System.cmd throwing error (ErlangError) Erlang error: :eagain

Questions / Help
1

Hello All,

What does the error below suggest?

** (ErlangError) Erlang error: :eagain
:erlang.open_port({:spawn_executable, '/path/encode'}, [:use_stdio, :exit_status, :binary, :hide, {:args, []}])
    (elixir 1.10.4) lib/system.ex:802: System.cmd/3

I have been using System.cmd for a long time in my code, but suddenly, it has began throwing the error above.

Any suggestions would be most appreciated.

Thank you.

2

Resource temporarily unavailable

2 Likes
3

Thanks, @denvaar.

4

I am still trying to figure out what system resource has been exhausted because all the various system parameters so far look okay.

5

What’s the script that you’re running do? By the way, if you look at the help docs for System.cmd/3 (Do this with h System.cmd in IEx console), it’s a little more specific about the error:

:eagain - there are no more available operating system processe

6

I am trying to run an external script, written in Ruby, to encrypt a file.

The second command you suggested did not have any effect.
I may probably have to restart the machine and see whether that will resolve the issue

7

After rebooting the server, it worked fine.

I am not too sure which system resources the Erlang VM was referring to.
Quite weird.

Thank you very much @denvaar for the assistance.

Regards,

Jerry

8

Most likely it was fork that returned eagain. From its manual:

       EAGAIN A system-imposed limit on the number of threads was
              encountered.  There are a number of limits that may
              trigger this error:

              *  the RLIMIT_NPROC soft resource limit (set via
                 setrlimit(2)), which limits the number of processes and
                 threads for a real user ID, was reached;

              *  the kernel's system-wide limit on the number of
                 processes and threads, /proc/sys/kernel/threads-max,
                 was reached (see proc(5));

              *  the maximum number of PIDs, /proc/sys/kernel/pid_max,
                 was reached (see proc(5)); or

              *  the PID limit (pids.max) imposed by the cgroup "process
                 number" (PIDs) controller was reached.