/
cluster_util.go
482 lines (454 loc) · 14.6 KB
/
cluster_util.go
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// Copyright 2015 The etcd 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 etcdserver
import (
"context"
"encoding/json"
"fmt"
"io/ioutil"
"net/http"
"sort"
"strconv"
"strings"
"time"
"go.etcd.io/etcd/api/v3/version"
"go.etcd.io/etcd/client/pkg/v3/types"
"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
"github.com/coreos/go-semver/semver"
"go.uber.org/zap"
)
// isMemberBootstrapped tries to check if the given member has been bootstrapped
// in the given cluster.
func isMemberBootstrapped(lg *zap.Logger, cl *membership.RaftCluster, member string, rt http.RoundTripper, timeout time.Duration) bool {
rcl, err := getClusterFromRemotePeers(lg, getRemotePeerURLs(cl, member), timeout, false, rt)
if err != nil {
return false
}
id := cl.MemberByName(member).ID
m := rcl.Member(id)
if m == nil {
return false
}
if len(m.ClientURLs) > 0 {
return true
}
return false
}
// GetClusterFromRemotePeers takes a set of URLs representing etcd peers, and
// attempts to construct a Cluster by accessing the members endpoint on one of
// these URLs. The first URL to provide a response is used. If no URLs provide
// a response, or a Cluster cannot be successfully created from a received
// response, an error is returned.
// Each request has a 10-second timeout. Because the upper limit of TTL is 5s,
// 10 second is enough for building connection and finishing request.
func GetClusterFromRemotePeers(lg *zap.Logger, urls []string, rt http.RoundTripper) (*membership.RaftCluster, error) {
return getClusterFromRemotePeers(lg, urls, 10*time.Second, true, rt)
}
// If logerr is true, it prints out more error messages.
func getClusterFromRemotePeers(lg *zap.Logger, urls []string, timeout time.Duration, logerr bool, rt http.RoundTripper) (*membership.RaftCluster, error) {
if lg == nil {
lg = zap.NewNop()
}
cc := &http.Client{
Transport: rt,
Timeout: timeout,
}
for _, u := range urls {
addr := u + "/members"
resp, err := cc.Get(addr)
if err != nil {
if logerr {
lg.Warn("failed to get cluster response", zap.String("address", addr), zap.Error(err))
}
continue
}
b, err := ioutil.ReadAll(resp.Body)
resp.Body.Close()
if err != nil {
if logerr {
lg.Warn("failed to read body of cluster response", zap.String("address", addr), zap.Error(err))
}
continue
}
var membs []*membership.Member
if err = json.Unmarshal(b, &membs); err != nil {
if logerr {
lg.Warn("failed to unmarshal cluster response", zap.String("address", addr), zap.Error(err))
}
continue
}
id, err := types.IDFromString(resp.Header.Get("X-Etcd-Cluster-ID"))
if err != nil {
if logerr {
lg.Warn(
"failed to parse cluster ID",
zap.String("address", addr),
zap.String("header", resp.Header.Get("X-Etcd-Cluster-ID")),
zap.Error(err),
)
}
continue
}
// check the length of membership members
// if the membership members are present then prepare and return raft cluster
// if membership members are not present then the raft cluster formed will be
// an invalid empty cluster hence return failed to get raft cluster member(s) from the given urls error
if len(membs) > 0 {
return membership.NewClusterFromMembers(lg, id, membs), nil
}
return nil, fmt.Errorf("failed to get raft cluster member(s) from the given URLs")
}
return nil, fmt.Errorf("could not retrieve cluster information from the given URLs")
}
// getRemotePeerURLs returns peer urls of remote members in the cluster. The
// returned list is sorted in ascending lexicographical order.
func getRemotePeerURLs(cl *membership.RaftCluster, local string) []string {
us := make([]string, 0)
for _, m := range cl.Members() {
if m.Name == local {
continue
}
us = append(us, m.PeerURLs...)
}
sort.Strings(us)
return us
}
// getVersions returns the versions of the members in the given cluster.
// The key of the returned map is the member's ID. The value of the returned map
// is the semver versions string, including server and cluster.
// If it fails to get the version of a member, the key will be nil.
func getVersions(lg *zap.Logger, cl *membership.RaftCluster, local types.ID, rt http.RoundTripper) map[string]*version.Versions {
members := cl.Members()
vers := make(map[string]*version.Versions)
for _, m := range members {
if m.ID == local {
cv := "not_decided"
if cl.Version() != nil {
cv = cl.Version().String()
}
vers[m.ID.String()] = &version.Versions{Server: version.Version, Cluster: cv}
continue
}
ver, err := getVersion(lg, m, rt)
if err != nil {
lg.Warn("failed to get version", zap.String("remote-member-id", m.ID.String()), zap.Error(err))
vers[m.ID.String()] = nil
} else {
vers[m.ID.String()] = ver
}
}
return vers
}
// decideClusterVersion decides the cluster version based on the versions map.
