MM-62533: Improvements for ExternalDBSettings (#880)

- We bump the postgres version to 14.9 as that is the version
after which "write forwarding" is available on a Global Aurora
Cluster.
- We also add the ClusterIdentifier for ExternalDBSettings
because we need to attach the DB security group to the DB cluster
like we do for a restored DB backup.

https://mattermost.atlassian.net/browse/MM-62533

config/deployer.sample.json

@@ -70,7 +70,8 @@
     "DriverName": "cockroach",
     "DataSource": "",
     "DataSourceReplicas": [],
-    "DataSourceSearchReplicas": []
+    "DataSourceSearchReplicas": [],
+    "ClusterIdentifier": "",
   },
   "ExternalBucketSettings": {
     "AmazonS3AccessKeyId": "",

config/deployer.sample.toml

@@ -82,6 +82,7 @@ DataSource = ''
 DataSourceReplicas = []
 DataSourceSearchReplicas = []
 DriverName = 'cockroach'
+ClusterIdentifier = ''
 
 [JobServerSettings]
 InstanceCount = 0

deployment/config.go

@@ -257,6 +257,8 @@ type ExternalDBSettings struct {
 	DataSourceReplicas []string `default:""`
 	// DSN to connect to the database search replicas
 	DataSourceSearchReplicas []string `default:""`
+	// ClusterIdentifier of the existing DB cluster.
+	ClusterIdentifier string `default:""`
 }
 
 // ExternalBucketSettings contains the necessary data

deployment/terraform/assets/variables.tf

@@ -106,7 +106,7 @@ variable "db_engine_version" {
   type = map(any)
   default = {
     "aurora-mysql"      = "8.0.mysql_aurora.3.05.2"
-    "aurora-postgresql" = "14.7"
+    "aurora-postgresql" = "14.9"
   }
 }
 

deployment/terraform/create.go

@@ -153,18 +153,24 @@ func (t *Terraform) Create(extAgent *ssh.ExtAgent, initData bool) error {
 		return err
 	}
 
-	// If we are restoring from a DB backup, then we need to hook up
+	// If we are restoring from a DB backup, or using an external database, then we need to hook up
 	// the security group to it.
-	if t.config.TerraformDBSettings.ClusterIdentifier != "" {
+	if t.config.TerraformDBSettings.ClusterIdentifier != "" || t.config.ExternalDBSettings.ClusterIdentifier != "" {
 		if len(t.output.DBSecurityGroup) == 0 {
 			return errors.New("No DB security group created")
 		}
+		var identifier string
+		if t.config.TerraformDBSettings.ClusterIdentifier != "" {
+			identifier = t.config.TerraformDBSettings.ClusterIdentifier
+		} else {
+			identifier = t.config.ExternalDBSettings.ClusterIdentifier
+		}
 
 		sgID := t.output.DBSecurityGroup[0].Id
 		args := []string{
 			"rds",
 			"modify-db-cluster",
-			"--db-cluster-identifier=" + t.config.TerraformDBSettings.ClusterIdentifier,
+			"--db-cluster-identifier=" + identifier,
 			"--vpc-security-group-ids=" + sgID,
 			"--region=" + t.config.AWSRegion,
 		}

docs/config/deployer.md

@@ -366,6 +366,12 @@ The list of dsn for external database read replicas
 
 The list of dsn for external database search replicas
 
+### ClusterIdentifier
+
+*string*
+
+ClusterIdentifier of the existing DB cluster.
+
 ## ExternalBucketSettings
 
 ### AmazonS3AccessKeyId