mirror of
https://github.com/kubernetes-sigs/kind.git
synced 2025-12-01 07:26:05 +07:00
147 lines
4.0 KiB
Go
147 lines
4.0 KiB
Go
/*
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Copyright 2020 The Kubernetes Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package podman
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import (
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"crypto/sha1"
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"encoding/binary"
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"net"
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"regexp"
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"strings"
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"sigs.k8s.io/kind/pkg/errors"
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"sigs.k8s.io/kind/pkg/exec"
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)
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// This may be overridden by KIND_EXPERIMENTAL_PODMAN_NETWORK env,
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// experimentally...
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//
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// By default currently picking a single network is equivalent to the previous
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// behavior *except* that we moved from the default bridge to a user defined
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// network because the default bridge is actually special versus any other
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// docker network and lacks the embedded DNS
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//
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// For now this also makes it easier for apps to join the same network, and
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// leaves users with complex networking desires to create and manage their own
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// networks.
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const fixedNetworkName = "kind"
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// ensureNetwork creates a new network
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// podman only creates IPv6 networks for versions >= 2.2.0
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func ensureNetwork(name string) error {
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// network already exists
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if checkIfNetworkExists(name) {
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return nil
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}
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// generate unique subnet per network based on the name
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// obtained from the ULA fc00::/8 range
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// Make N attempts with "probing" in case we happen to collide
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subnet := generateULASubnetFromName(name, 0)
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err := createNetwork(name, subnet)
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if err == nil {
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// Success!
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return nil
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}
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if isUnknownIPv6FlagError(err) ||
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isIPv6DisabledError(err) {
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return createNetwork(name, "")
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}
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// Only continue if the error is because of the subnet range
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// is already allocated
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if !isPoolOverlapError(err) {
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return err
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}
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// keep trying for ipv6 subnets
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const maxAttempts = 5
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for attempt := int32(1); attempt < maxAttempts; attempt++ {
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subnet := generateULASubnetFromName(name, attempt)
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err = createNetwork(name, subnet)
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if err == nil {
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// success!
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return nil
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} else if !isPoolOverlapError(err) {
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// unknown error ...
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return err
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}
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}
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return errors.New("exhausted attempts trying to find a non-overlapping subnet")
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}
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func createNetwork(name, ipv6Subnet string) error {
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if ipv6Subnet == "" {
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return exec.Command("podman", "network", "create", "-d=bridge", name).Run()
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}
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return exec.Command("podman", "network", "create", "-d=bridge",
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"--ipv6", "--subnet", ipv6Subnet, name).Run()
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}
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func checkIfNetworkExists(name string) bool {
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_, err := exec.Output(exec.Command(
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"podman", "network", "inspect",
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regexp.QuoteMeta(name),
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))
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return err == nil
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}
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func isUnknownIPv6FlagError(err error) bool {
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rerr := exec.RunErrorForError(err)
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return rerr != nil &&
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strings.Contains(string(rerr.Output), "unknown flag: --ipv6")
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}
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func isIPv6DisabledError(err error) bool {
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rerr := exec.RunErrorForError(err)
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return rerr != nil &&
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strings.Contains(string(rerr.Output), "is ipv6 enabled in the kernel")
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}
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func isPoolOverlapError(err error) bool {
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rerr := exec.RunErrorForError(err)
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if rerr == nil {
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return false
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}
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output := string(rerr.Output)
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return strings.Contains(output, "is already used on the host or by another config") ||
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strings.Contains(output, "is being used by a network interface") ||
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strings.Contains(output, "is already being used by a cni configuration")
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}
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// generateULASubnetFromName generate an IPv6 subnet based on the
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// name and Nth probing attempt
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func generateULASubnetFromName(name string, attempt int32) string {
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ip := make([]byte, 16)
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ip[0] = 0xfc
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ip[1] = 0x00
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h := sha1.New()
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_, _ = h.Write([]byte(name))
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_ = binary.Write(h, binary.LittleEndian, attempt)
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bs := h.Sum(nil)
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for i := 2; i < 8; i++ {
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ip[i] = bs[i]
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}
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subnet := &net.IPNet{
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IP: net.IP(ip),
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Mask: net.CIDRMask(64, 128),
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}
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return subnet.String()
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}
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