Install Jenkins slave as a Windows service in command line - jenkins

Question

I have been looking a lot on Google on how to install the service in
command line (so without manual interaction) but I am stuck on how to
get the jenkins-slave.exe
I found those instruction
https://wiki.jenkins.io/display/JENKINS/Installing+Jenkins+as+a+Windows+service
but I can't figure how to get the executable. I have downloaded and run
the slave.jar with the right key, which connects the slave, but the exe
is not generated.
I found this page
https://github.com/kohsuke/winsw/blob/master/doc/installation.md#winsw-installation-guide
to install it manually but that sounds like re-invented the wheel when
the jar can do it. Plus there is a risk the WinSW.exe is different and
doesn't get updated by the plugin (I saw some automatic update code in it).
So is there a way I can download the jenkins-slave.exe or generate it?
or is there a way to run the "Install as a service" in command line from
the slave.jar?

Answer 1

To answer my own question, after having contacted the plugin developers:
There is no actual way to download the exe from Jenkins directly, the slave.jar gets it from the master via the remoting protocol. I have created a request to be able to download it via an URL (as suggested by the developer), so it might be available in the future.
Right now the executable is a renamed Windows Service Wrapper binary: https://github.com/kohsuke/winsw so I used this binary the same way.
Regarding the configuration used by WinSW and XML files, I used the one from the GitHub repository https://github.com/jenkinsci/windows-slave-installer-module. The versions are compatible in terms of the configuration.
So basically I download the exe, get the private key from Jenkins and create the service using the configuration from the original plugin. Then I install the service using jenkins-slave.exe install.
Step by step:
Get the JNLP command from Jenkins (from the Node page) to get the private key, e.g. java -jar slave.jar -jnlpUrl http://jenkins...
Download the slave.jar file from Jenkins (gotten from the JNLP command)
Download the service wrapper executable, e.g. http://repo.jenkins-ci.org/public/com/sun/winsw/winsw/2.1.0/winsw-2.1.0-bin.exe
Rename winsw-2.1.0-bin.exe into jenkins-slave.exe
Setup the XML used to run the service (available in the module or directly on winsw website)
Setup the slave configuration XML file (available on the module source code)
Then install the service using jenkins-slave.exe install

Answer 2

What I would do is:
Download the slave.jar file (from the node's page of Jenkins)
Copy the java -jar slave.jar -jnlpUrl http://<YOUR URL HERE> command from the node's page
Paste this command into a new .bat file and save it
Register a scheduled task to run this .bat file when Windows starts

Answer 3

Or is there a way to run the "Install as a service" in command line from the slave.jar?
I don't use jenkins-slave.exe, but instead a custom script in which I can control the exact environment variable I want to set for the Jenkins slave, when launching java -jar slave.jar with the secret key you can see in the Jenkins master node page for that new slave.
To get slave.jar from the master onto the slave, execute from the slave Windows server:
curl -o slave.jar https://your.server/jenkins/jnlpJars/slave.jar
To replace the jenkins-slave.exe, I use a script declared as a Windows service, with nssm
The script is similar to agent.bat:
set PATH=C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0
set PATH=D:\Tools\SonarRunner\bin;%PATH%
set M2_HOME=D:\Tools\apache-maven-3.5.0
set PATH=%M2_HOME%\bin;%PATH%
set PATH=D:\Tools\apache-ant-1.9.3\bin;%PATH%
set GH=D:\Tools\Git
set PATH=%GH%\bin;%GH%\usr\bin;%GH%\mingw64\bin;%PATH%
set PATH=%JAVA_HOME%\bin;%PATH%
set WORKSPACE_FOLDER=D:\Jenkins\workspace
set GIT_WORKSPACE_FOLDER=D:\Jenkins\workspace
java -Xmx768m -jar slave.jar -jnlpUrl https://your.server/jenkins/computer/<SlaveName>/slave-agent.jnlp -secret 87ef3d...
That script is then called as a Windows service, ran by a dedicated user account:
runas /user:<domain>\<jenkinsUser> cmd ( enter `jenkinsUser` Windows password )
D:\Tools\nssm-2.24\win64\nssm.exe install <SlaveName> D:\Jenkins\agent.bat
Its Windows service is then configured:
sc config <SlaveName> obj= <domain>\<jenkinsUsers> password= <jenkinsUser password>
sc config <SlaveName> start= auto
For automating the installation of other software: see Chocolatey - Software Management Automation, The package manager for Windows.
To fully automate the declaration-side of slaves, use the web API to create the slave, and a groovy script to retrieve the Jenkins node/slave secret JnlpMac key.
See this script for the creation.
And the groovy script (with Jenkins 2.46 or newer) to get the secret key:
echo 'println jenkins.model.Jenkins.instance.nodesObject.getNode("my-agent")?.computer?.jnlpMac' \
| java -jar ~/Downloads/jenkins-cli.jar -s https://jenkins/ groovy =

