problem description

recently, I have been looking at things related to automated operation and maintenance devops, and some problems are not quite clear for the time being. Hope God to inform
premise: springcloud deployment, there are probably registry, configuration center, message center, order center, user center, activity center. 2 instances per center

1. If you use K8S and jenkins, to look at the materials on the Internet, it seems that you can only do it, and you can only build one center at a time. In other words, I have to build 6 new tasks on jenkins, and each time I launch it, it is my turn to build it. It seems normal to think about it. If I only change the code of a certain center, all I have to do is build the code of that center. Do big companies do this?

2. In fact, I don"t quite understand how to ask this question, but it seems that the specific implementation of devops can not be found on the Internet, it is all conceptual things. My understanding of devops is that it only needs to be built, and the online environment is all done. But it doesn"t seem to be possible. Are there any great gods who have this kind of experience? give me some guidance.