AWS Ubuntu Instance does not configure the second NIC
AWS Ubuntu EC2 Instance does not configure the second network interface
An AWS Ubuntu image will only have one network interface online although two were specified in the blueprint..
Overview
For specifics on why this occurs in AWS you can visit this AWS Knowledge Center Article for further details and resolutions across versions.
An example blueprint of an Ubuntu 18.04 image containing two Nics:
vm.nics.external-network
vm.nics.internal-network
#
# Demo Blueprint that configures a Network and launches an Instance
# Version
---
variables:
admin_username:
description: The username for the administrative user.
type: string
default: adminuser
admin_public_key:
description: The OpenSSH Public Key to use for administrative access.
type: string
location:
region:
demo-region:
country: USA
area: northwest
folder:
multi-cloud:
region: demo-region
networking:
network:
demo-network:
range:
- 10.0.0.0/16
- 10.100.0.0/16
public: true
subnet:
demo-internal-subnet:
range: 10.0.0.0/24
network: demo-network
firewall: demo-internal-firewall
demo-external-subnet:
range: 10.100.0.0/24
network: demo-network
firewall: demo-external-firewall
public: true
protocol:
ssh:
ports:
- port: 22
proto: tcp
http:
ports:
- port: 443
proto: tcp
https:
ports:
- port: 80
proto: tcp
firewall:
demo-internal-firewall:
rules:
- protocols: ssh
to: self
demo-external-firewall:
rules:
- protocols: ssh
to: self
- protocols: http
to: self
- protocols: https
to: self
compute:
image:
bionic:
publisher: Canonical
product: UbuntuServer
sku: 18.04-LTS
venue:
aws:
# if provisioning fails due to image not found, go to:
# https://cloud-images.ubuntu.com/locator/ec2/
# and search for "bionic amd64 ebs us-west-2"
image_id: ami-04bb0cc469b2b81cc
vm:
demo-instance:
cores: 1
memory: 2 gb
count: 1
image: bionic
configure:
admin:
username: (( admin_username ))
public_key: (( admin_public_key ))
disks:
data:
size: 128 GB
tags:
demo: multi-cloud
nics:
external-network: #Provides first discovered NIC external IP access to NAT server
ips:
- private:
type: dynamic
public:
type: static
firewall: demo-external-firewall
subnet: demo-external-subnet
internal-network:
ips:
- private:
type: dynamic
firewall: demo-internal-firewall
subnet: demo-internal-subnet
tags:
demo: multi-cloudWhen inspecting the VMs network via an SSH session we can see there is only one network interface online. ifconfig -a does not return an IP for the second Nic.
ifconfig -a
ens5: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 9001
inet 10.100.0.213 netmask 255.255.255.0 broadcast 10.100.0.255
inet6 fe80::cdd:2aff:fe16:231d prefixlen 64 scopeid 0x20<link>
ether 0e:dd:2a:16:23:1d txqueuelen 1000 (Ethernet)
RX packets 2052 bytes 952648 (952.6 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 1843 bytes 224428 (224.4 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ens6: flags=4098<BROADCAST,MULTICAST> mtu 1500
ether 0e:a6:a9:e6:e2:47 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 245 bytes 21283 (21.2 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 245 bytes 21283 (21.2 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0Running the ip address command shows the network interface named ens6 is state DOWN
ip address
1: lo: <LOOPBACK,UP,LOWER_UP> 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: ens5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9001 qdisc mq state UP group default qlen 1000
link/ether 0e:dd:2a:16:23:1d brd ff:ff:ff:ff:ff:ff
inet 10.100.0.213/24 brd 10.100.0.255 scope global dynamic ens5
valid_lft 2412sec preferred_lft 2412sec
inet6 fe80::cdd:2aff:fe16:231d/64 scope link
valid_lft forever preferred_lft forever
3: ens6: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
link/ether 0e:a6:a9:e6:e2:47 brd ff:ff:ff:ff:ff:ffResolution
Solution 1
Using a different AWS Linux image such as the Amazon Linux 2 AMI does not present this issue
Solution 2
Following the AWS knowledge center article for Ubuntu 18.0.4
Obtain the IP address for the affected secondary Network Interface in the amazon console under EC2 -> Network Interfaces:
SSH into your deployed Ubuntu instance with your SSH key
ssh <admin_username>@<ip>
Create a configuration file for the interface
sudo vi /etc/netplan/51-eth1.yamlyou can issue a :set paste in vi before copying the yaml contents to ensure proper formatting.
Add the following lines to the 51-eth1.yaml file with the obtained secondary IP,default gateway and subnet outlined in the blueprint.
If the adapter name is not eth1 in your instance as in this example, ensure the name is correct in /etc/netplan/51-eth1.yaml
ens6
10.0.0.47/24
10.0.0.1
network:
version: 2
renderer: networkd
ethernets:
ens6:
addresses:
- 10.0.0.47/24
dhcp4: no
routes:
- to: 0.0.0.0/0
via: 10.0.0.1 # Default gateway
table: 1000
- to: 10.0.0.27
via: 0.0.0.0
scope: link
table: 1000
routing-policy:
- from: 10.0.0.27
table: 1000Apply the network configuration:
sudo netplan --debug apply
Verify network now shows two active Nics in your instance:
ifconfig
ens5: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 9001
inet 10.100.0.213 netmask 255.255.255.0 broadcast 10.100.0.255
inet6 fe80::cdd:2aff:fe16:231d prefixlen 64 scopeid 0x20<link>
ether 0e:dd:2a:16:23:1d txqueuelen 1000 (Ethernet)
RX packets 6503 bytes 1343810 (1.3 MB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 2995 bytes 468603 (468.6 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ens6: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 10.0.0.47 netmask 255.255.255.0 broadcast 10.0.0.255
inet6 fe80::ca6:a9ff:fee6:e247 prefixlen 64 scopeid 0x20<link>
ether 0e:a6:a9:e6:e2:47 txqueuelen 1000 (Ethernet)
RX packets 1 bytes 42 (42.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 9 bytes 698 (698.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 301 bytes 26379 (26.3 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 301 bytes 26379 (26.3 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> 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: ens5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9001 qdisc mq state UP group default qlen 1000
link/ether 0e:dd:2a:16:23:1d brd ff:ff:ff:ff:ff:ff
inet 10.100.0.213/24 brd 10.100.0.255 scope global dynamic ens5
valid_lft 2918sec preferred_lft 2918sec
inet6 fe80::cdd:2aff:fe16:231d/64 scope link
valid_lft forever preferred_lft forever
3: ens6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 0e:a6:a9:e6:e2:47 brd ff:ff:ff:ff:ff:ff
inet 10.0.0.47/24 brd 10.0.0.255 scope global ens6
valid_lft forever preferred_lft forever
inet6 fe80::ca6:a9ff:fee6:e247/64 scope link
valid_lft forever preferred_lft foreverLast updated
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