If I want to develop a SaaS system and want to use k8's namespace to do isolation, i.e., I will create a namespace for every user, it's a multi-tenancy system, then, how many namespaces can I have? Will k8s be slowdown when namespace increases?
To answer your question, namespace is a logical entity that is used to isolate the application environment from another application environment. It doesn't consume cluster resources like cpu and memory. Ideally you can create any number of namespaces. Am not sure if there is a limit on number of namespaces that is allowed in a custer
On the other hand it is not a good approach to have one namespace each for user. Applications multi tenancy should be better handled in the application code itself. Namespace is recommended to isolate the environment like one for Development, one for TEST, one for QA and Another one for production