* Support grpc exporter.

* Support scope(all) metric export and finish document.

* Close exporter even in local debug env. And fix CI.

* Remove the system.out

* Fix absent 4.

* Support subscription from remote.

* Add the doc

* Update application.yml

* Added elasticsearch warehouse certification support

* Add the elasticsearch service for Http Basic instructions

* Update backend-storage.md

Change document.

* The role of OAP server.
Mixed: Receive agent data, level 1 aggregate, level 2 aggregate
Receiver: Receive agent data, level 1 aggregate
Aggregator: level 2 aggregate

* Mistake, stadalone default.

* Update application.yml

* #2327

Add a new module for share receiver server or to be a bridge of core server.

* Rename the module name.

* Extend envoy metric service, scope and OAL lexer/parser.

* Finish metric extension and oal.

* Make test env works.

* Finish test of envoy connection and memory metric.

* Change document.

* Finish docker compose test.

[Performance Improvement]Backend streaming thread model improvement

* The prototype of topN sql worker.

* Add scope and new manual dispatcher.

* no message

* Finish topN persistence codes. Not test yet. And query have not added.

* Finish the top n database statement persistent.

* Support different slow thresholds for different db types.

* Fix wrong db default threshold

* Finish new query protocol binding.

* Provide query empty implementation and sync ui.

* Finish all codes, hope it works :P
I will run the tests tonight.

* Fix

* Fix

* Fix a startup issue.

* Add time bucket to persistent.

* Fix wrong query result column name.

* Fix Database query.

* Fix checkstyle.

* Fix wrong order logic, and add a test case to verify, to fix https://github.com/apache/incubator-skywalking/pull/2239#discussion_r255948249

* Finish the basic codes of telemetry.

* Add many telemetry in oap.

* Fix a test case.

* Finish all telemetry metric.

* Fix format.

* Make telemetry works.

* Support JVM metrics.

* Add doc for telemetry.

* Fix typo.

* Fix #2135

* Finish the APIs of telemetry module.

* Add prometheus license.

* Active default telemetry provider.

* Provide consul cluster plugin.

* Change log and application config file.

* Add consul's config item into the docker's application.yml.

* Fixed bug.

* Add consul description into  readme.

* Add okhttp component license.

2. Zookeeper implementation of the cluster module using name space to support using same zookeeper cluster by different OAP clusters.

* Correct namespace description

* Support sampling trace at server side and keep metric right.

* Add a trace sampling document

* Fix wrong default value.

* Fix document issue.

* Fix assemble issue.

* Fix wrong settings and doc.

Also fixed several bugs in this merge.

* support set config from system.envs.

* Close the clients which are unreachable.
Remote client manager test case and comments.

* Test the GRPCRemote client.

* 1. Catch the throwable for onComplete method cause of it will throw exception when connection lost.
2. Check the gRPC channel state, send message when state is ready, wait 5 second when state is not ready.

Notice: gRPC channel getState with true parameter will trigger reconnect operation.

* gRPC client will reconnect to the server when network recorvered.

* Recovery application.yml

* Recovery proto module commit id.

* no message

* Fixed compile error.

* Change some codes to make zipkin receiver works, not done yet.

* @adriancole Zipkin receiver is coming back again.

* Fix document and fix for Zipkin receiver.

* Fix some bugs.

* Fix register bug.

* Fix transfer bug for new backend core.

* ZooKeeper Version Compatibility

* Update backend-cluster.md

Reorganize words. cc @peng-yongsheng

* Update application.yml

* Update application.yml

* H2 storage code skeleton.

* Add batch dao for H2.

* Fix wrong refactor.

* Add codes of other dao. No metric dao, wait for @peng-yongsheng new PR.

* Change license of distribution

* Add topology query in H2.

* Add more daos.

* Add some daos.

* Commit all H2 daos. Wait @peng-yongsheng to submit new IAggregationQueryDAO interface.

* Fix some CIs

* Fix wrong refactor, which causes h2 plugin failure.

* Fix all codes of H2 storage. :) and CI should pass. No test.

* Fix CI and typo

* Fix connection closed.

* Fix register bug

* no message

* Fixed service inventory register bug.

* Fix a compile issue.

* Sync change

* Reset es as default storage.

* Fix rat

* Fix H2 compile issue.

* Fix bugs for H2 storage.

* Fix bug in mesh.

* 1. Fix Thermodynamic query bug
2. Fix service inventory query bug
3. Fix missing traceid in trace query bug

* Fix query bug.

* Submit reverse caused by prev PR.

* Fix duplicate spans.

* Use H2 as default storage implementor.

* Fix bug in topology query.

* Fix CI

* Fix rat

* Fix two query in H2 storage.

* Fix H2 query

* Make release running in H2 mode and develop mode running is ES mode in default

* Support metrics downsampling.

* Fixed a check style error.

* Add generate indicator and dispatcher about service topology but not test.

* Delete call type from service relation.

* Streaming analysis topology test success.

* Fixed the check style error.

* Buffer stream.

* Buffer file reader.

* Buffer library performance test and functional test successfully.

* Fixed the code merge mistake.

* SkyWalking's trace receiver implementation.

* SkyWalking's trace receiver implementation.

* Delete collector module.

Add a lot of documents. @peng-yongsheng @hanahmily . Also @hanahmily , the k8 cluster management document and deploy document need you to add.

* Register start up.

* Service inventory register test success.

* Storage and Persistence.

* Storage config.

* Fixed the CI failure.

# 1447
Use `GET /api/v1/watch/namespaces/{namespace}/pods` api to watch pod's
containerIp which help collector containers to discovery each other.

* Receiver, aggregate, server finished.

* Cluster module implementation finished.

* Add login filter

Username and password are stored in application.yml with
prefix "security.user"

* Modify startup script and add webapp.yml config file

* Update quick-start document for default login username/password

* Update deploy document for new webapp.yml config file

* Update license for new files.

Fix IPMC checks for releasing.