[rabbitmq-discuss] Queries on processes connected to RabbitMQ node

[Priyanki Vashi]

Hi there ,

Can anyone throw some light on different processes, which get started when 
I run ./rabbitmq-server start. 

As an example I am putting details of different processes, which gets 
started. I have four node cluster and following is for two of the node 
started on port 5672 & 5675. Each node is showing total of 6 processes and 
then there is epmd daemon process. Same way I have rest of the two nodes 
and each having 6 processes connected to it. 
If I understand correctly out of this 6 process, one is parent process and 
rest 5 are child process as we can see from pid and ppid. Is it correct way 
to interpret this ? 


I want to understand this thoroughly, bcoz 

1) First thing, I wanted to tie every single node of my cluster to the 
specific CPU using linux 'taskset -c cpu -p pid' command. I have total of 
20 cpus so this how I want to control resources to understand how it scales 
with respect to CPU and what load every CPU would be under when I do stress 
testing with multiple producer and consumer.

2) Secondly I am also interested to measure the load on each CPU as a part 
of stress testings. So what is the suitable method to measure CPU load. I 
googled on this on internet and found either by using script or manually 
reading %cpu for every processes and addind them together to get total 
utilization of CPU. Is this correct way one can understand CPU utilization 
or ? 

3) Third thing was, Is the epmd -daemon is the First parent process, which 
is in the end of the list and probably started when I started my very first 
node. Though I am not sure since I did not track processes after every node 
starting. It's not very clear to me what is the importance of this process 
? 

4) Also, in rabbitmq management plugin there is a field called 'Erlang 
Processes', which shows numbers in the range of 120-130 for every node of 
my cluster. Is this really the number of Erlang process started by every 
node ?
    Even if there is no messages sent and received, this is the number. 
Will it increase with increase on load while running multiple producer and 
consumer ? 
    how does it map to the processes listed below for every node. What 
happens in theory if I kill this manually. (Since I don't want to disturb 
current setup so not trying and asking in the forum)

5) Lastly, is the below list covers all the processes, when rabbitmq node 
is started or I should grep on something else as well ? 

Thank you and hope so I can get some insight on my questions !

Best Regards,
Priyanki. 


I have four node cluster and when I grep on rabbitmq I see following set of 
processes connected with each node. As an example just pasted only two 
nodes printout.

root       7014      1  0 jun08 ?        00:00:00 /bin/sh 
/usr/sbin/rabbitmq-server
root       7021   7014  0 jun08 ?        00:00:00 su rabbitmq -s /bin/sh -c 
/usr/lib/rabbitmq/bin/rabbitmq-server 
rabbitmq   7030   7021  0 jun08 ?        00:00:00 sh -c 
/usr/lib/rabbitmq/bin/rabbitmq-server 
rabbitmq   7031   7030  3 jun08 ?        13:57:12 
/usr/lib/erlang/erts-5.10.1/bin/beam.smp -W w -K true -A30 -P 1048576 -- 
-root /usr/lib/erlang -progname erl -- -home /var/lib/rabbitmq -- -pa 
/usr/lib/rabbitmq/lib/rabbitmq_server-3.1.1/sbin/../ebin -noshell -noinput 
-s rabbit boot -sname rabbit8 -boot start_sasl -kernel 
inet_default_connect_options [{nodelay,true}] -rabbit tcp_listeners 
[{"auto",5675}] -sasl errlog_type error -sasl sasl_error_logger false 
-rabbit error_logger {file,"/var/log/rabbitmq/rabbit8.log"} -rabbit 
sasl_error_logger {file,"/var/log/rabbitmq/rabbit8-sasl.log"} -rabbit 
enabled_plugins_file "/etc/rabbitmq/enabled_plugins" -rabbit plugins_dir 
"/usr/lib/rabbitmq/lib/rabbitmq_server-3.1.1/sbin/../plugins" -rabbit 
plugins_expand_dir "/var/lib/rabbitmq/mnesia/rabbit8-plugins-expand" 
-os_mon start_cpu_sup false -os_mon start_disksup false -os_mon 
start_memsup false -mnesia dir "/var/lib/rabbitmq/mnesia/rabbit8" 
-rabbitmq_management listener [{port,15675}]
rabbitmq   7152   7031  0 jun08 ?        00:00:00 inet_gethost 4
rabbitmq   7153   7152  0 jun08 ?        00:00:00 inet_gethost 4
root       9570      1  0 jun08 ?        00:00:00 /bin/sh 
/usr/sbin/rabbitmq-server
root       9577   9570  0 jun08 ?        00:00:00 su rabbitmq -s /bin/sh -c 
/usr/lib/rabbitmq/bin/rabbitmq-server 
rabbitmq   9586   9577  0 jun08 ?        00:00:00 sh -c 
/usr/lib/rabbitmq/bin/rabbitmq-server 
rabbitmq   9587   9586  3 jun08 ?        14:54:43 
/usr/lib/erlang/erts-5.10.1/bin/beam.smp -W w -K true -A30 -P 1048576 -- 
-root /usr/lib/erlang -progname erl -- -home /var/lib/rabbitmq -- -pa 
/usr/lib/rabbitmq/lib/rabbitmq_server-3.1.1/sbin/../ebin -noshell -noinput 
-s rabbit boot -sname rabbit5 -boot start_sasl -kernel 
inet_default_connect_options [{nodelay,true}] -rabbit tcp_listeners 
[{"auto",5672}] -sasl errlog_type error -sasl sasl_error_logger false 
-rabbit error_logger {file,"/var/log/rabbitmq/rabbit5.log"} -rabbit 
sasl_error_logger {file,"/var/log/rabbitmq/rabbit5-sasl.log"} -rabbit 
enabled_plugins_file "/etc/rabbitmq/enabled_plugins" -rabbit plugins_dir 
"/usr/lib/rabbitmq/lib/rabbitmq_server-3.1.1/sbin/../plugins" -rabbit 
plugins_expand_dir "/var/lib/rabbitmq/mnesia/rabbit5-plugins-expand" 
-os_mon start_cpu_sup false -os_mon start_disksup false -os_mon 
start_memsup false -mnesia dir "/var/lib/rabbitmq/mnesia/rabbit5" 
-rabbitmq_management listener [{port,15672}]
rabbitmq   9708   9587  0 jun08 ?        00:00:00 inet_gethost 4
rabbitmq   9709   9708  0 jun08 ?        00:00:00 inet_gethost 4
root      71464  68985  0 03:14 pts/14   00:00:00 grep --color=auto rabbitmq
rabbitmq 228340      1  0 jun07 ?        00:00:11 
/usr/lib/erlang/erts-5.10.1/bin/epmd -daemon

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