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Add error handling to utility functions, remove assumptions about host #301

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Aug 22, 2018
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Add error handling to utility functions, remove assumptions about host #301

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133 changes: 65 additions & 68 deletions pkg/bootstrap/node.go
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Original file line number Diff line number Diff line change
Expand Up @@ -136,8 +136,7 @@ func runImageResize(poolSize int64) error {
var err error

if cmdPath, err = exec.LookPath("qemu-img"); err != nil {
// fall back to an ordinary abspath to qemu-img
cmdPath = "/usr/bin/qemu-img"
return fmt.Errorf("qemu-img not installed: %s", err)
}

args := []string{
Expand Down Expand Up @@ -169,8 +168,7 @@ func runMount() error {
var err error

if cmdPath, err = exec.LookPath("mount"); err != nil {
// fall back to an ordinary abspath to qemu-img
cmdPath = "/usr/bin/mount"
return fmt.Errorf("Cannot find mount command: %s", err)
}

args := []string{
Expand Down Expand Up @@ -203,8 +201,7 @@ func runBtrfsResize() error {
var err error

if cmdPath, err = exec.LookPath("btrfs"); err != nil {
// fall back to an ordinary abspath to qemu-img
cmdPath = "/usr/sbin/btrfs"
return fmt.Errorf("btrfs not installed: %s", err)
}

args := []string{
Expand Down Expand Up @@ -235,8 +232,7 @@ func runBtrfsDisableQuota() error {
var err error

if cmdPath, err = exec.LookPath("btrfs"); err != nil {
// fall back to an ordinary abspath to qemu-img
cmdPath = "/usr/sbin/btrfs"
return fmt.Errorf("btrfs not installed: %s", err)
}

args := []string{
Expand Down Expand Up @@ -272,16 +268,23 @@ func EnsureRequirements() error {
// modprobe overlay
// modprobe nf_conntrack
// echo "131072" > /sys/module/nf_conntrack/parameters/hashsize
ensureOverlayfs()
ensureConntrackHashsize()
if err := ensureOverlayfs(); err != nil {
return errors.Wrap(err, "error ensuring overlayfs loaded")
}
if err := ensureConntrackHashsize(); err != nil {
return err
}

// insert an iptables rules to allow traffic through cni0
ensureIptables()
if err := ensureIptables(); err != nil {
return err
}
// check for SELinux enforcing mode
ensureSelinux()
if err := ensureSelinux(); err != nil {
return err
}
// check for BaseImage version, either Container Linux or Flatcar Linux
ensureBaseImageVersion()
return nil
return ensureBaseImageVersion()
}

func isOverlayfsAvailable() bool {
Expand All @@ -305,8 +308,7 @@ func runModprobe(moduleName string) error {
var err error

if cmdPath, err = exec.LookPath("modprobe"); err != nil {
// fall back to an ordinary abspath
cmdPath = "/usr/sbin/modprobe"
return fmt.Errorf("Cannot find modprobe command: %s", err)
}

args := []string{
Expand All @@ -329,60 +331,55 @@ func runModprobe(moduleName string) error {
return nil
}

func ensureOverlayfs() {
if isOverlayfsAvailable() {
return
}
func ensureOverlayfs() error {
if !isOverlayfsAvailable() {

log.Println("Warning: overlayfs not found, docker would not run.")
log.Println("loading overlay module... ")
// This is an incorrect assumption. It depends on the docker
// storage driver
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In this function, code looks effectively similar as before.
But I'm not sure I understand this comment.
Are you saying that we should check for docker storage driver in the future?
In that case, we should create another github issue, or add TODO to the comment.

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issue added
#302

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Thanks for adding the issue.

