最近項(xiàng)目接入了灰度，但是在灰度的時(shí)候，概率性就出現(xiàn)Error choosing server for key null報(bào)錯(cuò)，如下圖：
一開始以為是哪里配置有問題，反復(fù)對ribbon配置進(jìn)行調(diào)整測試以后，還是會(huì)有問題，用jmeter在測試環(huán)境不停的請求，然后反復(fù)切換灰度，1000個(gè)請求，一定會(huì)概率出現(xiàn)幾個(gè)請求Error choosing server for key null，如下圖：
經(jīng)過幾天的方案查找和測試，最后終于通過Google找到了spring-cloud在GitHub上面的issues，鏈接是https://github.com/spring-cloud/spring-cloud-netflix/issues/2752
問題和我現(xiàn)在的情況一樣，主要原因就是版本bug，問題體現(xiàn)在Spring-cloud-netflix 1.4.x 使用的Ribbon 2.2.4；原文如下：
I am seeing this exact issue with Boot 1.5.10 and Edgware (RELEASE, SR1, SR2) too. I found this merged PR in Ribbon which seems to fix it.
It is a problem introduced fairly recently, in the 2.2.4 release of Ribbon, which is used by spring-cloud-netflix 1.4.x. There is no release > 2.2.4 yet, so downgrading to Dalston was the only viable option for me. Once the next release of Ribbon is out, this will be an easy fix.
而我們項(xiàng)目使用的SpringBoot 1.5.10 (SpringCloud Dalston.RELEASE)，果斷選了一個(gè)服務(wù)把版本升級(jí)到了SpringBoot 1.5.22 (SpringCloud Edgware.SR6)進(jìn)行測試，經(jīng)過jmeter反復(fù)請求測試，再也沒有出現(xiàn)過Error choosing server for key null報(bào)錯(cuò)，然后在把其他服務(wù)依次升級(jí)，在測試環(huán)境進(jìn)行了測試，再也沒出現(xiàn)過這個(gè)問題。
