Recently I was been asked to increase the MTU on the deployed openstack cluster at one of our customers. Since the beginning of my touch on openstack networking has been the hardest part to get my head around. In the first place because openstack does some nifty things on the networking path. But also cause for the use case at the customer a lot of customization has been done to get it implemented in their infrastructure.

Hence the shiver when the MTU question was been made..

Nevertheless together with a colleague who likes a challenge and has a profound knowledge …

last couple of days I have been fighting with the way an static ip is configured on an openstack virtual centos 6 instance. In our specific use case we ditched as many network openstack services as possible as I previously described.

We want to have the instances running in our current network spaces of the R&D department. In this department until some days ago we didn't had any DHCP server running. But a few weeks back we added an extra remote network space into our platform where we configured a remote compute-node.

This is where the issues started popping …

Some of you may already have notices others just stumbled on this post through a search engine, I have set up an openstack private cloud at one of our projects:

• vlan flat-neutron provider network
• layer2

We have noticed that the benefits of having a private cloud is spreading through the different teams within the organization and therefore the interest into this flexibility is growing. Since this wasn't the original use case we are encountering some design issues right now.

For the original instances the default overcommit ratios are fine. But the request for new machines with other goals are like …