log.Println("Warning: overlayfs not found, docker would not run.")
log.Println("loading overlay module... ")

if err := runModprobe("overlay"); err != nil {
log.Printf("error running modprobe overlay: %v\n", err)
return
if err := runModprobe("overlay"); err != nil {
return fmt.Errorf("error running modprobe overlay: %v\n", err)
}
}
return nil
}

func isConntrackLoaded() bool {
if _, err := os.Stat(ctHashsizeModparam); os.IsNotExist(err) {
log.Printf("nf_conntrack module is not loaded: %v\n", err)
return false
}

return true
}

func isConntrackHashsizeCorrect() bool {
func isConntrackHashsizeCorrect() (bool, error) {
hsByte, err := ioutil.ReadFile(ctHashsizeModparam)
if err != nil {
log.Printf("cannot read from %s: %v\n", ctHashsizeModparam, err)
return false
return false, fmt.Errorf("cannot read from %s: %v\n", ctHashsizeModparam, err)
}
hsStr := strings.TrimSpace(string(hsByte))
hs, err := strconv.Atoi(hsStr)
if err != nil {
log.Printf("parse error on %s: %v\n", hsStr, err)
return false
return false, fmt.Errorf("parse error on %s: %v\n", hsStr, err)
}

ctmaxByte, err := ioutil.ReadFile(ctMaxSysctl)
if err != nil {
log.Printf("cannot open %s: %v\n", ctMaxSysctl, err)
return false
return false, fmt.Errorf("cannot open %s: %v\n", ctMaxSysctl, err)
}
ctmaxStr := strings.TrimSpace(string(ctmaxByte))
ctmax, err := strconv.Atoi(ctmaxStr)
if err != nil {
log.Printf("parse error on %s: %v\n", ctmaxStr, err)
return false
return false, fmt.Errorf("parse error on %s: %v\n", ctmaxStr, err)
}

if hs < (ctmax / 4) {
log.Printf("hashsize(%d) should be greater than nf_conntrack_max/4 (%d).\n", hs, ctmax/4)
return false
return false, fmt.Errorf("hashsize(%d) should be greater than nf_conntrack_max/4 (%d).\n", hs, ctmax/4)
}

return true
return true, nil
}

func setConntrackHashsize() error {
Expand All @@ -393,28 +390,27 @@ func setConntrackHashsize() error {
return nil
}

func ensureConntrackHashsize() {
if !isConntrackLoaded() {
func ensureConntrackHashsize() error {
if result := isConntrackLoaded(); !result {
log.Println("Warning: nf_conntrack module is not loaded.")
log.Println("loading nf_conntrack module... ")

if err := runModprobe("nf_conntrack"); err != nil {
log.Printf("error running modprobe nf_conntrack: %v\n", err)
return
return fmt.Errorf("error running modprobe nf_conntrack: %v\n", err)
}
}

if isConntrackHashsizeCorrect() {
return
if _, err := isConntrackHashsizeCorrect(); err != nil {
return err
}

log.Println("Warning: kube-proxy could crash due to insufficient nf_conntrack hashsize.")
log.Printf("setting nf_conntrack hashsize to %s... ", ctHashsizeValue)

if err := setConntrackHashsize(); err != nil {
log.Printf("error setting conntrack hashsize: %v\n", err)
return
return fmt.Errorf("error setting conntrack hashsize: %v\n", err)
}
return nil
}

func setIptablesForwardPolicy() error {
Expand All @@ -424,8 +420,7 @@ func setIptablesForwardPolicy() error {
log.Println("making iptables FORWARD chain defaults to ACCEPT...")

if cmdPath, err = exec.LookPath("iptables"); err != nil {
// fall back to an ordinary abspath
cmdPath = "/sbin/iptables"
return fmt.Errorf("Cannot find iptables: %s", err)
}

// set the default policy for FORWARD chain to ACCEPT
Expand All @@ -452,13 +447,12 @@ func setIptablesForwardPolicy() error {
return nil
}

func isCniRuleLoaded() bool {
func isCniRuleLoaded() (bool, error) {
var cmdPath string
var err error

if cmdPath, err = exec.LookPath("iptables"); err != nil {
// fall back to an ordinary abspath
cmdPath = "/sbin/iptables"
return false, fmt.Errorf("Cannot find iptables: %s", err)
}

// check if a cni iptables rules already exists
Expand All @@ -482,19 +476,18 @@ func isCniRuleLoaded() bool {

if err := cmd.Run(); err != nil {
// error means that the rule does not exist
return false
return false, err
}

return true
return true, nil
}

func setAllowCniRule() error {
var cmdPath string
var err error

if cmdPath, err = exec.LookPath("iptables"); err != nil {
// fall back to an ordinary abspath
cmdPath = "/sbin/iptables"
return fmt.Errorf("Cannot find iptables: %s", err)
}

