func (wr *Wrangler) shardReplicationStatuses(shardInfo *topo.ShardInfo) ([]*topo.TabletInfo, []*myproto.ReplicationStatus, error) {
// FIXME(msolomon) this assumes no hierarchical replication, which is currently the case.
tabletMap, err := topo.GetTabletMapForShard(context.TODO(), wr.ts, shardInfo.Keyspace(), shardInfo.ShardName())
if err != nil {
return nil, nil, err
}
tablets := topotools.CopyMapValues(tabletMap, []*topo.TabletInfo{}).([]*topo.TabletInfo)
stats, err := wr.tabletReplicationStatuses(tablets)
return tablets, stats, err
}
func (wr *Wrangler) reparentShardLocked(keyspace, shard string, masterElectTabletAlias topo.TabletAlias, leaveMasterReadOnly, forceReparentToCurrentMaster bool) error {
shardInfo, err := wr.ts.GetShard(keyspace, shard)
if err != nil {
return err
}
tabletMap, err := topo.GetTabletMapForShard(context.TODO(), wr.ts, keyspace, shard)
if err != nil {
return err
}
slaveTabletMap, masterTabletMap := topotools.SortedTabletMap(tabletMap)
if shardInfo.MasterAlias == masterElectTabletAlias && !forceReparentToCurrentMaster {
return fmt.Errorf("master-elect tablet %v is already master - specify -force to override", masterElectTabletAlias)
}
masterElectTablet, ok := tabletMap[masterElectTabletAlias]
if !ok {
return fmt.Errorf("master-elect tablet %v not found in replication graph %v/%v %v", masterElectTabletAlias, keyspace, shard, topotools.MapKeys(tabletMap))
}
// Create reusable Reparent event with available info
ev := &events.Reparent{
ShardInfo: *shardInfo,
NewMaster: *masterElectTablet.Tablet,
}
if oldMasterTablet, ok := tabletMap[shardInfo.MasterAlias]; ok {
ev.OldMaster = *oldMasterTablet.Tablet
}
if !shardInfo.MasterAlias.IsZero() && !forceReparentToCurrentMaster {
err = wr.reparentShardGraceful(ev, shardInfo, slaveTabletMap, masterTabletMap, masterElectTablet, leaveMasterReadOnly)
} else {
err = wr.reparentShardBrutal(ev, shardInfo, slaveTabletMap, masterTabletMap, masterElectTablet, leaveMasterReadOnly, forceReparentToCurrentMaster)
}
if err == nil {
// only log if it works, if it fails we'll show the error
wr.Logger().Infof("reparentShard finished")
}
return err
}
// DeleteShard will do all the necessary changes in the topology server
// to entirely remove a shard. It can only work if there are no tablets
// in that shard.
func (wr *Wrangler) DeleteShard(keyspace, shard string) error {
shardInfo, err := wr.ts.GetShard(keyspace, shard)
if err != nil {
return err
}
tabletMap, err := topo.GetTabletMapForShard(context.TODO(), wr.ts, keyspace, shard)
if err != nil {
return err
}
if len(tabletMap) > 0 {
return fmt.Errorf("shard %v/%v still has %v tablets", keyspace, shard, len(tabletMap))
}
// remove the replication graph and serving graph in each cell
for _, cell := range shardInfo.Cells {
if err := wr.ts.DeleteShardReplication(cell, keyspace, shard); err != nil {
wr.Logger().Warningf("Cannot delete ShardReplication in cell %v for %v/%v: %v", cell, keyspace, shard, err)
}
for _, t := range topo.AllTabletTypes {
if !topo.IsInServingGraph(t) {
continue
}
if err := wr.ts.DeleteEndPoints(cell, keyspace, shard, t); err != nil && err != topo.ErrNoNode {
wr.Logger().Warningf("Cannot delete EndPoints in cell %v for %v/%v/%v: %v", cell, keyspace, shard, t, err)
}
}
if err := wr.ts.DeleteSrvShard(cell, keyspace, shard); err != nil && err != topo.ErrNoNode {
wr.Logger().Warningf("Cannot delete SrvShard in cell %v for %v/%v: %v", cell, keyspace, shard, err)
}
}
return wr.ts.DeleteShard(keyspace, shard)
}
// tabletExternallyReparentedLocked is called with the shard lock.
