Several ports of different networks can be connected to virtual machines. Port - the virtual network interface card of the instance for which security groups, connected network and DNS name are configured.

Connecting the network when creating a VM

By default, a virtual machine is connected to the external network (Ext-net) when it is created. This means that the virtual machine receives an IP address from a certain range (see below):

You can also create a new network on the fly when creating a virtual machine. In this case, the network parameters can be selected independently.

Adding a connection after creating a VM

To manage VM network connections in your MCS account, you should:

1. Go to the Virtual Machines page of the Cloud Computing section.
2. Open the instance card, go to the "Networks" tab. This page displays all network connections.
3. To add a network interface, you need to select "Add connection" and configure the parameters in accordance with the table:

   Name	Setting the port name
   Network to connect	Selecting the subnet to which the port will be connected
   DNS name	Available for private networks. Entering a DNS name that can be used to access the instance using private DNS
   Set IP address	Selecting an item allows you to enter a specific IP in the "IP Address" field. The address must belong to the selected subnet
   Firewall settings	Selecting security groups that establish traffic flow rules

4. After saving the parameters, the network interface will be added to the VM.

Security groups

When creating a virtual machine, the default security group is substituted (Firewall rule, traffic flow rule) " default ":

The Firewall " default " rule works as follows:

Inbound traffic : By default, only inbound traffic from instances in the default security group is allowed. In this case, traffic from the Internet is not allowed.

Outgoing traffic : By default, outgoing traffic is allowed within the internal network and to the Internet.

OpenStack CLI

To connect a network to a VM using the OpenStack client, you need to:

1. Get a list of networks:

 $ openstack network list --all

2. Get a list of security groups:

 $ openstack security group list

3. Get a list of ports on the network:

 $ openstack port list --long --network <network ID>

4. Create port:

 $ openstack port create --network <network ID> <port name>

As a result, a port with an IP address and a default security group will be created in the specified network.

It is also possible to create a port with the specified IP address, description, DNS name, security group and DHCP option :

 $ openstack port create --network <network ID> --fixed-ip subnet = <subnet ID>, ip-address = <IP address> --description <description> --dns-name <DNS name> --extra- dhcp-option name = time-servers, value = <IP address> --security-group <security group ID> <port name>

As a result of the command execution, the description and ID of the port will be obtained.

Next, you need to attach the port to the instance:

 $ openstack server add port <instance ID> <port ID>

You can view all ports of the virtual machine with the command:

 $ openstack port list --server <instance ID>