Issues if -Djava.net.preferIPv4Stack=true is not set

[Valentin Kulichenko]

Guys,

I noticed there are many issues on user forum that occur
of -Djava.net.preferIPv4Stack=true system property is not set.

Can someone explain the nature of these issues? What exactly in Ignite
requires this system property do be set? And can this be fixed/automated
somehow?

If fix is not possible, we need to clearly document this and print out a
warning on startup.

-Val

[dsetrakyan]

Any comments here? Do we really require IPv4 for some reason?

On Mon, Sep 18, 2017 at 9:51 AM, Valentin Kulichenko <
[hidden email]> wrote:

> Guys,
>
> I noticed there are many issues on user forum that occur
> of -Djava.net.preferIPv4Stack=true system property is not set.
>
> Can someone explain the nature of these issues? What exactly in Ignite
> requires this system property do be set? And can this be fixed/automated
> somehow?
>
> If fix is not possible, we need to clearly document this and print out a
> warning on startup.
>
> -Val
>

[yzhdanov]

Val, can you please provide links to threads you meant? I will take a look.

--Yakov

[Valentin Kulichenko]

Yakov,

Here are couple examples:
- http://apache-ignite-users.70518.x6.nabble.com/How-to-
correctly-shut-down-Ignite-Application-td12548.html
- http://apache-ignite-users.70518.x6.nabble.com/Nodes-
hanging-when-accessing-queue-td12343.html

*Andrey*, it seems that you give this kind of recommendation every now and
then. Can you please provide more detail on this? Is this something that
needs to be fixed in the product?

-Val

On Tue, Sep 19, 2017 at 4:36 AM, Yakov Zhdanov <[hidden email]> wrote:

> Val, can you please provide links to threads you meant? I will take a look.
>
> --Yakov
>

[yzhdanov]

Val, I see now.

For example, this http://apache-ignite-users.70518.x6.nabble.com/How-
to-correctly-shut-down-Ignite-Application-td12548.html could happen due to
address passed to
org.apache.ignite.internal.util.IgniteUtils#reachable(java.net.InetAddress,
int) is NULL.

I suspect there may be problems with ipv6 support as I personally cannot
name a deployment that runs over ipv6 and I doubt if it is useful. I will
file a ticket to output warning if prefer ipv4 property is not set. And
also a minor ticket to test and fix ipv6 support.

BTW, here are the tickets that are searchable by "ipv6" for now -
https://issues.apache.org/jira/browse/IGNITE-2405?jql=
text%20~%20%22ipv6%22%20and%20project%20%3D%20ignite

Issue to add warning - https://issues.apache.org/jira/browse/IGNITE-6502


--Yakov

[dsetrakyan]

Why don't we automatically set the preferIPv4Stack to true, unless the user
explicitly set it to false?

D.

On Tue, Sep 26, 2017 at 4:35 AM, Yakov Zhdanov <[hidden email]> wrote:

> Val, I see now.
>
> For example, this http://apache-ignite-users.70518.x6.nabble.com/How-
> to-correctly-shut-down-Ignite-Application-td12548.html could happen due to
> address passed to
> org.apache.ignite.internal.util.IgniteUtils#reachable(
> java.net.InetAddress,
> int) is NULL.
>
> I suspect there may be problems with ipv6 support as I personally cannot
> name a deployment that runs over ipv6 and I doubt if it is useful. I will
> file a ticket to output warning if prefer ipv4 property is not set. And
> also a minor ticket to test and fix ipv6 support.
>
> BTW, here are the tickets that are searchable by "ipv6" for now -
> https://issues.apache.org/jira/browse/IGNITE-2405?jql=
> text%20~%20%22ipv6%22%20and%20project%20%3D%20ignite
>
> Issue to add warning - https://issues.apache.org/jira/browse/IGNITE-6502
>
>
> --Yakov
>

[yzhdanov]

hmm.. Dmitry, your suggestion may work if Ignite is started before any of
network layer class is loaded/called. E.g. this will not work if Ignite is
started inside application or web server.

--Yakov

[dsetrakyan]

On Wed, Sep 27, 2017 at 5:08 AM, Yakov Zhdanov <[hidden email]> wrote:

> hmm.. Dmitry, your suggestion may work if Ignite is started before any of
> network layer class is loaded/called. E.g. this will not work if Ignite is
> started inside application or web server.
>

Sure, let's do it anyway. In addition, can we make sure that we provide
users with this suggestion in case of the common network errors? If yes,
can we file the ticket for 2.3?


>
> --Yakov
>

[yzhdanov]

The issue has already been picked up by VK.

Dmitry, after some thought I find it a little bit weird to set system
property automatically without any way to restore default behavior.

--Yakov

[Dmitriy Setrakyan-2]

On Thu, Sep 28, 2017 at 7:08 AM, Yakov Zhdanov <[hidden email]> wrote:

> The issue has already been picked up by VK.
>
> Dmitry, after some thought I find it a little bit weird to set system
> property automatically without any way to restore default behavior.
>

I am not sure I understand. Can you please explain?

[yzhdanov]

If user has Ignite deployment and does not want Ignite to automatically
change this property and does not want to set it to false. Which means user
wants to have completely default behavior as we have now.

--Yakov

[dsetrakyan]

Hm... I am not sure I understand why. But in any case, to the list, we
should provide proper error messages suggesting to change this property. Do
you agree?

D.

On Fri, Sep 29, 2017 at 3:18 AM, Yakov Zhdanov <[hidden email]> wrote:

> If user has Ignite deployment and does not want Ignite to automatically
> change this property and does not want to set it to false. Which means user
> wants to have completely default behavior as we have now.
>
> --Yakov
>