How To
Summary
If you use scripts to upgrade APM agents, you can inadvertently change the hostname from uppercase to lowercase, or from lowercase to uppercase.
Unix and Linux are case sensitive. Changing the hostname case changes the association of agent properties with the hostname. Consequently, the agent suddenly stops registering with the APM server.
This article shows you how to diagnose this scenario and restore connectivity.
Environment
Supported Linux servers
Steps
Agent names are case sensitive. At one time, there was an agent named 'MYHOST:LZ'. The agent was added to the Linux OS application and to these custom resource groups: GAC_SAP_JAVA and GAC_SAP_ABAP. But then, the agent name changed to 'myhost:LZ' (which could happen if the hostname was changed from uppercase to lowercase).
To recover, perform these steps:
a) Remove 'MYHOST:LZ' from the Linux OS application.
To remove an agent from an application, you edit the application and remove the agent component from it. See the online help or this Knowledge Center topic for more details:
Editing an application
https://www.ibm.com/support/knowledgecenter/SSHLNR_8.1.4/com.ibm.pm.doc/install/admin_apps_manageedit.html
b) Remove 'MYHOST:LZ' from the GAC_SAP_JAVA and GAC_SAP_ABAP resource groups.
To remove an agent from a resource group, you edit the group and delete the agent from the list of members. See the online help or this Knowledge Center topic for more details on editing resource groups:
Resource Group Manager
https://www.ibm.com/support/knowledgecenter/SSHLNR_8.1.4/com.ibm.pm.doc/install/admin_resourcegroupmgr_help.html
Note: When you edit a resource group and search for the agent you want to remove, select the checkmark symbol next to the agent name. That will remove the checkmark so that the agent is no longer assigned to the resource group. Then, click the 'Save' button to save the change to the group.
c) Wait 15 minutes
d) Then, add 'myhost:LZ' to the Linux OS application, and to the GAC_SAP_JAVA and GAC_SAP_ABAP resource groups.
Here is a technote that shows you how to clean up those agents that are not also in application views. This may help you clean up the offline agents. This is just a cleanup process
To recover, perform these steps:
a) Remove 'MYHOST:LZ' from the Linux OS application.
To remove an agent from an application, you edit the application and remove the agent component from it. See the online help or this Knowledge Center topic for more details:
Editing an application
https://www.ibm.com/support/knowledgecenter/SSHLNR_8.1.4/com.ibm.pm.doc/install/admin_apps_manageedit.html
b) Remove 'MYHOST:LZ' from the GAC_SAP_JAVA and GAC_SAP_ABAP resource groups.
To remove an agent from a resource group, you edit the group and delete the agent from the list of members. See the online help or this Knowledge Center topic for more details on editing resource groups:
Resource Group Manager
https://www.ibm.com/support/knowledgecenter/SSHLNR_8.1.4/com.ibm.pm.doc/install/admin_resourcegroupmgr_help.html
Note: When you edit a resource group and search for the agent you want to remove, select the checkmark symbol next to the agent name. That will remove the checkmark so that the agent is no longer assigned to the resource group. Then, click the 'Save' button to save the change to the group.
c) Wait 15 minutes
d) Then, add 'myhost:LZ' to the Linux OS application, and to the GAC_SAP_JAVA and GAC_SAP_ABAP resource groups.
Here is a technote that shows you how to clean up those agents that are not also in application views. This may help you clean up the offline agents. This is just a cleanup process
On APM 8.1.4 Console Agent Offline Alarms do not disappear
https://www.ibm.com/support/pages/node/1277422
See also Changing the agent managed system name
https://www.ibm.com/support/knowledgecenter/SSHLNR_8.1.4/com.ibm.pm.doc/install/msn_change_hostname.html
Document Location
Worldwide
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Historical Number
TS003109740
Product Synonym
APM; Application Performance Management
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Document Information
Modified date:
20 February 2020
UID
ibm13139203