mirror of https://github.com/k3s-io/k3s.git
141 lines
3.7 KiB
Go
141 lines
3.7 KiB
Go
// Copyright 2015 flannel authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package flannel
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import (
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"fmt"
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"net"
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"os"
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"path/filepath"
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"sync"
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"github.com/coreos/flannel/backend"
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"github.com/coreos/flannel/network"
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"github.com/coreos/flannel/pkg/ip"
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"github.com/coreos/flannel/subnet/kube"
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"golang.org/x/net/context"
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log "k8s.io/klog"
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// Backends need to be imported for their init() to get executed and them to register
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_ "github.com/coreos/flannel/backend/vxlan"
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)
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const (
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subnetFile = "/run/flannel/subnet.env"
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)
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func flannel(ctx context.Context, kubeConfigFile string) error {
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extIface, err := LookupExtIface()
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if err != nil {
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return err
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}
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sm, err := kube.NewSubnetManager("", kubeConfigFile)
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if err != nil {
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return err
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}
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config, err := sm.GetNetworkConfig(ctx)
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if err != nil {
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return err
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}
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// Create a backend manager then use it to create the backend and register the network with it.
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bm := backend.NewManager(ctx, sm, extIface)
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be, err := bm.GetBackend(config.BackendType)
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if err != nil {
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return err
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}
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bn, err := be.RegisterNetwork(ctx, sync.WaitGroup{}, config)
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if err != nil {
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return err
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}
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go network.SetupAndEnsureIPTables(network.MasqRules(config.Network, bn.Lease()), 60)
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go network.SetupAndEnsureIPTables(network.ForwardRules(config.Network.String()), 50)
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if err := WriteSubnetFile(subnetFile, config.Network, true, bn); err != nil {
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// Continue, even though it failed.
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log.Warningf("Failed to write subnet file: %s", err)
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} else {
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log.Infof("Wrote subnet file to %s", subnetFile)
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}
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// Start "Running" the backend network. This will block until the context is done so run in another goroutine.
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log.Info("Running backend.")
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bn.Run(ctx)
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return nil
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}
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func LookupExtIface() (*backend.ExternalInterface, error) {
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var iface *net.Interface
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var ifaceAddr net.IP
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var err error
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log.Info("Determining IP address of default interface")
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if iface, err = ip.GetDefaultGatewayIface(); err != nil {
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return nil, fmt.Errorf("failed to get default interface: %s", err)
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}
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ifaceAddr, err = ip.GetIfaceIP4Addr(iface)
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if err != nil {
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return nil, fmt.Errorf("failed to find IPv4 address for interface %s", iface.Name)
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}
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log.Infof("Using interface with name %s and address %s", iface.Name, ifaceAddr)
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if iface.MTU == 0 {
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return nil, fmt.Errorf("failed to determine MTU for %s interface", ifaceAddr)
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}
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return &backend.ExternalInterface{
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Iface: iface,
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IfaceAddr: ifaceAddr,
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ExtAddr: ifaceAddr,
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}, nil
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}
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func WriteSubnetFile(path string, nw ip.IP4Net, ipMasq bool, bn backend.Network) error {
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dir, name := filepath.Split(path)
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os.MkdirAll(dir, 0755)
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tempFile := filepath.Join(dir, "."+name)
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f, err := os.Create(tempFile)
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if err != nil {
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return err
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}
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// Write out the first usable IP by incrementing
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// sn.IP by one
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sn := bn.Lease().Subnet
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sn.IP += 1
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fmt.Fprintf(f, "FLANNEL_NETWORK=%s\n", nw)
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fmt.Fprintf(f, "FLANNEL_SUBNET=%s\n", sn)
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fmt.Fprintf(f, "FLANNEL_MTU=%d\n", bn.MTU())
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_, err = fmt.Fprintf(f, "FLANNEL_IPMASQ=%v\n", ipMasq)
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f.Close()
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if err != nil {
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return err
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}
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// rename(2) the temporary file to the desired location so that it becomes
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// atomically visible with the contents
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return os.Rename(tempFile, path)
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//TODO - is this safe? What if it's not on the same FS?
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}
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