Bug 869695

Created attachment 632838 [details]
Example cluster.conf

> Description of problem:
SAP instances started by SAPInstance cluster resource agent inherit limits on system resources (e.g. max # of open file descriptors) for root user.
SAP instances need higher limits on the maximum number of open files (ulimit -n), the maximum stack size (ulimit -s) and the maximum size of data segments (ulimit -d).
Those limits can not be applied by PAM due to the way that SAP processes are started by cluster, see "Additional info" below.

> Version-Release number of selected component (if applicable):
resource-agents-3.9.2-12.el6

> How reproducible:
Always.

> Steps to Reproduce:
1. Configure a clustered SAP instance (see attached cluster.conf example).
2. Start the clustered service that includes the SAP instance (clusvcadm -e).
3. Observe current resource limits of the instance processes:

# ps -ef | grep jepadm |grep -v grep
jepadm    6032     1  0 Oct23 ?        00:00:18 /usr/sap/JEP/ASCS00/exe/sapstartsrv pf=/sapmnt/JEP/profile/JEP_ASCS00_jep-ascs -D -u jepadm
jepadm    6307     1  0 Oct23 ?        00:00:00 sapstart pf=/sapmnt/JEP/profile/JEP_ASCS00_jep-ascs
jepadm    6322  6307  0 Oct23 ?        00:00:01 ms.sapJEP_ASCS00 pf=/usr/sap/JEP/SYS/profile/JEP_ASCS00_jep-ascs
jepadm    6323  6307  0 Oct23 ?        00:00:23 en.sapJEP_ASCS00 pf=/usr/sap/JEP/SYS/profile/JEP_ASCS00_jep-ascs
  
> Actual results:
# for i in 6032 6307 6322 6323 ; do echo "$i:"; cat /proc/$i/limits | egrep "open|data|stack"; done
6032:
Max data size             unlimited            unlimited            bytes     
Max stack size            10485760             unlimited            bytes     
Max open files            1024                 4096                 files     
6307:
Max data size             unlimited            unlimited            bytes     
Max stack size            10485760             unlimited            bytes     
Max open files            1024                 4096                 files     
6322:
Max data size             unlimited            unlimited            bytes     
Max stack size            10485760             unlimited            bytes     
Max open files            1024                 4096                 files     
6323:
Max data size             unlimited            unlimited            bytes     
Max stack size            10485760             unlimited            bytes     
Max open files            1024                 4096                 files

> Expected results:
Limits specified in /usr/sap/sapservices are taken into account by SAPInstance RA:

# for i in 6032 6307 6322 6323 ; do echo "$i:"; cat /proc/$i/limits | egrep "open|data|stack"; done
6032:
Max data size             unlimited            unlimited            bytes     
Max stack size            268435456            268435456            bytes     
Max open files            65536                65536                files     
6307:
Max data size             unlimited            unlimited            bytes     
Max stack size            268435456            268435456            bytes     
Max open files            65536                65536                files     
6322:
Max data size             unlimited            unlimited            bytes     
Max stack size            268435456            268435456            bytes     
Max open files            65536                65536                files     
6323:
Max data size             unlimited            unlimited            bytes     
Max stack size            268435456            268435456            bytes     
Max open files            65536                65536                files

> Additional info:

Currently the following sequence of events occurs when rgmanager starts a SAP Instance:

- rgmanager starts SAPInstance RA as root.
- SAPInstance starts sapstartsrv as root with the account username as a parameter ('-u'):
195     $SAPSTARTSRV pf=$SAPSTARTPROFILE -D -u $sidadm
                                                ^
- sapstartsrv process starts as root and drops privileges by calling setgid() and setuid() (and then clones into new processes).
- SAPInstance calls sapcontrol to start the instance:
270     output=`$SAPCONTROL -nr $InstanceNr -function Start`

- sapcontrol instructs sapstartsrv to start SAP instance as described in [1].

Due to this sequence of events:
- PAM limits configured in /etc/security/limits.conf as described in SAP note 1496410 are not applied to processes started by rgmanager/SAPInstance RA.
- limits configured in /usr/sap/sapservices as described in SAP note 1437105 are not applied either since instances are not started by /etc/init.d/sapinit but by rgmanager/SAPInstance RA instead.

SAPInstance RA should take limits configured in /usr/sap/sapservices into account.
If no limits are specified in /usr/sap/sapservices then safe default limits should be applied.

[1] http://help.sap.com/saphelp_nw73ehp1/helpdata/en/b3/903925c34a45e28a2861b59c3c5623/content.htm