Can't trigger 5V,10A relay using the output from a ESP8266 node MCU?
It is a good idea to look for the datasheet of your relay and examine not only the recommended coil voltage but the current required to actuate the relay. 

Most microcontroller modules can only source/sink a limited amount of current on their digital I/O lines (usually on the order of tens of milliamps). Relays can sometimes require over 100mA of current on their coils to remain "ON". 

In order to do this, look into using an NPN transistor as a common emitter switch. Your micro controller can easily saturate and "turn on" a transistor such as the 2n3904 transistor which is capable of switching loads on the order of a few hundred milliamps. You'll need a resistor between your microcontroller's pin and the base of the transistor. Again, many available schematics and how-to's can be found online. A simple 1K ohm resistor is suitable for limiting current to the base of the 2n3904 when using 5V logic. 

Be sure to also look into adding a "flyback diode" across the terminals of the relay's coil to prevent high voltage transients during switching on/off which can damage the transistor.

Hope this helps.