Created question in FIWARE Q/A platform on 14-04-2015 at 15:04
Please, ANSWER this question AT https://stackoverflow.com/questions/29629170/fiware-orion-context-broker-out-of-memory-issue

Question:
Fiware Orion context Broker Out of Memory Issue

Description:
I have deployed Orion Context Broker v0.20 on OpenStack - CentOS 6.5 with 4GB RAM | 2 VCPU | 5.0GB Disk.

It works as expected until the multi-threaded HTTP request (for 100 users) test with Apache JMeter 2.13.
The service shuts down with;

Out of memory: Kill process 5640 (contextBroker) score 946 or
sacrifice child Killed process 5640, UID 501, (contextBroker)
total-vm:15377736kB, anon-rss:3822

The problem seems to be the libmicrohttpd.

libmicrohttpd invoked oom-killer: gfp_mask=0x280da, order=0, oom_adj=0, oom_score_adj=0
libmicrohttpd cpuset=/ mems_allowed=0
Pid: 2551, comm: libmicrohttpd Not tainted 2.6.32-431.el6.x86_64 #1
Call Trace:
[<ffffffff810d05b1>] ? cpuset_print_task_mems_allowed+0x91/0xb0
[<ffffffff81122960>] ? dump_header+0x90/0x1b0
[<ffffffff8122798c>] ? security_real_capable_noaudit+0x3c/0x70
[<ffffffff81122de2>] ? oom_kill_process+0x82/0x2a0
[<ffffffff81122d21>] ? select_bad_process+0xe1/0x120
[<ffffffff81123220>] ? out_of_memory+0x220/0x3c0
[<ffffffff8112fb3c>] ? __alloc_pages_nodemask+0x8ac/0x8d0
[<ffffffff81167b9a>] ? alloc_pages_vma+0x9a/0x150
[<ffffffff81149c3c>] ? do_wp_page+0x52c/0x920
[<ffffffff8100bc2e>] ? invalidate_interrupt1+0xe/0x20
[<ffffffff8100bc2e>] ? invalidate_interrupt1+0xe/0x20
[<ffffffff8114a82d>] ? handle_pte_fault+0x2cd/0xb00
[<ffffffff8104eeb7>] ? pte_alloc_one+0x37/0x50
[<ffffffff8100bc2e>] ? invalidate_interrupt1+0xe/0x20
[<ffffffff8114b28a>] ? handle_mm_fault+0x22a/0x300
[<ffffffff8104a8d8>] ? __do_page_fault+0x138/0x480
[<ffffffff8105dbef>] ? finish_task_switch+0x4f/0xf0
[<ffffffff81527910>] ? thread_return+0x4e/0x76e
[<ffffffff8152d45e>] ? do_page_fault+0x3e/0xa0
[<ffffffff8152a815>] ? page_fault+0x25/0x30
Mem-Info:
Node 0 DMA per-cpu:
CPU 0: hi: 0, btch: 1 usd: 0
CPU 1: hi: 0, btch: 1 usd: 0
Node 0 DMA32 per-cpu:
CPU 0: hi: 186, btch: 31 usd: 30
CPU 1: hi: 186, btch: 31 usd: 30
Node 0 Normal per-cpu:
CPU 0: hi: 186, btch: 31 usd: 48
CPU 1: hi: 186, btch: 31 usd: 51
active_anon:771153 inactive_anon:199950 isolated_anon:352
active_file:17 inactive_file:48 isolated_file:38
unevictable:0 dirty:0 writeback:612 unstable:0
free:21204 slab_reclaimable:2119 slab_unreclaimable:5685
mapped:90 shmem:41 pagetables:3131 bounce:0
Node 0 DMA free:15740kB min:248kB low:308kB high:372kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15352kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes
lowmem_reserve[]: 0 3512 4017 4017
Node 0 DMA32 free:60708kB min:58868kB low:73584kB high:88300kB active_anon:2857740kB inactive_anon:593508kB active_file:72kB inactive_file:48kB unevictable:0kB isolated(anon):640kB isolated(file):0kB present:3596504kB mlocked:0kB dirty:0kB writeback:2444kB mapped:88kB shmem:0kB slab_reclaimable:44kB slab_unreclaimable:400kB kernel_stack:328kB pagetables:868kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:1248 all_unreclaimable? no
lowmem_reserve[]: 0 0 505 505
Node 0 Normal free:8368kB min:8464kB low:10580kB high:12696kB active_anon:231444kB inactive_anon:201556kB active_file:0kB inactive_file:144kB unevictable:0kB isolated(anon):896kB isolated(file):24kB present:517120kB mlocked:0kB dirty:0kB writeback:4kB mapped:272kB shmem:164kB slab_reclaimable:8432kB slab_unreclaimable:22340kB kernel_stack:1616kB pagetables:11656kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:312 all_unreclaimable? no
lowmem_reserve[]: 0 0 0 0
Node 0 DMA: 3*4kB 2*8kB 2*16kB 2*32kB 2*64kB 1*128kB 0*256kB 0*512kB 1*1024kB 1*2048kB 3*4096kB = 15740kB
Node 0 DMA32: 3*4kB 7*8kB 4*16kB 7*32kB 3*64kB 0*128kB 29*256kB 51*512kB 26*1024kB 0*2048kB 0*4096kB = 60708kB
Node 0 Normal: 346*4kB 188*8kB 101*16kB 47*32kB 15*64kB 5*128kB 2*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 8120kB
1824 total pagecache pages
1705 pages in swap cache
Swap cache stats: add 68397, delete 66692, find 1718/1909
Free swap = 0kB
Total swap = 262136kB
1048575 pages RAM
34863 pages reserved
1067 pages shared
988252 pages non-shared

Has anyone faced this issue or have suggestion to workaround it?

The JMeter Test Plan;

<?xml version="1.0" encoding="UTF-8"?>
<jmeterTestPlan version="1.2" properties="2.8" jmeter="2.13 r1665067">
<hashTree>
<HTTPSamplerProxy guiclass="HttpTestSampleGui" testclass="HTTPSamplerProxy" testname="HTTP Request" enabled="true">
<elementProp name="HTTPsampler.Arguments" elementType="Arguments" guiclass="HTTPArgumentsPanel" testclass="Arguments" testname="User Defined Variables" enabled="true">
<collectionProp name="Arguments.arguments"/>
</elementProp>
<stringProp name="HTTPSampler.domain">ORION_IP_ADDRESS</stringProp>
<stringProp name="HTTPSampler.port">1026</stringProp>
<stringProp name="HTTPSampler.connect_timeout"></stringProp>
<stringProp name="HTTPSampler.response_timeout"></stringProp>
<stringProp name="HTTPSampler.protocol"></stringProp>
<stringProp name="HTTPSampler.contentEncoding"></stringProp>
<stringProp name="HTTPSampler.path">/v1/contextTypes</stringProp>
<stringProp name="HTTPSampler.method">GET</stringProp>
<boolProp name="HTTPSampler.follow_redirects">true</boolProp>
<boolProp name="HTTPSampler.auto_redirects">false</boolProp>
<boolProp name="HTTPSampler.use_keepalive">true</boolProp>
<boolProp name="HTTPSampler.DO_MULTIPART_POST">false</boolProp>
<boolProp name="HTTPSampler.monitor">false</boolProp>
<stringProp name="HTTPSampler.embedded_url_re"></stringProp>
</HTTPSamplerProxy>
<hashTree/>
</hashTree>
</jmeterTestPlan>