DHCP

For assigning addresses to instances, Binero cloud uses the DHCP protocol. While its possible to do static IPs in the plattform, we highly recommend using it because it greatly simplifies adding new instances (they will become available with zero configuration needed). Instance IP-allocations are saved so there is no risk that an instance (as is the case traditionally with DHCP - which was typically used for client computers) would suddenly get another IP-address.

A DHCP scope (or pool) is part of a network range that is reserved for the DHCP server do deliver to its clients. The scope is setup on a private subnet when creating it, instructions are provided under each management tool.

DHCP, other than assigning addresses, also assigns the correct MTU to instances. This is very important for networking functionality in general so if opting to not use DHCP, we recommend reading the MTU article carefully to understand the MTU concept.

Tip

When assigning a DHCP scope (or pool), leave some room for potential statically assigned addresses as well as the gateway address. A typical recommendation would be to reserve the first 10-20 addresses in a subnet, depending on the subnet size. The remaining addresses would ideally go into the pool.

Routing via DHCP

Since DHCP provisions IP-configuration to instances, if there is a need to add :doc:static routes <../static-routing>` to instances (so called “Host routes”) for whatever reason, DHCP is a good way to accomplish this as any routes that are added to the DHCP subnet will get pushed to all instances on that subnet (existing as well as any new ones added). DHCP will only add routes on instances, which is only usable to route to other instances on the same subnet. To route to a destination outside the same subnet, the default route is normally used but a good use case for routing via DHCP is when a VPN is setup on the same subnet that does not do NAT. See below for how to add routing to a DHCP pool.

Add a route using the cloud management portal

To add a route using the Cloud management portal, follow these steps:

  • Press “Networking” and then “Networks” in the sidebar menu.

  • Press the network for which you want to add the route.

  • Press the edit icon (a small pencil) next to the subnet for which you want to add the route.

  • Press the “+” sign above “add host route”.

  • Under “Destination CIDR”, enter the destination network in CIDR notation.

  • Under “Nexthop (IP)” add the gateway address. This address needs to be in the subnet you are editing.

  • Press “Save subnet”.

Add a route using OpenStack Horizon

To add a route using the OpenStack Horizon, follow these steps:

  • Under “project”, click “Network” and then “Networks” in the sidebar menu.

  • Press the name of the network for which you want to add the route.

  • Press the “subnets” tab and then “edit subnet” button on the row of the subnet for which you want to add the route.

  • Press the “Subnet details” button.

  • Enter the route as destination subnet in `CIDR notation </networking/router/private-subnet/subnet-format>`,nexthop (gateway), for instance 192.168.10.0/24,192.168.1.5. A single route entry on a single row.

  • Press “Save”.

Add a route using OpenStack terminal client

To add a route using the using the OpenStack Terminal Client, follow these steps:

  • Run this command: openstack subnet list. Save the name of the subnet you want to add the route to.

  • Run this command: openstack subnet set --host-route destination=[DESTINATION_SUBNET],gateway=[GATEWAY] [NAME_OF_SUBNET], replacing the items in angle brackets with the information from the previous steps and the destination network and gateway/nexthop. If you want to know more options, use “-h” at the end of the command.

See also