[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[ https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12930686#action_12930686 ] Sergey Doroshenko commented on ZOOKEEPER-784: - Hi Patrick, Currently I'm in the final stage of my Facebook's internship, and I want to keep good pace and not be distracted by other things. Hopefully r-o mode is not release-blocking feature, so I hope it'll be ok if I resubmit the patch in 3 weeks. But if this should be done sooner, let me know and I'll try to find a time :) server-side functionality for read-only mode Key: ZOOKEEPER-784 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784 Project: Zookeeper Issue Type: Sub-task Components: server Reporter: Sergey Doroshenko Assignee: Sergey Doroshenko Fix For: 3.4.0 Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create ReadOnlyZooKeeperServer which comes into play when peer is partitioned. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[ https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12930692#action_12930692 ] Patrick Hunt commented on ZOOKEEPER-784: No worries, I'd like to get this in given you've done a bunch of work on it, qabot just flagged it given it's recently working again. thanks. server-side functionality for read-only mode Key: ZOOKEEPER-784 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784 Project: Zookeeper Issue Type: Sub-task Components: server Reporter: Sergey Doroshenko Assignee: Sergey Doroshenko Fix For: 3.4.0 Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create ReadOnlyZooKeeperServer which comes into play when peer is partitioned. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[ https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12901136#action_12901136 ] Flavio Junqueira commented on ZOOKEEPER-784: +1, great job, Sergey! And thanks for the clarification, I can't believe I missed that finally block. server-side functionality for read-only mode Key: ZOOKEEPER-784 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784 Project: Zookeeper Issue Type: Sub-task Components: server Reporter: Sergey Doroshenko Assignee: Sergey Doroshenko Fix For: 3.4.0 Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create ReadOnlyZooKeeperServer which comes into play when peer is partitioned. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[ https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12901028#action_12901028 ] Flavio Junqueira commented on ZOOKEEPER-784: Nice job, Sergey! It is pretty well done, so I just have a few comments: # It is worth adding a warn message to ZooKeeperServer to log when an old client connects to an ro-enabled server. Currently the catch block doesn't do anything; # The code of ReadOnlyRequestProcessor is straightforward, but it would be nice to add a high-level description to the beginning of the class (add javadocs in general); # I wonder if waiting to start the r-o server for a single tickTime is not too aggressive. Would it make sense to set a lower bound of say 2s? That is, we use the largest between tickTime and 2s. An alternative is to add an optional parameter to set this value; # I couldn't really understand how the r-o zookeeper server gets killed once the replica joins a working quorum (i.e., once it transitions to either FOLLOWING, LEADING, or OBSERVING). I understand that leader election keeps running regularly, and the ro server starts if the state of the server doesn't change within the timeout period, but I couldn't find the code that kills the r-o server in the case it starts and the replica is not LOOKING. Could you please point me out to code that does it? server-side functionality for read-only mode Key: ZOOKEEPER-784 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784 Project: Zookeeper Issue Type: Sub-task Components: server Reporter: Sergey Doroshenko Assignee: Sergey Doroshenko Fix For: 3.4.0 Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create ReadOnlyZooKeeperServer which comes into play when peer is partitioned. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[ https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12898832#action_12898832 ] Sergey Doroshenko commented on ZOOKEEPER-784: - Thanks Henry! Eagerly looking forward to another +1 and getting r-o mode into the trunk I also have a patch that applies above ZOOKEEPER-733 changes, so if those go to the trunk first, I'll upload the patch server-side functionality for read-only mode Key: ZOOKEEPER-784 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784 Project: Zookeeper Issue Type: Sub-task Components: server Reporter: Sergey Doroshenko Assignee: Sergey Doroshenko Fix For: 3.4.0 Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create ReadOnlyZooKeeperServer which comes into play when peer is partitioned. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[ https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12897338#action_12897338 ] Henry Robinson commented on ZOOKEEPER-784: -- Spectacular job, Sergey. I've taken a look at the code and I'm pretty satisfied - you've done a great job covering little things like JMX support, and good code comments and documentation. I'm going to wait for one of the other committers to come by and also give this a +1 since this is a substantial change. We may also decide to run a long-lived test with this patch to satisfy ourselves of the stability. But this looks very, very solid indeed. server-side functionality for read-only mode Key: ZOOKEEPER-784 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784 Project: Zookeeper Issue Type: Sub-task Components: server Reporter: Sergey Doroshenko Assignee: Sergey Doroshenko Fix For: 3.4.0 Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create ReadOnlyZooKeeperServer which comes into play when peer is partitioned. