forked from virtual-kubelet/virtual-kubelet
/
node.go
466 lines (401 loc) · 13.2 KB
/
node.go
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package vkubelet
import (
"context"
"encoding/json"
"fmt"
"time"
"github.com/cpuguy83/strongerrors/status/ocstatus"
pkgerrors "github.com/pkg/errors"
"github.com/virtual-kubelet/virtual-kubelet/log"
"github.com/virtual-kubelet/virtual-kubelet/providers"
"github.com/virtual-kubelet/virtual-kubelet/trace"
coord "k8s.io/api/coordination/v1beta1"
corev1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/types"
"k8s.io/apimachinery/pkg/util/strategicpatch"
"k8s.io/client-go/kubernetes/typed/coordination/v1beta1"
v1 "k8s.io/client-go/kubernetes/typed/core/v1"
)
// NewNode creates a new node.
// This does not have any side-effects on the system or kubernetes.
//
// Use the node's `Run` method to register and run the loops to update the node
// in Kubernetes.
func NewNode(p providers.NodeProvider, node *corev1.Node, leases v1beta1.LeaseInterface, nodes v1.NodeInterface, opts ...NodeOpt) (*Node, error) {
n := &Node{p: p, n: node, leases: leases, nodes: nodes}
for _, o := range opts {
if err := o(n); err != nil {
return nil, pkgerrors.Wrap(err, "error applying node option")
}
}
return n, nil
}
// NodeOpt are the functional options used for configuring a node
type NodeOpt func(*Node) error
// WithNodeDisableLease forces node leases to be disabled and to only update
// using node status
// Note that this will force status updates to occur on the ping interval frequency
func WithNodeDisableLease(v bool) NodeOpt {
return func(n *Node) error {
n.disableLease = v
return nil
}
}
// WithNodePingInterval sets the inteval for checking node status
func WithNodePingInterval(d time.Duration) NodeOpt {
return func(n *Node) error {
n.pingInterval = d
return nil
}
}
// WithNodeStatusUpdateInterval sets the interval for updating node status
// This is only used when leases are supported and only for updating the actual
// node status, not the node lease.
func WithNodeStatusUpdateInterval(d time.Duration) NodeOpt {
return func(n *Node) error {
n.statusInterval = d
return nil
}
}
// WithNodeLease sets the base node lease to use.
// If a lease time is set, it will be ignored.
func WithNodeLease(l *coord.Lease) NodeOpt {
return func(n *Node) error {
n.lease = l
return nil
}
}
// Node deals with creating and managing a node object in Kubernetes.
// It can register a node with Kubernetes and periodically update its status.
type Node struct {
p providers.NodeProvider
n *corev1.Node
leases v1beta1.LeaseInterface
nodes v1.NodeInterface
disableLease bool
pingInterval time.Duration
statusInterval time.Duration
lease *coord.Lease
chStatusUpdate chan *corev1.Node
}
// The default intervals used for lease and status updates.
const (
DefaultPingInterval = 5 * time.Second
DefaultStatusUpdateInterval = 1 * time.Minute
)
// Run registers the node in kubernetes and starts loops for updating the node
// status in Kubernetes.
//
// The node status must be updated periodically in Kubertnetes to keep the node
// active. Newer versions of Kubernetes support node leases, which are
// essentially light weight pings. Older versions of Kubernetes require updating
// the node status periodically.
//
// If Kubernetes supports node leases this will use leases with a much slower
// node status update (because some things still expect the node to be updated
// periodically), otherwise it will only use node status update with the configured
// ping interval.
func (n *Node) Run(ctx context.Context) error {
if n.pingInterval == time.Duration(0) {
n.pingInterval = DefaultPingInterval
}
if n.statusInterval == time.Duration(0) {
n.statusInterval = DefaultStatusUpdateInterval
}
if err := n.updateStatus(ctx); err != nil {
return pkgerrors.Wrap(err, "error registering node with kubernetes")
}
log.G(ctx).Info("Created node")
n.chStatusUpdate = make(chan *corev1.Node)
n.p.NotifyNodeStatus(ctx, func(node *corev1.Node) {
n.chStatusUpdate <- node
})
if !n.disableLease {
n.lease = newLease(n.lease)
setLeaseAttrs(n.lease, n.n, n.pingInterval*5)
l, err := ensureLease(ctx, n.leases, n.lease)
if err != nil {
if errors.IsNotFound(err) {
n.disableLease = true
} else {
return pkgerrors.Wrap(err, "error creating node lease")
}
}
log.G(ctx).Debug("Created node lease")
n.lease = l
}
if n.disableLease {
log.G(ctx).Info("Node leases not supported, falling back to only node status updates")
}
n.controlLoop(ctx)
return nil
}
func (n *Node) controlLoop(ctx context.Context) {
pingTimer := time.NewTimer(n.pingInterval)
defer pingTimer.Stop()
statusTimer := time.NewTimer(n.statusInterval)
defer statusTimer.Stop()
if n.disableLease {
// hack to make sure this channel always blocks since we won't be using it
if !statusTimer.Stop() {
<-statusTimer.C
}
}
for {
select {
case <-ctx.Done():
return
case updated := <-n.chStatusUpdate:
var t *time.Timer
if n.disableLease {
t = pingTimer
} else {
t = statusTimer
}
log.G(ctx).Debug("Received node status update")
// Performing a status update so stop/reset the status update timer in this
// branch otherwise there could be an uneccessary status update.
