Set up and manage VPC Network Peering

Google Cloud VPC Network Peering enables internal IP address connectivity across two Virtual Private Cloud (VPC) networks, regardless of whether they belong to the same Google Cloud project or organization. Peering supports connectivity between networks having any combination of IPv4-only, dual-stack, and IPv6-only subnets.

Before you begin

Read VPC Network Peering and About peering connections .
Enable the Compute Engine API in your project.

IAM permissions

Make sure that you have one of the following roles on the project:

Compute Network Admin role ( roles/compute.networkAdmin )
A custom role that includes the following permissions:
- compute.networks.addPeering
- compute.networks.updatePeering
- compute.networks.removePeering
- compute.networks.listPeeringRoutes

Create a peering configuration

Before you begin, you must have the name of the VPC network that you intend to peer with. If that network is located in another project, you must also have its project ID. You can't list peering requests for your VPC network. If necessary, ask the administrator of the network that you intend to peer with for the network name and project ID.

Your network and the other network are connected after each network has a peering configuration that references the other network. For more information, see About peering connections .

Google Cloud allows only one peering operation at a time across peered networks. For example, if you set up peering with one network and immediately try to set up another, the operation fails with the following: Error: There is a peering operation in progress on the local or peer network. Try again later.

Console

Perform the following steps for each side of the peering connection.

In the Google Cloud console, go to the VPC Network Peeringpage.

Go to VPC Network Peering
Click Create connection.
Click Continue.
In the Peering connection namefield, enter a name for your peering configuration.
In the Your VPC networkfield, select a network you want to peer.
In the Peered VPC networksection, select the network to peer with:
- If the network that you want to peer with is in the same project, select In project [name-of-your-project]and then the network to peer with.
- If the network that you want to peer with is in a different project, select In another project. Specify the project ID that includes the network you want to peer with and the name of the VPC network.
Select the IP version of routes that you want to exchange between the peered networks:
- IPv4 (single-stack): exchange IPv4 routes only.
- IPv4 and IPv6 (dual-stack): exchange both IPv4 and IPv6 routes.
To exchange IPv4 custom routes, in the Exchange IPv4 custom routessection, choose one or both of the following options:
- Import custom routes: import custom routes from the peer network. The peer network must enable custom route export for routes to be imported.
- Export custom routes: export custom routes to the peer network. The peer network must enable custom route import for routes to be exported.
If your network or the peer network has privately used public IPv4 ranges in their subnets, these routes are exported by default, but not imported by default.

To import privately used public IPv4 subnet routes, in the Exchange subnet routes with privately used public IPv4 addressessection, select Import subnet routes with public IP.
In Advanced optionssection, choose the update strategy for the peering connection:
- Independent (default): when this option is selected, either side of the peering connection can update or delete the connection at any time. For more information, see Connection mode .
- Consensus: when this option is selected, both sides of the peering connection must submit a deletion request before the connection can be deleted. For more information, see Connection mode .
Click Create.

gcloud

Use the gcloud compute networks peerings create command .

You can create a peering configuration using the default configuration, or you can customize your configuration.

Create a default peering configuration

To create a default peering configuration, run the following command:

gcloud compute networks peerings create PEERING_NAME 
\
    --network= NETWORK 
\
    --peer-project= PEER_PROJECT_ID 
\
    --peer-network= PEER_NETWORK_NAME 
\

Replace the following:

PEERING_NAME : the name of the peering configuration.
NETWORK : the name of the network in your project that you want to peer.
PEER_PROJECT_ID : the ID of the project that contains the network that you want to peer with. If the peer network is in the same project as your network, this flag is optional.
PEER_NETWORK_NAME : the name of the network that you want to peer with.

For example, to peer network-a in project-a with network-b in project-b , do the following:

Create a peering configuration for network-a . This step is usually performed by a network administrator of network-a .

gcloud compute networks peerings create peering-a \
    --network= network-a 
\
    --peer-project= project-b 
\
    --peer-network= network-b

Create a peering configuration for network-b . This step is usually performed by a network administrator of network-b .

gcloud compute networks peerings create peering-b \
    --network= network-b 
\
    --peer-project= project-a 
\
    --peer-network= network-a

The peering state changes to ACTIVE in both networks.