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[ https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12886667#action_12886667 ] Hadoop QA commented on ZOOKEEPER-784: - -1 overall. Here are the results of testing the latest attachment http://issues.apache.org/jira/secure/attachment/12449071/ZOOKEEPER-784.patch against trunk revision 961026. +1 @author. The patch does not contain any @author tags. +1 tests included. The patch appears to include 13 new or modified tests. +1 javadoc. The javadoc tool did not generate any warning messages. +1 javac. The applied patch does not increase the total number of javac compiler warnings. +1 findbugs. The patch does not introduce any new Findbugs warnings. +1 release audit. The applied patch does not increase the total number of release audit warnings. -1 core tests. The patch failed core unit tests. +1 contrib tests. The patch passed contrib unit tests. Test results: http://hudson.zones.apache.org/hudson/job/Zookeeper-Patch-h1.grid.sp2.yahoo.net/136/testReport/ Findbugs warnings: http://hudson.zones.apache.org/hudson/job/Zookeeper-Patch-h1.grid.sp2.yahoo.net/136/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html Console output: http://hudson.zones.apache.org/hudson/job/Zookeeper-Patch-h1.grid.sp2.yahoo.net/136/console This message is automatically generated. server-side functionality for read-only mode Key: ZOOKEEPER-784 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784 Project: Zookeeper Issue Type: Sub-task Components: server Reporter: Sergey Doroshenko Assignee: Sergey Doroshenko Fix For: 3.4.0 Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create ReadOnlyZooKeeperServer which comes into play when peer is partitioned. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[ https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12886686#action_12886686 ] Sergey Doroshenko commented on ZOOKEEPER-784: - Hudson says there's one failing test: QuorumZxidSyncTest.testBehindLeader. But that's strange. 1) I can't reproduce this on my machine -- all tests pass. 2) Also, this test was passing ok with previous patch. And current patch is nearly the same as the previous one, changes made after previous patch can't cause this test to fail. server-side functionality for read-only mode Key: ZOOKEEPER-784 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784 Project: Zookeeper Issue Type: Sub-task Components: server Reporter: Sergey Doroshenko Assignee: Sergey Doroshenko Fix For: 3.4.0 Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create ReadOnlyZooKeeperServer which comes into play when peer is partitioned. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[ https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12885332#action_12885332 ] Hadoop QA commented on ZOOKEEPER-784: - -1 overall. Here are the results of testing the latest attachment http://issues.apache.org/jira/secure/attachment/12448721/ZOOKEEPER-784.patch against trunk revision 960676. +1 @author. The patch does not contain any @author tags. +1 tests included. The patch appears to include 13 new or modified tests. -1 patch. The patch command could not apply the patch. Console output: http://hudson.zones.apache.org/hudson/job/Zookeeper-Patch-h1.grid.sp2.yahoo.net/132/console This message is automatically generated. server-side functionality for read-only mode Key: ZOOKEEPER-784 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784 Project: Zookeeper Issue Type: Sub-task Reporter: Sergey Doroshenko Assignee: Sergey Doroshenko Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create ReadOnlyZooKeeperServer which comes into play when peer is partitioned. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[ https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12885348#action_12885348 ] Hadoop QA commented on ZOOKEEPER-784: - -1 overall. Here are the results of testing the latest attachment http://issues.apache.org/jira/secure/attachment/12448725/ZOOKEEPER-784.patch against trunk revision 960686. +1 @author. The patch does not contain any @author tags. +1 tests included. The patch appears to include 13 new or modified tests. +1 javadoc. The javadoc tool did not generate any warning messages. +1 javac. The applied patch does not increase the total number of javac compiler warnings. +1 findbugs. The patch does not introduce any new Findbugs warnings. +1 release audit. The applied patch does not increase the total number of release audit warnings. -1 core tests. The patch failed core unit tests. +1 contrib tests. The patch passed contrib unit tests. Test results: http://hudson.zones.apache.org/hudson/job/Zookeeper-Patch-h7.grid.sp2.yahoo.net/93/testReport/ Findbugs warnings: http://hudson.zones.apache.org/hudson/job/Zookeeper-Patch-h7.grid.sp2.yahoo.net/93/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html Console output: http://hudson.zones.apache.org/hudson/job/Zookeeper-Patch-h7.grid.sp2.yahoo.net/93/console This message is automatically generated. server-side functionality for read-only mode Key: ZOOKEEPER-784 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784 Project: Zookeeper Issue Type: Sub-task Reporter: Sergey Doroshenko Assignee: Sergey Doroshenko Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create ReadOnlyZooKeeperServer which comes into play when peer is partitioned. