SNMP message to fetch the %CPU and %Memory

>I am trying to write a program in Java which should be able to send the SNMP message to and receive the response SNMP message from the server. I learnt that SNMP uses the User Datagram Protocol. But I am unaware how this DatagramSockets can be used and how to format the data to be sent to SNMP server?

Some times ago I used JoeSnmp to do this.

>It seems we have to encode/decode the data.

Sure!

Giant.

http://sourceforge.net/projects/joesnmp/

Here for the code:
http://www.opennms.org/files/releases/joeSNMP/latest/

Do you solved?

Hi Giant2

Not yet. I am looking into joeSnmp and other packages. I have to evoluate which is best for our project. My be by this weekend, I can come to some conclusion.

Thanks for your concern.
Regards
Murali

Ok.
Post what is your final decision.
Thanks.

Hi Giant2,

Please clarify me one thing. I am trying to understand what the joeSNMP can do.

With joeSnmp, can I get the system statistics of a remote server? I mean I will run a program on a manager machine (Could be a windows system with the joeSnmp jar package) and get the system statistics of a remote server?

Regards
Murali

Hi Giant2,

How far is JoeSNMP reliable?

Regards
Murali

I believe 99%. I tested for building the Agent and it goes well.
I didn't notice any defeating. It was not full because you must implement something, but it's good.
Building a ServerAgent the work must be really little big, but for the client (I understand you want to do this), it's a good API.

Hi Giant2,

Yeah, I want just the client part.

I was going thrpugh the test java program snmpwalk.class to get the ssCpuRawUser values etc,. This program appears to be taking only one OID at a time. For ex:

java org.opennms.test.snmpwalk -v 2 -c public -r 2 -t 10 -p 161 172.17.12.76 1.3.6.1.4.1.2021.11.50

1.3.6.1.4.1.2021.11.50 is for ssCpuRawUser.

I have two doubts here:

1. Can I fetch the values of ssCpuRawUser, ssCpuRawSystem, ssCpuRawIdle etc simultaneouly within one command? WIth the snmpget comman we can get do this by the following command:

snmpget -O v -c private localhost ssCpuRawSystem.0 ssCpuRawIdle.0 ssCpuRawUser.0

Can the same be achived by this joeSnmp?

2. I need to get the average %CPU usage for every 5 mins period. How can I achieve this?

Please help me in this regard. Its really urgent and I am worrying a lot as this is already delayed for me.

Thanks and Regards
Murali

>1. Can I fetch the values of ssCpuRawUser, ssCpuRawSystem, ssCpuRawIdle etc simultaneouly within one command? >WIth the snmpget comman we can get do this by the following command:

Maybe yes. It's possible to take some OID simultaneously. I don't remember if snmpget of JoeSNMP implement. (I checkit in the meantime).
But you can rewrite your own what snmpget do.

>2. I need to get the average %CPU usage for every 5 mins period. How can I achieve this?

I did something like this. I used a Timer (java.util.Timer) scheduled every 10 seconds. in the run method I made the getSNMP to the server.
SNMP is done only to get and set values, not to schedule task. So you must implement your own this feature.

Hi  Giant2

I can schdule the task programatically ( implementing a thread ). The problem is getting the required values through snmpget.

>Maybe yes. It's possible to take some OID simultaneously. I don't remember if snmpget of JoeSNMP implement. (I checkit in the meantime). But you can rewrite your own what snmpget do.

Do you mean, that I can write some thing like snmpget.java on my own similar to snmpwalk.java?

Please give me some sample source code u have implemented for both of my earlier requests.

Thanks and Regards
Murali

for multiple OID request see the "snmpwalkmv" taking with JoeSNMP sourcecode. In it you can specify many OID.