Customize a peering configuration

To customize a peering configuration, you can use the following optional parameters:

--stack-type sets the stack type for the peering connection. By default, only IPv4 routes are exchanged, and the stack type is set to IPV4_ONLY . To exchange both IPv4 and IPv6 routes, specify IPV4_IPV6 .
--import-custom-routes tells the network to accept custom routes from the peered network. The peered network must export the routes first.
--export-custom-routes tells the network to export custom routes to the peered network. The peered network must be set to import the routes.
--import-subnet-routes-with-public-ip tells the network to accept subnet routes from the peered network if that network has privately used public IPv4 addresses in its subnets. The peered network must export the routes first.
--export-subnet-routes-with-public-ip tells the network to export subnet routes that contain privately used public IPv4 addresses. The peered network must be set to import the routes.
--update-strategy sets the update strategy for the peering connection. By default, the update strategy is set to INDEPENDENT . To configure the connection to use consensus mode, specify CONSENSUS . The update strategy must be the same for both sides of the connection. For more information, see Connection mode .

Example: Exchange custom routes in a peering connection

To enable network-a in project-a and network-b in project-b to exchange custom routes, do the following when creating the peering connection:

Create a peering configuration for network-a . This step is usually performed by a network administrator of network-a .

gcloud compute networks peerings create peering-a \
    --network= network-a 
\
    --peer-project= project-b 
\
    --peer-network= network-b 
\
    --import-custom-routes

Create a peering configuration for network-b . This step is usually performed by a network administrator of network-b .

gcloud compute networks peerings create peering-b \
    --network= network-b 
\
    --peer-project= project-a 
\
    --peer-network= network-a 
\
    --export-custom-routes

The peering state changes to ACTIVE in both networks. For more information about this example, see the Peer two VPC networks quickstart.

Example: Create a peering connection in consensus mode

To create a peering connection in consensus mode, set the update strategy to CONSENSUS . In this example, you configure network-a in project-a to peer with network-b in project-b .

Create a peering configuration for network-a . This step is usually performed by a network administrator of network-a .

gcloud compute networks peerings create peering-a \
    --network= network-a 
\
    --peer-project= project-b 
\
    --peer-network= network-b 
\
    --update-strategy=CONSENSUS

Create a peering configuration for network-b . This step is usually performed by a network administrator of network-b .

gcloud compute networks peerings create peering-b \
    --network= network-b 
\
    --peer-project= project-a 
\
    --peer-network= network-a 
\
    --update-strategy=CONSENSUS

The peering state changes to ACTIVE in both networks.

Terraform

You can use a Terraform module to create a peering configuration.

 module "peering1" {
  source        = "terraform-google-modules/network/google//modules/network-peering"
  version       = "~> 12.0"
  local_network = var.local_network # Replace with self link to VPC network "foobar" in quotes
  peer_network  = var.peer_network  # Replace with self link to VPC network "other" in quotes
}

For the two peered VPC networks, each self link includes a project ID and the name of the VPC network. To get the self link for a VPC network, you can use the gcloud compute networks describe command or the networks.get method in each VPC network's project.

When you create a peering from the local_network to the peer_network , the peering relationship is bidirectional. The peering from the peer_network to the local_network gets created automatically.

To learn how to apply or remove a Terraform configuration, see Basic Terraform commands .

Verify that traffic is passing between peered VPC networks

You can use VPC Flow Logs to view network flows sent from and received by VM instances. You can also use Firewall Rules Logging to verify that traffic is passing between the networks. Create VPC firewall rules that allow (or deny) traffic between the peered networks, and turn on Firewall Rules Logging for those rules. You can then view which firewall rules were hit using Cloud Logging.

