Jie Yu created MESOS-8978:
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Summary: Command executor calling setsid breaks the tty support.
Key: MESOS-8978
URL: https://issues.apache.org/jira/browse/MESOS-8978
Project: Mesos
Issue Type: Bug
Affects Versions: 1.6.0, 1.5.1, 1.4.1
Reporter: Jie Yu
I was playing with
[msh|https://github.com/mesos/mesos-go/blob/master/api/v1/cmd/msh/msh.go] (one
example from [mesos-go|https://github.com/mesos/mesos-go]), which allows you to
launch a interactive shell in the Mesos cluster. It works by launch a container
with tty enabled, and then [attach to the container
input|https://github.com/apache/mesos/blob/master/include/mesos/v1/agent/agent.proto#L191-L201]
using the agent operator API.
However, I got the following error when doing the following:
{noformat}
Jies-MacBook-Pro:mesos-go jie$ ./msh -master 127.0.0.1:5050 -tty -interactive
-- /bin/sh -i
...
2018/06/05 11:51:35 original window size is 156 x 45
sh: cannot set terminal process group (-1): Inappropriate ioctl for device
sh: no job control in this shell
{noformat}
If I use `-pod`, the problem goes away. This only happens if command executor
is used.
A few research suggested that this issue is related to `setsid` (see this
[thread|https://github.com/Yelp/dumb-init/issues/51#issuecomment-227792216]).
Looks like we did an extra
`[setsid|https://github.com/apache/mesos/blob/1.6.x/src/launcher/executor.cpp#L512]`
in the command executor.
The setsid() system call to create a new process group detaches the spawned
process from a controlling tty. Therefore programs like bash complain, that
they can't use job control. Re-attaching the controlling tty won't work,
because the tty is still in use as a controlling tty for the command executor
process.
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