Change MTU Size For Existing Network Using OpenStack CLI/API

Problem

The need exists to increase MTU size for an existing Network in OpenStack such that the new instances created on that network will have Jumbo frames enabled on the network interface.  

Environment

• Platform9 Managed OpenStack - All Versions 
• OpenStack CLI - v4.0.0 and Higher               

Procedure

Network MTU can be increased via OpenStack CLI( latest version - 4.0.0 ) or via API call. 

1. To increase the MTU size via CLI OpenStack CLI use the following command
   

   # openstack network set --mtu 8950 <network id >

   Note: MTU option in the command is only available in the OpenStack CLI version 4.0.0 and higher.
2. To increase the MTU using the OpenStack API, use the following  command.

   # curl -s -H "X-Auth-Token: $TOKEN" -H "Content-Type: application/json"  -H "Accept: application/json" -X PUT -d '{"network": {"mtu": 8950}}' http://<Management Plane FQDN>:9696/v2.0/networks/<networkid> |jq

Additional Information

• To check the version of Openstack CLI use the following command.

  # pip show python-openstackclient

• To upgrade the OpenStack CLI version to the latest use the following command. 

  # pip install --upgrade python-openstackclient

• To obtain a token for API calls use the following command.

  # TOKEN=$(openstack token issue -c id -f value)