Issue with lxc network attach (Error: not found)

Hi, seems that I don’t understand syntax of ‘lxc network attach’ or have strange issue with the command.
I created new network bridge with the command ‘lxc network create testbr0’
Bridge seems to be working correctly, displayed with ‘lxc network list’ , ‘lxc network show testbr0’
Now I want to attach my bridge testbr0 to only one selected container as container interface eth1 with the command:
‘lxc network attach testcontainer0 testbr0 eth1’
and this command returns error:
‘Error: not found’

What I am missing or doing wrong?

The subcommand lxc network attach is composed like this:

$ lxc network attach --help
  Attach new network interfaces to containers

  lxc network attach [<remote>:]<network> <container> [<device name>] [<interface name>] [flags]

You have put the wrong order (network name and container name). LXD did not find the network name testcontainer0 and gave the error not found.

In addition, there are bash completion rules available, which means that when you are composing the command, you can press the Tab key to get the appropriate completion.
For example, type

lxc network attach
and press Tab. You will get the list of network names, where you can choose from. Once you write the network name, hit Spacebar to add a space and press Tab again. You will get the list of your container and you can choose from.

Thanks a lot, that helped out!