GetKubeletVersion is helper function that returns version of kubelet available in $PATH.

RunChecks runs each check, displays it's warnings/errors, and once all are processed will exit if any errors occurred.

RunInitMasterChecks executes all individual, applicable to Master node checks.

RunJoinNodeChecks executes all individual, applicable to node checks.

RunRootCheckOnly initializes checks slice of structs and call RunChecks.

TryStartKubelet attempts to bring up kubelet service.

CRICheck verifies the container runtime through the CRI.

DirAvailableCheck checks if the given directory either does not exist, or is empty.

Error defines struct for communicating error messages generated by preflight checks.

ExternalEtcdVersionCheck checks if version of external etcd meets the demand of kubeadm.

ExtraArgsCheck checks if arguments are valid.

FileAvailableCheck checks that the given file does not already exist.

FileContentCheck checks that the given file contains the string Content.

FileExistingCheck checks that the given file does not already exist.

FirewalldCheck checks if firewalld is enabled or active.

HostnameCheck checks if hostname match dns sub domain regex.

HTTPProxyCheck checks if https connection to specific host is going to be done directly or over proxy.

HTTPProxyCIDRCheck checks if https connection to specific subnet is going to be done directly or over proxy.

InPathCheck checks if the given executable is present in $PATH.

IsPrivilegedUserCheck verifies user is privileged (linux - root, windows - Administrator).

KubeletVersionCheck validates installed kubelet version.

KubernetesVersionCheck validates kubernetes and kubeadm versions.

PortOpenCheck ensures the given port is available for use.

ServiceCheck verifies that the given service is enabled and active.

SwapCheck warns if swap is enabled.

SystemVerificationCheck defines struct used for for running the system verification node check in test/e2e_node/system.

Checker validates the state of the system to ensure kubeadm will be successful as often as possible.