Troubleshooting the RMC connection between the logical partition and the HMC

To perform dynamic partitioning operations, you require a Resource Monitoring and Control (RMC) connection between the logical partition and the Hardware Management Console (HMC). If you cannot add or remove processors, memory, or I/O devices to or from a logical partition, check whether the RMC connection is active. Failure of the RMC connection is one of the most common reasons for failure of dynamic partitioning operations.

Before you begin, complete the following procedure:

Check the value of the RMC connection state that is cached in the data repository of the HMC by running the following command from the HMC command-line interface:
```
lssyscfg -r lpar -m cec_name -F name,rmc_state,rmc_ipaddr,rmc_osshutdown_capable,dlpar_mem_capable,
dlpar_proc_capable,dlpar_io_capable
```
The value of the rmc_state attribute must either be active or inactive. Also, all the capabilities must be enabled.
For example:
```
#lssyscfg -r lpar -m cec_name -F name,rmc_state,rmc_ipaddr,rmc_osshutdown_capable,dlpar_mem_capable,
dlpar_proc_capable,dlpar_io_capable
lpar01,1,9.5.23.194,1,1,1,1
....
lpar0n,1.9.5.24.###,1,1,1,1
```
If the value of the rmc_state attribute or all the capabilities are not set to 1, perform a system rebuild to refresh the data by running the chsysstate -m system name -o rebuild -r sys command. If the rebuild operation does not change the value, complete steps 2 and 3.
Ensure that the firewall of the HMC is lifted for the RMC port by using the HMC graphical user interface. For the procedure, see solution 1.
Ensure that the firewall of the HMC is authenticated for the HMC to receive the request from the logical partition and the logical partition is authenticated to receive the request from the HMC by either using Secure Shell (SSH) or Telnet.

When the operating system on the logical partition is Linux, ensure that Reliable Scalable Cluster Technology (RSCT) Red Hat Package Managers (RPMs) rsct.core, rsct.core.utils, and src are installed. For information about how to install the RPMs, see Service and productivity tools for SLES on POWER® Linux servers for SUSE Linux Enterprise Server operating system and Service and productivity tools For Managed RHEL for Red Hat Enterprise Linux operating system.

The following table lists the steps to check the RMC connection and possible solutions when the connection fails.

Table 1. Steps to check for RMC failure and solutions
Scenario	Solution
Verify whether the firewall settings block the logical partition that is managed by the HMC.	To verify the Firewall configuration of the LAN adapter, perform the following steps by using the HMC: In the navigation pane, open HMC Management. In the work pane, click Change Network Settings. Click the LAN Adapters tab. Select any LAN adapter other than the `eth0` adapter that connects the HMC with the service processor, and click Details. On the LAN Adapter tab, under Local area network information, verify whether Open is selected and Partition communication status is displayed as enabled. Click the Firewall Settings tab. Ensure that the RMC application is one of the applications that are displayed in Allowed Hosts. If it is not displayed in Allowed Hosts, select the RMC application under Available Applications and click Allow Incoming. Click OK.
Verify whether the /tmp folder in the HMC is 100% full by running the df command, with superuser privilege.	You must remove unused files in the /tmp folder to free up space.

Last updated: Fri, July 05, 2019