title: How do I start a Jenkins agent from the slave?
body: <p>Jenkins v2.89.3.</p>
  
  <p>I'm trying to start an agent but am getting the following error.</p>
  
  <pre><code>$ java -jar agent.jar -jnlpUrl http://localhost:8080/computer/testagent/slave-agent.jnlp
  Error: Unable to access jarfile agent.jar
  </code></pre>
  
  <p>The documentation from the wiki that I'm following is from here:</p>
  
  <p>Launch agent headlessly -
   <a href="https://wiki.jenkins.io/display/JENKINS/Distributed+builds#Distributedbuilds-Differentwaysofstartingagents" rel="nofollow noreferrer">https://wiki.jenkins.io/display/JENKINS/Distributed+builds#Distributedbuilds-Differentwaysofstartingagents</a></p>
  
  <p>The handbook section for managing nodes doesn't appear to have been written yet:
  <a href="https://jenkins.io/doc/book/managing/nodes/" rel="nofollow noreferrer">https://jenkins.io/doc/book/managing/nodes/</a></p>
  
  <p>If anyone know what I'm doing wrong, or another way I can start the agent from the slave (not from the master), please let me know.</p>