Configure SSL/TLS certificates

MySQL | PostgreSQL | SQL Server

This page describes how to enforce SSL/TLS encryption for an instance to ensure that all connections are encrypted. You can also learn more about how Cloud SQL uses self-managed SSL/TLS certificates to connect to Cloud SQL instances securely.

Overview

Cloud SQL creates a server certificate automatically when you create your instance. We recommend that you enforce all connections to use SSL/TLS.

To validate client/server identity using SSL/TLS certs, you need to create a client certificate and download the certificates to your PostgreSQL client host machine.

When you enforce SSL for an instance, the instance does not require a restart. However, changes to SSL/TLS certificates might result in an automatic restart of the instance and can incur downtime.

A change to SSL mode configuration applies only to new connections. If you enforce SSL and your instance has existing unencrypted connections, then the connections stay connected and unencrypted. To close any unencrypted connections and enforce SSL on all connections, you must restart your instance.

Enforce SSL/TLS encryption

You can use the SSL mode setting to enforce SSL encryption in the following ways:

Allow both non-SSL/non-TLS and SSL/TLS connections. The client certificate isn't verified for SSL/TLS connections. This is the default.
Only allow connections encrypted with SSL/TLS. The client certificate isn't verified for SSL connections.

Only allow connections encrypted with SSL/TLS and with valid client certificates.

If you select Allow non-SSL/non-TLS and SSL/TLS connections for your Cloud SQL instance, SSL/TLS connections are accepted, as well as unencrypted and unsecure connections. If you do not require SSL/TLS for all connections, unencrypted connections are still allowed. For this reason, if you are accessing your instance using public IP, we strongly recommend that you enforce SSL for all connections.

You can connect either directly to instances by using SSL/TLS certificates, or you can connect by using the Cloud SQL Auth Proxy or Cloud SQL Connectors. If you connect by using Cloud SQL Auth Proxy or Cloud SQL Connectors, then the connections are automatically encrypted with SSL/TLS. With Cloud SQL Auth Proxy and Cloud SQL Connectors, client and server identities are also automatically verified regardless of the SSL mode setting.

To enable requiring SSL/TLS, do the following:

Console

In the Google Cloud console, go to the Cloud SQL Instances page.

Go to Cloud SQL Instances
To open the Overview page of an instance, click the instance name.
Click Connections from the SQL navigation menu.
Select the Security tab.
Select one of the following:
- Allow unencrypted network traffic (not recommended)
- Allow only SSL connections. This option only allows connections using SSL/TLS encryption. Certificates aren't validated.
- Require trusted client certificates. This option only allows connections from clients that use a valid client certificate and are SSL encrypted. If a client or user connects using IAM database authentication, then they must use either the Cloud SQL Auth Proxy or Cloud SQL Connectors to enforce client identity verification.

gcloud

   gcloud sql instances patch INSTANCE_NAME \
   --ssl-mode=SSL_ENFORCEMENT_MODE

Replace SSL_ENFORCEMENT_MODE with one of the following options:

ALLOW_UNENCRYPTED_AND_ENCRYPTED allows non-SSL/non-TLS and SSL/TLS connections. For SSL connections, the client certificate is not verified. This is the default value.
ENCRYPTED_ONLY only allows connections encrypted with SSL/TLS. The client certificate isn't verified for SSL connections.
TRUSTED_CLIENT_CERTIFICATE_REQUIRED only allows connections encrypted with SSL/TLS and with valid client certificates. If a client or user connects using IAM database authentication, then they must use either the Cloud SQL Auth Proxy or Cloud SQL Connectors to enforce client identity verification.

