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Public Cloud Network Services - Known Limits

Stephanie R.
Updated

Learn about the known limitations of our Public Cloud Networking Services.

 

vRack and Public Cloud projects

For a given Public Cloud project, you can attach only one vRack. If you wish to build private connectivity between two (or more) Public Cloud projects, you need to attach the same vRack to those Public Cloud projects.

 

Load Balancer Floating IP in the OVHcloud Control Panel

If you choose to attach a Floating IP to your new Load Balancer instance, you can find the IP address:

 

You can also find the IP address of your Floating IP from the OVHcloud Control Panel by comparing the ID of your Load Balancer instance to the list of Public IPs:

  1. Select Public Cloud from the top navigation bar.
  2. Click Load Balancer from the left-hand navigation menu.
  3. Select your load balancer's Name.

PCI_network_resources_knownLimits01*.png

  1. On the next page, take note of the ID.

PCI_network_resources_knownLimits02**.png

  1. Click Public IPs from the left-hand navigation menu.
  2. Find the Floating IP that is associated with your Load Balancer instance.

PCI_network_resources_knownLimits03*.png

 

IPs used by services

When a service is spawned in a subnet, it uses some IPs from the subnet CIDR. The following table provides the number of IPs used by each service. If the subnet has a "small" number of available IPs, this can have an impact. If all L3 services are in use, the total number of IPs used will be 7. We advise using at least a /28 mask.

Used IPs by the service: In DHCP allocation pool Outside of allocation pool (gateway_ip)
DHCP 2  
Public Cloud Gateway 1 1
Public Cloud Load Balancer (Octavia) 3  

 

ICMP traffic toward Load Balancer IP

The traffic toward the Load Balancer IP (private IP or floating IP) is filtered. This means the ping on these IPs will not answer.

 

Instance bandwidth

To achieve the maximum bandwidth provided with each instance, you may need to use multi-flow.

For example, when using iperf to test your instance bandwidth, you can enable multi-flow by adding the -P n or --parallel n option. If n = 1 (which is the default if this option is omitted), you are testing bandwidth with a single flow. To achieve maximum bandwidth, you should increase the value of n.

 

Subnet allocation pool update

When updating an allocation pool (e.g., from [10.0.0.2:10.0.0.255] to [10.0.0.128:10.0.0.255]) all IPs already used before the allocation pool update are kept even if they are not in the new allocation pool.

For instance, if the subnet DHCP is activated, the IPs 10.0.0.2 and 10.0.0.3 will be used by DHCP servers and will still be used after the pool update.

To release these IPs, you need to delete the two DHCP ports. They will be recreated automatically in the updated allocation pool. This can be done in Horizon or using the OpenStack CLI.

For instance, you can delete all the dhcp ports from the private network with ID with:

openstack port list --network <PRIVATE_NETWORK_ID> --device-owner network:dhcp -f value -c ID | xargs -I {} openstack port delete {}

Then, check the newly created port that should be inside the updated IP allocation pool with:

openstack port list --network <PRIVATE_NETWORK_UID> --device-owner network:dhcp
+--------------------------------------+------+-------------------+---------------------------------------------------------------------------+--------+
| ID                                   | Name | MAC Address       | Fixed IP Addresses                                                        | Status |
+--------------------------------------+------+-------------------+---------------------------------------------------------------------------+--------+
| 4d991711-4322-4934-a06e-2e2b9cff2a56 |      | fa:16:3e:cc:48:27 | ip_address='10.0.0.129', subnet_id='578deb7c-211f-4f0f-8e45-c8ed07b3e16b' | ACTIVE |
| 738e3c59-439d-4eed-bded-c7c301717a8c |      | fa:16:3e:62:32:5e | ip_address='10.0.0.128', subnet_id='578deb7c-211f-4f0f-8e45-c8ed07b3e16b' | ACTIVE |
+--------------------------------------+------+-------------------+---------------------------------------------------------------------------+--------+

 

Go further

For more information and tutorials, please see our other Public Cloud support guides or explore the guides for other OVHcloud products and services.

If you need training or technical assistance to implement our solutions, contact your sales representative or click on this link to get a quote and ask our Professional Services experts for a custom analysis of your project.

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