...your code...

 
private Timer poll=new Timer();

public void polling(){
    logger.info("Starting polling");
    try{
      poll.cancel();
      poll.scheduleAtFixedRate(getNewPollingTimTask(), 0, 5000);//wait 5 secondi before starting polling
      }catch (java.lang.IllegalStateException ise){//the timer cannot be scheduled
        poll=new Timer();
        poll.scheduleAtFixedRate(getNewPollingTimTask(), 0, 5000);//wait 5 secondi before starting polling
        }
    }

  //create a TimerTask
  private TimerTask getNewPollingTimTask(){
    TimerTask tt=new TimerTask() {
      boolean firstPol=true;
      public void run() {
          if (!firstPol){
            logger.info("Starting poll");
            //CALL HERE YOUR METHOD TO GET THE VALUE USING SNMP
            long delay=50000;
            try{
              poll.cancel();
              poll.schedule(getNewPollingTimTask(),0,delay);//re-schedule after delay milliseconds
              }
            catch (java.lang.IllegalStateException ise){
              poll=new Timer();
              poll.schedule(getNewPollingTimTask(),0,delay);//re-schedule after delay milliseconds
              }
            }
          firstPol=false;
        }
      };
    return tt;
    }


Hope this help you.
Bye, Giant.

Hi Giant2 ,

Thanks for the code sample. I am sure u gave this is for scheduler. I am implementing a thread for scheduling.

I have modified the snmpwalk.java and wrote a snmpget.java class which can acept many OIDs and get the values. I could successfully fetch the values.

Now my problem is how to calculate the %Cpu of the User application for a period of 1 minute?

For ex: I could fetch the ssCpuRawIdle, ssCpuRawUser and ssCpuRawSystem at 10:00:00 Hrs. These values are say  6413622,  35307  and 6591 respectively.　
After 1 minute, i.e. at 10:01:00 hrs, the values are 6422453,  35407 and 6605 respectively.　

With these values, I could not make a formula which can give me the % average CPU usage by User applications? Can you please give me some idea?

Thanks and Regards
Murali

I did the same things asking to a Linux machine. At my project I let to calculate the average to the Linux server. (using the right MIB)
I believe if you want t o implement on the client side at each instant you cannot have the right average, but the average calculated from the first snmpget you did.
You can calculate the average following 2 ways:
1) create 2 variable: one for saving the total and one saving the number of SNMPget you did.
For each snmget you did: add to total the value you read; add 1 to numOfSNMPget.
The average will be total/numOfSNMPget

2) (but it's not really a real average) create 1 variable named "average".
For each snmget you did: add to average the value you read; make this instruction: average=average/2.
In the average variable there'll be the average calculated (but, I repeat, it's not a real average)

If you are interested to the average of use of a machine, I repeat the previous suggested.
Find some MIB(and Agent obviously) do this for you. So the only thing you must do to know the average is only a getSNMP.

Hope this help you.
Bye, Giant.

Do you solved?

Hi Giant2,

I am still working on this. I could make the snmpget class and simultaneously getting the values. I found in http://www.net-smp.org/FAQ.html on how to caclulate the % CPU Utilization. I am right now working on this. I hope this will be over soon.

Regards
Murali

sorry, but the address you posted is not reachable.

Whow, now I see the link.

Hi Giant2,

BTW, I could succesfully get the values of CPU usage. But the memory available is giving a problem. On t he SNMP agent side ( i.e. server side ) when I execute the following command,
snmpget -c private localhost memAvailReal.0
it is always resulting in the following value:

UCD-SNMP-MIB::memAvailReal.0 = INTEGER: -1

Any idea how to fetch the memAvailReal?

Regards
Murali

UCD-SNMP-MIB, so you follow my suggestion:
>Find some MIB(and Agent obviously) do this for you.
:)


I see you use
memAvailReal.0

try to use the oid representation of memAvailReal. Sometimes agent doesn't support the name casting.

Do you have the same problem with other oid? If yes, probably the agent (server side) doesn't go well.

I tried that also like

snmpget -c private localhost 1.3.6.1.4.1.2021.4.6.0

There is no problem with other OIDs.  My server is Redhat Linux. Is there any problem with Redhat Linux?

Murali

As I told before, probably the agent (server side) doesn't go well.
Check the Agent state and features enabled.

Please tell me how can I check whether the feature for memory MIBs enabled or not?

Regards
Murali

Sure.
The MIB you use is connected to an Agent.
The Agent has a producer. So you can see to what producer says about it.
Normally (in Linux) there are separated modules which take the data from the system environment (access to localhost files).
But to know what file and where, you must search to the producer documentation.
Each Agent could have a different way to access these data.