Settings for Cloud SQL for PostgreSQL

Terraform

To enforce SSL/TLS encryption, use a Terraform resource:

resource "google_sql_database_instance" "postgres_instance" {
  name             = "postgres-instance"
  region           = "asia-northeast1"
  database_version = "POSTGRES_14"
  settings {
    tier = "db-custom-2-7680"
    ip_configuration {
      # The following SSL enforcement options only allow connections encrypted with SSL/TLS and with
      # valid client certificates. Please check the API reference for other SSL enforcement options:
      # https://cloud.google.com/sql/docs/postgres/admin-api/rest/v1beta4/instances#ipconfiguration
      ssl_mode = "TRUSTED_CLIENT_CERTIFICATE_REQUIRED"
    }
  }
  # set `deletion_protection` to true, will ensure that one cannot accidentally delete this instance by
  # use of Terraform whereas `deletion_protection_enabled` flag protects this instance at the GCP level.
  deletion_protection = false
}

Apply the changes

To apply your Terraform configuration in a Google Cloud project, complete the steps in the following sections.

Prepare Cloud Shell

Launch Cloud Shell.
Set the default Google Cloud project where you want to apply your Terraform configurations.

You only need to run this command once per project, and you can run it in any directory.
```
export GOOGLE_CLOUD_PROJECT=PROJECT_ID
```
Environment variables are overridden if you set explicit values in the Terraform configuration file.

Prepare the directory

Each Terraform configuration file must have its own directory (also called a root module).

In Cloud Shell, create a directory and a new file within that directory. The filename must have the .tf extension—for example main.tf. In this tutorial, the file is referred to as main.tf.
```
mkdir DIRECTORY && cd DIRECTORY && touch main.tf
```
If you are following a tutorial, you can copy the sample code in each section or step.

Copy the sample code into the newly created main.tf.

Optionally, copy the code from GitHub. This is recommended when the Terraform snippet is part of an end-to-end solution.
Review and modify the sample parameters to apply to your environment.
Save your changes.
Initialize Terraform. You only need to do this once per directory.
```
terraform init
```
Optionally, to use the latest Google provider version, include the -upgrade option:
```
terraform init -upgrade
```

Apply the changes

Review the configuration and verify that the resources that Terraform is going to create or update match your expectations:
```
terraform plan
```
Make corrections to the configuration as necessary.
Apply the Terraform configuration by running the following command and entering yes at the prompt:
```
terraform apply
```
Wait until Terraform displays the "Apply complete!" message.
Open your Google Cloud project to view the results. In the Google Cloud console, navigate to your resources in the UI to make sure that Terraform has created or updated them.

Delete the changes

To delete your changes, do the following:

To disable deletion protection, in your Terraform configuration file set the deletion_protection argument to false.
```
deletion_protection =  "false"
```
Apply the updated Terraform configuration by running the following command and entering yes at the prompt:
```
terraform apply
```

Remove resources previously applied with your Terraform configuration by running the following command and entering yes at the prompt:
```
terraform destroy
```

REST v1

Before using any of the request data, make the following replacements:
- PROJECT_ID: The project ID
- SSL_ENFORCEMENT_MODE: Use one of the following options:
  - ALLOW_UNENCRYPTED_AND_ENCRYPTED: allows non-SSL/non-TLS and SSL/TLS connections. For SSL connections, the client certificate isn't verified. This is the default value.
  - ENCRYPTED_ONLY: only allows connections encrypted with SSL/TLS.
  - TRUSTED_CLIENT_CERTIFICATE_REQUIRED: only allows connections encrypted with SSL/TLS and with valid client certificates. If a client or user connects using IAM database authentication, then they must use either the Cloud SQL Auth Proxy or Cloud SQL Connectors to enforce client identity verification.
- INSTANCE_ID: The instance ID
HTTP method and URL:
```
PATCH https://sqladmin.googleapis.com/v1/projects/PROJECT_ID/instances/INSTANCE_ID
```
Request JSON body:
```
{
  "settings": {
    "ipConfiguration": {"sslMode": "SSL_ENFORCEMENT_MODE"}
  }
}
```
To send your request, expand one of these options:
curl (Linux, macOS, or Cloud Shell)

Note: The following command assumes that you have logged in to the gcloud CLI with your user account by running gcloud init or gcloud auth login , or by using Cloud Shell, which automatically logs you into the gcloud CLI . You can check the currently active account by running gcloud auth list.

