Details
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Bug
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Status: Open (View Workflow)
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Major
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Resolution: Unresolved
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None
Description
In Windows 10 version 1803, Microsoft started shipping OpenSSH in Windows, which was previously an optional beta feature. This causes problems for the sshagent step in Windows, which will produce a stacktrace resembling the following:
java.lang.RuntimeException: [ssh-agent] Could not find a suitable ssh-agent provider.
at com.cloudbees.jenkins.plugins.sshagent.SSHAgentStepExecution.initRemoteAgent(SSHAgentStepExecution.java:175)
at com.cloudbees.jenkins.plugins.sshagent.SSHAgentStepExecution.start(SSHAgentStepExecution.java:63)
at org.jenkinsci.plugins.workflow.cps.DSL.invokeStep(DSL.java:229)
at org.jenkinsci.plugins.workflow.cps.DSL.invokeMethod(DSL.java:153)
(snip!)
The problem is that Windows' OpenSSH binaries appear in the PATH ahead of those from Git, which means ssh-agent will be executed from C:\Windows\System32\OpenSSH.
There are two obvious workarounds for this – first, to uninstall Windows' OpenSSH (which can be done in the new Settings panel under "Manage optional features”). The other solution would be to tweak the system path so that Git's paths appear first, but this is likely to cause other problems in Windows. I also tried to set the GIT_SSH environment variable, but this did not seem to work.
It would be nice if the ssh-plugin either supported OpenSSH on Windows natively, or was smart enough to use the mingw binary provided on the system.
I had a quick look at the ssh-agent source code, and to support OpenSSH on Windows a fix would need to be made in the ExecRemoteAgent class. The OpenSSH agent service (which is disabled by default in Windows 10) doesn't produce the output that is expected by the ExecRemoteAgent class. Specifically, this class expects that ssh-agent will produce output resembling the following:
SSH_AUTH_SOCK=/tmp/whatever/agent.12283; export SSH_AUTH_SOCK;
SSH_AGENT_PID=12284; export SSH_AGENT_PID;
echo Agent pid 12284;
The class then attempts to extract the agent PID by parsing the text in the parseAgentEnv method. However, the ssh-agent implementation on Windows' OpenSSH client doesn't produce any output at all, which causes this exception to be thrown:
[ssh-agent] FATAL: Could not find a suitable ssh-agent provider
[ssh-agent] Diagnostic report
[ssh-agent] * Exec ssh-agent (binary ssh-agent on a remote machine)
[ssh-agent] java.lang.StringIndexOutOfBoundsException: String index out of range: -14
[ssh-agent] at java.lang.String.substring(String.java:1967)
[ssh-agent] at com.cloudbees.jenkins.plugins.sshagent.exec.ExecRemoteAgent.getAgentValue(ExecRemoteAgent.java:154)
[ssh-agent] at com.cloudbees.jenkins.plugins.sshagent.exec.ExecRemoteAgent.parseAgentEnv(ExecRemoteAgent.java:138)
(snip!)
I didn't dig any deeper into this, but my armchair opinion is that this class needs to find the PID in some other way than parsing stdout. I'm not sure exactly what way this would be. Microsoft is aware of this issue
see https://github.com/PowerShell/Win32-OpenSSH/issues/1145 but it is unclear if they will change the implementation just yet.
Attachments
Activity
muzammil_6701
I installed the windows git command line tools, that include ssh-agent and removed the Windows ssh-agent from my path,
The Powershell commands in my Dockerfile that does this:
RUN ${tmp_path} = ${env:PATH} `
; ${tmp_path} = (${tmp_path}.Split(';') | Where-Object { $_ -ne 'C:\Windows\System32\OpenSSH\' }) -join ';' `
; ${tmp_path} = 'C:\Program Files\Git\bin;C:\Program Files\Git\usr\bin;C:\Program Files\Git\mingw64\bin\;' + ${tmp_path} `
; [System.Environment]::SetEnvironmentVariable('PATH', ${tmp_path},[System.EnvironmentVariableTarget]::Machine) `
Zaitcev Peter
added a comment - I've changed agent PATH so it uses Git's SSH-Agent.
