Invalid or missing build flavor [oss])

[minkyu725]

Hello, I'm trying to use kafka-connect-elasticsearch as sink connector.

My Elasticsearch cluster uses oss-7.10.2 version, and when I run the connector, I got the error message below and fail.
ERROR Failed to create client to verify connection (Invalid or missing build flavor [oss])

I managed to run connector, but I had to downgrade kafka-connect-elasticsearch version.

kafka-connect-elasticsearch Versions	RestHighLevlClient Versions	Result
>= 13.0.0	>= 7.17.1	FAIL
<= 11.2.1	<= 7.9.3	SUCCESS

As I search the stacktrace, it seems that kafka-connect-elasticsearch uses RestHighLevelClient.info() for validation.
And since RestHighLevelClient 7.14 version, there appended version validation codes.

https://github.com/elastic/elasticsearch/blob/7.14/client/rest-high-level/src/main/java/org/elasticsearch/client/RestHighLevelClient.java#L2191

        if (major < 6) {
            return Optional.of("Elasticsearch version 6 or more is required");
        }

        if (major == 6 || (major == 7 && minor < 14)) {
            if ("You Know, for Search".equalsIgnoreCase(mainResponse.getTagline()) == false) {
                return Optional.of("Invalid or missing tagline [" + mainResponse.getTagline() + "]");
            }

            if (major == 7) {
                // >= 7.0 and < 7.14
                String responseFlavor = mainResponse.getVersion().getBuildFlavor();
                if ("default".equals(responseFlavor) == false) { // I think this is the point where validation error occurs.
                    // Flavor is unknown when running tests, and non-mocked responses will return an unknown flavor
                    if (Build.CURRENT.flavor() != Build.Flavor.UNKNOWN || "unknown".equals(responseFlavor) == false) {
                        return Optional.of("Invalid or missing build flavor [" + responseFlavor + "]");
                    }
                }
            }

            return Optional.empty();
        }

Can someone tell me is my guess right?
And if I want to use Elasticsearch oss build flavored version, should I use kafka-connect-elasticsearch versions under 13.0.0?
(If there is any property to make it compatible with oss build flavor, please let me know)

Thanks!

[SteveHNH]

I realize this comment is super old, but I just ran into this problem and you save me a ridiculous amount of time. I was able to get connect running with 11.2.7. Thanks for putting this out there.

[aonamrata]

I know, this is pretty old and still no replies on how to get it working with latest connector.. I am upgrading for security fixes from 11.1 so 11.2 is not a great option.