Tag: networks

I have a public interface in a Ubuntu 18.04 VM hosted by a provider that uses Openstack. Now I want to add a second additional interface to the internal network. I am not sure how to do that.

Using the web interface of the hosting provider, I can add the internal network. After adding this, I can see the network interface but no IP address is assigned. Restart doesn't help here either.

For example ip a sample

1: lo:  mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens3:  mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether fa:16:3e:e7:0b:19 brd ff:ff:ff:ff:ff:ff
    inet (MY PUBLIC IP)/24 brd 185.110.173.255 scope global dynamic ens3
       valid_lft 84480sec preferred_lft 84480sec
    inet6 fe80::f816:3eff:fee7:b19/64 scope link 
       valid_lft forever preferred_lft forever
3: ens7:  mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether fa:16:3e:e3:4f:3f brd ff:ff:ff:ff:ff:ff

My public IP appears but the interface I added has no IP address.

Add the ens7 interface for /etc/netplan/50-cloud-init.yaml as follows

# This file is generated from information provided by
# the datasource.  Changes to it will not persist across an instance.
# To disable cloud-init's network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
network:
    version: 2
    ethernets:
        ens3:
            dhcp4: true
            match:
                macaddress: fa:16:3e:e7:0b:19
            set-name: ens3
        ens7:
            dhcp4: true
            match:
                macaddress: fa:16:3e:e3:4f:3f
            set-name: ens7

When I run netplan apply My SSH connection is disconnected immediately and I can no longer access the machine from the Internet.

When I use the console and run ip a However, I see exactly the results I expected. ens3 has the correct public IP and ens7 It has the correct private ip.

I also have a Ubuntu 16.04 VM. Using that image in the cloud I could do this by editing /etc/network/interfaces.d/50-cloud-init.cfg and adding

auto eth1
iface eth1 inet dhcp

But now I want to do something similar in Ubuntu 18.04 VM.

Why can't I access the machine using SSH from the Internet? IP configuration looks good.

What is the correct way to add a VM to a second internal private network when using an Ubuntu 18.04 cloud image in OpenStack?

By the way, I am using the Ubuntu cloud image bionic-server-cloudimg-amd64.img