lxc-attach not a tty, so tmux/byobu is broken

[linas]

If you lxc-attach -n some-container, then tmux and byobu don't work. The reason for this becomes clear: tmux -v reports:

server started, pid 760
socket path /tmp/tmux-1002/default
new client 7
got 14 from client 7
got 14 from client 7
got 14 from client 7
got 14 from client 7
got 14 from client 7
got 14 from client 7
got 14 from client 7
got 14 from client 7
got 14 from client 7
got 14 from client 7
got 14 from client 7
got 14 from client 7
got 14 from client 7
got 14 from client 7
got 14 from client 7
got 14 from client 7
got 14 from client 7
got 14 from client 7
got 6 from client 7
fatal: tty_init: ttyname failed

This can be confirmed with the tty command which reports: not a tty

There is a simple work-around: say script /dev/null and then tty reports /dev/pts/1 and tmux works.

[linas]

Sorry: I should add: this is for the apt-get lxc on ubuntu 14.04 runing ubunutu 14.04 amd64 so it is the completely stock LTS version, and NOT the current github version, which maybe is fixed. Also: FYI: the docker folks have more or less exactly this same bug; they have a bug open in their github to cover this. They seem to be unable to wrap their minds around why anyone would want to do this, despite maybe a dozen "me too" posts.

[ericsnowcurrently]

FTR: docker/docker#8755

[brauner]

This is a known bug in glibc and @hallyn has send a fix to glibc (https://sourceware.org/ml/libc-alpha/2016-08/msg00307.html). It just needs to be applied.

[linas]

Wow! Awesome! Thank you @hallyn ! (I'm saying "awesome" because this is an interesting patch, not what I might have guessed.)

[linas]

I guess the normal protocol is to leave this open until glibc applies the patch, and then wait till it rolls out, test it, and then close this bug, which could take many months (!?). Unfortunately, the patch just missed the glibc 2.24 release by a week. I wonder what the chances are that debian/ubuntu might pick up the patch in their stable branches; I have no clue how that decision would get made.

[kfix]

the glibc fix seems to have been upstreamed recently: http://patchwork.ozlabs.org/patch/720749/
No idea when they will next cut a release that will be seen in Ubuntu.

[brauner]

This is the same issue that we've tracked in lxc/lxd#936 .

• A version of the required glibc patch has been upstreamed by @hallyn and me (lxc/lxd#936 (comment)).
• tmux should be fixed as of tmux/tmux@9b28200
• I've also sent patches to screen (https://git.savannah.gnu.org/cgit/screen.git/commit/?id=fbee2ab0bc0a3d9be9d6987dc5228f5bf46a07cb , https://git.savannah.gnu.org/cgit/screen.git/commit/?id=565b8901cad828d921038cd6235501c42d1c9a32 )

Once the distros pick-up on those you're good to go.