81d6077fc2
This commit adds basic support to run in compatibility mode with Flannel. This allows clusters running Flannel as their principal networking solution to leverage some advances Kilo features. In certain Flannel setups, the clusters can even leverage muti-cloud. For this, the cluster needs to either run in a full mesh, or Flannel needs to use the API server's external IP address.
109 lines
2.5 KiB
Go
109 lines
2.5 KiB
Go
// Copyright 2019 the Kilo 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 encapsulation
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import (
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"fmt"
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"net"
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"sync"
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"github.com/squat/kilo/pkg/iptables"
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"github.com/vishvananda/netlink"
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)
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const flannelDeviceName = "flannel.1"
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type flannel struct {
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iface int
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strategy Strategy
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ch chan netlink.LinkUpdate
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done chan struct{}
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// mu guards updates to the iface field.
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mu sync.Mutex
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}
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// NewFlannel returns an encapsulator that uses Flannel.
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func NewFlannel(strategy Strategy) Encapsulator {
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return &flannel{
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ch: make(chan netlink.LinkUpdate),
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done: make(chan struct{}),
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strategy: strategy,
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}
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}
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// CleanUp is a no-op.
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func (f *flannel) CleanUp() error {
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close(f.done)
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return nil
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}
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// Gw returns the correct gateway IP associated with the given node.
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func (f *flannel) Gw(_, _ net.IP, subnet *net.IPNet) net.IP {
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return subnet.IP
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}
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// Index returns the index of the Flannel interface.
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func (f *flannel) Index() int {
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return f.iface
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}
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// Init finds the Flannel interface index.
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func (f *flannel) Init(_ int) error {
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if err := netlink.LinkSubscribe(f.ch, f.done); err != nil {
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return fmt.Errorf("failed to subscribe to updates to %s: %v", flannelDeviceName, err)
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}
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go func() {
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var lu netlink.LinkUpdate
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for {
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select {
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case lu = <-f.ch:
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if lu.Attrs().Name == flannelDeviceName {
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f.mu.Lock()
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f.iface = lu.Attrs().Index
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f.mu.Unlock()
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}
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case <-f.done:
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return
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}
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}
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}()
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i, err := netlink.LinkByName(flannelDeviceName)
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if _, ok := err.(netlink.LinkNotFoundError); ok {
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return nil
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}
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if err != nil {
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return fmt.Errorf("failed to query for Flannel interface: %v", err)
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}
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f.mu.Lock()
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f.iface = i.Attrs().Index
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f.mu.Unlock()
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return nil
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}
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// Rules is a no-op.
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func (f *flannel) Rules(_ []*net.IPNet) []iptables.Rule {
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return nil
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}
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// Set is a no-op.
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func (f *flannel) Set(_ *net.IPNet) error {
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return nil
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}
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// Strategy returns the configured strategy for encapsulation.
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func (f *flannel) Strategy() Strategy {
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return f.strategy
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}
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