Linux – Converting Ubuntu 18.04 from interfaces to netplan for network configuration

linuxlinux-networkingnetplanUbuntuubuntu-18.04

An old employee at my place of work set up a Ubuntu 18.04 server instance to use the /etc/network/interfaces file for network configuration. This has been causing some issues and I would like to revert back to using the /etc/netplan/*.yaml file approach instead.

I did some research on converting from netplan to interfaces, and it looks like some packages were installed to switch over. However I would like to move back to the original configuration using the .yaml file for my network configuration.

How can I successfully convert back to using netplan? I know how to set the .yaml file up correctly, however it is switching the server back to use this configuration instead of the the /etc/network/interfaces file that I am having trouble with.

Thank you very much. Please let me know if you need any additional information and I will be happy to assist.

Best Regards

Best Answer

So it seems that I was able to comment out the contents of my /etc/network/interfaces file, configure my .yaml file with the correct network information, and then perform the following command:

sudo netplan apply

After doing so it pulled the network config from my .yaml file and everything appears to be functioning correctly. Is there anything else that I should be worried about?

I performed a reboot to be safe and it retained the IP that I set up in my .yaml file.

Related Solutions

NetPlan Not Applying Static IP for VLAN – Fix

Since this question may get other views, I thought I'd quickly answer.

The syntax of the YAML file must be correct in order for the items to be configured. Check the file with "netplan --debug generate" to see issues, else the generate and apply will configure whatever is valid, and ignore the rest (to be resilient - something is better than nothing).

In this case, the OP's indentation of the vlan section is incorrect. It must line up with the "ethernets" heading, indented from the "network" heading. Should be:

network:
  version: 2
  renderer: networkd
  ethernets:
    eth0: #the physical interface
    match:
      macaddress: "xx:xx:xx"
    dhcp4: no

    #this is the same IP I would get with dhcp
    addresses: [ "10.1.0.1/24" ]
    gateway4: 10.1.0.254
  vlans:
    lab1:
      id: 10
      link: eth0
      dhcp4: no
      addresses: [ "10.1.10.100/24" ]

Ubuntu 18.04 – Setup Network on Secondary Interface

The problem is almost certainly related to you attempting to set a default gateway on the secondary interface.

It is important to always remember that the default gateway isn't really a property of an individual interface instead it is a route added to the route table. The 'default gateway' is the route that is used when no other more specific routes do not match a given destination. If you attempt to add two default gateways with the same metric, only one or the other will work.

Best Answer

Related Solutions

NetPlan Not Applying Static IP for VLAN – Fix

Ubuntu 18.04 – Setup Network on Secondary Interface

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