// The returned version is the min server version in the map, or nil if the min
// version in unknown.
func decideClusterVersion(lg *zap.Logger, vers map[string]*version.Versions) *semver.Version {
var cv *semver.Version
lv := semver.Must(semver.NewVersion(version.Version))
for mid, ver := range vers {
if ver == nil {
return nil
}
v, err := semver.NewVersion(ver.Server)
if err != nil {
lg.Warn(
"failed to parse server version of remote member",
zap.String("remote-member-id", mid),
zap.String("remote-member-version", ver.Server),
zap.Error(err),
)
return nil
}
if lv.LessThan(*v) {
lg.Warn(
"leader found higher-versioned member",
zap.String("local-member-version", lv.String()),
zap.String("remote-member-id", mid),
zap.String("remote-member-version", ver.Server),
)
}
if cv == nil {
cv = v
} else if v.LessThan(*cv) {
cv = v
}
}
return cv
}
// allowedVersionRange decides the available version range of the cluster that local server can join in;
// if the downgrade enabled status is true, the version window is [oneMinorHigher, oneMinorHigher]
// if the downgrade is not enabled, the version window is [MinClusterVersion, localVersion]
func allowedVersionRange(downgradeEnabled bool) (minV *semver.Version, maxV *semver.Version) {
minV = semver.Must(semver.NewVersion(version.MinClusterVersion))
maxV = semver.Must(semver.NewVersion(version.Version))
maxV = &semver.Version{Major: maxV.Major, Minor: maxV.Minor}
if downgradeEnabled {
// Todo: handle the case that downgrading from higher major version(e.g. downgrade from v4.0 to v3.x)
maxV.Minor = maxV.Minor + 1
minV = &semver.Version{Major: maxV.Major, Minor: maxV.Minor}
}
return minV, maxV
}
// isCompatibleWithCluster return true if the local member has a compatible version with
// the current running cluster.
// The version is considered as compatible when at least one of the other members in the cluster has a
// cluster version in the range of [MinV, MaxV] and no known members has a cluster version
// out of the range.
// We set this rule since when the local member joins, another member might be offline.
func isCompatibleWithCluster(lg *zap.Logger, cl *membership.RaftCluster, local types.ID, rt http.RoundTripper) bool {
vers := getVersions(lg, cl, local, rt)
minV, maxV := allowedVersionRange(getDowngradeEnabledFromRemotePeers(lg, cl, local, rt))
return isCompatibleWithVers(lg, vers, local, minV, maxV)
}
func isCompatibleWithVers(lg *zap.Logger, vers map[string]*version.Versions, local types.ID, minV, maxV *semver.Version) bool {
var ok bool
for id, v := range vers {
// ignore comparison with local version
if id == local.String() {
continue
}
if v == nil {
continue
}
clusterv, err := semver.NewVersion(v.Cluster)
if err != nil {
lg.Warn(
"failed to parse cluster version of remote member",
zap.String("remote-member-id", id),
zap.String("remote-member-cluster-version", v.Cluster),
zap.Error(err),
)
continue
}
if clusterv.LessThan(*minV) {
lg.Warn(
"cluster version of remote member is not compatible; too low",
zap.String("remote-member-id", id),
zap.String("remote-member-cluster-version", clusterv.String()),
zap.String("minimum-cluster-version-supported", minV.String()),
)
return false
}
if maxV.LessThan(*clusterv) {
lg.Warn(
"cluster version of remote member is not compatible; too high",
zap.String("remote-member-id", id),
zap.String("remote-member-cluster-version", clusterv.String()),
zap.String("minimum-cluster-version-supported", minV.String()),
)
return false
}
ok = true
}
return ok
}
// getVersion returns the Versions of the given member via its
// peerURLs. Returns the last error if it fails to get the version.
