mirror of
https://github.com/k3s-io/k3s.git
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259 lines
7.7 KiB
Go
259 lines
7.7 KiB
Go
package flannel
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import (
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"context"
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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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"strings"
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"github.com/k3s-io/k3s/pkg/agent/util"
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"github.com/k3s-io/k3s/pkg/daemons/config"
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"github.com/k3s-io/k3s/pkg/version"
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"github.com/pkg/errors"
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"github.com/sirupsen/logrus"
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corev1 "k8s.io/api/core/v1"
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metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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"k8s.io/apimachinery/pkg/fields"
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typedcorev1 "k8s.io/client-go/kubernetes/typed/core/v1"
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utilsnet "k8s.io/utils/net"
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)
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const (
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cniConf = `{
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"name":"cbr0",
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"cniVersion":"0.3.1",
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"plugins":[
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{
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"type":"flannel",
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"delegate":{
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"hairpinMode":true,
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"forceAddress":true,
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"isDefaultGateway":true
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}
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},
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{
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"type":"portmap",
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"capabilities":{
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"portMappings":true
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}
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}
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]
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}
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`
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flannelConf = `{
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"Network": "%CIDR%",
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"EnableIPv6": %DUALSTACK%,
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"EnableIPv4": %IPV4_ENABLED%,
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"IPv6Network": "%CIDR_IPV6%",
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"Backend": %backend%
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}
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`
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vxlanBackend = `{
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"Type": "vxlan"
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}`
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hostGWBackend = `{
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"Type": "host-gw"
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}`
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ipsecBackend = `{
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"Type": "ipsec",
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"UDPEncap": true,
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"PSK": "%psk%"
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}`
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wireguardBackend = `{
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"Type": "extension",
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"PreStartupCommand": "wg genkey | tee %flannelConfDir%/privatekey | wg pubkey",
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"PostStartupCommand": "export SUBNET_IP=$(echo $SUBNET | cut -d'/' -f 1); ip link del flannel.1 2>/dev/null; echo $PATH >&2; wg-add.sh flannel.1 && wg set flannel.1 listen-port 51820 private-key %flannelConfDir%/privatekey && ip addr add $SUBNET_IP/32 dev flannel.1 && ip link set flannel.1 up && ip route add $NETWORK dev flannel.1",
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"ShutdownCommand": "ip link del flannel.1",
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"SubnetAddCommand": "read PUBLICKEY; wg set flannel.1 peer $PUBLICKEY endpoint $PUBLIC_IP:51820 allowed-ips $SUBNET persistent-keepalive 25",
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"SubnetRemoveCommand": "read PUBLICKEY; wg set flannel.1 peer $PUBLICKEY remove"
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}`
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emptyIPv6Network = "::/0"
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ipv4 = iota
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ipv6
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)
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func Prepare(ctx context.Context, nodeConfig *config.Node) error {
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if err := createCNIConf(nodeConfig.AgentConfig.CNIConfDir); err != nil {
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return err
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}
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return createFlannelConf(nodeConfig)
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}
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func Run(ctx context.Context, nodeConfig *config.Node, nodes typedcorev1.NodeInterface) error {
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logrus.Infof("Starting flannel with backend %s", nodeConfig.FlannelBackend)
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if err := waitForPodCIDR(ctx, nodeConfig.AgentConfig.NodeName, nodes); err != nil {
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return errors.Wrap(err, "flannel failed to wait for PodCIDR assignment")
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}
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netMode, err := findNetMode(nodeConfig.AgentConfig.ClusterCIDRs)
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if err != nil {
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return errors.Wrap(err, "failed to check netMode for flannel")
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}
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go func() {
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err := flannel(ctx, nodeConfig.FlannelIface, nodeConfig.FlannelConfFile, nodeConfig.AgentConfig.KubeConfigKubelet, nodeConfig.FlannelIPv6Masq, netMode)
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if err != nil && !errors.Is(err, context.Canceled) {
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logrus.Fatalf("flannel exited: %v", err)
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}
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}()
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return nil
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}
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// waitForPodCIDR watches nodes with this node's name, and returns when the PodCIDR has been set.
