Most of the connectivity problems between Operations Center (OC), the Client controllers (CC), and JNLP Agents usually come from the same causes:
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The JNLP communication is going through intermediate routing elements like HAProxy…/ELB. The main problem on this case, is that usually the configuration is done as if the protocol was HTTP. However, JNLP is a TCP protocol which requires to set-up a timeout of 15 minutes in order to avoid disconnections produced by these intermediate elements. The best approach is explained on this article, which is to bypass this elements.
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Add in all the CCs the OC hostname under Manage Jenkins -> Manage plugins [Advanced tab] in the No Proxy Host section. If the URL to access OC is
https://oc.jenkins.example.com, then it is expected to have justoc.jenkins.example.comin the No Proxy Host section.
Infrastructure
Bypass the intermediate elements in the CloudBees Jenkins platform (CJPOC-CJPCC) communication
The ELB/…/HAProxy is usually not correctly configured for the JNLP port. The recommendation is NOT to use the ELB/…/HAProxy, but instead bypass this intermediate element by: adding this Java Argument in OC -Dhudson.TcpSlaveAgentListener.hostName=<OC_MACHINE_HOSTNAME>. If you don’t want to perform a restart, after adding the Java Argument you can use run in the Script Console TcpSlaveAgentListener.CLI_HOST_NAME="CJOC_HOSTNAME"
Notes:
1. Get the hostname of you instance by Manage Jenkins -> Script Console println java.net.InetAddress.getLocalHost().
2. For dynamic IPs you could use Groovy hook script with TcpSlaveAgentListener.CLI_HOST_NAME=java.net.InetAddress.getLocalHost().
To check if the set-up was correctly performed you can run the command below and check that the header X-Jenkins-CLI-Host is present with the value we added.
$curl -I https://cm-1.jenkins.example.com:8080/ HTTP/1.1 200 OK Date: Thu, 13 Jul 2017 11:49:29 GMT X-Content-Type-Options: nosniff Set-Cookie: JSESSIONID.7b40bd3d=hbc0fd3lhh0w1bg9cusqtea8r;Path=/;HttpOnly Expires: 0 Cache-Control: no-cache,no-store,must-revalidate X-Hudson-Theme: default Content-Type: text/html;charset=UTF-8 X-Hudson: 1.395 X-Jenkins: 2.60.1.1 X-Jenkins-Session: 1af0d556 X-Hudson-CLI-Port: 54789 X-Jenkins-CLI-Port: 54789 X-Jenkins-CLI2-Port: 54789 X-Jenkins-CLI-Host: cjpcm-1.jenkins.example.com X-Frame-Options: sameorigin X-Instance-Identity: MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAlx9/b60USmo2Eexm8TBtkcG881tkAP77iBbct0gDlSLaDdhbP7thD86Mu3WQVxmq23Rzqd/WR2VpN+JaQCQYttQ/KdxqnkTPZFO4vYy7n9E0pWgw8VKVZ9WEPfwfDEf4tHm/NmT4i43YrG4oeJvrVrGpwDp7vBviZNzQqOlcxLsr6njOX3+aZMYGkSdkduKgtKB5tV5qJSQxNFw/3I9HuxSZlaWMyni9NhAs1jGJ7EaxKT3Jtix56EY+vIRY43YhLU6YvnU/O6R2H9KdmxyFjthr1H3x8Wjfo1qYqePIL73bjA5guRyZZirbKL+1ep9LjTqJZYpH3EUjGoiBtYeyiwIDAQAB Content-Length: 17904 Server: Jetty(9.2.z-SNAPSHOT)
Application
Only in case a Proxy is configured in the CloudBees Jenkins platform Client controllers (CJPCC)
In case there is proxy set-up in the controller under Manage Jenkins -> Manage plugins [Advanced tab] you must add the OC hostname into the No Proxy Host section at the controler level. i.e If the URL to access OC is https://oc.jenkins.example.com, then it is expected to have just oc.jenkins.example.com in the No Proxy Host section at the controller level.