kubeadm系列-01-preflight究竟有多少check

// Checker validates the state of the system to ensure kubeadm will be
// successful as often as possible.
type Checker interface {
	Check() (warnings, errorList []error)
	Name() string
}

// ContainerRuntimeCheck verifies the container runtime.
type ContainerRuntimeCheck struct {
	runtime utilruntime.ContainerRuntime
}

// Name returns label for RuntimeCheck.
func (ContainerRuntimeCheck) Name() string {
	return "CRI"
}

// Check validates the container runtime
func (crc ContainerRuntimeCheck) Check() (warnings, errorList []error) {
	klog.V(1).Infoln("validating the container runtime")
	if err := crc.runtime.IsRunning(); err != nil {
		errorList = append(errorList, err)
	}
	return warnings, errorList
}

// IsRunning checks if runtime is running
func (runtime *CRIRuntime) IsRunning() error {
	if out, err := runtime.crictl("info").CombinedOutput(); err != nil {
		return errors.Wrapf(err, "container runtime is not running: output: %s, error", string(out))
	}
	return nil
}

InPathCheck{executable: "crictl", mandatory: true, exec: execer},
InPathCheck{executable: "conntrack", mandatory: true, exec: execer},
InPathCheck{executable: "ip", mandatory: true, exec: execer},
InPathCheck{executable: "iptables", mandatory: true, exec: execer},
InPathCheck{executable: "mount", mandatory: true, exec: execer},
InPathCheck{executable: "nsenter", mandatory: true, exec: execer},
InPathCheck{executable: "ebtables", mandatory: false, exec: execer},
InPathCheck{executable: "ethtool", mandatory: false, exec: execer},
InPathCheck{executable: "socat", mandatory: false, exec: execer},
InPathCheck{executable: "tc", mandatory: false, exec: execer},
InPathCheck{executable: "touch", mandatory: false, exec: execer})

// DefaultSysSpec is the default SysSpec for Linux
var DefaultSysSpec = SysSpec{
	OS: "Linux",
	KernelSpec: KernelSpec{
		Versions: []string{`^3\.[1-9][0-9].*$`, `^([4-9]|[1-9][0-9]+)\.([0-9]+)\.([0-9]+).*$`}, // Requires 3.10+, or newer
		// TODO(random-liu): Add more config
		// TODO(random-liu): Add description for each kernel configuration:
		Required: []KernelConfig{
			{Name: "NAMESPACES"},
			{Name: "NET_NS"},
			{Name: "PID_NS"},
			{Name: "IPC_NS"},
			{Name: "UTS_NS"},
			{Name: "CGROUPS"},
			{Name: "CGROUP_CPUACCT"},
			{Name: "CGROUP_DEVICE"},
			{Name: "CGROUP_FREEZER"},
			{Name: "CGROUP_PIDS"},
			{Name: "CGROUP_SCHED"},
			{Name: "CPUSETS"},
			{Name: "MEMCG"},
			{Name: "INET"},
			{Name: "EXT4_FS"},
			{Name: "PROC_FS"},
			{Name: "NETFILTER_XT_TARGET_REDIRECT", Aliases: []string{"IP_NF_TARGET_REDIRECT"}},
			{Name: "NETFILTER_XT_MATCH_COMMENT"},
			{Name: "FAIR_GROUP_SCHED"},
		},
		Optional: []KernelConfig{
			{Name: "OVERLAY_FS", Aliases: []string{"OVERLAYFS_FS"}, Description: "Required for overlayfs."},
			{Name: "AUFS_FS", Description: "Required for aufs."},
			{Name: "BLK_DEV_DM", Description: "Required for devicemapper."},
			{Name: "CFS_BANDWIDTH", Description: "Required for CPU quota."},
			{Name: "CGROUP_HUGETLB", Description: "Required for hugetlb cgroup."},
			{Name: "SECCOMP", Description: "Required for seccomp."},
			{Name: "SECCOMP_FILTER", Description: "Required for seccomp mode 2."},
		},
		Forbidden: []KernelConfig{},
	},
	Cgroups: []string{"cpu", "cpuacct", "cpuset", "devices", "freezer", "memory", "pids"},
	CgroupsOptional: []string{
		// The hugetlb cgroup is optional since some kernels are compiled without support for huge pages
		// and therefore lacks corresponding hugetlb cgroup
		"hugetlb",
		// The blkio cgroup is optional since some kernels are compiled without support for block I/O throttling.
		// Containerd and cri-o will use blkio to track disk I/O and throttling in both cgroup v1 and v2.
		"blkio",
	},
	CgroupsV2:         []string{"cpu", "cpuset", "devices", "freezer", "memory", "pids"},
	CgroupsV2Optional: []string{"hugetlb", "blkio"},
	RuntimeSpec: RuntimeSpec{
		DockerSpec: &DockerSpec{
			Version:     []string{`1\.1[1-3]\..*`, `17\.0[3,6,9]\..*`, `18\.0[6,9]\..*`, `19\.03\..*`, `20\.10\..*`},
			GraphDriver: []string{"aufs", "btrfs", "overlay", "overlay2", "devicemapper", "zfs"},
		},
	},
}