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func waitForPodCIDR(ctx context.Context, nodeName string, nodes typedcorev1.NodeInterface) error {
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fieldSelector := fields.Set{metav1.ObjectNameField: nodeName}.String()
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watch, err := nodes.Watch(ctx, metav1.ListOptions{FieldSelector: fieldSelector})
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if err != nil {
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return err
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}
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defer watch.Stop()
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for ev := range watch.ResultChan() {
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node, ok := ev.Object.(*corev1.Node)
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if !ok {
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return fmt.Errorf("could not convert event object to node: %v", ev)
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}
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if node.Spec.PodCIDR != "" {
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break
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}
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}
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logrus.Info("Flannel found PodCIDR assigned for node " + nodeName)
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return nil
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}
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func createCNIConf(dir string) error {
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logrus.Debugf("Creating the CNI conf in directory %s", dir)
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if dir == "" {
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return nil
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}
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p := filepath.Join(dir, "10-flannel.conflist")
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return util.WriteFile(p, cniConf)
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}
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func createFlannelConf(nodeConfig *config.Node) error {
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var ipv4Enabled string
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logrus.Debugf("Creating the flannel configuration for backend %s in file %s", nodeConfig.FlannelBackend, nodeConfig.FlannelConfFile)
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if nodeConfig.FlannelConfFile == "" {
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return errors.New("Flannel configuration not defined")
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}
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if nodeConfig.FlannelConfOverride {
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logrus.Infof("Using custom flannel conf defined at %s", nodeConfig.FlannelConfFile)
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return nil
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}
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netMode, err := findNetMode(nodeConfig.AgentConfig.ClusterCIDRs)
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if err != nil {
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logrus.Fatalf("Flannel error checking netMode: %v", err)
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return err
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}
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if netMode == ipv4 || netMode == (ipv4+ipv6) {
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ipv4Enabled = "true"
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} else {
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ipv4Enabled = "false"
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}
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confJSON := strings.ReplaceAll(flannelConf, "%IPV4_ENABLED%", ipv4Enabled)
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if netMode == ipv4 {
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confJSON = strings.ReplaceAll(confJSON, "%CIDR%", nodeConfig.AgentConfig.ClusterCIDR.String())
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confJSON = strings.ReplaceAll(confJSON, "%DUALSTACK%", "false")
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confJSON = strings.ReplaceAll(confJSON, "%CIDR_IPV6%", emptyIPv6Network)
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} else if netMode == (ipv4 + ipv6) {
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confJSON = strings.ReplaceAll(confJSON, "%CIDR%", nodeConfig.AgentConfig.ClusterCIDR.String())
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confJSON = strings.ReplaceAll(confJSON, "%DUALSTACK%", "true")
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for _, cidr := range nodeConfig.AgentConfig.ClusterCIDRs {
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if utilsnet.IsIPv6(cidr.IP) {
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// Only one ipv6 range available. This might change in future: https://github.com/kubernetes/enhancements/issues/2593
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confJSON = strings.ReplaceAll(confJSON, "%CIDR_IPV6%", cidr.String())
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}
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}
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} else {
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confJSON = strings.ReplaceAll(confJSON, "%CIDR%", "0.0.0.0/0")
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confJSON = strings.ReplaceAll(confJSON, "%DUALSTACK%", "true")
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for _, cidr := range nodeConfig.AgentConfig.ClusterCIDRs {
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if utilsnet.IsIPv6(cidr.IP) {
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// Only one ipv6 range available. This might change in future: https://github.com/kubernetes/enhancements/issues/2593
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confJSON = strings.ReplaceAll(confJSON, "%CIDR_IPV6%", cidr.String())
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}
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}
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}
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var backendConf string
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switch nodeConfig.FlannelBackend {
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case config.FlannelBackendVXLAN:
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backendConf = vxlanBackend
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case config.FlannelBackendHostGW:
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backendConf = hostGWBackend
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case config.FlannelBackendIPSEC:
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backendConf = strings.ReplaceAll(ipsecBackend, "%psk%", nodeConfig.AgentConfig.IPSECPSK)
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if err := setupStrongSwan(nodeConfig); err != nil {
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return err
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}
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case config.FlannelBackendWireguard:
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backendConf = strings.ReplaceAll(wireguardBackend, "%flannelConfDir%", filepath.Dir(nodeConfig.FlannelConfFile))
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default:
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return fmt.Errorf("Cannot configure unknown flannel backend '%s'", nodeConfig.FlannelBackend)
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}
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confJSON = strings.ReplaceAll(confJSON, "%backend%", backendConf)
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logrus.Debugf("The flannel configuration is %s", confJSON)
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return util.WriteFile(nodeConfig.FlannelConfFile, confJSON)
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}
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func setupStrongSwan(nodeConfig *config.Node) error {
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// if data dir env is not set point to root
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dataDir := os.Getenv(version.ProgramUpper + "_DATA_DIR")
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if dataDir == "" {
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dataDir = "/"
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}
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dataDir = filepath.Join(dataDir, "etc", "strongswan")
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info, err := os.Lstat(nodeConfig.AgentConfig.StrongSwanDir)
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// something exists but is not a symlink, return
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if err == nil && info.Mode()&os.ModeSymlink == 0 {
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return nil
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}
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if err == nil {
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target, err := os.Readlink(nodeConfig.AgentConfig.StrongSwanDir)
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// current link is the same, return
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if err == nil && target == dataDir {
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return nil
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}
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}
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// clean up strongswan old link
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os.Remove(nodeConfig.AgentConfig.StrongSwanDir)
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// make new strongswan link
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return os.Symlink(dataDir, nodeConfig.AgentConfig.StrongSwanDir)
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}
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// fundNetMode returns the mode (ipv4, ipv6 or dual-stack) in which flannel is operating
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func findNetMode(cidrs []*net.IPNet) (int, error) {
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dualStack, err := utilsnet.IsDualStackCIDRs(cidrs)
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if err != nil {
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return 0, err
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}
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if dualStack {
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return ipv4 + ipv6, nil
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}
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for _, cidr := range cidrs {
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if utilsnet.IsIPv4CIDR(cidr) {
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return ipv4, nil
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}
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if utilsnet.IsIPv6CIDR(cidr) {
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return ipv6, nil
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}
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}
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return 0, errors.New("Failed checking netMode")
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}
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