How to update LXD container Ubuntu image from 16.04 to 18.04

To update the Ubuntu image used by an LXD container from version 16.04 to version 18.04, you can use the lxc command-line utility. Here are the steps to update the image:

1. First, stop the container that you want to update:

lxc stop CONTAINER_NAME

Replace CONTAINER_NAME with the name of the container that you want to update.

2. Then, update the container's image to the latest available version of Ubuntu 18.04 LTS:

lxc image update ubuntu-18.04

This command will download the latest available version of the Ubuntu 18.04 LTS image and update the container to use this image.

3. Once the image has been updated, you can start the container again:

lxc start CONTAINER_NAME

4. You can verify that the container is now using the updated image by logging in to the container and running the lsb_release -a command, which will display the current Ubuntu version.

For more information about updating an LXD container's image, you can consult the LXD documentation or visit the LXD website.

Note: It is important to backup your data before upgrading the container's image, as the process can be risky and may result in data loss.