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From Aravind Musigumpula <Aravind.Musigump...@amdocs.com>
Subject RE: Monitor the neighbour JVM using neihbour's member-timeout
Date Mon, 18 Dec 2017 13:25:28 GMT
Hi Community,

Can you please give your suggestions on the below solution.

I have raised a pull request for the same : https://github.com/apache/geode/pull/1075 .


Thanks,
Aravind Musigumpula 

-----Original Message-----
From: Aravind Musigumpula 
Sent: Friday, November 03, 2017 3:23 PM
To: dev@geode.apache.org
Subject: RE: Monitor the neighbour JVM using neihbour's member-timeout

Thanks Bruce for suggestions, I will change the new variables from InternalDistributedMember
to NetView and do changes related to backward compatibility.

Now I know that there is another way that member can be removed from the view i.e if any member
is sending a message and waits for ack-wait-threshold, if there is no response from the target
the sender will do final check and remove it from the view if there is still no response.

But I don't understand how deprecating the settings member-timeout, ack-wait-threshold, ack-severe-alert-threshold
into one will solve the problem. The main problem is that we want a member to survive in the
view for longer time than others.

If we deprecate the settings into one setting and pass the setting to monitoring member(say
A), then it will use the target member(say B which we want to survive in view for longer time)
timeout for health monitoring and ack-wait-threshold to wait for the response for any message
before doing final check.
But what if some other member(say C) which is monitoring any other member(say D) have the
member-timeout and ack-wait-threshold some smaller values. So if member C messages to B, C
uses the smaller value of ack-wait-threshold(which is of member D) to get a response and does
the final check again on basis of smaller member-timeout. So still member B can be kicked
out of the view in small amount of time.

I think this can be solved simply if we use the member-timeout of suspected member in the
final check where we establish TCP connection. We don't need to club those three settings
as well. We can set the member-timeout of a particular member to a higher value and the member
which monitors it uses its own member-timeout as it is now, but during the final check it
uses the suspected member-timeout(which is a greater value). The final check is common place
in both the no heartbeat scenario and no response for a message scenario.

Are there any concerns around this new proposal ?


Thanks,
Aravind Musigumpula 

-----Original Message-----
From: Bruce Schuchardt [mailto:bschuchardt@pivotal.io]
Sent: Thursday, September 07, 2017 10:42 PM
To: dev@geode.apache.org
Subject: Re: Monitor the neighbour JVM using neihbour's member-timeout

I think this might be an acceptable change though I doubt many people would find it useful.

It's already possible to set different member-timeouts on each node of the distributed system
but the meaning of the setting is the inverse of what's proposed here, so having the current
setting be different in each node is pretty useless.

I think the initiation of suspect processing ought to be addressed if we make this change. 
The ack-wait-threshold and ack-severe-alert-threshold aren't based on the member-timeout but
ought to be.  This would make it possible to initiate suspect processing with different timing
for different nodes.  It would still leave the question of slow backup operations hanging: 
If you're waiting for one node that's blocked waiting for a response from another node (say
a node holding a backup
bucket) you are going to initiate suspect processing on the node you're waiting on & not
those other (backup) nodes.

Rolling upgrade will also be a problem since old members aren't going to cough up their member-timeout
settings.  What should be used as a membership timeout for the old members during an upgrade?

If we proceed with this idea I'd prefer that we deprecate member-timeout, ack-wait-threshold
and ack-severe-alert-threshold and have new settings with the "ack" settings being multiples
of the new membership timeout setting.

Concerning the PR, it isn't acceptable in its current form. 
InternalDistributedMember identifiers are often transmitted in messages and increasing their
size affects performance.  Any new member attributes need to be added to NetView instead
of InternalDistributedMember.


On 8/22/17 12:35 AM, Aravind Musigumpula wrote:
> Hi Team,
>
> We have a requirement to configure  different member timeout for different members as
we need some members to survive in the view for longer time than the other the members before
being kicked out of the view in case they aren't responding.
>
>
> 1.       Now with the current monitoring system it is not possible to determine when
the member will be kicked out of the view if we configure different member-timeout's for some
required members.
>
> 2.       Because if a member is not responding to any heartbeat requests, the member
who is monitoring the non-responding member will initiate check member request.
>
> 3.       In this check member request monitoring member pings the non-responding member
and waits for member-timeout of monitoring member for a response.
>
> 4.       If still there is no response, it will initiate a final suspect request to coordinator
where the coordinator does the final check waiting for coordinators member-timeout.
>
> 5.       If coordinator did not get any response, it will remove the non-responding member
from the view and publishes it.
>
> 6.       So, Here the time period for removing a member depends on its monitoring member's
and coordinator's timeout. But the monitoring member depends on the view but it may change
from time to time.
>
> So, now when a monitoring-member doing the check on a member, if we wait for the non-responding
member's timeout instead of the monitoring member-timeout, then the time when the non-responding
member will be removed from the view depends on its own member-timeout and the coordinators
member-timeout.
> Hence we can configure different member-timeout for the required members.
>
> I created a pull request based on the above scenario: 
> https://github.com/apache/geode/pull/717
>
> Is the above approach correct? Do we have any concerns around this area?
> Please give your insights on this issue.
>
> Thanks,
> Aravind Musigumpula
>
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>
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This message and the information contained herein is proprietary and confidential and subject
to the Amdocs policy statement,

you may review at https://www.amdocs.com/about/email-disclaimer <https://www.amdocs.com/about/email-disclaimer>

This message and the information contained herein is proprietary and confidential and subject
to the Amdocs policy statement,

you may review at https://www.amdocs.com/about/email-disclaimer <https://www.amdocs.com/about/email-disclaimer>


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