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OVN and Openstack - Configuration and interfaces assignment

Hi, I'm trying to understand how ovn in openstack works and I'm focused on a particular kind of configuration: One controller node and N compute nodes with distributed virtual router. Please, excuse me if I'm going to ask stupid questions, but I have doubts about this even after tried to search in documentation. Basically I need to know if some assumptions are true: 1) If I use distributed virtual routing and I have provider networks (flat or vlans, not important), I have to connect all compute nodes to the overlay network AND to the provider network. Is this true? Furthermore, I have to connect compute nodes to the management network, so in total I need at least 3 network interface card for each compute node. Please give me a feedback on this.

2) I studied OVN and it seems to me that the connection between the ovn-controller (on compute nodes) and southbound database use the management network and not the overlay network. It makes sense in my opinion because in this way there is a real separation between control plane and data plane. So, can I avoid to connect the openstack controller node to the overlay network? if this is true, it seems that I need only 1 interface on the openstack controller node, just for management. Is this correct? (yes, I know I can connect external network, api network and so on... but minimal functionality can be obtained only with management network in a basic installation)

3) In a configuration where DVR is active, what is the purpose of the gateway node? (please use this reference architecture: https://docs.openstack.org/networking-ovn/latest/admin/refarch/refarch.html ). It seems to me that I can completely remove the gateway node.

Thank you, Marco

OVN and Openstack - Configuration and interfaces assignment

Hi, I'm trying to understand how ovn in openstack works and I'm focused on a particular kind of configuration: One controller node and N compute nodes with distributed virtual router. Please, excuse me if I'm going to ask stupid questions, but I have doubts about this even after tried to search in documentation. Basically I need to know if some assumptions are true: true:

1) If I use distributed virtual routing and I have provider networks (flat or vlans, not important), I have to connect all compute nodes to the overlay network AND to the provider network. Is this true? Furthermore, I have to connect compute nodes to the management network, so in total I need at least 3 network interface card for each compute node. Please give me a feedback on this.

2) I studied OVN and it seems to me that the connection between the ovn-controller (on compute nodes) and southbound database use the management network and not the overlay network. It makes sense in my opinion because in this way there is a real separation between control plane and data plane. So, can I avoid to connect the openstack controller node to the overlay network? if this is true, it seems that I need only 1 interface on the openstack controller node, just for management. Is this correct? (yes, I know I can connect external network, api network and so on... but minimal functionality can be obtained only with management network in a basic installation)

3) In a configuration where DVR is active, what is the purpose of the gateway node? (please use this reference architecture: https://docs.openstack.org/networking-ovn/latest/admin/refarch/refarch.html ). It seems to me that I can completely remove the gateway node.

Thank you, Marco

OVN and Openstack - Configuration and interfaces assignment

Hi, I'm trying to understand how ovn in openstack works and I'm focused on a particular kind of configuration: One controller node and N compute nodes with distributed virtual router. Please, excuse me if I'm going to ask stupid questions, but I have doubts about this even after tried to search in documentation. Basically I need to know if some assumptions are true:

1) If I use distributed virtual routing and I have provider networks (flat or vlans, not important), I have to connect all compute nodes to the overlay network AND to the provider network. Is this true? Furthermore, I have to connect compute nodes to the management network, so in total I need at least 3 network interface card for each compute node. Please give me a feedback on this.

2) I studied OVN and it seems to me that the connection between the ovn-controller (on compute nodes) and southbound database use the management network and not the overlay network. It makes sense in my opinion because in this way there is a real separation between control plane and data plane. So, can I avoid to connect the openstack controller node to the overlay network? if this is true, it seems that I need only 1 interface on the openstack controller node, just for management. Is this correct? (yes, I know I can connect external network, api network and so on... but minimal functionality can be obtained only with management network in a basic installation)

3) In a configuration where DVR is active, what is the purpose of the gateway node? (please use this reference architecture: https://docs.openstack.org/networking-ovn/latest/admin/refarch/refarch.html ). It seems to me that I can completely remove the gateway node.

Thank you, you,

Marco