Symptoms

Hosting CP does not load and gives Service Unavailable message.

Checking /var/log/poa-ui.log on the UI server for the corresponding session, the action flow is stuck on the following line:

2016-08-31 22:25:46,235            ec-70 DEBUG  CORBA                #10006: Plesk.APS._APSManagerStub.getApplicationXMLMetadata(user_id=1 (su_user_id=1)) >>> entry

There is no corresponding getApplicationXMLMetadata call appearing in /var/log/poa.log on the OA Management Node.

SaaS service controller is alive, but has too many connections in CLOSE_WAIT status as seen in netstat output:

# pgrep -f SaaS
19415
# netstat -antp | grep 19415
...
tcp        1      0 10.124.45.159:42005         10.124.45.159:5432          CLOSE_WAIT  19415/SoLoader
tcp        1      0 10.124.45.159:45992         10.124.45.159:5432          CLOSE_WAIT  19415/SoLoader
tcp        1      0 10.124.45.159:45942         10.124.45.159:5432          CLOSE_WAIT  19415/SoLoader
tcp        1      0 10.124.45.159:42473         10.124.45.159:5432          CLOSE_WAIT  19415/SoLoader
tcp        1      0 10.124.45.159:33984         10.124.45.159:5432          CLOSE_WAIT  19415/SoLoader
tcp        1      0 10.124.45.159:33966         10.124.45.159:5432          CLOSE_WAIT  19415/SoLoader
tcp        1      0 10.124.45.159:45974         10.124.45.159:5432          CLOSE_WAIT  19415/SoLoader
...

OA Management Node runs in a Virtuozzo container, and there are the following errors on the hardware node:

[root@vz ~]# dmesg  |tail
[29780191.405447] Fatal resource shortage: kmemsize, UB 101.
[29780191.405828] Fatal resource shortage: kmemsize, UB 101.
[29780191.406227] Fatal resource shortage: kmemsize, UB 101.

where 101 is the container ID of MN.

Cause

Insufficient UBC resources result in SaaS service controller outage.

Resolution

For Virtuozzo version 4.7 and 6.0, remove all UBC parameters from the container's configuration file and set only RAM and SWAP limits:

# vzctl set 101 --ram 8G --swap 16G --vm_overcommit 0 --save

vm_overcommit setting will remove all limits for memory allocation, while memory usage will be limited to 8GB.

For older Virtuozzo versions, SLM limit can be set for the container:

# vzctl set 101 --slmmode slm --slmmemorylimit 8G --save

Internal content