Chris Paquin

AI, Virtualization, Containers, Infrastructure, Linux

Category: Monitoring

  • How to use SAR on Redhat

    Eyeball Sar is a system monitor command used to display system activity. Sar ts installed via the sysstat rpm. Use the command below to install sysstat.

    [root@fedora ~]# yum -y install sysstat

    Once installed you can check out the sysstat config file (/etc/sysconfig/sysstat) and configure how long to sar will keep your logfiles, on my system the default was 7 days. I changed this to 30 days.

    The cron job for sar is located here (/etc/cron.d/sysstat) if you want to modify it as well.

    Once installed and configured to your liking you must ensure that it starts and runs at boot time. I accomplished this via the command below.

    [root@fedora ~]# chkconfig sysstat on && service sysstat start

    Once up and running it will write its logs out to /var/log/sa, and you can read those files with the following command (sar -d <filename>, where filename is the name of the file that you want to read). Note that in the examples below, 3 is the interval, and 10 is the count.

    Additionally you may run sar interactively, below are a few sample commands.

    View disk i/o and transfer rate stats:

    sar -b 3 10

    View memory and swap space stats:

    sar -r 3 10

    View swapping stats:

    sar -W 3 10

    View network stats:

    sar -n DEV 3 10

    View CPU stats:

    sar -P ALL 3 10

  • Enabling SNMP in ESXi 4.1 using the Remote CLI

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    Based on the fact that ESX 4.1 is the last major release of ESX, I decided that I would make myself familiar with managing ESXi hosts.  Since I monitor all my hosts via Zenoss, I figured that I needed to get snmp up and running first.

    So I first when out and installed the remote cli for ESX on my ubuntu desktop.  The rcli can be downloaded here. The remote cli allows you to run command administrative commands against ESX/ESXi systems. Its availbile for Windows or Linux.

    Configuring on ESXi 4.1, Licensed

    First configure your community string, target, and port:

    vicfg-snmp –server <ESXi_ip> -c <communityname> -p 161 -t <destination_host>@161/<community name>

    Then enable it using the command below:

    vicfg-snmp –server <ESXi_ip> -E

    Next verify your settings:

    vicfg-snmp –server <ESXi_ip> -s

    Now test your settings:

    vicfg-snmp –server <ESXi_ip> -T

    These settings are written out to /etc/vmware/snmp.xml. Sample file below.

    /etc/vmware # cat snmp.xml
    <config>
    <snmpSettings>
    <communities>pubic</communities>
    <enable>true</enable>
    <port>161</port>
    <targets>10.1.xx.xx@161 public</targets>
    </snmpSettings>

    Configuring on ESXi 4.0, Free/Foundation

    I had a couple of ESXi 4.0 free hosts to configure, but my attempts to configure them using the cli failed as the snmp settings via cli were read only. So the first thing that you need to do is enable the unsupported console. Instructions can be found here.

    Once you are able to ssh to the ESXi box, you need to edit the following file by hand, /etc/vmware/snmp.xml. Use the sample file above as a template and modify your ip, port, and string as needed. I use vi to edit mine.

    Then run the command below

    services.sh restart

    You can then verify your settings using the remote cli by running the command below against your esxi box.

    vicfg-snmp –server <ESXi_ip> -T