1. weight 大于0

如果腳本監測失敗，優先級不變，如果成功，優先級增加，如果后續監測失敗，則優先級在增加的基礎上回退，這個weight不會持續增加或減小，只會存在兩個值

2. weight 小于0

如果腳本監測失敗，優先級降低，如果成功，優先級不變，這個weight不會持續增加或減小，只會存在兩個值


另外，keepalived啟動時，不論rise和fall的設置的是多少，首次監測腳本，都會根據上面的原則調整，后續的調整則要只有在進入fall和rise到達之后才會調整



       The  default  weight equals 0, which means that any VRRP instance moni-
       toring the script will transition to the fault state after 
       consecutive  failures  of the script. After that,  consecu-
       tive successes will cause VRRP instances  to  leave  the  fault  state,
       unless  they are also in the fault state due to other scripts or inter-
       faces that they are tracking.

       A  positive  weight  means  that     successes   will   add
         to the priority of all VRRP instances which monitor it.
       On the opposite, a negative weight will be subtracted from the  initial
       priority in case of  failures.


參考：??https://www.keepalived.org/manpage.html??