This is such a major effort: getting up to speed on existing code bases to the point you can add to them.
It's a great thing that different projects have different scopes! If you're just looking to contribute to some project to gain experience, it might be a good idea to start with some smaller scoped-project before jumping into larger ones.
For example, if you're interested to contributing to the core of Kubernetes, maybe start by contributing to a plugin that interact with Kubernetes. Eventually, while trying to contribute to the plugin, you get indirectly exposed to some of the internals of the parent project, and eventually you'll be able to faster jump into contributing to Kubernetes itself.
Comments
It's a great thing that different projects have different scopes! If you're just looking to contribute to some project to gain experience, it might be a good idea to start with some smaller scoped-project before jumping into larger ones.
For example, if you're interested to contributing to the core of Kubernetes, maybe start by contributing to a plugin that interact with Kubernetes. Eventually, while trying to contribute to the plugin, you get indirectly exposed to some of the internals of the parent project, and eventually you'll be able to faster jump into contributing to Kubernetes itself.