There are a couple of possible ways to manage users and groups in a LXC container:
1. Use the standard system utilities: You can manage users and groups in a LXC container the same way you would on any normal Linux system. For example, you can use the following command to open a shell in the container:
```
lxc-attach -n mycontainer
```
Once you are in the container you can manage users with commands like useradd, usermod, userdel, or manage groups with groupadd, groupmod, groupdel etc.
1. Use LXD to create a user profile for the container: LXD allows you to create and manage profiles, which can include user and group settings. You can then apply these profiles to your containers. To create a profile use the lxc profile command, for example:
```
lxc profile create myuser
```
And then edit the profile to add your user and group settings:
```
lxc profile edit myuser
```
This will open the profile in your text editor, allowing you to make changes.
Once your profile is ready, you can assign it to a container with the following command:
\`\`\`shell
lxc profile assign mycontainer myuser
\`\`\`
Remember that access and rights for users and groups inside the LXC containers are isolated from the rest of the system, meaning, a user/ group created inside the LXC container don’t exist on the host or other containers unless explicitly created.