if !t.Stop() {
<-t.C
}
n.n.Status = updated.Status
if err := n.updateStatus(ctx); err != nil {
log.G(ctx).WithError(err).Error("Error handling node status update")
}
t.Reset(n.statusInterval)
case <-statusTimer.C:
if err := n.updateStatus(ctx); err != nil {
log.G(ctx).WithError(err).Error("Error handling node status update")
}
statusTimer.Reset(n.statusInterval)
case <-pingTimer.C:
if err := n.handlePing(ctx); err != nil {
log.G(ctx).WithError(err).Error("Error while handling node ping")
} else {
log.G(ctx).Debug("Successful node ping")
}
pingTimer.Reset(n.pingInterval)
}
}
}
func (n *Node) handlePing(ctx context.Context) (retErr error) {
ctx, span := trace.StartSpan(ctx, "node.handlePing")
defer span.End()
defer func() {
span.SetStatus(ocstatus.FromError(retErr))
}()
if err := n.p.Ping(ctx); err != nil {
return pkgerrors.Wrap(err, "error while pinging the node provider")
}
if n.disableLease {
return n.updateStatus(ctx)
}
return n.updateLease(ctx)
}
func (n *Node) updateLease(ctx context.Context) error {
l, err := UpdateNodeLease(ctx, n.leases, newLease(n.lease))
if err != nil {
return err
}
n.lease = l
return nil
}
func (n *Node) updateStatus(ctx context.Context) error {
updateNodeStatusHeartbeat(n.n)
node, err := UpdateNodeStatus(ctx, n.nodes, n.n)
if err != nil {
return err
}
n.n = node
return nil
}
func ensureLease(ctx context.Context, leases v1beta1.LeaseInterface, lease *coord.Lease) (*coord.Lease, error) {
l, err := leases.Create(lease)
if err != nil {
switch {
case errors.IsNotFound(err):
log.G(ctx).WithError(err).Info("Node lease not supported")
return nil, err
case errors.IsAlreadyExists(err):
if err := leases.Delete(lease.Name, nil); err != nil && !errors.IsNotFound(err) {
log.G(ctx).WithError(err).Error("could not delete old node lease")
return nil, pkgerrors.Wrap(err, "old lease exists but could not delete it")
}
l, err = leases.Create(lease)
}
}
return l, err
}
// UpdateNodeLease updates the node lease.
//
// If this function returns an errors.IsNotFound(err) error, this likely means
// that node leases are not supported, if this is the case, call UpdateNodeStatus
// instead.
//
// If you use this function, it is up to you to syncronize this with other operations.
func UpdateNodeLease(ctx context.Context, leases v1beta1.LeaseInterface, lease *coord.Lease) (*coord.Lease, error) {
ctx, span := trace.StartSpan(ctx, "node.UpdateNodeLease")
defer span.End()
ctx = span.WithFields(ctx, log.Fields{
"lease.name": lease.Name,
"lease.time": lease.Spec.RenewTime,
})
if lease.Spec.LeaseDurationSeconds != nil {
ctx = span.WithField(ctx, "lease.expiresSeconds", *lease.Spec.LeaseDurationSeconds)
}
l, err := leases.Update(lease)
if err != nil {
if errors.IsNotFound(err) {
log.G(ctx).Debug("lease not found")
l, err = ensureLease(ctx, leases, lease)
}
if err != nil {
span.SetStatus(ocstatus.FromError(err))
return nil, err
}
log.G(ctx).Debug("created new lease")
} else {
log.G(ctx).Debug("updated lease")
}
return l, nil
}
// just so we don't have to allocate this on every get request
var emptyGetOptions = metav1.GetOptions{}
// PatchNodeStatus patches node status.
// Copied from github.com/kubernetes/kubernetes/pkg/util/node
func PatchNodeStatus(nodes v1.NodeInterface, nodeName types.NodeName, oldNode *corev1.Node, newNode *corev1.Node) (*corev1.Node, []byte, error) {
patchBytes, err := preparePatchBytesforNodeStatus(nodeName, oldNode, newNode)
if err != nil {
return nil, nil, err
}
updatedNode, err := nodes.Patch(string(nodeName), types.StrategicMergePatchType, patchBytes, "status")
if err != nil {
return nil, nil, fmt.Errorf("failed to patch status %q for node %q: %v", patchBytes, nodeName, err)
}
return updatedNode, patchBytes, nil
}
func preparePatchBytesforNodeStatus(nodeName types.NodeName, oldNode *corev1.Node, newNode *corev1.Node) ([]byte, error) {
oldData, err := json.Marshal(oldNode)
if err != nil {
return nil, fmt.Errorf("failed to Marshal oldData for node %q: %v", nodeName, err)
}
// Reset spec to make sure only patch for Status or ObjectMeta is generated.
