Add unmanaged tablet flag at vttablet level

changelog/20.0/20.0.0/summary.md

@@ -5,6 +5,7 @@
 - **[Major Changes](#major-changes)**
   - **[Breaking changes](#breaking-changes)**
     - [`shutdown_grace_period` Default Change](#shutdown-grace-period-default)
+    - [New `unmanaged` Flag](#unmanaged-flag)
   - **[Query Compatibility](#query-compatibility)**
     - [Vindex Hints](#vindex-hints)
     - [Update with Limit Support](#update-limit)
@@ -28,6 +29,12 @@ This makes reparenting in Vitess resilient to client errors, and prevents Planne
 
 In order to preserve the old behaviour, the users can set the flag back to `0 seconds` causing open transactions to never be shutdown, but in that case, they run the risk of PlannedReparentShard calls timing out.
 
+#### <a id="unmanaged-tablet"/> New `unmanaged` Flag
+
+New flag `--unmanaged` has been introduced in this release to make it easier to flag unmanaged tablets. It also runs validations to make sure the unmanaged tablets are configured properly.
+
+Starting this release, all unmanaged tablets should specify this flag.
+
 ### <a id="query-compatibility"/>Query Compatibility
 
 #### <a id="vindex-hints"/> Vindex Hints

go/flags/endtoend/vtcombo.txt

@@ -397,6 +397,7 @@ Flags:
       --tx_throttler_config string                                       The configuration of the transaction throttler as a text-formatted throttlerdata.Configuration protocol buffer message. (default "target_replication_lag_sec:2 max_replication_lag_sec:10 initial_rate:100 max_increase:1 emergency_decrease:0.5 min_duration_between_increases_sec:40 max_duration_between_increases_sec:62 min_duration_between_decreases_sec:20 spread_backlog_across_sec:20 age_bad_rate_after_sec:180 bad_rate_increase:0.1 max_rate_approach_threshold:0.9")
       --tx_throttler_healthcheck_cells strings                           A comma-separated list of cells. Only tabletservers running in these cells will be monitored for replication lag by the transaction throttler.
       --unhealthy_threshold duration                                     replication lag after which a replica is considered unhealthy (default 2h0m0s)
+      --unmanaged                                                        Indicates an unmanaged tablet, i.e. using an external mysql-compatible database
       --v Level                                                          log level for V logs
   -v, --version                                                          print binary version
       --vmodule vModuleFlag                                              comma-separated list of pattern=N settings for file-filtered logging

go/flags/endtoend/vttablet.txt

@@ -399,6 +399,7 @@ Flags:
       --tx_throttler_config string                                       The configuration of the transaction throttler as a text-formatted throttlerdata.Configuration protocol buffer message. (default "target_replication_lag_sec:2 max_replication_lag_sec:10 initial_rate:100 max_increase:1 emergency_decrease:0.5 min_duration_between_increases_sec:40 max_duration_between_increases_sec:62 min_duration_between_decreases_sec:20 spread_backlog_across_sec:20 age_bad_rate_after_sec:180 bad_rate_increase:0.1 max_rate_approach_threshold:0.9")
       --tx_throttler_healthcheck_cells strings                           A comma-separated list of cells. Only tabletservers running in these cells will be monitored for replication lag by the transaction throttler.
       --unhealthy_threshold duration                                     replication lag after which a replica is considered unhealthy (default 2h0m0s)
+      --unmanaged                                                        Indicates an unmanaged tablet, i.e. using an external mysql-compatible database
       --v Level                                                          log level for V logs
   -v, --version                                                          print binary version
       --vmodule vModuleFlag                                              comma-separated list of pattern=N settings for file-filtered logging

go/vt/vttablet/tabletserver/tabletenv/config.go

@@ -17,6 +17,7 @@
 package tabletenv
 
 import (
+	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -27,9 +28,11 @@
 	"google.golang.org/protobuf/encoding/prototext"
 
 	"vitess.io/vitess/go/flagutil"
+	"vitess.io/vitess/go/mysql"
 	"vitess.io/vitess/go/streamlog"
 	"vitess.io/vitess/go/vt/dbconfigs"
 	"vitess.io/vitess/go/vt/log"
+	"vitess.io/vitess/go/vt/mysqlctl"
 	"vitess.io/vitess/go/vt/servenv"
 	"vitess.io/vitess/go/vt/sqlparser"
 	"vitess.io/vitess/go/vt/throttler"
@@ -213,6 +216,8 @@
 	fs.BoolVar(&currentConfig.EnableViews, "queryserver-enable-views", false, "Enable views support in vttablet.")
 
 	fs.BoolVar(&currentConfig.EnablePerWorkloadTableMetrics, "enable-per-workload-table-metrics", defaultConfig.EnablePerWorkloadTableMetrics, "If true, query counts and query error metrics include a label that identifies the workload")
+
+	fs.BoolVar(&currentConfig.UnmanagedTablet, "unmanaged", false, "Indicates an unmanaged tablet, i.e. using an external mysql-compatible database")
 }
 
 var (
@@ -298,6 +303,8 @@
 type TabletConfig struct {
 	DB *dbconfigs.DBConfigs `json:"db,omitempty"`
 
