Namespaces

This guide provides a comprehensive overview of Namespaces.

A Namespace is a unit of isolation within the Temporal Platform.

A single Namespace is still multi-tenant.

Usage

Namespaces are created on the Temporal Cluster, and provide a range of controls to achieve isolation on Workflow Executions.

• Namespaces are a mechanism for resource isolation. Heavy traffic from one Namespace will not impact other Namespaces running on the same Cluster. For example, you can use Namespaces to match the development lifecycle by having separate dev and prod Namespaces.
• If no other Namespace is specified, the Temporal Cluster uses the Namespace "default" for all Temporal SDKs and tctl. See the Registration section for details.
• Namespaces created on self-hosted Temporal Clusters are case-sensitive. For example, foo and Foo are two different Namespaces. On Temporal Cloud, Namespaces are case-insensitive, and we recommend using lowercase for Namespace names to avoid potential issues.
• Membership: Task Queue

  What is a Task Queue?

  A Task Queue is a first-in, first-out queue that a Worker Process polls for Tasks.

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  names and Workflow Ids

  What is a Workflow Id?

  A Workflow Id is a customizable, application-level identifier for a Workflow Execution that is unique to an Open Workflow Execution within a Namespace.

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  must all correspond to a specific Namespace. For example, when a Workflow Execution is spawned, it does so within a specific Namespace.
• Uniqueness: Temporal guarantees a unique Workflow Id within a Namespace. Workflow Executions may have the same Workflow Id if they are in different Namespaces.
• Namespace Configuration: Various configuration options like the Retention Period

  What is a Retention Period?

  A Retention Period is the amount of time a Workflow Execution Event History remains in the Cluster's persistence store.

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  and the Archival

  What is Archival?

  Archival is a feature that automatically backs up Event Histories from Temporal Cluster persistence to a custom blob store after the Closed Workflow Execution retention period is reached.

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  destination are configured per Namespace through a special CRUD API or through tctl.

Registration

Registering a Namespace creates the Namespace on the Temporal Cluster. When you register your Namespace, you must also set the Retention Period

What is a Retention Period?

A Retention Period is the amount of time a Workflow Execution Event History remains in the Cluster's persistence store.

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for the Namespace.

On Temporal Cloud, use the Temporal Cloud UI or tcld commands to create and manage Namespaces.

On self-hosted Temporal Cluster, you can register your Namespaces using tctl (recommended) or programmatically using APIs. Note that these APIs and tctl commands will not work with Temporal Cloud.

All SDKs require a Namespace on the Temporal Cluster (or Temporal Cloud) for their Client calls. If not set using Client options, the Workflow Client API looks for the default Namespace. If there is no default Namespace registered with your Temporal Cluster (or Temporal Cloud), all calls will throw errors. You must register your Namespace with the Temporal Cluster (or Temporal Cloud) before setting it in your Client.

On self-hosted Temporal Clusters, you can register your Namespaces in the following ways:

• In your Cluster setup, create your Namespaces, including the default, in your setup script. For example:

  • If deploying through Docker Compose or using the auto-setup image in a custom Docker Compose application, the Namespace "default" is created, through the auto-setup script.
  • If deploying through the Temporal Helm charts, you can create the "default" Namespace by using tctl; for example, tctl --namespace default namespace register.

• Use the tctl namespace register command with the --retention modfiier to register your Namespaces, one at a time, and set the Retention Period on each.

  • How to register a new Namespace using tctl

• In your Client program, register your Namespace using RegisterNamespaceRequest API available in all the SDKs.

  • How to register a new Namespace using SDK

Note that registering a Namespace takes up to 15 seconds to complete. Ensure that you are waiting for this process to complete before making calls to the Namespace.

Manage Namespaces

Use a custom Authorizer

What is an Authorizer Plugin?

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on your Frontend Service in the Temporal Cluster to set restrictions on who can create, update, or deprecate Namespaces.

On Temporal Cloud, use the Temporal Cloud UI or tcld commands to manage Namespaces.

On self-hosted Temporal Cluster, you can manage your registered Namespaces using tctl (recommended) or programmatically using APIs. Note that these APIs and tctl commands will not work with Temporal Cloud.

• Update information and configuration for a registered Namespace on your Temporal Cluster:

  • With tctl: tctl namespace update
  • Use the [UpdateNamespace API]9(/application-development/features#namespaces) to update configuration on a Namespace.

• Get details for a registered Namespace on your Temporal Cluster:

  • With tctl: tctl namespace describe
  • Use the DescribeNamespace API to return information and configuration details for a registered Namespace.

• Get details for all registered Namespaces on your Temporal Cluster:

  • With tctl: tctl namespace list
  • Use the ListNamespace API to return information and configuration details for all registered Namespaces on your Temporal Cluster.

• Deprecate a Namespace: The DeprecateNamespace API updates the state of a registered Namespace to "DEPRECATED". Once a Namespace is deprecated, you cannot start new Workflow Executions on it. All existing and running Workflow Executions on a deprecated Namespace will continue to run.

Setting

Set Namespaces in your SDK Client to isolate your Workflow Executions to the Namespace. If you do not set a Namespace, all Workflow Executions started using the Client will be associated with the "default" Namespace. This means, you must have a default Namespace called "default" registered with your Temporal Cluster. See Registration for details.

• How to set the Namespace for a Temporal Client
• How to list Namespaces in a Cluster using tctl
• How to view (describe) Namespace metadata and details using tctl

Global Namespace

A Global Namespace is a Namespace

What is a Namespace?

A Namespace is a unit of isolation within the Temporal Platform

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that exists across Clusters when Multi-Cluster Replication

What is Multi-Cluster Replication?

Multi-Cluster Replication is a feature which asynchronously replicates Workflow Executions from active Clusters to other passive Clusters, for backup and state reconstruction.

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is set up.

• How to register a Global Namespace
• How to change the active Cluster for a Global Namespace

The Global Namespace feature enables Workflow Executions to progress through another Cluster in the event of a failover.

A Global Namespace may be replicated to any number of Clusters, but is active in only one Cluster at any given time.

For a failover to be successful, Worker Processes must be polling for Tasks for the Global Namespace on all Clusters.

A Global Namespace has a failover version. Because a failover can be triggered from any Cluster, the failover version prevents certain conflicts from occurring if a failover is mistakenly triggered simultaneously on two Clusters.

Only the active Cluster dispatches Tasks

What is a Task?

A Task is the context needed to make progress with a specific Workflow Execution or Activity Execution.

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; however, certain conflicts are possible. Unlike regular Namespaces, which provide at-most-once semantics for an Activity Execution, Global Namespaces can support only at-least-once semantics (see Conflict resolution). Worker Processes on the standby Clusters are idle until a failover occurs and their Cluster becomes active.

Temporal Application API calls made to a non-active Cluster are rejected with a NamespaceNotActiveError which contains the name of the current active Cluster. It is the responsibility of the Temporal Application to call the Cluster that is currently active.