// Note that we don't reset ObjectMeta here, because:
// 1. This aligns with Nodes().UpdateStatus().
// 2. Some component does use this to update node annotations.
newNode.Spec = oldNode.Spec
newData, err := json.Marshal(newNode)
if err != nil {
return nil, fmt.Errorf("failed to Marshal newData for node %q: %v", nodeName, err)
}
patchBytes, err := strategicpatch.CreateTwoWayMergePatch(oldData, newData, corev1.Node{})
if err != nil {
return nil, fmt.Errorf("failed to CreateTwoWayMergePatch for node %q: %v", nodeName, err)
}
return patchBytes, nil
}
// UpdateNodeStatus triggers an update to the node status in Kubernetes.
// It first fetches the current node details and then sets the status according
// to the passed in node object.
//
// If you use this function, it is up to you to syncronize this with other operations.
// This reduces the time to second-level precision.
func UpdateNodeStatus(ctx context.Context, nodes v1.NodeInterface, n *corev1.Node) (*corev1.Node, error) {
ctx, span := trace.StartSpan(ctx, "UpdateNodeStatus")
defer span.End()
var node *corev1.Node
oldNode, err := nodes.Get(n.Name, emptyGetOptions)
if err != nil {
if !errors.IsNotFound(err) {
span.SetStatus(ocstatus.FromError(err))
return nil, err
}
log.G(ctx).Debug("node not found")
newNode := n.DeepCopy()
newNode.ResourceVersion = ""
node, err = nodes.Create(newNode)
if err != nil {
return nil, err
}
log.G(ctx).Debug("created new node")
return node, nil
}
log.G(ctx).Debug("got node from api server")
node = oldNode.DeepCopy()
node.ResourceVersion = ""
node.Status = n.Status
ctx = addNodeAttributes(ctx, span, node)
// Patch the node status to merge other changes on the node.
updated, _, err := PatchNodeStatus(nodes, types.NodeName(n.Name), oldNode, node)
if err != nil {
return nil, err
}
log.G(ctx).WithField("node.resourceVersion", updated.ResourceVersion).
WithField("node.Status.Conditions", updated.Status.Conditions).
Debug("updated node status in api server")
return updated, nil
}
func newLease(base *coord.Lease) *coord.Lease {
var lease *coord.Lease
if base == nil {
lease = &coord.Lease{}
} else {
lease = base.DeepCopy()
}
lease.Spec.RenewTime = &metav1.MicroTime{Time: time.Now()}
return lease
}
func setLeaseAttrs(l *coord.Lease, n *corev1.Node, dur time.Duration) {
if l.Name == "" {
l.Name = n.Name
}
if l.Spec.HolderIdentity == nil {
l.Spec.HolderIdentity = &n.Name
}
if l.Spec.LeaseDurationSeconds == nil {
d := int32(dur.Seconds()) * 5
l.Spec.LeaseDurationSeconds = &d
}
}
func updateNodeStatusHeartbeat(n *corev1.Node) {
now := metav1.NewTime(time.Now())
for i, _ := range n.Status.Conditions {
n.Status.Conditions[i].LastHeartbeatTime = now
}
}
// NaiveNodeProvider is a basic node provider that only uses the passed in context
// on `Ping` to determine if the node is healthy.
type NaiveNodeProvider struct{}
// Ping just implements the NodeProvider interface.
// It returns the error from the passed in context only.
func (NaiveNodeProvider) Ping(ctx context.Context) error {
return ctx.Err()
}
// NotifyNodeStatus implements the NodeProvider interface.
//
// This NaiveNodeProvider does not support updating node status and so this
// function is a no-op.
func (NaiveNodeProvider) NotifyNodeStatus(ctx context.Context, f func(*corev1.Node)) {
}
type taintsStringer []corev1.Taint
func (t taintsStringer) String() string {
var s string
for _, taint := range t {
if s == "" {
s = taint.Key + "=" + taint.Value + ":" + string(taint.Effect)
} else {
s += ", " + taint.Key + "=" + taint.Value + ":" + string(taint.Effect)
}
}
return s
}
func addNodeAttributes(ctx context.Context, span trace.Span, n *corev1.Node) context.Context {
return span.WithFields(ctx, log.Fields{
"node.UID": string(n.UID),
"node.name": n.Name,
"node.cluster": n.ClusterName,
"node.taints": taintsStringer(n.Spec.Taints),
})
}