I have an opensuse/42.3 container I exported to a tarball and imported on another system (I will call it “target system”), which is bionic with LXD 3.0.1.
tmux and screen work fine in the system where I exported the image from but there is a strange issue in the target system. The issue only occurs when security.privileged is true. When it’s false everything works as expected.
Issue description
Here is the issue: When I start tmux, it exits the process immediately without error messages. screen demonstrates the same behavior but it notifies that the process exited. No useful information is given to stderr. I ran tmux with strace and found the internal communication between the server and client. This message was transferred through the socket:
create session failed: : Operation not permitted
This is right after tmux server tries to spawn /bin/bash --
Workaround
I am not sure if it is a workaround or expected behavior. I added my user to tty group with:
usermod -aGtty <my-user>
and re-logged in. This fixed the issue. Now I can use those tools with security.privileged true.
Why?
I don’t know why it happens. tty has the same id in the host and container.