在 Rancher 中出现 Rolling-Back (Expected state running but got stopped)，无法再次升级的解决

1、在 Rancher 中升级失败，回滚时出现 Rolling-Back (Expected state running but got stopped)，如图1

图1

2、点击查看日志的链接，如图2

图2

2018/6/13 下午6:26:01/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:26:06/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:26:20/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:26:36/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:26:50/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:27:06/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:27:21/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:27:36/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:27:51/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:28:20/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:28:50/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:29:06/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:30:06/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:31:06/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:32:06/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:32:11/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:33:21/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable
2018/6/13 下午6:34:21/config/init/config0.sh: line 2: PCS_API_CFG_DB_HOST: unbound variable

3、日志: webtv-pcs-1，提示：PCS_API_CFG_DB_HOST，未绑定变量(可以明确的是，之前是绑定了环境变量的，原因暂未找到)，如图3

图3

4、克隆服务为 pcs-backup，选择镜像，registry-vpc.cn-beijing.aliyuncs.com/cmc/pcs-api:dev_dev-0.4.7，升级，如图4、图5

图4

图5

5、pcs-backup 升级成功后，删除服务 pcs，如图6

图6

6、编辑 pcs-backup，修改名称为 pcs，如图7

图7