故障现象：[ ERROR ] - [x2openEuler-upgrade] - [Backup]: rsync files error, returned 20, error info was: file has vanished: “/run/pcscd/pcscd.pid”
file has vanished: “/run/systemd/journal/streams/8:80768”
rsync error: received SIGINT, SIGTERM, or SIGHUP (code 20) at rsync.c(638) [sender=3.1.2]
[ ERROR ] - [x2openEuler-upgrade] - [Backup]: back up operation failed
[ ERROR ] - [x2openEuler-upgrade] - back up files error
[ ERROR ] - [centos2openEuler]: x2openEuler-upgrade backup failed, please check
报错截图：
解决思路：
1，查看日志是备份文件这一步出错；
2，查看待升级节点上的rsync服务未启动
3，引导用户回退任务，然后在待升级节点上启动rsync服务，重试升级任务。