Static routes

Static routes

Static routing can be used if there is a device on the cloud subnet that acts as a router. You can:

• configure static routes in a subnet where devices, such as cloud servers, reside;
• configure static routes on the cloud router.

To configure static routes on a global router, use the following instructions Configure routing on a global router.

Examples of tasks to be solved⁠

Internet access for a network connected to a global router⁠

For example, a cloud platform's private network is connected to a global router, and you need to:

• configure Internet access for cloud servers that are located in subnets of this private network;
• Configure Internet access for the Managed Kubernetes cluster private subnet to deploy nodes;
• Use a public IP address for a cloud server or for a load balancer on a private network;
• Use the cloud router as a gateway to access the internet for servers or hosts from other pools and services.

Sending traffic through a cloud server (proxy)⁠

If you need to send traffic to other subnets, you can use the cloud server as a gateway and configure static routing. For example:

• configure access to the Internet from a subnet;
• configure connectivity to the external infrastructure via VPN.

Configure static routes in a subnetwork⁠

You can use as the source subnet:

• a private subnet;
• subnet of the global router;
• public subnet — only through the OpenStack CLI;
• private networks and public subnets to which access is configured in different projects (with the tag Кросспроектная) — only through the OpenStack CLI.

You cannot set a metric (route weight or cost) for a static route, so you cannot configure two or more routes with the same source subnet and destination subnet.

Control panel

When configuring a static route in the control panel, you can select a private subnet or a global router subnet as the source subnet.

1. In control panels from the top menu, press Products and select Cloud servers.
2. Go to the section Network → tab Private networks.
3. Open the private network page → tab Subnetworks.
4. In the subnet card, open the block Automatic network settings.
5. Click Add a route.
6. Enter the CIDR of the destination subnet, which is the subnet to which traffic will be routed.
7. Enter the gateway (next-hop) — the IP address through which devices on the source subnet will route traffic to the destination subnet. You can enter any address from the source subnet.
8. Click .
9. Apply the changes. To do this update the network settings on devices in the subnetwork.

OpenStack CLI

When configuring a static route through the OpenStack CLI, you can select as the source subnet: a private subnet, a global router subnet, a public subnet, and a private or public subnet that is configured to be accessed by different projects (with a tagged Кросспроектная).

1. Open the OpenStack CLI.

2. Configure a static route:

   openstack subnet set \
     --host-route destination=<destination_subnet_cidr>,gateway=<next_hop_ip_address> \
     <subnet>

   Specify:

   • <destination_subnet_cidr> — CIDR of the destination subnet to which the traffic will be routed, e.g. 172.16.0.8/29;
   • <next_hop_ip_address> — gateway (next-hop) — The IP address through which devices on the source subnet will route traffic to the destination subnet. You can enter any address from the source subnet;
   • <subnet> — ID or name of the source subnet, can be viewed with the command openstack subnet list.

   If you have previously configured static routes and want to delete all routes and add a new route at the same time, use the parameter --no-host-route:

   openstack subnet set \
     --no-host-route \
     --host-route destination=<destination_subnet_cidr>,gateway=<next_hop_ip> \
     <subnet>

3. Check that the static route has been added. To do this, look in the command output for the parameters destination (destination subnet) and gateway (next-hop):

   openstack subnet show <subnet>

4. Apply the changes. To do this update the network settings on devices in the subnetwork.

Configure static routes on the cloud router⁠

OpenStack CLI

1. Open the OpenStack CLI.

2. Configure a static route:

   openstack router add route \
     --route destination=<destination_subnet_cidr>,gateway=<next_hop_ip_address> \
     <router>

   Specify:

   • <destination_subnet_cidr> — CIDR of the destination subnet to which the traffic will be routed, e.g. 172.16.0.8/29;
   • <next_hop_ip_address> — gateway (next-hop) — the IP address that is specified on the cloud router, e.g. 172.16.0.1. Can be viewed with the command openstack router show <router>value ip_address in the field interfaces_info;
   • <router> — The ID or name of the cloud router, can be viewed using the command openstack router list.