Save the request body in a file named request.json, and execute the following command:
```
curl -X PATCH \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     -H "Content-Type: application/json; charset=utf-8" \
     -d @request.json \
     "https://sqladmin.googleapis.com/v1/projects/PROJECT_ID/instances/INSTANCE_ID"
```
PowerShell (Windows)

Note: The following command assumes that you have logged in to the gcloud CLI with your user account by running gcloud init or gcloud auth login . You can check the currently active account by running gcloud auth list.

Save the request body in a file named request.json, and execute the following command:
```
$cred = gcloud auth print-access-token
$headers = @{ "Authorization" = "Bearer $cred" }

Invoke-WebRequest `
    -Method PATCH `
    -Headers $headers `
    -ContentType: "application/json; charset=utf-8" `
    -InFile request.json `
    -Uri "https://sqladmin.googleapis.com/v1/projects/PROJECT_ID/instances/INSTANCE_ID" | Select-Object -Expand Content
```
You should receive a JSON response similar to the following:
Response
```
{
  "kind": "sql#operation",
  "targetLink": "https://sqladmin.googleapis.com/v1/projects/PROJECT_ID/instances/INSTANCE_ID",
  "status": "PENDING",
  "user": "user@example.com",
  "insertTime": "2020-01-20T21:30:35.667Z",
  "operationType": "UPDATE",
  "name": "OPERATION_ID",
  "targetId": "INSTANCE_ID",
  "selfLink": "https://sqladmin.googleapis.com/v1/projects/PROJECT_ID/operations/OPERATION_ID",
  "targetProject": "PROJECT_ID"
}
```

REST v1beta4

Before using any of the request data, make the following replacements:
- PROJECT_ID: The project ID
- SSL_ENFORCEMENT_MODE: Use one of the following options:
  - ALLOW_UNENCRYPTED_AND_ENCRYPTED: allows non-SSL/non-TLS and SSL/TLS connections. For SSL connections, the client certificate isn't verified. This is the default value.
  - ENCRYPTED_ONLY: only allows connections encrypted with SSL/TLS.
  - TRUSTED_CLIENT_CERTIFICATE_REQUIRED: only allows connections encrypted with SSL/TLS and with valid client certificates. If a client or user connects using IAM database authentication, then they must use either the Cloud SQL Auth Proxy or Cloud SQL Connectors to enforce client identity verification.
- INSTANCE_ID: The instance ID
HTTP method and URL:
```
PATCH https://sqladmin.googleapis.com/sql/v1beta4/projects/PROJECT_ID/instances/INSTANCE_ID
```
Request JSON body:
```
{
  "settings": {
    "ipConfiguration": {"sslMode": "SSL_ENFORCEMENT_MODE"}
  }
}
```
To send your request, expand one of these options:
curl (Linux, macOS, or Cloud Shell)

Note: The following command assumes that you have logged in to the gcloud CLI with your user account by running gcloud init or gcloud auth login , or by using Cloud Shell, which automatically logs you into the gcloud CLI . You can check the currently active account by running gcloud auth list.

Save the request body in a file named request.json, and execute the following command:
```
curl -X PATCH \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     -H "Content-Type: application/json; charset=utf-8" \
     -d @request.json \
     "https://sqladmin.googleapis.com/sql/v1beta4/projects/PROJECT_ID/instances/INSTANCE_ID"
```
PowerShell (Windows)

Note: The following command assumes that you have logged in to the gcloud CLI with your user account by running gcloud init or gcloud auth login . You can check the currently active account by running gcloud auth list.

