k3s/pkg/agent/flannel/flannel.go

147 lines
4.1 KiB
Go

//
// Copyright 2015 flannel authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package flannel
import (
"fmt"
"net"
"os"
"path/filepath"
"sync"
"github.com/flannel-io/flannel/backend"
"github.com/flannel-io/flannel/network"
"github.com/flannel-io/flannel/pkg/ip"
"github.com/flannel-io/flannel/subnet/kube"
"golang.org/x/net/context"
log "k8s.io/klog"
// Backends need to be imported for their init() to get executed and them to register
_ "github.com/flannel-io/flannel/backend/extension"
_ "github.com/flannel-io/flannel/backend/hostgw"
_ "github.com/flannel-io/flannel/backend/ipsec"
_ "github.com/flannel-io/flannel/backend/vxlan"
)
const (
subnetFile = "/run/flannel/subnet.env"
)
func flannel(ctx context.Context, flannelIface *net.Interface, flannelConf, kubeConfigFile string) error {
extIface, err := LookupExtInterface(flannelIface)
if err != nil {
return err
}
sm, err := kube.NewSubnetManager(ctx, "", kubeConfigFile, "flannel.alpha.coreos.com", flannelConf)
if err != nil {
return err
}
config, err := sm.GetNetworkConfig(ctx)
if err != nil {
return err
}
// Create a backend manager then use it to create the backend and register the network with it.
bm := backend.NewManager(ctx, sm, extIface)
be, err := bm.GetBackend(config.BackendType)
if err != nil {
return err
}
bn, err := be.RegisterNetwork(ctx, &sync.WaitGroup{}, config)
if err != nil {
return err
}
go network.SetupAndEnsureIPTables(network.MasqRules(config.Network, bn.Lease()), 60)
go network.SetupAndEnsureIPTables(network.ForwardRules(config.Network.String()), 50)
if err := WriteSubnetFile(subnetFile, config.Network, true, bn); err != nil {
// Continue, even though it failed.
log.Warningf("Failed to write subnet file: %s", err)
} else {
log.Infof("Wrote subnet file to %s", subnetFile)
}
// Start "Running" the backend network. This will block until the context is done so run in another goroutine.
log.Info("Running backend.")
bn.Run(ctx)
return nil
}
func LookupExtInterface(iface *net.Interface) (*backend.ExternalInterface, error) {
var ifaceAddr net.IP
var err error
if iface == nil {
log.Info("Determining IP address of default interface")
if iface, err = ip.GetDefaultGatewayInterface(); err != nil {
return nil, fmt.Errorf("failed to get default interface: %s", err)
}
} else {
log.Info("Determining IP address of specified interface: ", iface.Name)
}
ifaceAddr, err = ip.GetInterfaceIP4Addr(iface)
if err != nil {
return nil, fmt.Errorf("failed to find IPv4 address for interface %s", iface.Name)
}
log.Infof("Using interface with name %s and address %s", iface.Name, ifaceAddr)
if iface.MTU == 0 {
return nil, fmt.Errorf("failed to determine MTU for %s interface", ifaceAddr)
}
return &backend.ExternalInterface{
Iface: iface,
IfaceAddr: ifaceAddr,
ExtAddr: ifaceAddr,
}, nil
}
func WriteSubnetFile(path string, nw ip.IP4Net, ipMasq bool, bn backend.Network) error {
dir, name := filepath.Split(path)
os.MkdirAll(dir, 0755)
tempFile := filepath.Join(dir, "."+name)
f, err := os.Create(tempFile)
if err != nil {
return err
}
// Write out the first usable IP by incrementing
// sn.IP by one
sn := bn.Lease().Subnet
sn.IP++
fmt.Fprintf(f, "FLANNEL_NETWORK=%s\n", nw)
fmt.Fprintf(f, "FLANNEL_SUBNET=%s\n", sn)
fmt.Fprintf(f, "FLANNEL_MTU=%d\n", bn.MTU())
_, err = fmt.Fprintf(f, "FLANNEL_IPMASQ=%v\n", ipMasq)
f.Close()
if err != nil {
return err
}
// rename(2) the temporary file to the desired location so that it becomes
// atomically visible with the contents
return os.Rename(tempFile, path)
//TODO - is this safe? What if it's not on the same FS?
}