+	UnmanagedTablet bool `json:"unmanaged,omitempty"`
+
 	OltpReadPool ConnPoolConfig `json:"oltpReadPool,omitempty"`
 	OlapReadPool ConnPoolConfig `json:"olapReadPool,omitempty"`
 	TxPool       ConnPoolConfig `json:"txPool,omitempty"`
@@ -861,6 +868,9 @@
 
 // Verify checks for contradicting flags.
 func (c *TabletConfig) Verify() error {
+	if err := c.verifyUnmanagedTabletConfig(); err != nil {
+		return err
+	}
 	if err := c.verifyTransactionLimitConfig(); err != nil {
 		return err
 	}
@@ -882,6 +892,51 @@
 	return nil
 }
 
+// verifyUnmanagedTabletConfig checks unmanaged tablet related config for sanity
+func (c *TabletConfig) verifyUnmanagedTabletConfig() error {
+	// Skip checks if tablet is not unmanaged
+	if !c.UnmanagedTablet {
+		return nil
+	}
+
+	// Throw error if both host and socket are null
+	if !c.DB.HasGlobalSettings() {
+		return errors.New("no connection parameters specified but unmanaged mode specified")
+	}
+	if c.DB.App.User == "" {
+		return errors.New("database app user not specified")
+	}
+	if c.DB.App.Password == "" {
+		return errors.New("database app user password not specified")
+	}
+	if !mysqlctl.DisableActiveReparents {
+		return errors.New("fixing replication should be disabled on unmanaged tablets")
+	}
+
+	return c.checkConnectionForExternalMysql()
+}
+
+// Test connectivity of external mysql
+func (c *TabletConfig) checkConnectionForExternalMysql() error {
+	params := mysql.ConnParams{
+		Host:       c.DB.Host,
+		Port:       c.DB.Port,
+		DbName:     c.DB.DBName,
+		Uname:      c.DB.App.User,
+		Pass:       c.DB.App.Password,
+		UnixSocket: c.DB.Socket,
+	}
+
+	conn, err := mysql.Connect(context.Background(), &params)
+	if err != nil {
+		return err
+	}
+
+	defer conn.Close()
+
+	return conn.Ping()
+}
+
 // verifyTransactionLimitConfig checks TransactionLimitConfig for sanity
 func (c *TabletConfig) verifyTransactionLimitConfig() error {
 	actual, dryRun := c.EnableTransactionLimit, c.EnableTransactionLimitDryRun

go/vt/vttablet/tabletserver/tabletenv/config_test.go

@@ -24,8 +24,10 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
+	"vitess.io/vitess/go/mysql/fakesqldb"
 	"vitess.io/vitess/go/test/utils"
 	"vitess.io/vitess/go/vt/dbconfigs"
+	"vitess.io/vitess/go/vt/mysqlctl"
 	"vitess.io/vitess/go/vt/throttler"
 	"vitess.io/vitess/go/vt/topo/topoproto"
 	"vitess.io/vitess/go/vt/vterrors"
@@ -444,3 +446,43 @@ func TestVerifyTxThrottlerConfig(t *testing.T) {
 		})
 	}
 }
+
+func TestVerifyUnmanagedTabletConfig(t *testing.T) {
+	oldDisableActiveReparents := mysqlctl.DisableActiveReparents
+	defer func() {
+		mysqlctl.DisableActiveReparents = oldDisableActiveReparents
+	}()
+
+	config := defaultConfig
+
+	db := fakesqldb.New(t)
+	defer db.Close()
+
+	params := db.ConnParams()
+	config.DB = dbconfigs.NewTestDBConfigs(*params, *params, "")
+
+	// By default, unmanaged mode should be false
+	err := config.verifyUnmanagedTabletConfig()
+	assert.Nil(t, err)
+
+	config.UnmanagedTablet = true
+	err = config.verifyUnmanagedTabletConfig()
+	assert.EqualError(t, err, "no connection parameters specified but unmanaged mode specified")
+
+	config.DB.Socket = db.ConnParams().UnixSocket
+	err = config.verifyUnmanagedTabletConfig()
+	assert.EqualError(t, err, "database app user not specified")
+
+	config.DB.App.User = "testUser"
+	err = config.verifyUnmanagedTabletConfig()
+	assert.EqualError(t, err, "database app user password not specified")
+
+	config.DB.App.Password = "testPassword"
+	mysqlctl.DisableActiveReparents = false
+	err = config.verifyUnmanagedTabletConfig()
+	assert.EqualError(t, err, "fixing replication should be disabled on unmanaged tablets")
+
+	mysqlctl.DisableActiveReparents = true
+	err = config.verifyUnmanagedTabletConfig()
+	assert.Nil(t, err)
+}