Attila Sasvari created OOZIE-2638:
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Summary: Ssh action fails if .bashrc contain a script
Key: OOZIE-2638
URL: https://issues.apache.org/jira/browse/OOZIE-2638
Project: Oozie
Issue Type: Improvement
Reporter: Attila Sasvari
Priority: Minor
Right now SshActionExecutor runs the SCP command as part of executing the SSH
action.
As a consequence, if the target SSH user has some command/script in their rc
file (e.g. .bashrc) that outputs to the standard output in non-interactive
sessions, the action will fail with
UNKOWN_ERROR: Not able to perform operation [scp -o PasswordAuthentication=no
-o KbdInteractiveDevices=no -o StrictHostKeyChecking=no -o ConnectTimeout=20 ...
It turns out, it is the way how openssh SCP works. So if something else is
written to stdout (for example an ls in .bashrc), it will fail and return 1.
See
https://github.com/apache/oozie/blob/master/core/src/main/java/org/apache/oozie/action/ssh/SshActionExecutor.java#L695
To overcome this limitation, we should investigate alternatives that do not
have this limitation.
JSch (https://mvnrepository.com/artifact/com.jcraft/jsch) can be such an
alternative.
References:
- Is this shell interactive?
https://www.gnu.org/software/bash/manual/html_node/Is-this-Shell-Interactive_003f.html
- https://github.com/openssh/libopenssh/blob/master/ssh/scp.c
-
http://stackoverflow.com/questions/12440287/scp-doesnt-work-when-echo-in-bashrc/12442753#12442753
- https://bugzilla.redhat.com/show_bug.cgi?id=20527
-
http://unix.stackexchange.com/questions/120080/what-are-ssh-tty-and-ssh-connection
* As a workaround, one could detect in their .bashrc (or the corresponding rc
file of the shell they prefer) if they are in an SCP / non-interactive session,
do not echo anything on noninteractive shell.
For example, if I put the following into my .bashrc
[[ $- == i ]] || return
SCP will work. But there can be situations where commands must be run. We could
silent them (by redirecting stderr/stdout), but I believe it is not so
convenient for a lot of users.
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