Resolving MID Server issues

  • Release version: Zurich
  • Updated July 31, 2025
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    Summary of Resolving MID Server issues

    This guide helps ServiceNow customers troubleshoot and resolve issues related to the MID Server. It covers monitoring practices, connectivity testing, log file analysis, and the use of Java Flight Recorder for JVM diagnostics. It also outlines procedures for addressing common MID Server problems, managing resource thresholds, and handling upgrade errors.

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    Monitoring and Troubleshooting MID Server

    • Log and Service Monitoring: Verify MID Server activity by checking logs (agent0.log.0, wrapper.txt) and confirming the presence of the agent0.log.0.lck lock file. On Windows hosts, monitor the MID Server process via the Services console and track Java memory usage according to the wrapper-override.conf configuration.
    • Connectivity Checks: Test network connectivity between the MID Server host and the ServiceNow instance to identify and resolve issues caused by firewalls, access control lists, or routing errors.
    • Status and Alerts: Review MID Server status on the MID Servers page within the instance and configure email, SMS, or push notifications for timely alerts. The MID Server Down notification is enabled by default.
    • Java Flight Recorder (JFR): Utilize JFR on hosts with Java 14+ to analyze JVM memory and thread events. Start, stop, and write JFR recordings directly from the MID Server instance. JFR files are automatically cleaned after 24 hours, with configurable retention settings.

    Common Issues and Resolution Procedures

    • Active MID Server Issues: The instance maintains a dedicated table to publish active MID Server problems and warn of resource overuse.
    • Post-Cloning Credential Issues: Automatic detection and notifications alert administrators to credential problems following instance cloning.
    • Resource Threshold Alerts: Warnings are triggered when CPU or JVM memory usage exceeds set thresholds, enabling custom notifications or scripts.
    • User Connectivity Issues: Problems with MID Server user logins and network connections are logged in the eccagentissue table, with events available for automation or alerts.
    • Debugging Output: Detailed or summary debugging logs for MID Server user issues can be enabled manually for deeper analysis.
    • Upgrade Troubleshooting: The Upgrade History module records each MID Server upgrade attempt and tracks progress and errors to facilitate troubleshooting.
    • MID Server Fails to Start: Typically caused by configuration errors; customers should verify settings and logs to diagnose startup failures.

    Practical Next Steps for Customers

    • Regularly monitor MID Server logs and status through the instance interface and host system tools.
    • Test and maintain network connectivity to avoid communication interruptions.
    • Configure notifications to receive immediate alerts on MID Server downtime or resource issues.
    • Use Java Flight Recorder for advanced JVM diagnostics when troubleshooting performance or stability problems.
    • Leverage the Upgrade History module to address and resolve upgrade-related errors.
    • Consult the ServiceNow Knowledge Base for additional MID Server troubleshooting articles and best practices.

    Troubleshoot problems with the MID Server to find solutions. Monitor the MID Server to receive alerts about issues as they occur. Troubleshooting procedures exist to resolve specific problems with the MID Server. The Knowledge Base on Hi contains several articles to help you troubleshoot MID Server issues.

    Monitor the MID Server

    Monitoring a MID Server involves verifying entries in log files, confirming network connectivity, and checking MID server status.

    • If the MID Server is on a Windows host, navigate to the Windows Services console, locate the service name that matches the name that appears from the wrapper-override.conf file. If the MID Server process is the only Java process running on the host, monitor the memory used by java.exe and alert on less than the maximum configured memory defined in the ~\agent\conf\wrapper-override.conf folder.

    • Ensure that the agent0.log.0.lck file appears in the ~\agent\logs folder to confirm that the MID Server running and logging system activity in the agent0.log.0 file.

    • Review the following logs for warning, critical, and severe errors: ~\agent\logs\agent0.log.0 ~\agent\logs\wrapper.txt See Manage ECC Queue content for a MID Server to see how to open log entries from the instance.

    • Test MID Server connectivity to confirm that the MID Server host is able to communicate with the instance. Resolve any issues with the network connectivity such as conflicts with firewalls, access control lists, and routing errors.

    • From the MID Server instance, navigate to the MID Servers page, and review the status of the MID Server. For additional information, click a Name.

    • Set up email, SMS, and push notifications to alert you when issues occur with MID servers. The MID Server Down notification is enabled by default. See Notifications for details.

    Java Flight Recorder

    Java Flight Recorder (JFR) uses an articulate data model to analyze Java Virtual Machine (JVM) internal and application specific memory usage and thread related details. On hosts with Java 14 or later, Event Streaming enables analysis of specific JVM or application events.

    The JFR file actions Start JFR Recording, Stop JFR Recording, or Write JFR File, are accessed on the instance in the MID Server's Related Links. By starting and stopping the JFR recording, you can dump JFR data to the disk on demand. While JFR recording is on, you can write to the JFR file from the MID Server instance page.

    The JFR file is deleted by a scheduler to clean the data after 24 hours. This default behavior can be overridden by adding the following configuration parameter in the config.xml: <parameter name="mid.jfr.data.clean.interval" value="<time in milisec>"/>

    Custom JFR events can be written to JFR file. To disable event writing, add the following configuration parameter to the config.xml: <parameter name="mid.jfr.record.aprobe" value="false”/>

    Troubleshooting procedures

    The following procedures provide information on resolving specific problems with the MID Server. Knowledge Base articles also cover a wide range of issues. If you are encountering problems which are not covered in these procedures, search the Knowledge Base for related articles. For instance, if you are experiencing symptoms such as the MID Server going down or not responding, or CIs being duplicated during discovery, see KB0597571 for information and recommended solutions.

    MID Server active issues
    The ServiceNow® instance has a dedicated table that publishes active issues with MID Servers and alerts administrators when a MID Server is in danger of exceeding its resources.
    Active MID Server post-cloning credential issues
    The system provides automatic processes to detect and notify you of possible MID Server credential issues after instance cloning.
    MID Server resource threshold alerts
    The instance displays warnings when a MID Server breaches its resource thresholds for CPU and JVM memory usage, enabling users to create email notifications or custom scripts when a breach occurs.
    MID Server user connectivity issues
    The instance writes issues involving MID Server user logins and network connectivity to the MID Server Issue [ecc_agent_issue] table and creates events you can use in custom scripts or to send email notifications.
    Interpreting MID Server user debugging output
    Debugging output from the system log is available in either a summary or detailed view for MID Server user issues, but must be enabled manually.
    MID Server Upgrade History
    Use this module to troubleshoot errors that occur during the MID Server upgrade process. The MID Server Upgrade Histories table contains a record of each instance upgrade. The MID Server Upgrade Stages table shows the status of each MID Server and its upgrade progress, including any errors encountered.