What is the difference between objects project and namespace in Openshift 4.x

Solution 1:

A project is essentially the same as a namespace, but OpenShift provides additional administrative controls for projects.

If you're deploying software on OpenShift you'll basically use the project exactly the same way as a Kubernetes namespace, except a normal user can be prevented from creating their own projects, requiring a cluster administrator to do that. (It appears that your cluster allows you to create your own projects, or you're using a personal cluster such as CodeReady Containers or its predecessor Minishift.)

From the docs:

Projects are the unit of isolation and collaboration in OpenShift. A project has one or more members, a quota on the resources that the project may consume, and the security controls on the resources in the project. Within a project, members may have different roles - project administrators can set membership, editors can create and manage the resources, and viewers can see but not access running containers. In a normal cluster project administrators are not able to alter their quotas - that is restricted to cluster administrators.

Listing or watching projects will return only projects the user has the reader role on.

An OpenShift project is an alternative representation of a Kubernetes namespace. Projects are exposed as editable to end users while namespaces are not. Direct creation of a project is typically restricted to administrators, while end users should use the requestproject resource.