mjhjmtu

I'm trying to run an unprivileged Vagrant box using LXD, but I can't get the ID mappings to work.

First try:

$ sudo rm /etc/subu,gid
$ echo "root:1000000:65536" | sudo tee /etc/subu,gid
root:1000000:65536
$ sudo systemctl restart lxd
$ vagrant destroy -f
$ vagrant up
…
==> default: Machine has not been created yet, starting...
==> default: The host machine does not support LXD synced folders.
==> default: 
==> default: To use this feature, you must first configure ID mappings for the
==> default: current user in /etc/subuid and /etc/subgid. For more information,
==> default: refer to `vagrant lxd shadow --help`.
==> default: 
==> default: Importing LXC image...
==> default: Waiting for machine to boot. This may take a few minutes...
/home/username/.vagrant.d/gems/2.6.1/gems/vagrant-lxd-0.3.4/lib/vagrant-lxd/driver.rb:429:in `block (2 levels) in ipv4_address': undefined method `' for nil:NilClass (NoMethodError)
…

OK, let's follow the advice:

$ vagrant lxd shadow --help
In order to use shared folders, you must first add the effective user
and group ID (which are currently 1000 and 1000) to the host machine's
subuid(5) and subgid(5) files:

 $ echo root:1000:1 | sudo tee -a /etc/subuid
 $ echo root:1000:1 | sudo tee -a /etc/subgid

For more information about these commands, and user/group ID mapping in
general, refer to this article:

 https://insights.ubuntu.com/2017/06/15/custom-user-mappings-in-lxd-containers/
$ sudo rm /etc/subu,gid
$ echo root:1000:1 | sudo tee -a /etc/subuid
root:1000:1
$ echo root:1000:1 | sudo tee -a /etc/subgid
root:1000:1
$ sudo systemctl restart lxd
$ vagrant destroy -f
$ vagrant up
…
==> default: Waiting for machine to boot. This may take a few minutes...
/home/username/.vagrant.d/gems/2.6.1/gems/vagrant-lxd-0.3.4/lib/vagrant-lxd/driver.rb:429:in `block (2 levels) in ipv4_address'Root: undefined method `' for nil:NilClass (NoMethodError)

sharee

I tried the same as the previous but a count of 1000 instead of just 1, and got the following result:

The underlying error message was: Create container: Create LXC container: LXD doesn't have a uid/gid allocation. In this mode, only privileged containers are supported

Now what can I try? What nothing seems to explain is which username/UID should be in the first column - the user running the Vagrant command? The UID of the user inside the container? Always "root", even when running unprivileged containers? Ditto for the second and third columns. Some sources seem to think that the second number should start at 100,000 or 1,000,000. Some sources put 1 for the third number and others put 65,536. Even man subuid doesn't really explain how and why it should be used for people unfamiliar with "subordinate user IDs."