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758fc0f8ad
Problem with old code was that during downgrade only members with downgrade target version were allowed to join. This is unrealistic as it doesn't handle any members to disconnect/rejoin.
76 lines
3.0 KiB
Go
76 lines
3.0 KiB
Go
// Copyright 2020 The etcd 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 version
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import (
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"github.com/coreos/go-semver/semver"
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"go.etcd.io/etcd/api/v3/version"
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"go.uber.org/zap"
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)
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type DowngradeInfo struct {
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// TargetVersion is the target downgrade version, if the cluster is not under downgrading,
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// the targetVersion will be an empty string
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TargetVersion string `json:"target-version"`
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// Enabled indicates whether the cluster is enabled to downgrade
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Enabled bool `json:"enabled"`
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}
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func (d *DowngradeInfo) GetTargetVersion() *semver.Version {
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return semver.Must(semver.NewVersion(d.TargetVersion))
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}
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// isValidDowngrade verifies whether the cluster can be downgraded from verFrom to verTo
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func isValidDowngrade(verFrom *semver.Version, verTo *semver.Version) bool {
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return verTo.Equal(*allowedDowngradeVersion(verFrom))
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}
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// MustDetectDowngrade will detect local server joining cluster that doesn't support it's version.
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func MustDetectDowngrade(lg *zap.Logger, sv, cv *semver.Version) {
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// only keep major.minor version for comparison against cluster version
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sv = &semver.Version{Major: sv.Major, Minor: sv.Minor}
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// if the cluster disables downgrade, check local version against determined cluster version.
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// the validation passes when local version is not less than cluster version
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if cv != nil && sv.LessThan(*cv) {
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lg.Panic(
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"invalid downgrade; server version is lower than determined cluster version",
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zap.String("current-server-version", sv.String()),
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zap.String("determined-cluster-version", version.Cluster(cv.String())),
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)
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}
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}
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func allowedDowngradeVersion(ver *semver.Version) *semver.Version {
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// Todo: handle the case that downgrading from higher major version(e.g. downgrade from v4.0 to v3.x)
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return &semver.Version{Major: ver.Major, Minor: ver.Minor - 1}
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}
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// IsValidVersionChange checks the two scenario when version is valid to change:
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// 1. Downgrade: cluster version is 1 minor version higher than local version,
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// cluster version should change.
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// 2. Cluster start: when not all members version are available, cluster version
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// is set to MinVersion(3.0), when all members are at higher version, cluster version
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// is lower than local version, cluster version should change
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func IsValidVersionChange(cv *semver.Version, lv *semver.Version) bool {
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cv = &semver.Version{Major: cv.Major, Minor: cv.Minor}
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lv = &semver.Version{Major: lv.Major, Minor: lv.Minor}
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if isValidDowngrade(cv, lv) || (cv.Major == lv.Major && cv.LessThan(*lv)) {
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return true
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}
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return false
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}
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