Quick Start CentOS7

Quick Start - CentOS7

Time required

20 minutes or so.

Assumptions

• You have a CentOS7 server installed with "Minimal" package
• You login to the server using "centos" user id
• "centos" user is configured to use "sudo"
• You are going to graph the traffic of the device "rtr", whose IP address is 192.168.0.254
• You have configured the device to be polled with a community name "public"
• The update frequency of traffic data is 5 minutes

Steps

1. Make sure that SELinux is disabled.

$ getenforce
Disabled

2. Install "net-snmp-utils", "httpd", "unzip" and "epel-release". "epel-release" is needed to install "jq".

$ sudo yum -y install net-snmp-utils httpd unzip epel-release

3. Install "jq"

$ sudo yum -y install jq

4. Download nwUsagi code.

$ curl -o /tmp/nwusagi.zip https://codeload.github.com/datacrat/nwusagi/zip/master

5. Unzip the code into "/var/lib" directory

$ cd /var/lib
$ sudo unzip /tmp/nwusagi.zip

6. Rename the extracted directory "nwusage-master" to "nwusagi"

$ sudo mv nwusagi-master nwusagi

7. Change the owner of "nwusagi" tree to "apache:apache"

$ sudo chown -R apache:apache nwusagi

8. Make your user id belong to "apache" user

$ sudo usermod -G apache centos

9. Logout then re-login to group membership make effect

10. Make "nwusagi/conf", "nwusagi/data/live" and "nwusagi/tmp" to be group-writable

$ cd /var/lib
$ sudo chmod g+w nwusagi/conf nwusagi/data/live nwusagi/tmp

11. Check if "rtr" (192.168.0.254) is reachable via SNMP using "public" community

$ snmpwalk -v2c -c public 192.168.0.254 ifIndex
(You will see the series of the output like "IF-MIB::ifIndex.1 = INTEGER: 1")

12. Add the entry for "rtr" into "nwusagi/conf/devices"

$ echo -e "rtr\t192.168.0.254\tpublic" >> nwusagi/conf/devices

13. Add a crontab entry to poll "rtr" every 5 minutes

$ crontab -l > /tmp/$(whoami)_crontab 2> /dev/null
$ echo "0-59/5 * * * * /var/lib/nwusagi/bin/nwuUpdate.sh rtr" >> /tmp/$(whoami)_crontab
$ crontab /tmp/$(whoami)_crontab

14. Wait for the 1st poll and check if the data collection is successful

$ cat nwusagi/data/live/rtr 
(You will see a series of numbers in a row separated in TAB)

15. Configure apache to serve WDC as designated in nwUsagi

$ sudo sh -c "echo \"IncludeOptional /var/lib/nwusagi/conf/httpd-*.conf\" >> /etc/httpd/conf/httpd.conf"

16. Start apache

$ sudo systemctl start httpd

17. Configure firewalld to allow access via TCP/80

$ sudo firewall-cmd --add-service=http --permanent
$ sudo firewall-cmd --reload

18. Launch Tableau in your PC/Mac and navigate "Connect" -> "Web Data Connector". You will see the screen like below.

19. Put "http://<Your CentOS7's IP>/nwusagi/wdc.html?device=rtr" into URL field. Wait for contents (Device name, list of columns) to appear

20. You will see "Pull Data" button in the bottom of the window. Press it

21. In the bottom of the window displayed, press "Sheet 1"

22. From "Dimensions", drag "Timestamp" and drop it to "Columns". Hover over the dragged item (should be "YEAR(Timesta..)", press triangle and select "More" -> "Minute"

23. From "Measures" pick one of the metrics and drag&drop it to "Rows"

24. You will see a continuous line graph is drawn

Note: To update (refresh) the data to be drawn, navigate "Data" -> "nwUsage WDC ()" -> "Refresh".

Enjoy!