Homeworks

Goal:

Learn how to configure and run Linux Virtual Server (LVS-NAT and LVS-DR).
Learn how to compile/upgrade the Linux kernel and to configure the machine name and network interface.

Assignment Date: 10/2/2003
Due Day: 11/9/2003
Lab Reservation:

Description:

I have set up 8 small virtual machines as real servers running Redhat 9 Linux and apache web servers . 4 runs on ardor and 4 runs on dilbert. Each only uses 32MBytes of main memory and about 700MBytes of disk space. Note that on dilbert there are also duplicate rsnat1 and rsnat2. If you are assigned to run on dilbert, you can use them also. Since we are using private LAN, the 192.168.2.0/24 on dilbert is different from that on ardor. The IP address assigned to the eth2 interfaces of the 8 virtual machines are

On ardor

On dilbert

Lab Reservation:

Due to limited disk space and the relative speed of the machines, we are divided into two groups. First group only uses the dilbert machine. It consists of students with following login: twbiles, ycai, mechrist, pdcook, asdeshmu, gkgodava. The rest of the class constitutes the second group and uses ardor. Use account cs526 and same password to access these two host machines. The lab reservation web page for 10/3-16/2003 is here.
For 10/17-22/2003 lab serveration, use this web page.

d:\vmware\cs526 contains a folder with your login name. Copy the content of d:\vmware\cs526hw3\lvs directory to your designated directory. d:\vmware\cs526hw3\lvs contains the virtual machine files of a redhat 9 with 2.4.20-8 kernel.

In Exercise 1, configure your virtual machine to have its own domain name and IP address. In Exercise 2, upgrade it to 2.4.21 kernel and patch it with lvs code. In Exercise 3, configure it as the lvs-nat director to work with rsnat1 and rsnat2 real servers as a web cluster. In Exercise 4, configure it as lvs-dr director to work with rsdr1 and rsdr2 real server as a web cluster.

Exercise 1. Run and Configure the virtual machine with its own domain name and IP address.

Exercise 2. Upgrade kernel to 2.4.21 and patches with lvs code.

Exercise 3. Configure LVS-NAT.

In this exercise, we will learn how to configure your lvs using LVS-NAT configuration.
You have a lvsnat virtual machines as a reference.
Login to lvsnat.csnet.uccs.edu (128.198.61.61) using cs526 as username and our typical password.
You will see a set of shell files with .sh file extension. For example, natwrr.sh is used to set up the virtual machine to run lvs-nat and weighted round robin scheduling discipline.
You are to set up the scheduling with 3:2 ratio to real servers rsnat1 and rsnat2 respectively by modifying the natwlc.sh.
Include your natwlc.sh as part of exercise2 answers.
Before running the natwlc.sh, we should set up rsnat1 and rsnat2 to use your lvs, <yourlogin>lvs, as gateway.
To do that, use ssh to login rsnat1 or rsnat2 as root and use our cs526 password.
[root@lvsnat root]# ssh -l root 192.168.2.111
The authenticity of host '192.168.2.111 (192.168.2.111)' can't be established.
RSA key fingerprint is 0d:da:08:20:c9:3c:62:54:c5:7b:4a:b7:50:af:0a:9d.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.2.111' (RSA) to the list of known hosts.
root@192.168.2.111's password: xxxxxxxxxxx
Last login: Thu Oct 2 13:09:35 2003
[root@rsnat1 root]# netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
192.168.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth2
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth2
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
0.0.0.0 192.168.2.61 0.0.0.0 UG 0 0 0 eth2
[root@rsnat1 root]# route add default gw 192.168.2.71
The above assume eth2 inteface of your lvs is associated with 192.168.2.71
Once set up for both real server, you are ready to run natwlc.sh.
You will get the following output:
[root@lvsnat lvs]# ./natwlc.sh
rmmod: module ip_vs_wlc is not loaded
insmod: a module named ip_vs already exists
PING 192.168.2.111 (192.168.2.111) 56(84) bytes of data.
64 bytes from 192.168.2.111: icmp_seq=1 ttl=64 time=1.48 ms
--- 192.168.2.111 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 1.480/1.480/1.480/0.000 ms
PING 192.168.2.112 (192.168.2.112) 56(84) bytes of data.
64 bytes from 192.168.2.112: icmp_seq=1 ttl=64 time=2.51 ms

