How to configure jumbo frames in SUSE OpenStack Cloud

This document (7017289) is provided subject to the disclaimer at the end of this document.

Environment

SUSE OpenStack Cloud 4
SUSE OpenStack Cloud 5

Situation

The default network proposal uses a MTU value of 1500.
Depending on the deployment needs the MTU setting has to be re-configured to improve the peformance.

Resolution

Configure MTU for storage and admin networks in crowbar proposal.

Steps required:
1. Edit the network proposal with 'crowbar network proposal edit default' on the admin node. Verify that the "mtu" option doesn't exist in corresponding section and then add it. Use a value of 9000 for jumbo frames:

        "storage": {
         ...
         "mtu": 9000,
                      ...

Note that only the storage and admin network can use a different MTU. For any other network this value will be ignored.

2. Edit the data bag of corresponding network. On the admin node execute 'knife data bag edit crowbar storage_network' and edit the network section as in step 1.

3. Edit the corresponding node role with 'knife role edit crowbar-node_name'. Again add the 'mtu' option to the corresponding network section.

Cause

The default template lists an optional MTU option in the storage and admin network sections (/opt/dell/chef/data_bags/crowbar/bc-template-network.json):

        "storage": {
          "conduit": "intf1",
          "vlan": 200,
          "use_vlan": true,
          "add_bridge": false,
          "mtu": 1500,
          "subnet": "192.168.125.0",
          "netmask": "255.255.255.0",
          "broadcast": "192.168.125.255",
          "ranges": {
            "host": { "start": "192.168.125.10", "end": "192.168.125.239" }

As this is an optional parameter it is not shown anywhere in the proposal and must be manually added and distributed on the nodes.

Disclaimer

This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.