Doc about trustStorePath and trustStorePass

[chanjarster]

Currently there is a remark on storage.elasticsearch.trustStorePath and trustStorePass:

Only works when username and password are enabled.

See below:

skywalking/docs/en/setup/backend/configuration-vocabulary.md

Lines 91 to 92 in 1acba5d

	| - | - | trustStorePath | Trust JKS file path. Only works when username and password are enabled. | SW_STORAGE_ES_SSL_JKS_PATH | - |
	| - | - | trustStorePass | Trust JKS file password. Only works when username and password are enabled. | SW_STORAGE_ES_SSL_JKS_PASS | - |

I think that's not accurate, should be:

• trustStorePath Trust JKS file path. Provide if protocol is https, the JKS file should contains Elasticsearch's CA certificate.
• trustStorePass Trust JKS file password. Provide if Trust JKS file needs a password.

[wu-sheng]

@hanahmily Your scope, I think.

[hanahmily]

There was a precondition that the username and password should be present before 8.8.0 https://github.com/apache/skywalking/blob/v8.7.0/oap-server/server-library/library-client/src/main/java/org/apache/skywalking/oap/server/library/client/elasticsearch/ElasticSearchClient.java#L167

The new restful-based elasticsearch client doesn't have such limitations. I think we have a chance to update the document.

From the current codes, the ES client intends to load them when trustStorePath exists, regardless of the protocol.

[chanjarster]

Maybe the code need to be changed. After all, trustStorePath only make sense if protocol is https, is it?

[wu-sheng]

HTTPS should be required.