| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| github.com/pkg/errors | Package errors provides simple error handling primitives. |
| k8s.io/kubernetes/cmd/kubeadm/app/cmd/options | Package options provide a central point for defining flags for kubeadm cobra commands, no matter if hard coded commands or autogenerated command for phases. |
| k8s.io/kubernetes/cmd/kubeadm/app/cmd/phases/upgrade | Package upgrade holds the common phases for 'kubeadm upgrade'. |
| k8s.io/kubernetes/cmd/kubeadm/app/cmd/phases/workflow | Package workflow implements a workflow manager to be used for implementing composable kubeadm workflows. |
| k8s.io/kubernetes/cmd/kubeadm/app/features | |
| k8s.io/kubernetes/cmd/kubeadm/app/phases/upgrade | |
| k8s.io/kubernetes/cmd/kubeadm/app/preflight | |
| k8s.io/kubernetes/cmd/kubeadm/app/util/apiclient | Package apiclient contains wrapping logic for Kubernetes API clients. |
| k8s.io/utils/exec | Package exec provides an injectable interface and implementations for running commands. |
| os | Package os provides a platform-independent interface to operating system functionality. |