Answer 4

Using this windows service wrapper works too:
https://github.com/winsw/winsw
follow their installation, but you should update the xml with your desired configuration, be sure to remove all " in pathes within the xml and disable websockets in the jenkins master configuration page of the agent:
step by step:
download the exe: WinSW-x64.exe from https://github.com/winsw/winsw/releases
create your workspace-dir on the agent and paste it there, rename the WinSW-x64.exe to jenkins-slave.exe
copy your jenkins-slave.xml there, it should looke like:
<service>
<id>jenkins</id>
<name>Jenkins</name>
<description>This service runs Jenkins continuous integration system.</description>
<env name="JENKINS_HOME" value="%BASE%"/>
<executable>C:\Program Files\RedHat\java-1.8.0-openjdk-1.8.0.275-1\jre\bin\java.exe</executable>
<arguments>-jar %BASE%\slave.jar -jnlpUrl https://<your_jenkins>.jenkins.bshg.com/computer/RBGWCW0281/jenkins-agent.jnlp -secret <your_secret> -workDir C:\<workspace-dir>\ -noCertificateCheck</arguments>
<logmode>rotate</logmode>
<onfailure action="restart" />
<delayedAutoStart/>
<!--
If uncommented, download the Remoting version provided by the Jenkins master.
Enabling for HTTP implies security risks (e.g. replacement of JAR via DNS poisoning). Use on your own risk.
NOTE: This option may fail to work correctly (e.g. if Jenkins is located behind HTTPS with untrusted certificate).
In such case the old agent version will be used; you can replace slave.jar manually or to specify another download URL.
-->
<download from="https://<your_jenkins>.jenkins.bshg.com/jnlpJars/slave.jar" to="%BASE%\slave.jar"/>
<!--
In the case WinSW gets terminated and leaks the process, we want to abort
these runaway JAR processes on startup to prevent "Slave is already connected errors" (JENKINS-28492).
-->
<extensions>
<!-- This is a sample configuration for the RunawayProcessKiller extension. -->
<extension enabled="true"
className="winsw.Plugins.RunawayProcessKiller.RunawayProcessKillerExtension"
id="killOnStartup">
<pidfile>%BASE%\jenkins_agent.pid</pidfile>
<stopTimeout>5000</stopTimeout>
<stopParentFirst>false</stopParentFirst>
</extension>
</extensions>
</service>
Use the option delayed Auto start, to ensure all the network services are started, that jenkins connect can not fail.
And i recommend to use a registry key to give the service more time to start:
Insert registry-key to give services more time to start:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\]
"ServicesPipeTimeout"=dword:0001d4c0
You can check here fore detailed info: https://serverfault.com/questions/622432/how-do-i-increase-windows-service-startup-timeout
And finally I recommend to autostart your jenkins at least once a week. with a scheduled task:
<?xml version="1.0" encoding="UTF-16"?>
<Task version="1.2" xmlns="http://schemas.microsoft.com/windows/2004/02/mit/task">
<RegistrationInfo>
<Date>2020-04-30T12:47:51.8471206</Date>
<Author>Domain/User</Author>
<Description>Some Comment</Description>
<URI>\CI-Restart</URI>
</RegistrationInfo>
<Triggers>
<CalendarTrigger>
<StartBoundary>2020-05-01T01:00:00</StartBoundary>
<Enabled>true</Enabled>
<ScheduleByDay>
<DaysInterval>1</DaysInterval>
</ScheduleByDay>
</CalendarTrigger>
</Triggers>
<Principals>
<Principal id="Author">
<UserId>whatever</UserId>
<LogonType>Password</LogonType>
<RunLevel>HighestAvailable</RunLevel>
</Principal>
</Principals>
<Settings>
<MultipleInstancesPolicy>IgnoreNew</MultipleInstancesPolicy>
<DisallowStartIfOnBatteries>true</DisallowStartIfOnBatteries>
<StopIfGoingOnBatteries>true</StopIfGoingOnBatteries>
<AllowHardTerminate>true</AllowHardTerminate>
<StartWhenAvailable>false</StartWhenAvailable>
<RunOnlyIfNetworkAvailable>false</RunOnlyIfNetworkAvailable>
<IdleSettings>
<StopOnIdleEnd>true</StopOnIdleEnd>
<RestartOnIdle>false</RestartOnIdle>
</IdleSettings>
<AllowStartOnDemand>true</AllowStartOnDemand>
<Enabled>true</Enabled>
<Hidden>false</Hidden>
<RunOnlyIfIdle>false</RunOnlyIfIdle>
<WakeToRun>false</WakeToRun>
<ExecutionTimeLimit>PT72H</ExecutionTimeLimit>
<Priority>7</Priority>
</Settings>
<Actions Context="Author">
<Exec>
<Command>shutdown</Command>
<Arguments>/r /f /t 10 /d p:2:3 /c "CI-reconnect"</Arguments>
</Exec>
</Actions>
</Task>
Now do (with admin rights)
jenkins-slave.exe install
jenkins-slave.exe start
Your Jenkins will run forever!
Another recommendation: Enable the BIOS-setting to start pc on power-on. If you have troubles with interruptions of power-supply.