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High CPU utilization in HostOS with Docker Swarm

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306
Visibility:
Public
Votes:
0
Category:
ontap-9
Specialty:
perf
Last Updated:

Applies to

  • ONTAP 8.2 or newer
  • Docker Swarm

Issue

  • High CPU is visible on one or more nodes
  • Running node -run <node_name> -command top against the node shows vldb with high WCPU%

Example:

 PID USERNAME     THR PRI NICE   SIZE    RES STATE   C   TIME   WCPU COMMAND
 6685 root         101  47    0   290M   109M uwait   1    ??? 410.99% vldb <-----------
 1709 root         231  66    0  1092M   449M RUN     7    ??? 141.06% mgwd
 1929 root           1   8    -     0K    64K WAIT    3 1141.4  8.79% NwkThd_04
 3308 root           1  12    -     0K    64K RUN     0 366.6H  8.69% wafl_exempt00
 1927 root           1   8    -     0K    64K WAIT    3 1142.8  8.64% NwkThd_02
 3312 root           1  12    -     0K    64K RUN     0 366.6H  8.54% wafl_exempt04
 3310 root           1  12    -     0K    64K RUN     1 366.7H  8.50% wafl_exempt02

 

  • system node run -node <node_name> rdfile /etc/log/mlog/mgwd.log contains entries similar to the following, where aaa.bbb.ccc.ddd is an IP address belonging to one or more Docker Swarm servers

Example:

 

Tue Jul 14 2020 13:28:30 +02:00 [kern_mgwd:info:1709] ontapi :: aaa.bbb.ccc.ddd :: docker :: volume-get-iter :: This request exceeds the configured session limit (10) for your Vserver ("<VSERVER_NAME>"). :: Throttled
Tue Jul 14 2020 13:28:31 +02:00 [kern_mgwd:info:1709] ontapi :: aaa.bbb.ccc.ddd :: docker :: volume-get-iter :: This request exceeds the configured session limit (10) for your Vserver ("<VSERVER_NAME>"). :: Throttled
Tue Jul 14 2020 13:28:31 +02:00 [kern_mgwd:info:1709] ontapi :: aaa.bbb.ccc.ddd :: docker :: volume-size :: This request exceeds the configured session limit (10) for your Vserver ("<VSERVER_NAME>"). :: Throttled
Tue Jul 14 2020 13:28:31 +02:00 [kern_mgwd:info:1709] ontapi :: aaa.bbb.ccc.ddd :: docker :: volume-get-iter :: This request exceeds the configured session limit (10) for your Vserver ("<VSERVER_NAME>"). :: Throttled
Tue Jul 14 2020 13:28:31 +02:00 [kern_mgwd:info:1709] ontapi :: aaa.bbb.ccc.ddd :: docker :: volume-size :: This request exceeds the configured session limit (10) for your Vserver ("<VSERVER_NAME>"). :: Throttled
Tue Jul 14 2020 13:28:32 +02:00 [kern_mgwd:info:1709] ontapi :: aaa.bbb.ccc.ddd :: docker :: volume-get-iter :: This request exceeds the configured session limit (10) for your Vserver ("<VSERVER_NAME>"). :: Throttled
Tue Jul 14 2020 13:28:32 +02:00 [kern_mgwd:info:1709] ontapi :: aaa.bbb.ccc.ddd :: docker :: volume-size :: This request exceeds the configured session limit (10) for your Vserver ("<VSERVER_NAME>"). :: Throttled

 

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