# Managing multilocation canaries
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## Creating a multilocation canary
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To create a multilocation canary, follow the steps in [Creating a canary](CloudWatch_Synthetics_Canaries_Create.md) and select additional Regions under **Locations**. The current Region is automatically selected as the primary location.

When you create a multilocation canary, the following requirements apply:
+ You can add up to 50 replica locations.
+ The canary script .zip file must not exceed 50 MB.
+ The canary name must not already exist in any of the selected replica Regions.
+ Replica locations must be supported CloudWatch Synthetics commercial Regions. The primary Region cannot be selected as a replica location.
+ Multilocation canaries cannot be associated with a group. If your canary belongs to a group, disassociate it from all groups before adding replica locations.
+ If your canary requires VPC connectivity, you must configure VPC settings for each replica Region separately. VPC settings are not inherited from the primary.
+ Tags are not replicated to replica Regions. To add tags to a replica, navigate to the replica Region and add tags directly.

After creation, replicas are provisioned asynchronously. You can monitor the replication progress on the canary detail page in the **Configuration** tab. When a replica reaches `InSync` state, it is fully provisioned and running. You can also view the replica canary directly in the replica Region. For more information, see [Replication status](#CloudWatch_Synthetics_MultiLocation_ReplicationStatus_Manage).

If a replica fails to provision, the primary canary is still created successfully. The failed replica displays an `Inconsistent` replication status. You can retry by updating the canary.

## Adding or removing replica locations
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To add or remove replica locations, edit the canary from the primary Region and update the selections under **Locations**. You cannot edit a multilocation canary from a replica Region. For more information about editing a canary, see [Edit or delete a canary](synthetics_canaries_deletion.md).

When you add or remove replica locations, the following requirements apply:
+ You cannot modify a multilocation canary while replication is in progress. Wait for all replicas to reach `InSync` or `Inconsistent` state before making changes. For more information, see [Replication status](#CloudWatch_Synthetics_MultiLocation_ReplicationStatus_Manage).
+ When you add replica locations, you must include the canary code in your request.
+ When you update a canary that has inconsistent replicas, you must include the canary code, unless you are removing all inconsistent replicas in the same request.
+ You cannot add and remove the same location in a single request.
+ You cannot remove a replica location that does not exist.

## Starting and stopping a multilocation canary
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When you start or stop a multilocation canary, the action applies to the primary canary and all replica locations.

When you start or stop a multilocation canary, the following requirements apply:
+ You must start or stop the canary from the primary Region. Start and stop operations are not permitted from a replica Region.
+ You cannot start or stop a multilocation canary while replication is in progress. Wait for all replicas to reach `InSync` or `Inconsistent` state before starting or stopping. For more information, see [Replication status](#CloudWatch_Synthetics_MultiLocation_ReplicationStatus_Manage).
+ The canary must be in the `READY` or `STOPPED` state to start, or in the `RUNNING` state to stop.

## Deleting a multilocation canary
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To delete a multilocation canary, you must first remove all replica locations. For more information, see [Edit or delete a canary](synthetics_canaries_deletion.md). The following requirements apply:
+ You must delete the canary from the primary Region. Delete operations are not permitted from a replica Region.
+ Wait for all replicas to be fully removed before you attempt to delete. You can monitor removal progress in the **Configuration** tab. For more information, see [Replication status](#CloudWatch_Synthetics_MultiLocation_ReplicationStatus_Manage).
+ The canary must be in the `STOPPED`, `READY`, or `ERROR` state. If the canary is running, stop it first.

## Replication status
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Replication status indicates the synchronization state of a replica with the primary canary. You can view the replication status on the canary detail page in the **Configuration** tab.

Replicas can have the following replication status values:
+ **InProgress** — The replica is being created or updated. Changes from the primary are being propagated to the replica.
+ **InSync** — The replica is fully synchronized with the primary canary configuration.
+ **Inconsistent** — The replica is out of sync with the primary canary. This can occur if a propagation failed. You can retry by updating the canary again.

The overall *ReplicationState* on the primary canary shows the aggregate state across all replicas. If any replica is `InProgress`, the overall state is `InProgress`. If any replica is `Inconsistent`, the overall state is `Inconsistent`.