// insert an iptables rules to allow traffic through cni0
Expand Down Expand Up @@ -525,28 +518,29 @@ func setAllowCniRule() error {
return nil
}

func ensureIptables() {
func ensureIptables() error {
if err := setIptablesForwardPolicy(); err != nil {
log.Printf("error running iptables: %v\n", err)
return
return fmt.Errorf("error running iptables: %v\n", err)
}

if !isCniRuleLoaded() {
if result, _ := isCniRuleLoaded(); !result {
log.Println("setting iptables rule to allow CNI traffic...")
if err := setAllowCniRule(); err != nil {
log.Printf("error running iptables: %v\n", err)
return
return fmt.Errorf("error running iptables: %v\n", err)
}
}
return nil
}

func isSELinuxEnforcing() bool {
var cmdGetPath string
var err error

if cmdGetPath, err = exec.LookPath("getenforce"); err != nil {
// fall back to an ordinary abspath
cmdGetPath = "/usr/sbin/getenforce"
// If we do not have getenforce, we do not have selinux
// (e.g. Ubuntu host). So by definition it cannot
// be enforcing
return false
}

argsGet := []string{
Expand All @@ -572,10 +566,11 @@ func isSELinuxEnforcing() bool {
return false
}

func ensureSelinux() {
func ensureSelinux() error {
if isSELinuxEnforcing() {
log.Fatalln("ERROR: SELinux enforcing mode is enabled. You will need to disable it with 'sudo setenforce 0' for kube-spawn to work properly.")
}
return nil
}

func checkBaseImageSemver(baseImageVer string) error {
Expand Down Expand Up @@ -660,8 +655,7 @@ func pullBaseImage() error {

// TODO: use machinectl pkg
if cmdPath, err = exec.LookPath("machinectl"); err != nil {
// fall back to an ordinary abspath to machinectl
cmdPath = "/usr/bin/machinectl"
return fmt.Errorf("systemd-nspawn / machinectl not installed: %s", err)
}

args := []string{
Expand All @@ -687,11 +681,12 @@ func pullBaseImage() error {
return nil
}

func ensureBaseImageVersion() {
func ensureBaseImageVersion() error {
if err := checkBaseImageVersion(); err != nil {
log.Println(err)
log.Fatalf("You will need to remove the image by 'sudo machinectl remove %s' then the next run of kube-spawn will download version %s of coreos image automatically.", BaseImageName, baseImageStableVersion)
}
return nil
}

func PrepareBaseImage() error {
Expand All @@ -704,7 +699,9 @@ func PrepareBaseImage() error {
} else {
// If BaseImageName is not new enough, remove the existing image,
// then next time `kube-spawn up` will download a new image again.
ensureBaseImageVersion()
if err := ensureBaseImageVersion(); err != nil {
return err
}
}
return nil
}
4 changes: 3 additions & 1 deletion pkg/bootstrap/util.go
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Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,9 @@ const (
// It returns error if OverlayFS is not supported.
// - taken from https://github.com/rkt/rkt/blob/master/common/common.go
func PathSupportsOverlay(path string) error {
ensureOverlayfs()
if err := ensureOverlayfs(); err != nil {
return err
}
if !isOverlayfsAvailable() {
return fmt.Errorf("overlayfs is not available")
}
Expand Down
3 changes: 2 additions & 1 deletion pkg/cluster/cluster.go
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Original file line number Diff line number Diff line change
Expand Up @@ -351,6 +351,7 @@ func (c *Cluster) Start(numberNodes int, cniPluginDir string, cniPlugin string)
if err != nil {
return err
}
log.Printf("new poolSize to be : %d\n", poolSize)
if err := bootstrap.EnlargeStoragePool(poolSize); err != nil {
return err
}
Expand Down Expand Up @@ -448,7 +449,7 @@ func (c *Cluster) Start(numberNodes int, cniPluginDir string, cniPlugin string)
return errors.Wrapf(err, "failed to kubeadm init %q", masterMachine.Name)
}
if err := applyNetworkPlugin(masterMachine.Name, cniPlugin, cliWriter); err != nil {
return err
return errors.Wrapf(err, "Failed to apply network plugin %q", cniPlugin)
}

adminKubeconfigSource := path.Join(c.MachineRootfsPath(), masterMachine.Name, "etc/kubernetes/admin.conf")
Expand Down