Update a peering connection

When you update an existing peering connection, you can do the following:

Change whether your VPC network exports or imports custom routes or privately used public IPv4 subnet routes to or from the peer VPC network.
Update the peering connection to enable or disable the exchange of IPv6 routes between the peered networks.
Update the peering connection mode from independent (default) to consensus, by changing the update strategy for the connection .

Your network imports routes only if the peer network is also exporting the routes, and the peer network receives routes only if it imports them.

Update a connection (independent mode)

Console

In the Google Cloud console, go to the VPC Network Peeringpage.

Go to VPC Network Peering
Select the peering connection to update.
Click Edit.
To update the IP version of routes that you want to exchange between the peered networks, select one of the following:
- IPv4 (single-stack): stop the existing exchange of IPv6 routes and continue exchanging only IPv4 routes.
- IPv4 and IPv6 (dual-stack): start exchanging both IPv4 and IPv6 routes, provided the matching peering configuration also has this option enabled.
To exchange IPv4 custom routes, in the Exchange IPv4 custom routessection, choose one or both of the following options:
- Import custom routes: import custom routes from the peer network. The peer network must enable custom route export for routes to be imported.
- Export custom routes: export custom routes to the peer network. The peer network must enable custom route import for routes to be exported.
If your network or the peer network has privately used public IPv4 ranges in their subnets, these routes are exported by default, but not imported by default.

To import privately used public IPv4 subnet routes, in the Exchange subnet routes with privately used public IPv4 addressessection, select Import subnet routes with public IP.
Click Save.

gcloud

Use the gcloud compute networks peerings update command . The square brackets [] in the following command indicate optional flags:

--stack-type sets the stack type for the peering connection. By default, only IPv4 routes are exchanged, and the stack type is set to IPV4_ONLY . To exchange both IPv4 and IPv6 routes, specify IPV4_IPV6 .
--import-custom-routes tells the network to accept custom routes from the peered network. The peered network must export the routes first.
--export-custom-routes tells the network to export custom routes to the peered network. The peered network must be set to import the routes.
--import-subnet-routes-with-public-ip tells the network to accept subnet routes from the peered network if that network is using privately used public IPv4 addresses in its subnets. The peered network must export the routes first.
--export-subnet-routes-with-public-ip tells the network to export subnet routes that contain privately used public IPv4 addresses. The peered network must be set to import the routes.
--update-strategy sets the update strategy for the peering connection. By default, the update strategy is set to INDEPENDENT . To configure the connection to use consensus mode, specify CONSENSUS . The update strategy must be the same for both sides of the connection For more information, see Connection mode .

gcloud compute networks peerings update PEERING_NAME 
\
    --network= NETWORK 
\
    [--stack-type= STACK_TYPE 
] \
    [--import-custom-routes] \
    [--export-custom-routes] \
    [--export-subnet-routes-with-public-ip] \
    [--import-subnet-routes-with-public-ip] \
    [--update-strategy= UPDATE_STRATEGY 
]

Replace the following:

PEERING_NAME : the name of the existing peering configuration.
NETWORK : the name of the network in your project that is peered.
STACK_TYPE : the stack type for the peering connection.
- Specify IPV4_ONLY to stop the existing exchange of IPv6 routes and continue exchanging only IPv4 routes.
- Specify IPV4_IPV6 to start exchanging both IPv4 and IPv6 routes, provided the matching peering connection also has stack_type set to IPV4_IPV6 .
UPDATE_STRATEGY : the update strategy for the peering connection—either INDEPENDENT (default) or CONSENSUS . To use this option, see Update a connection to consensus mode .

Update a connection to consensus mode

You update a peering connection from independent (default) to consensus mode by changing the update strategy for the connection. Before changing the update strategy, review the requirements for consensus mode .

Console

In the Google Cloud console, go to the VPC Network Peeringpage.

Go to VPC Network Peering
Click the peering connection to update.
Click Edit.
In the Advanced optionssection, select Consensus.
Click Save.

