Set default node count is 4.
Set default node count is 4.

set default node count is 4. If uers wants more than 4
nodes. Use c5, c6.... name the other nodes.

Signed-off-by: Jin Qing <82160768a1b0174bd1d090c239be37508c32549f@qq.com>

sharpbear/DNA,superJinQing/DNA,luodanwg/DNA,BooniesFX/DNA,zhengq1/DNA,luodanwg/DNA,zhengq1/DNA,BooniesFX/DNA,sharpbear/DNA,dreamfly281/DNA,dreamfly281/DNA,zhouziyan/DNA,superJinQing/DNA,zhouziyan/DNA,qingche123/DNA,qingche123/DNA