Save the request body in a file named request.json, and execute the following command:
```
$cred = gcloud auth print-access-token
$headers = @{ "Authorization" = "Bearer $cred" }

Invoke-WebRequest `
    -Method PATCH `
    -Headers $headers `
    -ContentType: "application/json; charset=utf-8" `
    -InFile request.json `
    -Uri "https://sqladmin.googleapis.com/sql/v1beta4/projects/PROJECT_ID/instances/INSTANCE_ID" | Select-Object -Expand Content
```
You should receive a JSON response similar to the following:
Response
```
{
  "kind": "sql#operation",
  "targetLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/PROJECT_ID/instances/INSTANCE_ID",
  "status": "PENDING",
  "user": "user@example.com",
  "insertTime": "2020-01-20T21:30:35.667Z",
  "operationType": "UPDATE",
  "name": "OPERATION_ID",
  "targetId": "INSTANCE_ID",
  "selfLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/PROJECT_ID/operations/OPERATION_ID",
  "targetProject": "PROJECT_ID"
}
```

Server certificates

Cloud SQL creates a server certificate automatically when you create your instance. As long as the server certificate is valid, you don't need to actively manage your server certificate. Cloud SQL lets you select between two different certificate authority (CA) hierarchies. The CA hierarchy that you select becomes the server CA mode of the instance. If you're using per-instance CA as the server CA mode for your instance, then the server certificates have an expiration date of 10 years. If you're using shared CA as the server CA mode of your instance (Preview), then the server certificate has an expiration date of 1 year. After the expiration date, the server certificate is no longer valid, and clients can no longer establish a secure connection to your instance using that certificate. If a client is configured to verify the CA or verify the hostname in the server certificate, then that client's connections to Cloud SQL instances with expired server certificates will fail. To prevent disruption to client connections, rotate the server certificate before the certificate expires. You're periodically notified that the server certificate is nearing expiration. The notifications are sent the following number of days before the expiration date: 90, 30, 10, 2, and 1.

You can get information about your server certificate, such as when it was created, and when it expires. Before the expiration date, you can create a new one manually.

Console

In the Google Cloud console, go to the Cloud SQL Instances page.

Go to Cloud SQL Instances
To open the Overview page of an instance, click the instance name.
Click Connections from the SQL navigation menu.
Select the Security tab.
Go to the Manage server certificates section.
You can see the expiration date of your server certificate in the table.

gcloud

For instances that use self-signed server certificates (per-instance CA):

To get information about the server certificate, use the sql ssl server-ca-certs list command:
```
gcloud sql ssl server-ca-certs list \
--instance=INSTANCE_NAME
```
To create a server certificate, use the sql ssl server-ca-certs create command:
```
gcloud sql ssl server-ca-certs create \
--instance=INSTANCE_NAME
```

Download the certificate information to a local PEM file:

gcloud sql ssl server-ca-certs list \
--format="value(cert)" \
--instance=INSTANCE_NAME > \
FILE_PATH/FILE_NAME.pem

Update all of your clients to use the new information by copying the downloaded file to your client host machines, replacing the existing server-ca.pem files.

For instances that use server certificates issued by a shared CA (Preview):

To get information about the server certificate, use the beta sql ssl server-certs list command:
```
gcloud beta sql ssl server-certs list \
   --instance=INSTANCE_NAME
```
To create a server certificate, use the beta sql ssl server-certs create command:
```
gcloud beta sql ssl server-certs create \
   --instance=INSTANCE_NAME
```

Download the certificate information to a local PEM file:

gcloud beta sql ssl server-certs list \
   --format="value(ca_cert.cert)" \
   --instance=INSTANCE_NAME > \
   FILE_PATH/FILE_NAME.pem

Update all of your clients to use the new information by copying the downloaded file to your client host machines, replacing the existing server-ca.pem files.

Terraform

To provide server certificate information as an output, use a Terraform data source:

Add the following to your Terraform configuration file:

   data "google_sql_ca_certs" "ca_certs" {
     instance = google_sql_database_instance.default.name
   }

   locals {
     furthest_expiration_time = reverse(sort([for k, v in data.google_sql_ca_certs.ca_certs.certs : v.expiration_time]))[0]
     latest_ca_cert           = [for v in data.google_sql_ca_certs.ca_certs.certs : v.cert if v.expiration_time == local.furthest_expiration_time]
   }

   output "db_latest_ca_cert" {
     description = "Latest CA certificate used by the primary database server"
     value       = local.latest_ca_cert
     sensitive   = true
   }

To create the server-ca.pem file, run the following command:

   terraform output db_latest_ca_cert > server-ca.pem

Client certificates

Create a new client certificate

You can create up to 10 client certificates for each instance. To create client certificates, you must have the Cloud SQL Admin IAM role.

