kubernetes/cmd/kubeadm/app/util/env.go

// GetProxyEnvVars builds a list of environment variables in order to use the right proxy.
// Passing nil for environment will make the function use the OS environment.
func GetProxyEnvVars(environment []string) []kubeadmapi.EnvVar { … }

// MergeKubeadmEnvVars merges values of environment variable slices.
// The values defined in later slices overwrite values in previous ones.
func MergeKubeadmEnvVars(envList ...[]kubeadmapi.EnvVar) []v1.EnvVar { … }