SQL10003C There are not enough system resources to process the request. The request cannot be processed.

If you see this: -

SQL10003C  There are not enough system resources to process the request.  The request cannot be processed.

when trying to run commands against DB2 e.g. db2level, db2start, db2licm etc. then make one simple check :-)

hostname

mta2015_1.uk.ibm.com

ping `hostname`

PING mta2015_1.uk.ibm.com (192.168.33.129) 56(84) bytes of data.
64 bytes from mta2015_1.uk.ibm.com (192.168.33.129): icmp_seq=1 ttl=64 time=0.020 ms
64 bytes from mta2015_1.uk.ibm.com (192.168.33.129): icmp_seq=2 ttl=64 time=0.099 ms
^C
--- mta2015_1.uk.ibm.com ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1493ms
rtt min/avg/max/mdev = 0.020/0.059/0.099/0.040 ms

cat /home/db2inst1/sqllib/db2nodes.cfg 

0 mta2015_1.uk.ibm.com 0

It's important that db2nodes.cfg matches the hostname of the server, and that the hostname is resolvable.

I hit this issue having changed my OS hostname AFTER I created my DB2 instance :-)