Here are some important things to know about client certificates:

If you lose the private key for a certificate, you must create a new one; the private key cannot be recovered.
By default, the client certificate has an expiration date of 10 years.
You are not notified when client certificates are nearing expiration.
Your Cloud SQL instance must be in the running state to create a SSL certificate.

Console

In the Google Cloud console, go to the Cloud SQL Instances page.

Go to Cloud SQL Instances
To open the Overview page of an instance, click the instance name.
Click Connections from the SQL navigation menu.
Select the Security tab.
Click Create client certificate.
In the Create a client certificate dialog, add a unique name.
Click Create.
In the first section of the New SSL certificate created dialog, click Download client-key.pem to download the private key to a file named client-key.pem.
Important: Store this private key securely. If you lose it, you must create a new client certificate.
In the second section, click Download client-cert.pem to download the client certificate to a file named client-cert.pem.
In the third section, click Download server-ca.pem to download the server certificate to a file named server-ca.pem.
Click Close.

gcloud

Create a client certificate using the ssl client-certs create command:
```
gcloud sql ssl client-certs create CERT_NAME client-key.pem \
--instance=INSTANCE_NAME
```
Important: Store this private key securely. If you lose it, you must create a new client certificate.
Retrieve the public key for the certificate you just created and copy it into the client-cert.pem file with the ssl client-certs describe command:
```
gcloud sql ssl client-certs describe CERT_NAME \
--instance=INSTANCE_NAME \
--format="value(cert)" > client-cert.pem
```

Copy the server certificate into the server-ca.pem file using the instances describe command:

gcloud sql instances describe INSTANCE_NAME \
--format="value(serverCaCert.cert)" > server-ca.pem

Terraform

To create a client certificate, use a Terraform resource:

resource "google_sql_ssl_cert" "postgres_client_cert" {
  common_name = "postgres_common_name"
  instance    = google_sql_database_instance.postgres_instance.name
}

REST v1

Create an SSL/TLS certificate, giving it a unique name for this instance:

Before using any of the request data, make the following replacements:

project-id: The project ID
instance-id: The instance ID
client-cert-name: The client cert name

HTTP method and URL:

POST https://sqladmin.googleapis.com/v1/projects/project-id/instances/instance-id/sslCerts

Request JSON body:

{
  "commonName" : "client-cert-name"
}

To send your request, expand one of these options:

curl (Linux, macOS, or Cloud Shell)

Note: The following command assumes that you have logged in to the gcloud CLI with your user account by running gcloud init or gcloud auth login , or by using Cloud Shell, which automatically logs you into the gcloud CLI . You can check the currently active account by running gcloud auth list.

Save the request body in a file named request.json, and execute the following command:

curl -X POST \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     -H "Content-Type: application/json; charset=utf-8" \
     -d @request.json \
     "https://sqladmin.googleapis.com/v1/projects/project-id/instances/instance-id/sslCerts"

PowerShell (Windows)

Note: The following command assumes that you have logged in to the gcloud CLI with your user account by running gcloud init or gcloud auth login . You can check the currently active account by running gcloud auth list.