// It returns if agent.refreshTablet should be called, and the error.
// Note both are set independently (can have both true and an error).
func (agent *ActionAgent) tabletExternallyReparentedLocked(ctx context.Context, externalID string, interrupted chan struct{}) (bool, error) {
// re-read the tablet record to be sure we have the latest version
tablet, err := agent.TopoServer.GetTablet(agent.TabletAlias)
if err != nil {
return false, err
}
// read the shard, make sure again the master is not already good.
shardInfo, err := agent.TopoServer.GetShard(tablet.Keyspace, tablet.Shard)
if err != nil {
return false, err
}
if shardInfo.MasterAlias == tablet.Alias {
log.Infof("TabletExternallyReparented: tablet became the master before we get the lock?")
return false, nil
}
log.Infof("TabletExternallyReparented called and we're not the master, doing the work")
// Read the tablets, make sure the master elect is known to the shard
// (it's this tablet, so it better be!).
// Note we will keep going with a partial tablet map, which usually
// happens when a cell is not reachable. After these checks, the
// guarantees we'll have are:
// - global cell is reachable (we just locked and read the shard)
// - the local cell that contains the new master is reachable
// (as we're going to check the new master is in the list)
// That should be enough.
tabletMap, err := topo.GetTabletMapForShard(ctx, agent.TopoServer, tablet.Keyspace, tablet.Shard)
switch err {
case nil:
// keep going
case topo.ErrPartialResult:
log.Warningf("Got topo.ErrPartialResult from GetTabletMapForShard, may need to re-init some tablets")
default:
return false, err
}
masterElectTablet, ok := tabletMap[tablet.Alias]
if !ok {
return false, fmt.Errorf("this master-elect tablet %v not found in replication graph %v/%v %v", tablet.Alias, tablet.Keyspace, tablet.Shard, topotools.MapKeys(tabletMap))
}
// Create reusable Reparent event with available info
ev := &events.Reparent{
ShardInfo: *shardInfo,
NewMaster: *tablet.Tablet,
ExternalID: externalID,
}
if oldMasterTablet, ok := tabletMap[shardInfo.MasterAlias]; ok {
ev.OldMaster = *oldMasterTablet.Tablet
}
defer func() {
if err != nil {
event.DispatchUpdate(ev, "failed: "+err.Error())
}
}()
// sort the tablets, and handle them
slaveTabletMap, masterTabletMap := topotools.SortedTabletMap(tabletMap)
event.DispatchUpdate(ev, "starting external from tablet")
// We fix the new master in the replication graph.
// Note after this call, we may have changed the tablet record,
// so we will always return true, so the tablet record is re-read
// by the agent.
event.DispatchUpdate(ev, "mark ourself as new master")
err = agent.updateReplicationGraphForPromotedSlave(ctx, tablet)
if err != nil {
// This suggests we can't talk to topo server. This is bad.
return true, fmt.Errorf("updateReplicationGraphForPromotedSlave failed: %v", err)
}
// Once this tablet is promoted, remove it from our maps
delete(slaveTabletMap, tablet.Alias)
delete(masterTabletMap, tablet.Alias)
// Then fix all the slaves, including the old master. This
// last step is very likely to time out for some tablets (one
// random guy is dead, the old master is dead, ...). We
// execute them all in parallel until we get to
// wr.ActionTimeout(). After this, no other action with a
// timeout is executed, so even if we got to the timeout,
// we're still good.
event.DispatchUpdate(ev, "restarting slaves")
logger := logutil.NewConsoleLogger()
tmc := tmclient.NewTabletManagerClient()
topotools.RestartSlavesExternal(agent.TopoServer, logger, slaveTabletMap, masterTabletMap, masterElectTablet.Alias, func(ti *topo.TabletInfo, swrd *actionnode.SlaveWasRestartedArgs) error {
return tmc.SlaveWasRestarted(ctx, ti, swrd)
})
// Compute the list of Cells we need to rebuild: old master and
// all other cells if reparenting to another cell.