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[ https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12885349#action_12885349 ] Sergey Doroshenko commented on ZOOKEEPER-784: - I've updated the wiki page (http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode) to address backwards compatibility, searching of r/w server during r-o mode, session handling and other questions, and made it more structured overall. Soon I will also add some use case / recipe updated with regard to read-only mode. Overall, the latest patch presents ready-to-use implementation of the read-only mode feature. It's fully backwards compatible, new server is safe to use along with old ones, new client is safe to use against old servers etc. Documentation and tests will be improved of course, but again, this patch is ready to use. You could try this if you're interested. Consult the wiki page about usage and design details. server-side functionality for read-only mode Key: ZOOKEEPER-784 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784 Project: Zookeeper Issue Type: Sub-task Reporter: Sergey Doroshenko Assignee: Sergey Doroshenko Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create ReadOnlyZooKeeperServer which comes into play when peer is partitioned. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[ https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12884753#action_12884753 ] Hadoop QA commented on ZOOKEEPER-784: - -1 overall. Here are the results of testing the latest attachment http://issues.apache.org/jira/secure/attachment/12448584/ZOOKEEPER-784.patch against trunk revision 958096. +1 @author. The patch does not contain any @author tags. +1 tests included. The patch appears to include 13 new or modified tests. +1 javadoc. The javadoc tool did not generate any warning messages. +1 javac. The applied patch does not increase the total number of javac compiler warnings. -1 findbugs. The patch appears to introduce 1 new Findbugs warnings. +1 release audit. The applied patch does not increase the total number of release audit warnings. -1 core tests. The patch failed core unit tests. +1 contrib tests. The patch passed contrib unit tests. Test results: http://hudson.zones.apache.org/hudson/job/Zookeeper-Patch-h1.grid.sp2.yahoo.net/130/testReport/ Findbugs warnings: http://hudson.zones.apache.org/hudson/job/Zookeeper-Patch-h1.grid.sp2.yahoo.net/130/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html Console output: http://hudson.zones.apache.org/hudson/job/Zookeeper-Patch-h1.grid.sp2.yahoo.net/130/console This message is automatically generated. server-side functionality for read-only mode Key: ZOOKEEPER-784 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784 Project: Zookeeper Issue Type: Sub-task Reporter: Sergey Doroshenko Assignee: Sergey Doroshenko Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create ReadOnlyZooKeeperServer which comes into play when peer is partitioned. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[ https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12882975#action_12882975 ] Hadoop QA commented on ZOOKEEPER-784: - -1 overall. Here are the results of testing the latest attachment http://issues.apache.org/jira/secure/attachment/12448163/ZOOKEEPER-784.patch against trunk revision 958096. +1 @author. The patch does not contain any @author tags. +1 tests included. The patch appears to include 10 new or modified tests. +1 javadoc. The javadoc tool did not generate any warning messages. +1 javac. The applied patch does not increase the total number of javac compiler warnings. +1 findbugs. The patch does not introduce any new Findbugs warnings. -1 release audit. The applied patch generated 20 release audit warnings (more than the trunk's current 17 warnings). +1 core tests. The patch passed core unit tests. +1 contrib tests. The patch passed contrib unit tests. Test results: http://hudson.zones.apache.org/hudson/job/Zookeeper-Patch-h1.grid.sp2.yahoo.net/125/testReport/ Release audit warnings: http://hudson.zones.apache.org/hudson/job/Zookeeper-Patch-h1.grid.sp2.yahoo.net/125/artifact/trunk/patchprocess/releaseAuditDiffWarnings.txt Findbugs warnings: http://hudson.zones.apache.org/hudson/job/Zookeeper-Patch-h1.grid.sp2.yahoo.net/125/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html Console output: http://hudson.zones.apache.org/hudson/job/Zookeeper-Patch-h1.grid.sp2.yahoo.net/125/console This message is automatically generated. server-side functionality for read-only mode Key: ZOOKEEPER-784 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784 Project: Zookeeper Issue Type: Sub-task Reporter: Sergey Doroshenko Assignee: Sergey Doroshenko Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create ReadOnlyZooKeeperServer which comes into play when peer is partitioned. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[
https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12881746#action_12881746
]
Henry Robinson commented on ZOOKEEPER-784:
--
I like the idea of fake sessions fine, although I think that the upgrade
process might be complex. Another possibility is to do away with sessions in
read-only mode (because they're mainly used to maintain state about watches,
which don't make sense on a read-only server).
Sergey - just looked over your patch. Nice job! Couple of questions:
1. In QuorumPeer.java, I can't quite follow the logic in this part of the patch:
{code}
while (running) {
switch (getPeerState()) {
case LOOKING:
+LOG.info(LOOKING);
+ReadOnlyZooKeeperServer roZk = null;
try {
-LOG.info(LOOKING);
+roZk = new ReadOnlyZooKeeperServer(
+logFactory, this,
+new ZooKeeperServer.BasicDataTreeBuilder(),
+this.zkDb);
+roZk.startup();
+
{code}
- is it sensible to start a ROZKServer every time a server enters the 'LOOKING'
state, or should there be some kind of delay before it decides it is
partitioned? Otherwise when a leader is lost and the quorum is doing a
re-election, r/w clients that try and connect would get (I think) 'can't be
read-only' messages .
