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From Stanislav Lukyanov <stanlukya...@gmail.com>
Subject RE: ipFinder configuration for Samples
Date Thu, 28 Feb 2019 11:31:02 GMT

Our product is for engineers sitting in one office.
Companies which use Ignite have many engineers running Ignite on their laptops the same way
as companies that make changes to Ignite.
 “Could it be because of the multicast?” is one of the questions I ask every time I see
a question on SO
or user list, and I would be happy not to.

The activity of changing the examples from multicast to local addresses was started and stopped
multiple times,
but AFAIR most of the community was in favor of this change.

Moreover, our default configuration (when discoSpi is not set– such as in default-config.xml)
uses multicast. I’d change that to a localhost VmIPFinder.

If we want an easy start of the examples (even though I think each user would want to use
examples with multicast 
exactly once, if ever) let’s add multiple configs or a switch to ignite.sh. I believe it’s
better than showing multicast as default.

Regarding the address list – AFAIR Ignite tries to scan the multicast group first. Only
after that it 
will try to connect to addresses from the list. So, the list is a bit misleading.

Finally, if Hazelcast uses multicast by default – well, probably they should turn that off
as well.

My 2 cents,

From: Yakov Zhdanov
Sent: 28 февраля 2019 г. 12:53
To: dev@ignite.apache.org
Subject: Re: ipFinder configuration for Samples


I remember we did the opposite change some time ago - switched VM IP finder
to multicast. That was done for user being able to start cluster spanning
multiple machines using examples configuration. With this change you
removed all the working samples for starting really distributed environment.

What was the problem? Multicast IP finder has the list of addresses that we
try to connect to on start. As far as clashes - it seems it affects only
engineers sitting in one office, but they can set up env var to override
default mcast group. The primary goal for switching to multicast was to
allow people new to Ignite to quickly start the cluster.

As far as I remember hazelcast has multicast enabled by default. Can
anybody check this?


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