cells := []string{shardInfo.MasterAlias.Cell}
if shardInfo.MasterAlias.Cell != tablet.Alias.Cell {
cells = nil
}
// now update the master record in the shard object
event.DispatchUpdate(ev, "updating shard record")
log.Infof("Updating Shard's MasterAlias record")
shardInfo.MasterAlias = tablet.Alias
if err = topo.UpdateShard(ctx, agent.TopoServer, shardInfo); err != nil {
return true, err
}
// and rebuild the shard serving graph
event.DispatchUpdate(ev, "rebuilding shard serving graph")
log.Infof("Rebuilding shard serving graph data")
if _, err = topotools.RebuildShard(ctx, logger, agent.TopoServer, tablet.Keyspace, tablet.Shard, cells, agent.LockTimeout, interrupted); err != nil {
return true, err
}
event.DispatchUpdate(ev, "finished")
return true, nil
}
func (wr *Wrangler) applySchemaShardComplex(statusArray []*TabletStatus, shardInfo *topo.ShardInfo, preflight *myproto.SchemaChangeResult, masterTabletAlias topo.TabletAlias, change string, newParentTabletAlias topo.TabletAlias, force bool) (*myproto.SchemaChangeResult, error) {
// apply the schema change to all replica / slave tablets
for _, status := range statusArray {
// if already applied, we skip this guy
diffs := myproto.DiffSchemaToArray("after", preflight.AfterSchema, status.ti.Alias.String(), status.beforeSchema)
if len(diffs) == 0 {
log.Infof("Tablet %v already has the AfterSchema, skipping", status.ti.Alias)
continue
}
// make sure the before schema matches
diffs = myproto.DiffSchemaToArray("master", preflight.BeforeSchema, status.ti.Alias.String(), status.beforeSchema)
if len(diffs) > 0 {
if force {
log.Warningf("Tablet %v has inconsistent schema, ignoring: %v", status.ti.Alias, strings.Join(diffs, "\n"))
} else {
return nil, fmt.Errorf("Tablet %v has inconsistent schema: %v", status.ti.Alias, strings.Join(diffs, "\n"))
}
}
// take this guy out of the serving graph if necessary
ti, err := wr.ts.GetTablet(status.ti.Alias)
if err != nil {
return nil, err
}
typeChangeRequired := ti.Tablet.IsInServingGraph()
if typeChangeRequired {
// note we want to update the serving graph there
err = wr.changeTypeInternal(ti.Alias, topo.TYPE_SCHEMA_UPGRADE)
if err != nil {
return nil, err
}
}
// apply the schema change
log.Infof("Applying schema change to slave %v in complex mode", status.ti.Alias)
sc := &myproto.SchemaChange{Sql: change, Force: force, AllowReplication: false, BeforeSchema: preflight.BeforeSchema, AfterSchema: preflight.AfterSchema}
_, err = wr.ApplySchema(status.ti.Alias, sc)
if err != nil {
return nil, err
}
// put this guy back into the serving graph
if typeChangeRequired {
err = wr.changeTypeInternal(ti.Alias, ti.Tablet.Type)
if err != nil {
return nil, err
}
}
}
// if newParentTabletAlias is passed in, use that as the new master
if !newParentTabletAlias.IsZero() {
log.Infof("Reparenting with new master set to %v", newParentTabletAlias)
tabletMap, err := topo.GetTabletMapForShard(context.TODO(), wr.ts, shardInfo.Keyspace(), shardInfo.ShardName())
if err != nil {
return nil, err
}
slaveTabletMap, masterTabletMap := topotools.SortedTabletMap(tabletMap)
newMasterTablet, err := wr.ts.GetTablet(newParentTabletAlias)
if err != nil {
return nil, err
}
// Create reusable Reparent event with available info
ev := &events.Reparent{
ShardInfo: *shardInfo,
NewMaster: *newMasterTablet.Tablet,
}
if oldMasterTablet, ok := tabletMap[shardInfo.MasterAlias]; ok {
ev.OldMaster = *oldMasterTablet.Tablet
}
err = wr.reparentShardGraceful(ev, shardInfo, slaveTabletMap, masterTabletMap, newMasterTablet /*leaveMasterReadOnly*/, false)
if err != nil {
return nil, err
}
// Here we would apply the schema change to the old
// master, but after a reparent it's in Scrap state,
// so no need to. When/if reparent leaves the
// original master in a different state (like replica
// or rdonly), then we should apply the schema there
// too.