Save the request body in a file named request.json, and execute the following command:

$cred = gcloud auth print-access-token
$headers = @{ "Authorization" = "Bearer $cred" }

Invoke-WebRequest `
    -Method POST `
    -Headers $headers `
    -ContentType: "application/json; charset=utf-8" `
    -InFile request.json `
    -Uri "https://sqladmin.googleapis.com/v1/projects/project-id/instances/instance-id/sslCerts" | Select-Object -Expand Content

You should receive a JSON response similar to the following:

Response

{
  "kind": "sql#sslCertsInsert",
  "operation": {
    "kind": "sql#operation",
    "targetLink": "https://sqladmin.googleapis.com/v1/projects/project-id/instances/instance-id",
    "status": "PENDING",
    "user": "user@example.com",
    "operationType": "UPDATE",
    "name": "operation-id",
    "targetId": "instance-id",
    "selfLink": "https://sqladmin.googleapis.com/v1/projects/project-id/operations/operation-id",
    "targetProject": "doc-test-01",
    "insertTime": "2020-02-13T00:11:20.677Z"
  },
  "serverCaCert": {
    "kind": "sql#sslCert",
    "certSerialNumber": "server-cert-serial-number",
    "cert": "server-cert-value",
    "commonName": "server-cert-name,
    "sha1Fingerprint": "server-cert-sha1Fingerprint",
    "instance": "instance-id",
    "selfLink": "https://sqladmin.googleapis.com/v1/projects/project-id/instances/instance-id/sslCerts/operation-id",
    "createTime": "2019-11-25T20:12:06.764Z",
    "expirationTime": "2029-11-22T20:13:06.764Z"
  },
  "clientCert": {
    "certInfo": {
      "kind": "sql#sslCert",
      "certSerialNumber": "client-cert-serial-number-2",
      "cert": "client-cert-value",
      "commonName": "client-cert-name",
      "sha1Fingerprint": "client-cert-sha1Fingerprint-2",
      "instance": "instance-id",
      "selfLink": "https://sqladmin.googleapis.com/v1/projects/project-id/instances/instance-id/sslCerts/operation-id",
      "createTime": "2020-02-13T00:10:20.595Z",
      "expirationTime": "2030-02-10T00:11:20.595Z"
    },
    "certPrivateKey": "private-key-value"
  }
}

Copy all of the certificate contents within the quotation marks (but not the quotation marks themselves) from the response into local files as follows:
1. Copy serverCaCert.cert into server-ca.pem.
2. Copy clientCert.cert into client-cert.pem.
3. Copy certPrivateKey into client-key.pem.
Important: Store this private key securely. If you lose it, you must create a new client certificate.

REST v1beta4

Create an SSL/TLS certificate, giving it a unique name for this instance:

Before using any of the request data, make the following replacements:

project-id: The project ID
instance-id: The instance ID
client-cert-name: The client cert name

HTTP method and URL:

POST https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id/sslCerts

Request JSON body:

{
  "commonName" : "client-cert-name"
}

To send your request, expand one of these options:

curl (Linux, macOS, or Cloud Shell)

Save the request body in a file named request.json, and execute the following command:

curl -X POST \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     -H "Content-Type: application/json; charset=utf-8" \
     -d @request.json \
     "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id/sslCerts"

PowerShell (Windows)

Save the request body in a file named request.json, and execute the following command:

$cred = gcloud auth print-access-token
$headers = @{ "Authorization" = "Bearer $cred" }

Invoke-WebRequest `
    -Method POST `
    -Headers $headers `
    -ContentType: "application/json; charset=utf-8" `
    -InFile request.json `
    -Uri "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id/sslCerts" | Select-Object -Expand Content

You should receive a JSON response similar to the following:

Response

{
  "kind": "sql#sslCertsInsert",
  "operation": {
    "kind": "sql#operation",
    "targetLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id",
    "status": "PENDING",
    "user": "user@example.com",
    "operationType": "UPDATE",
    "name": "operation-id",
    "targetId": "instance-id",
    "selfLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/operations/operation-id",
    "targetProject": "doc-test-01",
    "insertTime": "2020-02-13T00:11:20.677Z"
  },
  "serverCaCert": {
    "kind": "sql#sslCert",
    "certSerialNumber": "server-cert-serial-number",
    "cert": "server-cert-value",
    "commonName": "server-cert-name,
    "sha1Fingerprint": "server-cert-sha1Fingerprint",
    "instance": "instance-id",
    "selfLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id/sslCerts/operation-id",
    "createTime": "2019-11-25T20:12:06.764Z",
    "expirationTime": "2029-11-22T20:13:06.764Z"
  },
  "clientCert": {
    "certInfo": {
      "kind": "sql#sslCert",
      "certSerialNumber": "client-cert-serial-number-2",
      "cert": "client-cert-value",
      "commonName": "client-cert-name",
      "sha1Fingerprint": "client-cert-sha1Fingerprint-2",
      "instance": "instance-id",
      "selfLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id/sslCerts/operation-id",
      "createTime": "2020-02-13T00:10:20.595Z",
      "expirationTime": "2030-02-10T00:11:20.595Z"
    },
    "certPrivateKey": "private-key-value"
  }
}

