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 QueueWhat is a Task Queue?
  
  A Task Queue is a first-in, first-out queue that a Worker Process polls for Tasks.
  
  Learn more names and Workflow IdsWhat 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.
  
  Learn more 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 PeriodWhat is a Retention Period?
  
  A Retention Period is the amount of time a Workflow Execution Event History remains in the Cluster's persistence store.
  
  Learn more and the ArchivalWhat 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.
  
  Learn more 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 PeriodWhat is a Retention Period?

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

Learn more 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
  • How to register a new Namespace using SDKHow to create and manage Namespaces
    
    You can create, update, deprecate or delete your Namespaces using either tctl or SDK APIs..
    
    Learn more

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

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 AuthorizerWhat is an Authorizer Plugin?

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Learn more 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 APIHow to create and manage Namespaces
    
    You can create, update, deprecate or delete your Namespaces using either tctl or SDK APIs..
    
    Learn more to update configuration on a Namespace.

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

  • With tctl: tctl namespace describe
  • Use the DescribeNamespace APIHow to create and manage Namespaces
    
    You can create, update, deprecate or delete your Namespaces using either tctl or SDK APIs..
    
    Learn more 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 APIHow to create and manage Namespaces
    
    You can create, update, deprecate or delete your Namespaces using either tctl or SDK APIs..
    
    Learn more to return information and configuration details for all registered Namespaces on your Temporal Cluster.

• Deprecate a Namespace: The DeprecateNamespace APIHow to create and manage Namespaces
  
  You can create, update, deprecate or delete your Namespaces using either tctl or SDK APIs..
  
  Learn more 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.

• Delete a Namespace: Deletes a Namespace and all Workflow Executions on the Namespace. Note that this API is supported for Temporal Server version 1.17 and later.

• With tctl: tctl namespace delete. Note that this feature is only available in the tctl v2.0.0-beta.

• Use the DeleteNamespace APIHow to create and manage Namespaces
  
  You can create, update, deprecate or delete your Namespaces using either tctl or SDK APIs..
  
  Learn more to delete a registered Namespaces. All the running Workflow Executions on a deleted Namespace are also deleted.

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 NamespaceWhat is a Namespace?

A Namespace is a unit of isolation within the Temporal Platform

Learn more that exists across Clusters when Multi-Cluster ReplicationWhat 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.

Learn more 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 TasksWhat is a Task?

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

Learn more; 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 resolutionWhat 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.

Learn more). 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.