SAP Basis Tech Supports

Symptom

During the web based cross communication across web applications deployed on the same engine using http/https protocol, an exception with message ‘unknown host’ or ‘Connection to system REPOSITORY using application REPOSITORY lost’ is thrown. Although the same url is accessible over browser and the target server is up and running. For e.g. Integration Builder Directory communicating with Enterprise Service Repository application.
Other terms

‘Unknown Host’, PI, Exchange Infrastructure, Integration repository, Integration builder directory, runtime, Enterprise Service Repository, HmiCoreException, ‘Connection to system REPOSITORY using application REPOSITORY lost’, Response code is 500 or 503, response message is “Unknown Host”‘
Reason and Prerequisites

There are two or more web applications deployed on the server (j2ee engine). For cross communication with each other internally, application uses http/https protocol and java.net.URLConnection class or other api to connect. During the connection an exception with message ‘Unknown Host’ is thrown. To check if this note is applicable to problem, please verify the following first:
1. The target server and application are up and in running state.
2. The same target URL for which application throws an error is accessible over the browser directly.
If any of the above two conditions do not met, please verify the state of engine/application, bring it to running state and try executing afterwards.
If the exception is thrown even after the verification of above two conditions, the issue could be due to the proxy configuration on engine. The proxy configured does not identify the hostname in the target URL.
Solution

The reported issue is not an XI issue, but this is configuration issue in which proxies are incorrectly set on engine. Therefore any web based cross application communication using HttpUrlConnection class over http(s) will fail.
The solution to the problem lies in setting up the proxies correctly. There are 3 options available to solve the issues. Solutions required to have the user with OS and J2EE Admin access permissions.
Option 1: Applicable to releases prior to NetWeaver 7.10
For releases prior to 7.10, there was no SOA management. So use the config tool/Visual administrator as described in SAP note 816022 to set the property ‘http.nonProxyHosts’ to the correct value. Value must include hostname and fully qualified hostname. You must restart the servers afterwards.
Option 2: Applicable to releases 7.10 to 7.10 SP-level #04 of component ESPFRAMEWORK. Open the NWA and goto SOA Management–> System Global Setting. If there is a proxy host specified, please check if the hostname in host url)> is contained in the exclude list. Multiple entries are separated
by “|”.
Option 3: Please refer SAP Note: 1060476, software component EP-PSERV to verify that portal service is not defining any Bypass Proxy server settings. If it is required, please add the server hostname (unqualified and fully qualified) to the Bypass proxy server list.
Option 4: Attached along with the note is archive containing two jsps. Please follow the steps mentioned below:
1. Copy the jsps to /usr/sap//j2ee/cluster/apps/sap.com/com.sap.engine.docs.examples/servlet_jsp/_default/root location on engine#s file system.
2. Access http://:/listProps.jsp
Check for property ‘http.proxySet’, it should be true, then check property ‘http.nonProxyHosts’ and verify that its value do not contain hostname/fully qualified hostname.
3. Copy the current value of ‘http.nonProxyHosts’ property, add hostname and fully qualified hostname to existing list separated by ‘|’. e.g if hostname is abcd and fully qualified is abcd.wdf.sap.corp then add |abcd|abcd.wdf.sap.corp.
4. Open setProps.jsp, update the value of ‘http.nonProxyHosts’ with new value while setting up the property in System.setProperty api call. System.setProperty(’http.nonProxyHosts’,’‘).
5. Access http://:/setProps.jsp and verify the new property is set.
6. Access the functionality which was failining earlier and verify that it works.
The above steps will set the setting only for current running environment (vm), properties will be reset on engine restart.
If setting up the properties via configtool is not solving the problem, please provide the following information with the message so that correct component to handle the problem can be identified:
1. Enable the sap jvm trace. Please refer the URL ‘http://sapjvm.wdf.sap.corp:1080/releasedetails/90′ for the same. User needs to set following 2 system properties via configtool:
com.sap.jvm.trace.System.setProperty=true
com.sap.jvm.trace.System.setProperty.filename= This points to FILE where jvm traces will be written.
e.g. com.sap.jvm.trace.System.setProperty.filename=/usr/sap///work/System.setProperty.log
2. Attach the following with the message:
a). Snap shot of configtool, displaying all the 3 system properties that have been set (http.nonProxyHosts, and 2 sap jvm properties).
b). After the restart of engine, jvm trace file.
c). Output of executing the URL http://:/listProps.jsp