The update strategy changes to Consensusfor the local configuration. To complete the update request, a network administrator for the peer network must accept the request by performing steps 1-4 for the peer configuration.

After both configurations are updated, the effective update strategy of the peering connection changes to Consensus.

gcloud

Use the gcloud compute networks peerings update command .

Update the local peering configuration:
```
gcloud compute networks peerings update PEERING_NAME 
\
    --network= NETWORK 
\
    --update-strategy=CONSENSUS
```
Replace the following:
- PEERING_NAME : the name of the existing peering configuration.
- NETWORK : the name of the network in your project that is peered.
View the status of the update request:
```
gcloud compute networks describe NETWORK 
```
Replace NETWORK with the name of the network in your project that is peered.

In the output, the consensusState field must display the following status:
- In the configuration for the local network, PENDING_PEER_ACKNOWLEDGMENT
- In the matching configuration for the peer network, PENDING_LOCAL_ACKNOWLEDGMENT
Accept the update request by running the command in step 1 for the peer side of the connection.

This step is usually performed by a network administrator for the peer network. After the request is complete, the consensusState field changes to IN_SYNC for both configurations.

To revert an update request that is waiting for approval by the peer network, reset the update strategy to independent.

List peering connections

List existing peering connections to view their status and whether they're importing or exporting custom routes.

Console

In the Google Cloud console, go to the VPC Network Peeringpage.

Go to VPC Network Peering
Select the peering connection to view its details.

gcloud

gcloud compute networks peerings list

View a peering connection

Console

In the Google Cloud console, go to the VPC Network Peeringpage.

Go to VPC Network Peering
In the Statuscolumn, view the status of your connection.

gcloud

Use the gcloud compute networks describe command .

gcloud compute networks describe NETWORK

Replace NETWORK with the name of the network in your project that is peered.

In the output, the peerings.connectionStatus field describes the effective status of the peering connection. For more information, see Connection status .

List peering routes

Console

Use the Effective routestab to view all applicable route types in a VPC network, including imported peering subnet, peering static, and peering dynamic routes.

In the Google Cloud console, go to the Routespage.

Go to Routes
On the Effective routestab, do the following:
- Select a VPC network.
- Select a Region.
Click View.
Click the Filtertext field, and do the following:
- Choose Typefrom the Propertiesmenu.
- Choose one of the following from the Valuesmenu.
  - Peering subnet: to see subnet routes from peer VPC networks.
  - Peering static: to see imported static routes from peer VPC networks.
  - Peering dynamic: to see imported dynamic routes from peer VPC networks.
Optionally, click Show suppressed routesto view routes that are suppressed. Place your pointer over the icon in the Statuscolumn to view the reason why a route has been suppressed. The reason includes a link to the routing order documentation with an explanation.

gcloud

Use the following Google Cloud CLI command to:

List route exports sent from your VPC network to peer VPC networks.
List route import candidates for your VPC network.

gcloud compute networks peerings list-routes PEERING_NAME 
\
    --network= NETWORK 
\
    --region= REGION 
\
    --direction= DIRECTION

Replace the following:

PEERING_NAME : the name of an existing peering connection.
NETWORK : the name of the network in your project that is peered.
REGION : the region where you want to list all dynamic routes. Subnet and static routes are global and are shown for all regions.
DIRECTION : specifies whether to list imported ( incoming ) or exported ( outgoing ) routes.

Delete a peering connection

When a peering configuration is deleted in your network, the peering connection becomes inactive in the other network, and all routes shared among the networks are removed.

The procedure for deleting a peering connection depends on the update strategy configured for the connection:

Independent (default): you or a network administrator for the peer VPC network can delete the connection at any time. See Delete a connection (independent mode) .
Consensus: both you and a network administrator for the peer VPC network must submit a delete request before the connection can be deleted. See Delete a connection (consensus mode) .

Delete a connection (independent mode)

To delete a peering connection in independent mode (default), do the following.

Console

In the Google Cloud console, go to the VPC Network Peeringpage.