2. What are you doing about watches? It seems to me that setting a watch turns
a read operation into a read / write operation, and the client should be told
that watch registration failed. If you can do this you don't have to worry so
much about session migration because there's very little session state
maintained by a ROZKServer on behalf of the client.
3. This patch has got to the point where it might be good if you started adding
some tests to validate any further development you do.
server-side functionality for read-only mode
Key: ZOOKEEPER-784
URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784
Project: Zookeeper
Issue Type: Sub-task
Reporter: Sergey Doroshenko
Assignee: Sergey Doroshenko
Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch,
ZOOKEEPER-784.patch
As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create
ReadOnlyZooKeeperServer which comes into play when peer is partitioned.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[ https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12881313#action_12881313 ] Sergey Doroshenko commented on ZOOKEEPER-784: - --- Question about session handling --- For now (latest patch) when r/o client connects to a partitioned server, new fake session is created for it -- fake because it exists only in this server. When server regains the quorum, during this session's revalidation it will be rejected as invalid since leader didn't see this it. From users' point of view it'd be good to transparently upgrade such session to a usual session. The idea is that if leader sees that given session is invalid but also belongs to read-only client then it re-assigns new id to id and sends this new id to the client. The idea is good but seems error-prone. For example, what to do with r/o clients that were partitioned (and connected to partitioned server) for longer than sess timeout? At leader their sessions have already been expired, so they should be rejected. Re-assigning new session to such clients doesn't look right. But the problem here is that when servers see an invalid session they can't tell if they never saw it or if they saw it but it was expired. So, if quorum rejects r/o session (which implies this session either was never seen by quorum or is expired), there are two options from users' point of view: * ZooKeeper object becomes invalid, and application should create a new one. Reliable and consistent with current ZK * server transparently re-assigns session id for such client. Seems to have many potential problems, as described above What do you think? server-side functionality for read-only mode Key: ZOOKEEPER-784 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784 Project: Zookeeper Issue Type: Sub-task Reporter: Sergey Doroshenko Assignee: Sergey Doroshenko Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create ReadOnlyZooKeeperServer which comes into play when peer is partitioned. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[ https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12879405#action_12879405 ] Patrick Hunt commented on ZOOKEEPER-784: I read through the wiki page, I think this is an awesome feature! A few high level questions came to mind: 1) please be clear in the wiki page on b/w compatibility. There's some discussion of this, but what I mean is be very explicit regarding client-server compatibility, server-server compatibility. Have individual sections for this: a) new client new server (obv compat) b) new server new server (ditto) c) new client (using r/o client mode) old server (?) d) new server - old server (?) 2) be clear on how the client library will search for r/o server vs w/r server (if ensemble has internal partitioning) be clear on how this will work if no servers at all are available. In particular I'm interested in how the client will backoff vs hammering (constantly connecting/disconnecting to servers) 3) add use cases that explain to users exactly how this will benefit them. go through some actual use cases such as leader election, group membership, and dynamic config. You should clearly spellout how the user's client code will handle these cases when using r/o mode. You might for example rewrite the recipes from the recipes page for the r/o supported version. Detail any special considerations the user might need to consider. For example, in the case of leader election you might detail how this is handled from zk perspective (client attached to r/o server) but also detail the considerations the user should have - such as the leader may have changed, what might the user have to consider. (leader can change if client A is connected to r/o server while the rest of the service (other clients of zk) might be connected to a r/w server, during which time the users's leadership changes). etc... We'll need this anyway for the user docs, doing it upfront on the jira will help you both for that and while developing the feature/tests. server-side functionality for read-only mode Key: ZOOKEEPER-784 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784 Project: Zookeeper Issue Type: Sub-task Reporter: Sergey Doroshenko Assignee: Sergey Doroshenko Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create ReadOnlyZooKeeperServer which comes into play when peer is partitioned. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-784) server-side functionality for read-only mode
[ https://issues.apache.org/jira/browse/ZOOKEEPER-784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12879407#action_12879407 ] Patrick Hunt commented on ZOOKEEPER-784: For b/w compat I forgot: old client - new server as well as new client not using the r/o feature against new/old server. I might have missed others... server-side functionality for read-only mode Key: ZOOKEEPER-784 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-784 Project: Zookeeper Issue Type: Sub-task Reporter: Sergey Doroshenko Assignee: Sergey Doroshenko Attachments: ZOOKEEPER-784.patch, ZOOKEEPER-784.patch, ZOOKEEPER-784.patch As per http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode , create ReadOnlyZooKeeperServer which comes into play when peer is partitioned. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
