[zeppelin] branch master updated: [ZEPPELIN-4875]. Add document for interpreter recovery

[zj...@apache.org]

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zjffdu pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/zeppelin.git


The following commit(s) were added to refs/heads/master by this push:
     new 7bc7c63  [ZEPPELIN-4875]. Add document for interpreter recovery
7bc7c63 is described below

commit 7bc7c63d7c68af4f69091454b87f3464245cc031
Author: Jeff Zhang <zj...@apache.org>
AuthorDate: Sat Jun 6 00:12:00 2020 +0800

    [ZEPPELIN-4875]. Add document for interpreter recovery
    
    ### What is this PR for?
    
    Add document explaining what is interpreter recovery and how to use it.
    
    ### What type of PR is it?
    [ Documentation ]
    
    ### Todos
    * [ ] - Task
    
    ### What is the Jira issue?
    * https://issues.apache.org/jira/browse/ZEPPELIN-4875
    
    ### How should this be tested?
    * CI pass
    
    ### Screenshots (if appropriate)
    
    ### Questions:
    * Does the licenses files need update? No
    * Is there breaking changes for older versions? No
    * Does this needs documentation? No
    
    Author: Jeff Zhang <zj...@apache.org>
    
    Closes #3803 from zjffdu/ZEPPELIN-4875 and squashes the following commits:
    
    9c2e71ef0 [Jeff Zhang] [ZEPPELIN-4875]. Add document for interpreter recovery
---
 .../themes/zeppelin/img/docs-img/flink_recovery.gif   | Bin 0 -> 1553326 bytes
 docs/usage/interpreter/overview.md                    |  10 +++++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/docs/assets/themes/zeppelin/img/docs-img/flink_recovery.gif b/docs/assets/themes/zeppelin/img/docs-img/flink_recovery.gif
new file mode 100644
index 0000000..dcd5d1e
Binary files /dev/null and b/docs/assets/themes/zeppelin/img/docs-img/flink_recovery.gif differ
diff --git a/docs/usage/interpreter/overview.md b/docs/usage/interpreter/overview.md
index 20989ee..b1bbf60 100644
--- a/docs/usage/interpreter/overview.md
+++ b/docs/usage/interpreter/overview.md
@@ -158,4 +158,12 @@ val username = "{SOME_CREDENTIAL_ENTITY.user}"
 Before 0.8.0, shutting down Zeppelin also meant to shutdown all the running interpreter processes. Usually, an administrator will shutdown the Zeppelin server for maintenance or upgrades, but would not want to shut down the running interpreter processes.
 In such cases, interpreter process recovery is necessary. Starting from 0.8.0, users can enable interpreter process recovery via the setting `zeppelin.recovery.storage.class` as 
 `org.apache.zeppelin.interpreter.recovery.FileSystemRecoveryStorage` or other implementations if available in the future. By default it is `org.apache.zeppelin.interpreter.recovery.NullRecoveryStorage`,
- which means recovery is not enabled. Enabling recovery means shutting down Zeppelin would not terminate interpreter processes, and when Zeppelin is restarted, it would try to reconnect to the existing running interpreter processes. If you want to kill all the interpreter processes after terminating Zeppelin even when recovery is enabled, you can run `bin/stop-interpreter.sh` 
+ which means recovery is not enabled. `zeppelin.recovery.dir` is used for specify where to store the recovery metadata. 
+Enabling recovery means shutting down Zeppelin would not terminate interpreter processes, and when Zeppelin is restarted, it would try to reconnect to the existing running interpreter processes. If you want to kill all the interpreter processes after terminating Zeppelin even when recovery is enabled, you can run `bin/stop-interpreter.sh`.
+ 
+In 0.8.x, Zeppelin server would reconnect to the running interpreter process only when you run paragraph again, but it won't recover the running paragraph. E.g. if you restart zeppelin server when some paragraph is still running,
+then when you restart Zeppelin, although the interpreter process is still running, you won't see the paragraph is running in frontend. In 0.9.x, we fix it by recovering the running paragraphs.
+Here's one screenshot of how one running paragraph of flink interpreter works.
+
+
+<img src="{{BASE_PATH}}/assets/themes/zeppelin/img/docs-img/flink_recovery.gif" width="800px">