Go to VPC Network Peering
Select the checkbox next to the peering connection that you want to remove.
Click Delete.

The status of the connection changes to Inactivefor the peer network. To remove the inactive configuration, a network administrator for the peer network performs these steps for the peer side of the connection.

gcloud

Use the gcloud compute networks peerings delete command .

gcloud compute networks peerings delete PEERING_NAME 
\
    --network= NETWORK

Replace the following:

PEERING_NAME : the name of the peering configuration to delete.
NETWORK : the name of the network in your project that is peered.

The status of the connection changes to INACTIVE for the peer network. To remove the inactive configuration, a network administrator for the peer network performs this step for the peer side of the connection.

Delete a connection (consensus mode)

To delete a peering connection in consensus mode, do the following.

Console

In the Google Cloud console, go to the VPC Network Peeringpage.

Go to VPC Network Peering
Click the peering connection that you want to remove.
On the Peering connection detailspage, click Request deleteand then Confirm.
Accept the deletion request by performing steps 1-3 for the peer side of the connection.

These steps are usually performed by a network administrator for the peer network. After both sides of the peering connection submit the deletion request, the status of the connection changes to Active, delete acknowledgedfor both configurations.
Select the peering connection that you want to remove and then click Delete.

The status of the connection changes to Inactivefor the peer network. To remove the inactive configuration, the network administrator for the peer network performs this step for the peer side of the connection.

gcloud

Use the gcloud compute networks peerings request-delete and gcloud compute networks peerings delete commands.

Initiate a deletion request:
```
gcloud compute networks peerings request-delete PEERING_NAME 
\
    --network= NETWORK 
```
Replace the following:
- PEERING_NAME : the name of the peering connection to delete.
- NETWORK : the name of the network in your project that is peered.
View the status of the deletion request:
```
gcloud compute networks describe NETWORK 
```
Replace NETWORK with the name of the network in your project that is peered.

In the output, the deleteStatus field must display the following status:
- In the configuration for the local network, LOCAL_DELETE_REQUESTED
- In the matching configuration for the peer network, PEER_DELETE_REQUESTED
Accept the deletion request by running the command in step 1 for the peer side of the connection.

This step is usually performed by a network administrator for the peer network. After both sides of the connection submit the deletion request, the status of the deleteStatus field changes to DELETE_ACKNOWLEDGED for both configurations.
Delete the peering connection:
```
gcloud compute networks peerings delete PEERING_NAME 
\
    --network= NETWORK 
```
Replace the following:
- PEERING_NAME : the name of the peering configuration to delete.
- NETWORK : the name of the network in your project that is peered.
The status of the connection changes to INACTIVE for the peer network. To remove the inactive configuration, the network administrator for the peer network performs this step for the peer side of the connection.

Troubleshooting

The following sections describe how to troubleshoot issues with VPC Network Peering.

Peer VMs are unreachable

After the peering connection is ACTIVE, it may take up to a minute for all the traffic flows to be set up between the peered networks. This time depends on the size of the networks that are peering. If you have recently set up the peering connection, wait up to a minute and try again. Also, ensure that there are no firewall rules blocking access to or from peer VPC network subnet CIDRs.

Custom routes are missing

This section describes how to troubleshoot missing custom routes.

Check the peering connection state

To check the state of your peering connection, do the following:

List peering connections .
Identify the peering connection to troubleshoot, and review its peering state.
1. If the state is ACTIVE , follow the steps in the next section.
2. If the peering state is INACTIVE , a network administrator for the other network needs to create a peering configuration to your VPC network.

