Troubleshooting
Problem
Connection attempts fail to the Liberty server. The error can happen when TCPIP is restarted. But can also happen in this scenario:
- The z/OS system is running in a CINET environment (to be able run multiple TCPIP stacks) versus an INET environment (where only 1 TCPIP stack can run)
- The Liberty server is started after TCPIP is up, but before PAGENT is up (with AT-TLS).
Diagnosing The Problem
The MVS system log will show that Liberty is started after TCPIP but before this message comes out:
EZZ4250I AT-TLS SERVICES ARE AVAILABLE FOR tcpip_stack_name
If Liberty is running with *=info, the messages.log shows an FFDC is written out
FFDC1015I: An FFDC Incident has been created: "java.io.IOException: EDC5122I Input/output error. com.ibm.ws.tcpchannel.internal.NBAcceptChannelSelector 288"
An FFDC is created that contains:
Exception = java.io.IOException
Source = com.ibm.ws.tcpchannel.internal.NBAcceptChannelSelector
probeid = 288
Stack Dump = java.io.IOException: EDC5122I Input/output error. (errno2=0x12AA044F)
at sun.nio.ch.PollArrayWrapper.poll(PollArrayWrapper.java:145)
at sun.nio.ch.PollSelectorImpl.doSelect(PollSelectorImpl.java:104)
at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:98)
at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:109)
at com.ibm.ws.tcpchannel.internal.ChannelSelector.run(ChannelSelector.java:168)
at java.lang.Thread.run(Thread.java:825)
Resolving The Problem
There are 2 ways to bypass this issue:
- start or restart the Liberty server. In the case with PAGENT/AT-TLS, do this after the EZZ4250I.
- Use a modify command to pause and resume the Liberty server. Pausing and resuming a Liberty server from the z/OS console
An entry in the IBM Ideas portal has been opened for Liberty to be enhanced to recover from this error: Enhance liberty to recover from java.io.IOException: EDC5122I Input/output error. (errno2=0x12AA044F)
Document Location
Worldwide
[{"Type":"MASTER","Line of Business":{"code":"LOB36","label":"IBM Automation"},"Business Unit":{"code":"BU053","label":"Cloud \u0026 Data Platform"},"Product":{"code":"SS8L5V","label":"IBM z\/OS Liberty Embedded base element"},"ARM Category":[{"code":"a8m0z0000001h7hAAA","label":"IBM WebSphere Liberty-All Platforms-\u003ELiberty Profile-\u003ELiberty z\/OS"}],"ARM Case Number":"TS006846570","Platform":[{"code":"PF035","label":"z\/OS"}],"Version":"All Versions"}]
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Document Information
Modified date:
30 November 2021
UID
ibm16518654