Copy all of the certificate contents within the quotation marks (but not the quotation marks themselves) from the response into local files as follows:
1. Copy serverCaCert.cert into server-ca.pem.
2. Copy clientCert.cert into client-cert.pem.
3. Copy certPrivateKey into client-key.pem.
Important: Store this private key securely. If you lose it, you must create a new client certificate.

At this point, you have:

A server certificate saved as server-ca.pem.
A client public key certificate saved as client-cert.pem.
A client private key saved as client-key.pem.

Depending on which tool you use to connect, these three items are specified in different ways. For example, when connecting using psql command-line client, these three files are the values for the sslrootcert, sslcert, and sslkey parameters in the psql connection string. For an example connection using psql client and SSL/TLS, see Connecting with psql client.

About server identity verification

Server identity verification depends on the server certificate authority (CA) hierarchy configuration of your Cloud SQL instance.

If your instance is configured to use the per-instance CA, verifying the CA also verifies the server identity since each instance has a unique CA.

If your instance is configured to use the shared CA (Preview), then verifying the hostname along with verifying the CA is required for server identity verification since server CAs are shared across instances.

If you have per-instance CA, you can only perform DNS name based server identity verification for Private Service Connect instances.

If you have shared CA (Preview), you can perform DNS name based server identity verification for all types of instances, namely Private Service Connect, private service access, and public IP instances.

You can view which CA hierarchy is configured for a Cloud SQL instance by viewing instance details.

For more information, see View instance information or the following section, Enable server identity verification.

Enable server identity verification

If you select shared CAs as the server CA mode of your Cloud SQL instance (Preview), then we recommend that you also enable server identity verification. Instances that use shared CA as the server CA mode contain the instance DNS name in the Subject Alternative Name (SAN) field of the server certificate. You can get this DNS name by using the instance lookup API and using the response as a hostname for server identity verification. You need to set up DNS resolution for the DNS name.

To enable server identity verification, complete the following steps:

Retrieve the DNS name.
1. To view summary information about a Cloud SQL instance, including the DNS name of the instance, use the gcloud sql instances describe command:
```
gcloud sql instances describe INSTANCE_NAME \
  --project=PROJECT_ID
```
  Make the following replacements:
  - INSTANCE_NAME: the name of the Cloud SQL instance
  - PROJECT_ID: the ID or project number of the Google Cloud project that contains the instance
2. In the response, verify that the DNS name appears. This name has the following pattern:
```
INSTANCE_UID.PROJECT_DNS_LABEL.REGION_NAME.sql.goog.
```
  For example:
  
  1a23b4cd5e67.1a2b345c6d27.us-central1.sql.goog.
Create the DNS record in a DNS zone. If you are connecting privately, then create the DNS record in a private DNS zone in the corresponding Virtual Private Cloud (VPC) network.
When you connect to the Cloud SQL for PostgreSQL instance, configure the DNS name as the hostname. Then enable server identity verification in your client.

For example, when using the psql client, specify the flag sslmode=verify-full. Other PostgreSQL client drivers have similar configuration flags.

What's next

Manage SSL/TLS certificates on your Cloud SQL instance.
Learn more about how encryption is handled in Google Cloud.
Connect to your Cloud SQL instance using SSL/TLS certificates.
Learn more about how PostgreSQL uses SSL/TLS certificates.