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Merge pull request #29907 from luxas/lookup_ip_better

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Automatic merge from submit-queue

[kubelet] Auto-discover node IP if neither cloud provider exists and IP is not explicitly specified

One example where the earlier implementation failed is when running kubelet on CoreOS (bare-metal), where the nameserver is set to `8.8.8.8`. kubelet tries to lookup the node name agains Google DNS, which obviously fails. The kubelet won't recover after that.

The workaround hsa been to set `--hostname-override` to an IP address, but it's quite annoying to try to make a multi-distro way of getting the IP in bash for example. This way is much cleaner.

Refactored the function a little bit at the same time

@vishh @yujuhong @resouer @Random-Liu
This commit is contained in:
Kubernetes Submit Queue 2016-08-06 02:26:30 -07:00 committed by GitHub
commit 3dad8f7c06
1 changed files with 30 additions and 40 deletions
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70
pkg/kubelet/kubelet_node_status.go
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@ -282,9 +282,9 @@ func (kl *Kubelet) recordNodeStatusEvent(eventtype, event string) {
kl.recorder.Eventf(kl.nodeRef, eventtype, event, "Node %s status is now: %s", kl.nodeName, event)
}
// Set addresses for the node.
// Set IP addresses for the node.
func (kl *Kubelet) setNodeAddress(node *api.Node) error {
// Set addresses for the node.
if kl.cloud != nil {
instances, ok := kl.cloud.Instances()
if !ok {
@ -293,56 +293,46 @@ func (kl *Kubelet) setNodeAddress(node *api.Node) error {
// TODO(roberthbailey): Can we do this without having credentials to talk
// to the cloud provider?
// TODO(justinsb): We can if CurrentNodeName() was actually CurrentNode() and returned an interface
// TODO: If IP addresses couldn't be fetched from the cloud provider, should kubelet fallback on the other methods for getting the IP below?
nodeAddresses, err := instances.NodeAddresses(kl.nodeName)
if err != nil {
return fmt.Errorf("failed to get node address from cloud provider: %v", err)
}
node.Status.Addresses = nodeAddresses
} else {
var ipAddr net.IP
var err error
// 1) Use nodeIP if set
// 2) If the user has specified an IP to HostnameOverride, use it
// 3) Lookup the IP from node name by DNS and use the first non-loopback ipv4 address
// 4) Try to get the IP from the network interface used as default gateway
if kl.nodeIP != nil {
node.Status.Addresses = []api.NodeAddress{
{Type: api.NodeLegacyHostIP, Address: kl.nodeIP.String()},
{Type: api.NodeInternalIP, Address: kl.nodeIP.String()},
}
ipAddr = kl.nodeIP
} else if addr := net.ParseIP(kl.hostname); addr != nil {
node.Status.Addresses = []api.NodeAddress{
{Type: api.NodeLegacyHostIP, Address: addr.String()},
{Type: api.NodeInternalIP, Address: addr.String()},
}
ipAddr = addr
} else {
addrs, err := net.LookupIP(node.Name)
if err != nil {
return fmt.Errorf("can't get ip address of node %s: %v", node.Name, err)
} else if len(addrs) == 0 {
return fmt.Errorf("no ip address for node %v", node.Name)
} else {
// check all ip addresses for this node.Name and try to find the first non-loopback IPv4 address.
// If no match is found, it uses the IP of the interface with gateway on it.
for _, ip := range addrs {
if ip.IsLoopback() {
continue
}
if ip.To4() != nil {
node.Status.Addresses = []api.NodeAddress{
{Type: api.NodeLegacyHostIP, Address: ip.String()},
{Type: api.NodeInternalIP, Address: ip.String()},
}
break
}
var addrs []net.IP
addrs, err = net.LookupIP(node.Name)
for _, addr := range addrs {
if !addr.IsLoopback() && addr.To4() != nil {
ipAddr = addr
break
}
}
if len(node.Status.Addresses) == 0 {
ip, err := utilnet.ChooseHostInterface()
if err != nil {
return err
}
if ipAddr == nil {
ipAddr, err = utilnet.ChooseHostInterface()
}
}
node.Status.Addresses = []api.NodeAddress{
{Type: api.NodeLegacyHostIP, Address: ip.String()},
{Type: api.NodeInternalIP, Address: ip.String()},
}
}
if ipAddr == nil {
// We tried everything we could, but the IP address wasn't fetchable; error out
return fmt.Errorf("can't get ip address of node %s. error: %v", node.Name, err)
} else {
node.Status.Addresses = []api.NodeAddress{
{Type: api.NodeLegacyHostIP, Address: ipAddr.String()},
{Type: api.NodeInternalIP, Address: ipAddr.String()},
}
}
}