log.Infof("Skipping schema change on old master %v in complex mode, it's been Scrapped", masterTabletAlias)
}
return &myproto.SchemaChangeResult{BeforeSchema: preflight.BeforeSchema, AfterSchema: preflight.AfterSchema}, nil
}
func TestTabletExternallyReparented(t *testing.T) {
ctx := context.Background()
ts := zktopo.NewTestServer(t, []string{"cell1", "cell2"})
wr := wrangler.New(logutil.NewConsoleLogger(), ts, time.Minute, time.Second)
// Create an old master, a new master, two good slaves, one bad slave
oldMaster := NewFakeTablet(t, wr, "cell1", 0, topo.TYPE_MASTER)
newMaster := NewFakeTablet(t, wr, "cell1", 1, topo.TYPE_REPLICA,
TabletParent(oldMaster.Tablet.Alias))
goodSlave1 := NewFakeTablet(t, wr, "cell1", 2, topo.TYPE_REPLICA,
TabletParent(oldMaster.Tablet.Alias))
goodSlave2 := NewFakeTablet(t, wr, "cell2", 3, topo.TYPE_REPLICA,
TabletParent(oldMaster.Tablet.Alias))
badSlave := NewFakeTablet(t, wr, "cell1", 4, topo.TYPE_REPLICA,
TabletParent(oldMaster.Tablet.Alias))
// Add a new Cell to the Shard, that doesn't map to any read topo cell,
// to simulate a data center being unreachable.
si, err := ts.GetShard("test_keyspace", "0")
if err != nil {
t.Fatalf("GetShard failed: %v", err)
}
si.Cells = append(si.Cells, "cell666")
if err := topo.UpdateShard(ctx, ts, si); err != nil {
t.Fatalf("UpdateShard failed: %v", err)
}
// Slightly unrelated test: make sure we can find the tablets
// even with a datacenter being down.
tabletMap, err := topo.GetTabletMapForShardByCell(ctx, ts, "test_keyspace", "0", []string{"cell1"})
if err != nil {
t.Fatalf("GetTabletMapForShardByCell should have worked but got: %v", err)
}
master, err := topotools.FindTabletByIPAddrAndPort(tabletMap, oldMaster.Tablet.IPAddr, "vt", oldMaster.Tablet.Portmap["vt"])
if err != nil || master != oldMaster.Tablet.Alias {
t.Fatalf("FindTabletByIPAddrAndPort(master) failed: %v %v", err, master)
}
slave1, err := topotools.FindTabletByIPAddrAndPort(tabletMap, goodSlave1.Tablet.IPAddr, "vt", goodSlave1.Tablet.Portmap["vt"])
if err != nil || slave1 != goodSlave1.Tablet.Alias {
t.Fatalf("FindTabletByIPAddrAndPort(slave1) failed: %v %v", err, master)
}
slave2, err := topotools.FindTabletByIPAddrAndPort(tabletMap, goodSlave2.Tablet.IPAddr, "vt", goodSlave2.Tablet.Portmap["vt"])
if err != topo.ErrNoNode {
t.Fatalf("FindTabletByIPAddrAndPort(slave2) worked: %v %v", err, slave2)
}
// Make sure the master is not exported in other cells
tabletMap, err = topo.GetTabletMapForShardByCell(ctx, ts, "test_keyspace", "0", []string{"cell2"})
master, err = topotools.FindTabletByIPAddrAndPort(tabletMap, oldMaster.Tablet.IPAddr, "vt", oldMaster.Tablet.Portmap["vt"])
if err != topo.ErrNoNode {
t.Fatalf("FindTabletByIPAddrAndPort(master) worked in cell2: %v %v", err, master)
}
tabletMap, err = topo.GetTabletMapForShard(ctx, ts, "test_keyspace", "0")
if err != topo.ErrPartialResult {
