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From Pavel Kovalenko <jokse...@gmail.com>
Subject Re: Deprecate force server mode for clients.
Date Thu, 09 Aug 2018 09:51:10 GMT
Andrey,

Huge +1 for that.
"Force server mode" increases the complexity of understanding how cluster
in ring mode works without real benefits.
If a user wants to start client node first before server nodes have
started, he can adjust timeouts on connection and spin till a client is
connected. Ability to join client node to topology without server nodes
looks dubious.
As we have thin clients and Zookeeper Discovery SPI this mode looks like a
crutch and should be removed.

2018-08-09 12:41 GMT+03:00 Andrey Mashenkov <andrey.mashenkov@gmail.com>:

> Hi Igniters,
>
> I've found that KernalContext.clientNode() and TcpDusciveryNode.isClient()
> means different and it looks confusing.
>
> 1. The first one return true if "node is configured as client" and false
> otherwise,
> 2. The second one can return false if server mode is forced for client (via
> TcpDiscoverySpi.setForceServerMode(true)) ,
>  so actually true value means "a client node is out of the ring".
>
> Thus, TcpDiscoveryNode.isClient() semantic is broken and  we can get
> confusing results on client node with forced server mode,
> when kernalContext.clientNode() return true and
> kernalContex.localNode().isClient() return false.
>
> Also, we have a number of places in code where node.isClient() method is
> used.
>
> My suggestion is
> 1. Deprecate force server mode and plan to remove it to next major release.
> 2. Fix TcpDiscoveryNode,isClient() semantic e.g. to use node attributes to
> make ClusterNode.isClient method consistent with node configuration.
> 2. Add isRingNode (possibly package private) with current
> TcpDiscoveryNode.isClient() semantic to preserve compatibility.
>
> Any pros or cons?
>
> --
> Best regards,
> Andrey V. Mashenkov
>

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