Use oc rsh to run for loop in container (openshift remote ssh)?

Question

Based on:

https://unix.stackexchange.com/questions/1459/remote-for-loop-over-ssh

I am trying to run a for loop command through oc rsh but it fails with below error:

$ oc rsh my-app-10-lprki 'for i in /var/lib/*; do echo $i; done'
exec failed: container_linux.go:345: starting container process caused "exec: \"for i in /var/lib/*; do echo $i; done\": stat for i in /var/lib/*; do echo $i; done: no such file or directory"
command terminated with exit code 1

I have also tried without quotes, with double quotes but that also fails.

This works fine (without quotes):

$ oc rsh my-app-10-lprki ls -la /var/lib/
total 24
drwxr-xr-x.  1 root       root   104 Nov 22 22:21 .
drwxr-xr-x.  1 root       root    17 Sep 28  2017 ..
drwxr-xr-x.  2 root       root    44 Sep 28  2017 alternatives

Any suggestions on how to run a for loop remotely through oc rsh like (that currently fails):

oc rsh my-app-10-lprki 'for i in /var/lib/*; do echo $i; done'

?

Based on below suggestions I have also tried:

$ oc rsh my-app-10-lprki -- /bin/sh  -c  'for i in `ls  /var/lib`; do echo $i; done'
exec failed: container_linux.go:345: starting container process caused "exec: \"--\": executable file not found in $PATH"
command terminated with exit code 1

and:

$ oc rsh my-app-10-lprki -- /bin/bash  -c  'for i in `ls  /var/lib`; do echo $i; done'
exec failed: container_linux.go:345: starting container process caused "exec: \"--\": executable file not found in $PATH"
command terminated with exit code 1

and:

$ oc rsh my-app-10-lprki -- /usr/bin/bash  -c  'for i in `ls  /var/lib`; do echo $i; done'
exec failed: container_linux.go:345: starting container process caused "exec: \"--\": executable file not found in $PATH"
command terminated with exit code 1

Where:

$ oc rsh my-app-10-lprki which bash
/usr/bin/bash

Hi, can you try with `oc rsh my-app-10-lprki -- bash -c "for i in /var/lib/*; do echo $i; done"` — Suresh Vishnoi, Nov 27 '19 at 10:22
That gives: exec failed: container_linux.go:345: starting container process caused "exec: \"--\": executable file not found in $PATH" — u123, Nov 27 '19 at 10:32
use `/bin/bash or /bin/sh` instead of `bash` depending on the shell in your container. — Suresh Vishnoi, Nov 27 '19 at 11:36
Can you describe your pod `oc describe pod $POD_NAME` assuming that its running — Suresh Vishnoi, Nov 27 '19 at 18:14

score 4 · Answer 1 · answered Nov 27 '19 at 18:28

4

This did the trick:

oc exec my-app-10-lprki -- bash -c 'for i in /var/lib/; do echo $i; done'

answered Nov 27 '19 at 18:28

u123

15,603
58
186
303

glad, it worked. quite strange that it does not work with `rsh`. could be a bug. – Suresh Vishnoi Nov 27 '19 at 18:51

score 1 · Answer 2 · answered Nov 27 '19 at 11:44

1

Assuming /bin/sh the shell in your container

oc rsh my-app-10-lprki -- /bin/sh  -c  'for i in `ls  /var/lib`; do echo $i; done'

will list out the files in /var/lib directory

here is the example of mysql pod

[suresh.vishnoi@blah ~]$ oc exec  mysql-4-lnlpx --  /bin/sh  -c  'for i in `ls  /var/lib`; do echo $i; done'
alternatives
dbus
games
initramfs
machines
misc
mysql
rhsm
rpm
rpm-state
selinux
systemd
yum

answered Nov 27 '19 at 11:44

Suresh Vishnoi

17,341
8
47
55

Can you rsh into the pod and run `echo "$SHELL"` or `which sh` or `which bash` ? – Suresh Vishnoi Nov 27 '19 at 17:56
Yes I did that see my updated post. But looks like it works when using exec instead and with slightly different parameters – u123 Nov 27 '19 at 18:39

Use oc rsh to run for loop in container (openshift remote ssh)?

2 Answers2