--- 192.168.2.112 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 2.515/2.515/2.515/0.000 ms
IP Virtual Server version 1.0.10 (size=65536)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 128.198.61.61:http wlc
-> 192.168.2.112:http Masq 2 0 0
-> 192.168.2.111:http Masq 3 0 0
The last three lines should show up. If it does not, check the shell file and the network configurations on all three machines. In the script, we include ping to test if the connection between lvs and real server is up.
Once the lvs is ready, you can go to a web browser and type "http://128.198.61.71/" and see if the return web pages are from those real servers appearing in 3 to 2 ratio.
After the exercise, make sure you reset the default gateway of real servers back to 192.168.2.61 so that others and me can continue to try the 128.198.61.61 VIP.

Exercise 4. Configure LVS-DR.

Read the LVS-DR chapter of the LVS how to document.

Here we will use rsdr1 (128.198.61.101) and rsdr2 (128.198.61.102) as real servers.
We will use only the eth0 interface (128.198.61.0/25 subnet address) on the real servers and lvs. Turn off eth1 and eth2.
Use 128.198.61.1 as default gateway.
Configure LVS-DR with the same weighted least connection scheduling as in Exercise 3.
Find out whether the performance is better than LVS-NAT.
Email me the shell script (drwlc.sh) and routing tables contents of your lvs, and the two real servers.

From Tim Biles:

For those who don’t have Remote Desktop Connection or Terminal Services Client, here is the link to download it directly from Microsoft. It is the latest version which will run on 95/98/Me/NT/2000/XP.

http://www.microsoft.com/downloads/details.aspx?FamilyID=a8255ffc-4b4a-40e7-a706-cde7e9b57e79&DisplayLang=en

LVS-DR

We need to patch kernel to use the hidden flag feature.

[root@rsnat2 lvs]# wget http://www.ssi.bg/~ja/hidden-2.4.20pre10-1.diff
--21:31:40-- http://www.ssi.bg/%7Eja/hidden-2.4.20pre10-1.diff
=> `hidden-2.4.20pre10-1.diff'
Resolving www.ssi.bg... done.
Connecting to www.ssi.bg[217.79.71.85]:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 6,526 [text/plain]

100%[====================================>] 6,526 13.50K/s ETA 00:00

21:31:46 (13.50 KB/s) - `hidden-2.4.20pre10-1.diff' saved [6526/6526]

[root@rsnat2 linux]# ls *.diff
hidden-2.4.20pre10-1.diff
[root@rsnat2 linux]# patch -p1 < hidden-2.4.20pre10-1.diff
patching file Documentation/filesystems/proc.txt
Hunk #1 succeeded at 1567 (offset -6 lines).
patching file Documentation/networking/ip-sysctl.txt
Hunk #1 succeeded at 489 (offset 44 lines).
patching file include/linux/inetdevice.h
patching file include/linux/sysctl.h
Hunk #1 succeeded at 344 (offset 5 lines).
patching file net/ipv4/arp.c
patching file net/ipv4/devinet.c
Hunk #2 succeeded at 1057 (offset 24 lines).

Homework #3. Configure a Linux Virtual Server

Lab Reservation:

From Tim Biles: For those who don’t have Remote Desktop Connection or Terminal Services Client, here is the link to download it directly from Microsoft. It is the latest version which will run on 95/98/Me/NT/2000/XP.

From Tim Biles:

For those who don’t have Remote Desktop Connection or Terminal Services Client, here is the link to download it directly from Microsoft. It is the latest version which will run on 95/98/Me/NT/2000/XP.