func getVersion(lg *zap.Logger, m *membership.Member, rt http.RoundTripper) (*version.Versions, error) {
cc := &http.Client{
Transport: rt,
}
var (
err error
resp *http.Response
)
for _, u := range m.PeerURLs {
addr := u + "/version"
resp, err = cc.Get(addr)
if err != nil {
lg.Warn(
"failed to reach the peer URL",
zap.String("address", addr),
zap.String("remote-member-id", m.ID.String()),
zap.Error(err),
)
continue
}
var b []byte
b, err = ioutil.ReadAll(resp.Body)
resp.Body.Close()
if err != nil {
lg.Warn(
"failed to read body of response",
zap.String("address", addr),
zap.String("remote-member-id", m.ID.String()),
zap.Error(err),
)
continue
}
var vers version.Versions
if err = json.Unmarshal(b, &vers); err != nil {
lg.Warn(
"failed to unmarshal response",
zap.String("address", addr),
zap.String("remote-member-id", m.ID.String()),
zap.Error(err),
)
continue
}
return &vers, nil
}
return nil, err
}
func promoteMemberHTTP(ctx context.Context, url string, id uint64, peerRt http.RoundTripper) ([]*membership.Member, error) {
cc := &http.Client{Transport: peerRt}
// TODO: refactor member http handler code
// cannot import etcdhttp, so manually construct url
requestUrl := url + "/members/promote/" + fmt.Sprintf("%d", id)
req, err := http.NewRequest("POST", requestUrl, nil)
if err != nil {
return nil, err
}
req = req.WithContext(ctx)
resp, err := cc.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
b, err := ioutil.ReadAll(resp.Body)
if err != nil {
return nil, err
}
if resp.StatusCode == http.StatusRequestTimeout {
return nil, ErrTimeout
}
if resp.StatusCode == http.StatusPreconditionFailed {
// both ErrMemberNotLearner and ErrLearnerNotReady have same http status code
if strings.Contains(string(b), ErrLearnerNotReady.Error()) {
return nil, ErrLearnerNotReady
}
if strings.Contains(string(b), membership.ErrMemberNotLearner.Error()) {
return nil, membership.ErrMemberNotLearner
}
return nil, fmt.Errorf("member promote: unknown error(%s)", string(b))
}
if resp.StatusCode == http.StatusNotFound {
return nil, membership.ErrIDNotFound
}
if resp.StatusCode != http.StatusOK { // all other types of errors
return nil, fmt.Errorf("member promote: unknown error(%s)", string(b))
}
var membs []*membership.Member
if err := json.Unmarshal(b, &membs); err != nil {
return nil, err
}
return membs, nil
}
// getDowngradeEnabledFromRemotePeers will get the downgrade enabled status of the cluster.
func getDowngradeEnabledFromRemotePeers(lg *zap.Logger, cl *membership.RaftCluster, local types.ID, rt http.RoundTripper) bool {
members := cl.Members()
for _, m := range members {
if m.ID == local {
continue
}
enable, err := getDowngradeEnabled(lg, m, rt)
if err != nil {
lg.Warn("failed to get downgrade enabled status", zap.String("remote-member-id", m.ID.String()), zap.Error(err))
} else {
// Since the "/downgrade/enabled" serves linearized data,
// this function can return once it gets a non-error response from the endpoint.
return enable
}
}
return false
}
// getDowngradeEnabled returns the downgrade enabled status of the given member
// via its peerURLs. Returns the last error if it fails to get it.
func getDowngradeEnabled(lg *zap.Logger, m *membership.Member, rt http.RoundTripper) (bool, error) {
cc := &http.Client{
Transport: rt,
}
var (
err error
resp *http.Response
)
for _, u := range m.PeerURLs {
addr := u + DowngradeEnabledPath
resp, err = cc.Get(addr)
if err != nil {
lg.Warn(
"failed to reach the peer URL",
zap.String("address", addr),
zap.String("remote-member-id", m.ID.String()),
zap.Error(err),
)
continue
}
var b []byte
b, err = ioutil.ReadAll(resp.Body)
resp.Body.Close()
if err != nil {
lg.Warn(
"failed to read body of response",
zap.String("address", addr),
zap.String("remote-member-id", m.ID.String()),
zap.Error(err),
)
continue
}
var enable bool
if enable, err = strconv.ParseBool(string(b)); err != nil {
lg.Warn(
"failed to convert response",
zap.String("address", addr),
zap.String("remote-member-id", m.ID.String()),
zap.Error(err),
)
continue
}
return enable, nil
}
return false, err
}
// isMatchedVersions returns true if all server versions are equal to target version, otherwise return false.
// It can be used to decide the whether the cluster finishes downgrading to target version.
func isMatchedVersions(lg *zap.Logger, targetVersion *semver.Version, vers map[string]*version.Versions) bool {
for mid, ver := range vers {
if ver == nil {
return false
}
v, err := semver.NewVersion(ver.Cluster)
if err != nil {
lg.Warn(
"failed to parse server version of remote member",
zap.String("remote-member-id", mid),
zap.String("remote-member-version", ver.Server),
zap.Error(err),
)
return false
}
if !targetVersion.Equal(*v) {
lg.Warn("remotes server has mismatching etcd version",
zap.String("remote-member-id", mid),
zap.String("current-server-version", v.String()),
zap.String("target-version", targetVersion.String()),
)
return false
}
}
return true
}
func convertToClusterVersion(v string) (*semver.Version, error) {
ver, err := semver.NewVersion(v)
if err != nil {
// allow input version format Major.Minor
ver, err = semver.NewVersion(v + ".0")
if err != nil {
return nil, ErrWrongDowngradeVersionFormat
}
}
// cluster version only keeps major.minor, remove patch version
ver = &semver.Version{Major: ver.Major, Minor: ver.Minor}
return ver, nil
}