t.Fatalf("GetTabletMapForShard should have returned ErrPartialResult but got: %v", err)
}
master, err = topotools.FindTabletByIPAddrAndPort(tabletMap, oldMaster.Tablet.IPAddr, "vt", oldMaster.Tablet.Portmap["vt"])
if err != nil || master != oldMaster.Tablet.Alias {
t.Fatalf("FindTabletByIPAddrAndPort(master) failed: %v %v", err, master)
}
// On the elected master, we will respond to
// TABLET_ACTION_SLAVE_WAS_PROMOTED
newMaster.FakeMysqlDaemon.MasterAddr = ""
newMaster.StartActionLoop(t, wr)
defer newMaster.StopActionLoop(t)
// On the old master, we will only respond to
// TABLET_ACTION_SLAVE_WAS_RESTARTED.
oldMaster.FakeMysqlDaemon.MasterAddr = newMaster.Tablet.MysqlIpAddr()
oldMaster.StartActionLoop(t, wr)
defer oldMaster.StopActionLoop(t)
// On the good slaves, we will respond to
// TABLET_ACTION_SLAVE_WAS_RESTARTED.
goodSlave1.FakeMysqlDaemon.MasterAddr = newMaster.Tablet.MysqlIpAddr()
goodSlave1.StartActionLoop(t, wr)
defer goodSlave1.StopActionLoop(t)
goodSlave2.FakeMysqlDaemon.MasterAddr = newMaster.Tablet.MysqlIpAddr()
goodSlave2.StartActionLoop(t, wr)
defer goodSlave2.StopActionLoop(t)
// On the bad slave, we will respond to
// TABLET_ACTION_SLAVE_WAS_RESTARTED with bad data.
badSlave.FakeMysqlDaemon.MasterAddr = "234.0.0.1:3301"
badSlave.StartActionLoop(t, wr)
defer badSlave.StopActionLoop(t)
// First test: reparent to the same master, make sure it works
// as expected.
tmc := tmclient.NewTabletManagerClient()
ti, err := ts.GetTablet(oldMaster.Tablet.Alias)
if err != nil {
t.Fatalf("GetTablet failed: %v", err)
}
if err := tmc.TabletExternallyReparented(wr.Context(), ti, ""); err != nil {
t.Fatalf("TabletExternallyReparented(same master) should have worked")
}
// Second test: reparent to a replica, and pretend the old
// master is still good to go.
// This tests a bad case; the new designated master is a slave,
// but we should do what we're told anyway
ti, err = ts.GetTablet(goodSlave1.Tablet.Alias)
if err != nil {
t.Fatalf("GetTablet failed: %v", err)
}
if err := tmc.TabletExternallyReparented(wr.Context(), ti, ""); err != nil {
t.Fatalf("TabletExternallyReparented(slave) error: %v", err)
}
// This tests the good case, where everything works as planned
t.Logf("TabletExternallyReparented(new master) expecting success")
ti, err = ts.GetTablet(newMaster.Tablet.Alias)
if err != nil {
t.Fatalf("GetTablet failed: %v", err)
}
if err := tmc.TabletExternallyReparented(wr.Context(), ti, ""); err != nil {
t.Fatalf("TabletExternallyReparented(replica) failed: %v", err)
}
// Now double-check the serving graph is good.
// Should only have one good replica left.
addrs, err := ts.GetEndPoints("cell1", "test_keyspace", "0", topo.TYPE_REPLICA)
if err != nil {
t.Fatalf("GetEndPoints failed at the end: %v", err)
}
if len(addrs.Entries) != 1 {
t.Fatalf("GetEndPoints has too many entries: %v", addrs)
}
}