Always create snapshot when cluster version changes

When downgrading or offline migration, etcd read the maximum version from the WAL files, so as to ensure the operation is allowed. It also reads the verson from `ClusterVersionSet` request, so we should create a snapshot when cluster version chanages, so as not to block the downgrade or migration operations. Signed-off-by: Benjamin Wang <[email protected]>
etcd-io · Jan 6, 2025 · 5386eef · 5386eef
1 parent be38b22
commit 5386eef
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Showing 2 changed files with 5 additions and 11 deletions.
diff --git a/server/etcdserver/apply/apply.go b/server/etcdserver/apply/apply.go
@@ -415,7 +415,6 @@ func (a *applierMembership) ClusterVersionSet(r *membershippb.ClusterVersionSetR
 	prevVersion := a.cluster.Version()
 	newVersion := semver.Must(semver.NewVersion(r.Ver))
 	a.cluster.SetVersion(newVersion, api.UpdateCapability, shouldApplyV3)
-	// Force snapshot after cluster version downgrade.
 	if prevVersion != nil && newVersion.LessThan(*prevVersion) {
 		lg := a.lg
 		if lg != nil {
@@ -424,8 +423,9 @@ func (a *applierMembership) ClusterVersionSet(r *membershippb.ClusterVersionSetR
 				zap.String("new-cluster-version", newVersion.String()),
 			)
 		}
-		a.snapshotServer.ForceSnapshot()
 	}
+	// Force snapshot when cluster version changes.
+	a.snapshotServer.ForceSnapshot()
 }
 
 func (a *applierMembership) ClusterMemberAttrSet(r *membershippb.ClusterMemberAttrSetRequest, shouldApplyV3 membership.ShouldApplyV3) {

diff --git a/tests/e2e/utl_migrate_test.go b/tests/e2e/utl_migrate_test.go
@@ -90,16 +90,10 @@ func TestEtctlutlMigrate(t *testing.T) {
 			expectStorageVersion: &version.V3_6,
 		},
 		{
-			name:                 "Downgrade v3.6 to v3.5 should fail until it's implemented",
+			name:                 "Downgrade v3.6 to v3.5 should work",
 			targetVersion:        "3.5",
-			expectLogsSubString:  "cannot downgrade storage, WAL contains newer entries",
-			expectStorageVersion: &version.V3_6,
-		},
-		{
-			name:                "Downgrade v3.6 to v3.5 with force should work",
-			targetVersion:       "3.5",
-			force:               true,
-			expectLogsSubString: "forcefully cleared storage version",
+			expectLogsSubString:  "updated storage version",
+			expectStorageVersion: nil, // 3.5 doesn't have the field `storageVersion`, so it returns nil.
 		},
 		{
 			name:                 "Upgrade v3.6 to v3.7 with force should work",