However, it still fails with the same error.
00:00:02.890 locadmin@WIN10-VM-TEST d:\Jenkins_AppCTS\workspace\ssh-agent-test-pipeline>where ssh-agent 00:00:02.890 C:\Git\usr\bin\ssh-agent.exe 00:00:04.465 [Pipeline] sshagent 00:00:04.470 FATAL: [ssh-agent] Could not find specified credentials 00:00:04.470 [ssh-agent] Looking for ssh-agent implementation... 00:00:04.521 Could not find ssh-agent: IOException: Cannot run program "ssh-agent": CreateProcess error=2, The system cannot find the file specified 00:00:04.521 Check if ssh-agent is installed and in PATH 00:00:04.521 [ssh-agent] FATAL: Could not find a suitable ssh-agent provider 00:00:04.521 [ssh-agent] Diagnostic report
Zaitcev Peter
added a comment - I've changed agent PATH so it uses Git's SSH-Agent.
However, it still fails with the same error.
00:00:02.890 locadmin@WIN10-VM-TEST d:\Jenkins_AppCTS\workspace\ssh-agent-test-pipeline>where ssh-agent
00:00:02.890 C:\Git\usr\bin\ssh-agent.exe
00:00:04.465 [Pipeline] sshagent
00:00:04.470 FATAL: [ssh-agent] Could not find specified credentials
00:00:04.470 [ssh-agent] Looking for ssh-agent implementation...
00:00:04.521 Could not find ssh-agent: IOException: Cannot run program "ssh-agent" : CreateProcess error=2, The system cannot find the file specified
00:00:04.521 Check if ssh-agent is installed and in PATH
00:00:04.521 [ssh-agent] FATAL: Could not find a suitable ssh-agent provider
00:00:04.521 [ssh-agent] Diagnostic report
aab
added a comment - I uninstalled the openssh client (some 8.1 version) and rebooted the jenkins slave (windows 10) then the machine started using the openssh-client from /usr/bin/ssh (MSYS_NT-10.0-WOW) it's version is OpenSSH_7.6p1, OpenSSL 1.0.2n 7 Dec 2017, now if I type the ssh-agent I get the following info
PS C:\Users\jenkins> ssh-agent SSH_AUTH_SOCK=/tmp/ssh-RbgKCjtDtgXm/agent.7016; export SSH_AUTH_SOCK; SSH_AGENT_PID=1872; export SSH_AGENT_PID; echo Agent pid 1872; PS C:\Users\jenkins>
With the version installed earlier, I used to get nothing when I entered command ssh-agent.
aab
added a comment - I uninstalled the openssh client (some 8.1 version) and rebooted the jenkins slave (windows 10) then the machine started using the openssh-client from /usr/bin/ssh (MSYS_NT-10.0-WOW) it's version is OpenSSH_7.6p1, OpenSSL 1.0.2n 7 Dec 2017, now if I type the ssh-agent I get the following info
PS C:\Users\jenkins> ssh-agent
SSH_AUTH_SOCK=/tmp/ssh-RbgKCjtDtgXm/agent.7016; export SSH_AUTH_SOCK;
SSH_AGENT_PID=1872; export SSH_AGENT_PID;
echo Agent pid 1872;
PS C:\Users\jenkins>
With the version installed earlier, I used to get nothing when I entered command ssh-agent.
Any progress on this, I also have this issue using the Windows OpenSSH
I get the following
[ssh-agent] Looking for ssh-agent implementation... [ssh-agent] Exec ssh-agent (binary ssh-agent on a remote machine) $ ssh-agent [ssh-agent] FATAL: Could not find a suitable ssh-agent providerIf I run my container with: "PowerShell -c "Get-Command ssh-agent""
I get