Troubleshoot an `ACTIVE` connection

To troubleshoot missing custom routes in an ACTIVE peering connection:

List peering routes in your VPC network. In the Effective routestab, do the following:
1. Consider that the regions in which dynamic routes are programmed depends on the dynamic routing mode of the VPC network that exports custom routes. For more details, see Effects of the dynamic routing mode . In global dynamic routing mode, only the highest ranked dynamic route is programmed in regions that don't match the region of the next hop.
2. Click the Show suppressed routestoggle to the on position, then check for your route. To view the reason why a route has been suppressed, point to the icon in the Statuscolumn. Google Cloud provides route conflict resolution on a region-by-region basis in the VPC network that imports routes using VPC Network Peering.
3. Look for a warning indicating that your VPC network has reached the limit for the dynamic routes per region per peering group quota . If your VPC network has reached the limit for this quota, one or more peering dynamic routes aren't programmed. Because it's not possible to show exactly which peering dynamic routes aren't programmed, request a quota limit increase for the dynamic routes per region per peering group quota.
If you still don't see the route you expect, do the following:
1. Review your peering configuration, and update your peering configuration if necessary so that it imports custom routes.
2. Ensure that the route is not one of the following route types that can't be exchanged using VPC Network Peering:
  - Peering subnet, peering static, and peering dynamic routes in a peered VPC network that are received from its other peer networks cannot be exchanged to your VPC network using VPC Network Peering.
  - Static routes that use the default internet gateway next hop and static routes with network tags cannot be exchanged using VPC Network Peering.
  For more information, see Route exchange options .
3. Ask a network administrator of the peered VPC network to:
  1. List routes in their VPC network , looking for the route you expect.
  2. Review their peering configuration, and update the peering configuration if necessary so that it exports custom routes.

Traffic destined for a peer network is being dropped

You can use Connectivity Tests to help determine why traffic destined for a peer network is being dropped. If traffic should be sent using custom routes, see Custom routes are missing .

Traffic is being sent to an unexpected next hop

You can use Connectivity Tests to help determine why traffic is being sent to an unexpected next hop. If traffic should be sent using custom routes, see Custom routes are missing .

Unable to peer with a particular VPC network

If you cannot create a peering configuration with certain VPC networks, an organization policy might be constraining the VPC networks that your network can peer with. In the organization policy, add the network to the list of allowed peers or contact your organization administrator. For more information, refer to the constraints/compute.restrictVpcPeering constraint.

IPv6 routes are not exchanged

First, verify that both your peering connection and the peering connection of the peered VPC network have their stack types set to IPV4_IPV6 . If necessary:

Update your peering connection to set its stack type to IPV4_IPV6 .
Ask a network administrator of the peered VPC network to update their peering connection, setting its stack type to IPV4_IPV6 .

After both peering connections have their stack types set to IPV4_IPV6 , IPv6 subnet routes (both internal and external) are exchanged. IPv6 subnet routes are unique among all Google Cloud VPC networks.

To exchange IPv6 custom routes:

Update your peering connection to import and export custom routes.
Ask a network administrator of the peered VPC network to update their peering connection to import and export custom routes.

What's next

For more information about VPC routing, see Routes .
For limits related to VPC Network Peering, see VPC Network Peering limits .
For information about how to use an internal passthrough Network Load Balancer as the next hop for a custom static route, see Use an internal passthrough Network Load Balancer as a next hop .

Set up and manage VPC Network Peering

Before you begin

IAM permissions

Create a peering configuration

Console

gcloud

Create a default peering configuration

Customize a peering configuration

Example: Exchange custom routes in a peering connection

Example: Create a peering connection in consensus mode

Terraform

Verify that traffic is passing between peered VPC networks

Update a peering connection

Update a connection (independent mode)

Console

gcloud

Update a connection to consensus mode

Console

gcloud

List peering connections

Console

gcloud

View a peering connection

Console

gcloud

List peering routes

Console

gcloud

Delete a peering connection

Delete a connection (independent mode)

Console

gcloud

Delete a connection (consensus mode)

Console

gcloud

Troubleshooting

Peer VMs are unreachable

Custom routes are missing

Check the peering connection state

Troubleshoot an ACTIVE connection

Traffic destined for a peer network is being dropped

Traffic is being sent to an unexpected next hop

Unable to peer with a particular VPC network

IPv6 routes are not exchanged

What's next

Troubleshoot an `ACTIVE` connection