Problem with "echo ~ && sleep 0"

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1

Ansible baby steps failure. Can’t even ‘-m ping’ ;-(
I’m a first time Ansible user and starting from the beginning.
The first real task from the Introduction to Ansible is a connectivity test.
After setting everything up the ping is bailing out on me with this generic error message:

    "msg": "MODULE FAILURE: No start of json char found\nSee stdout/stderr for the exact error",

After debugging I traced i down to

ssh -C -o ControlMaster=auto -o ControlPersist=60s -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o ConnectTimeout=10 monitor.lan "/bin/sh -c \\\\\'echo ~ && sleep 0\\\\\'"

That gives me a

/home/koos: 'echo: command not found

Changing this command to (notice the ‘ls’ at the end of the line)

ssh -C -o ControlMaster=auto -o ControlPersist=60s -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o ConnectTimeout=10 monitor.lan ls   
bin
tmp

makes it work. So the

/bin/sh -c \\\\\'echo ~ && sleep 0

seems to be the culprit.

I’m on openSUSE Leap 15.6 (both machines) with proper home directory, default shell = bash and ssh pubkey authentication. Ansible=15.6

How do I get to overcome level 1?

2

It may be helpful to tell us what Ansible command string you were running. Assuming that you are using the ping module, it should look like this:

➜  tmp ansible -i inventory -m ping serverb       
[WARNING]: Platform linux on host serverb is using the discovered Python interpreter at /usr/bin/python3.9, but future installation of another Python interpreter
could change the meaning of that path. See https://docs.ansible.com/ansible-core/2.17/reference_appendices/interpreter_discovery.html for more information.
serverb | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python3.9"
    },
    "changed": false,
    "ping": "pong"
}

If you are invoking the command directly, something like this should be expected:

➜  tmp ansible -i inventory -m command -a 'uptime' serverb
[WARNING]: Platform linux on host serverb is using the discovered Python interpreter at /usr/bin/python3.9, but future installation of another Python interpreter
could change the meaning of that path. See https://docs.ansible.com/ansible-core/2.17/reference_appendices/interpreter_discovery.html for more information.
serverb | CHANGED | rc=0 >>
 18:15:02 up 10 days,  9:00,  1 user,  load average: 0.02, 0.02, 0.00

I ran the echo command to see if I can reproduce what you are getting, but I am not:

➜  tmp ansible -i inventory -m command -a 'echo hello' serverb 
[WARNING]: Platform linux on host serverb is using the discovered Python interpreter at /usr/bin/python3.9, but future installation of another Python interpreter
could change the meaning of that path. See https://docs.ansible.com/ansible-core/2.17/reference_appendices/interpreter_discovery.html for more information.
serverb | CHANGED | rc=0 >>
hello
1 Like
3

Apologies for the missing command. I’m running:

$ ansible -i inventory monitor.lan -m ping

The outcome is the same for root and non-root. I’ve tried it against other servers in my small home network. I’ve got the following node results:

  • Leap 15.4: OK
  • Leap 15.5: Fail
  • Leap 15.6: Fail
  • Leap 15.6: OK
  • Leap Micro 16.1: OK

I’m on a limb saying it’s a local openSUSE issue. I need to dig further. And I’ve got no idea yet where to look. But it’s good to know it could work :wink: Thanks for your help so far!

4

TL;DR
What OS are you logging into and as what user and what shell is that user configured with?

run grep $USER /etc/passwd

and the last item in the output should be your shell.

If the echo command is not found, you’re probably using a very limited shell on a system with very limited commands available or your PATH. Most shells will have echo as a builtin and most systems will also have /bin/echo as a command.

The user you are logging in with might have a high-security, limited shell for sftp access only or some other specific purpose shell. It could even be set to ‘/bin/true’ if the user is not intended for logins, but for running services only, like ‘www’.

1 Like
5

See earlier posts:

I’ve already increased the nodes tested against:

All users are regular users.
I did think of security settings. openSUSE is transitioning from AppArmor to SELinux, but if you install a default server/desktop, you’ll get the medium settings with lots of wiggle room. In fact the Leap 15.4 which works has AppArmor enabled. And the Leap Micro has SELinux enabled. So I’m doubting this is the root cause. But I’m not knowledgeable enough in that department to rule it out completely. I’m saying this as ‘echo’ is a shell built-in. I don’t know how that works security wise. May I should hack the command and try ‘/bin/echo’