Failure to post to Kafka

[DmitryLitvintsev]

In the past I was complaining about failure to post to Kafka after upgrade to 8.2.

I believe I finally got to the bottom of it.

dcache.kafka.bootstrap-servers=lssrv08:9092

I think the issue is due to:

telnet -6 lssrv08 9092
Trying 2620:6a:0:8430:f0:0:240:59...
telnet: connect to address 2620:6a:0:8430:f0:0:240:59: Connection refused

vs

 telnet -4 lssrv08 9092
Trying 131.225.240.59...
Connected to lssrv08.
Escape character is '^]'.

And I think the failure to connect to Kafka started to happen due to patch:

da994201

That added:

    -Djava.net.preferIPv6Addresses=system \

And indeed if I edit

/usr/share/dcache/defaults/dcache.properties

and remove that line - things work.

Question - is there convenient way to override/remove this property? Should I be redefining the whole of dcache.java.options in dcache.conf ?

Thanks

[kofemann]

The problem is obviously in a network configuration that IPv4 and IPv6 have different firewall rules or IPv6 address points to a different host.

as a workaround, you can add -Djava.net.preferIPv6Addresses=ipv4 to extra options:

dcache.java.options.extra=-Djava.net.preferIPv6Addresses=ipv4

As extra options added after standard option, the value will be overwritten

[DmitryLitvintsev]

yeah, I thought so too - I thought it was just a matter of firewall configuration and opened a ticket with "them" long ago. But then it turned almost insurmountable. The service runs on container and they cannot figure IPv6 for it looks like. Meanwhile I need data in ELK. Thanks for the tip. I will use it meanwhile!

[kofemann]

Actually, the valid values are true, false and system. All other values threated as false

[paulmillar]

Just FYI, in the past, system doesn't work with all JVMs.

(Also, I would say the "correct" solution is simply to remove the AAAA record from DNS, until the IPv6 deployment is fixed ;-)