How do we specify multiple hosts (assuming primary, secondary) for a consumer client ?
Below is the function signature from their header
OmmConsumerConfig& host( const EmaString& host = "localhost:14002" );
It can accept “host:port”, however in our current setup of trep/rfa, we provide 2 hosts, i.e. "host1 host2"
Want to know if there is such provision for Consumer with Ema sdk.
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OmmConsumerConfig::host() is used to specify a hostname and port.
It doesn't support multiple hosts.
To use multiple hosts, you need to specify it in the EMA configuration via the ChannelSet configuration. 
You can specify this in the EMAConfig.xml. For example:
<ConsumerGroup> <ConsumerList> <Consumer> <Name value="Consumer_1"/> <!-- ChannelSet is optional --> <ChannelSet value="Channel_1, Channel_2"/> <!-- Logger is optional: defaulted to "File + Success" --> <Logger value="Logger_1"/> <!-- Dictionary is optional: defaulted to "ChannelDictionary" --> <Dictionary value="Dictionary_1"/> </Consumer> </ConsumerList> </ConsumerGroup> ...
Otherwise, you can use the programmatic configuration feature of EMA, as shown in the 421_MP_ProgrammaticCfg example.
Hello @ryusuke.kamimura
Another resource that might help you with the EMA failover/reconnect logic is The Mechanics of EMA Connection and Item Recovery article.
As well as my colleague's answer, you may also find the Channels and ChannelSets section of the following article useful - Enterprise Message API (EMA) - Configuration Overview | Refinitiv Developers
