[ZEPPELIN-3778] Cluster synchronize notes & authorization

[xunliu]

What is this PR for?

In cluster mode, The user creates, modifies, and deletes the note on any of the zeppelin servers.
All need to be notified to all the zeppelin servers in the cluster to synchronize the update of Notebook. Failure to do so will result in the user not being able to continue while switching to another server.

1. Listen for note create/delete/update events
2. Listen for note Notebook Authorization events
3. Broadcast note update event

What type of PR is it?

[Feature]

What is the Jira issue?

• https://issues.apache.org/jira/browse/ZEPPELIN-3778

How should this be tested?

• CI Pass

Screenshots (if appropriate)

Sync note event

Sync note Authorization

Questions:

• Does the licenses files need update?
• Is there breaking changes for older versions?
• Does this needs documentation?

[xunliu]

@zjffdu , @felixcheung , Please help me review code, Thanks!

[felixcheung]

can it have race condition?

1. server #1 renames a note
2. server #2 deletes the same note

[felixcheung]

why is if (LOGGER.isDebugEnabled()) { needed? LOGGER.debug should be enough?

[xunliu]

Because need to synchronize the create, rename, delete, set read permissions, write permissions, execute permissions, so need to synchronize the more information, there will be a lot of synchronization information in the log file.
So need add if (LOGGER.isDebugEnabled())

[felixcheung]

I'm not sure I understand. you are saying logging is useful for debugging, and there could be a lot of information.
isn't debug log will be filtered out if debug log is not enabled?

[xunliu]

In the development phase, the debug information is very useful for developers, but after the development is completed, the debug information will be very much. In the log log file, there is a lot of synchronization information, which affects the system administrator to check whether the system is normal.
So, I think these debug messages don't need to be printed to the log file after development. :-)

[felixcheung]

can this be joined to the line before? formatting is a bit strange.

[xunliu]

Modified to this?

Set<String> set = gson.fromJson(jsonSet, new TypeToken<Set<String>>() {}.getType());

[felixcheung]

seem that way. new TypeToken<Set<String>>() {} (together) seems to be how it is used.

[xunliu]

Ok, I am going to change it.

[xunliu]

Hi, @felixcheung , This is a good question. #3387 (review)

1. server [ZEPPELIN-4] Sync the version of dependencies with Spark #1 renames a note
2. server minor doc update for running on YARN #2 deletes the same note

If rename is effective, the deletion will fail.
If you delete the gentleman, then rename will fail.

[felixcheung]

sure, that's assuming rename or delete is atomic? it could be in the middle of one and both operations failing and leading to data loss etc?

for example, it does look like if there are two move or rename concurrently there is a chance the note will be duplicated

https://github.com/apache/zeppelin/blob/master/zeppelin-zengine/src/main/java/org/apache/zeppelin/notebook/NoteManager.java#L210

server1

    NoteNode noteNode = getNoteNode(notePath);

server2

    NoteNode noteNode = getNoteNode(notePath);

then both execute these concurrently

    noteNode.getParent().removeNote(getNoteName(notePath));  // not sure removeNote will fail
    noteNode.setNotePath(newNotePath);
    String newParent = getFolderName(newNotePath);
    Folder newFolder = getOrCreateFolder(newParent);
    newFolder.addNoteNode(noteNode);

[xunliu]

@felixcheung , Thank you for asking this question. :-)
I think that implementing atomicity in a distributed system is a big issue.
I think, after the distributed features of zeppelin go online, After zeppelin has more user groups, Think about it again. Are you saying ok?
Zeppelin's distributed clustering model is used by a large number of analysts in our company every day. There have been no cases where different analysts are working on the same note.
Because notes are generally not only shared with members of the group. There won't be many users working on the same note at the same time.

[xunliu]

Will merge if no more comments