How to enable high availability

Adding a replica to a new or existing Namespace enables Temporal Cloud's high availability features. Once added, Temporal Cloud starts replicating ongoing and existing Workflows, along with their metadata. After replication is complete and your replica is ready, your Namespace is prepared for failover. If an incident occurs, failover transfers control from the active Namespace to the replica.

This page shows you how to:

• Create a new high availability Namespace
• Upgrade an existing Namespace for high availability functionality
• Discontinue high availability replication

Create a high availability Namespace

To create a new replicated Namespace, you can use the Temporal Cloud Web site or the tcld command line utility. Here's how:

Approach	Instructions
Temporal Cloud Web UI	1. Visit Temporal Cloud in your Web browser. 2. During Namespace creation, specify the active region for the Namespace. 3. Select "Add a replica". Adding a replica in the same region enables Replication. Adding a replica in a different region enables Multi-region Replication.
Temporal tcld CLI	At the command line, enter: tcld namespace create \     --namespace <namespace_id>.<account_id> \     --region <active_region> \     --region <replica_region> Specify the region codes as arguments to the two --region flags. Using the same region replicates to an isolation zone within that region. Using a different region within the same continent creates a multi-region Namespace. Before pressing return, add your authentication credentials. For example, --ca-certificate-file <path-to-pem-file>.

note

Replication is not supported in all regions. For multi-region replication, pairing is limited to regions within the same continent. For more details, refer to ["Regional availability"].(/cloud/high-availabilityregional-availability).

Upgrade an existing Namespace to high availability functionality

Upgrade an existing single-region Namespace to high availability features by establishing a replica. The following sections explain how. You can either create a replica within the current region or deploy the replica to a different region.

Temporal Cloud Web UI

Follow these steps to upgrade an existing Namespace:

1. Visit Temporal Cloud Namespaces in your Web browser
2. Navigate to the Namespace details page
3. Select the “Add a replica” button.
4. Choose either Replication (in the same region) or Multi-region Replication (across regions). If you select Multi-region Replication, specify which region

The web interface will present an estimated time for replication to complete. This time is based on your selection and the size and scale of the Workflows in your Namespace. An email alert is dispatched once your highly available Namespace is ready for use.

Temporal 'tcld' CLI

Enter the following at the command-line to upgrade a Namespace for replication:

tcld namespace add-region \
    --namespace <namespace_id>.<account_id> \
    --region <region>

Specify the added region code as an argument to the --region flag.

• Using the current region replicates to an isolation zone within your existing region.
• Using a different region within the same continent creates a multi-region Namespace.

Before pressing return, add your authentication credentials. For example, --ca-certificate-file <path-to-pem-file>.

An email alert is sent once your multi-region Namespace is ready for use.

Discontinue high availability replication

Removing a Namespace replica removes the high availability and automatic failover features that provide Temporal's highest service level agreement. To disable these features and end charges:

1. Navigate to the Namespace details page in Temporal Cloud.
2. On the “Region” card, select the option to “Remove Replica”.

The replica will be deleted and your Namespace will no longer be highly available. You will no longer be charged for this feature.

note

After removing a replica, Temporal Cloud can't re-enable replication in the same region for a given Namespace for seven days.