Hi Pavel,
my problem is in the JDK Client Connector
(
https://java.net/projects/tyrus/sources/code/content/containers/jdk-client/src/main/java/org/glassfish/tyrus/container/jdk/client/JdkClientContainer.java?rev=d86f5679c524ae65ba9254306c413acce1e51c85)
The getSocketAddress method only delivers a single SocketAddress and if
the first IP address returned is the server that is unavailable then the
client is completely incapable of connecting to the alternate address.
Windows appears to cache the query for the TTL duration and always
delivers the addresses in the same order, even if the DNS is set up to
round robin.
So connectSynchronously always fails when the first address in the
possible addresses for a server can't be reached.
In my opinion, the client should be using
InetAddress#getAllByName(String host) to get multiple addresses (if
defined) and attempt to connect to them all in the returned order.
One could argue that the SocketChannel in TransportFilter#handleConnect
should try all the available addresses but that is obviously not the case.
Maybe the completion handler could use an array of the available addresses.
--
Bill
On 20/11/16 19:23, Pavel Bucek wrote:
> Hi Bill,
>
> what exactly is the issue about and how is it related to Tyrus (client)?
>
> Tyrus cannot influence name resolution and you can try to connect
> until connected, simply by implementing it by yourself or using Tyrus
> feature (see [1]).
>
> If you'd ask me how to do the scenario you specified, I'd recommend
> putting some kind of LB in front of both servers. Then the client
> (websocket or anything else) would connect to the LB, which will then
> redirect to the live instance. This has obvious benefits (defined load
> balancing, monitoring, ...), but requires additional machine.
>
> Regards,
> Pavel
>
> [1]
> https://tyrus.java.net/apidocs/1.13/org/glassfish/tyrus/client/ClientManager.ReconnectHandler.html
>
>
> On 20/11/2016 14:51, Bill Mair wrote:
>> Hi,
>>
>> in a feasibility test I set up a server name with 2 IP addresses
>> (machines) associated with it.
>>
>> This is to support high availability and allow one of the servers to
>> be off line for maintenance or failure and make sure that the service
>> is still available through the second instance.
>>
>> The connection repeatedly fails if the first SocketAddress being
>> returned by Windows DNS client is not available and no attempt to
>> connect to the other server being made.
>>
>> In a HA production environment I think that it is essential that
>> tyrus should attempt to connect to all IP addresses associated with a
>> server's name.
>>
>> Any advice would be appreciated.
>>
>> Bill Mair
>>
>