OPS345 Lab 3
- www instance was created in the last lab, with a static private IP, and port fowarding done from port 2211 on router to port 22 on www.
- yum install httpd iptables-services
- enable iptables
- before starting the service, we'll configure the server to store all webpages on a separate volume: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ebs-attaching-volume.html
- 1GB in us-east-1a
- rename to www-data
- attach to www (note reboot is not required)
- ls /dev/xvd* -l # note /dev/xvdf
- vgcreate vg_www /dev/xvdf
- lvcreate -n lv_www -l 100%FREE vg_www
- blkid
- ls /dev/mapper/vg_www-lv_www
- mkfs.ext4 -L www /dev/mapper/vg_www-lv_www
- vi /etc/fstab
- /dev/mapper/vg_www-lv_www /var/www ext4 defaults 0 0
- mount /var/www/
- ls /var/www/
- mount | grep /dev/xvd
- ls /var/www/
- mkdir /var/www/html
- vi /var/www/html/index.php
Hello. My web server still works.<br /> If this shows the current date and time, PHP works too:<br /> <?php system("date"); ?> - chown -R andrew /var/www/html
- systemctl start httpd
- On router: iptables -t nat -I PREROUTING -p tcp --dport 80 -j DNAT --to 10.3.45.11:80
- On www: iptables -I INPUT 3 -p tcp --dport 80 -j ACCEPT
- service iptables save
- Edit security group, allow HTTP
- ss -atnp on router and www
- install php, restart httpd
- make proper html page:
<html> <head> <style> body {background-color: powderblue;} table {border-spacing: 1cm 0cm;} h2 {color: blue;} th {text-align: left;} p {color: red; font-weight: bold;} </style> </head> <body> Hello. My web server still works.<br /> If this shows the current date and time, PHP works too:<br /><br /> <?php system("date"); ?> <h2>Instance Info</h2> <table> <tr><th>Configuration</th><th>Value</th></tr> <tr> <td><p>Private IP</p></td> <td><?php system("curl http://169.254.169.254/latest/meta-data/local-ipv4"); ?></td> </tr> <tr> <td><p>Public IP</p></td> <td><?php system("curl http://169.254.169.254/latest/meta-data/public-ipv4"); ?></td> </tr> </table> </body> </html> - Removing public ip doesn't work. Have to modify subnet and recreate the vm:
- Terminate www, rename it to www-deleted.
- Modify subnet to not auto-assign public IPs.
- Recreate the www instance with the same steps, except specify a primary ip.
- Install httpd, php
- To get yum install to work, allocate a new elastic ip "temporary" and associate with www
- Note that www-data was not deleted when the original www was terminated. Attach it to www now.
- All the data on the logical volume is still there, but fstab is gone, add lv-www back into there.
- Start httpd, everything should be back to as it was.
- Dissasociate the public ip. Everything should keep working.
- Add a 404 check for missing ip:
<?php
system("curl http://169.254.169.254/latest/meta-data/public-ipv4 2>&1| grep -q '404 - Not Found'", $rc);
if ($rc == 0)
echo "None found";
else
system("curl http://169.254.169.254/latest/meta-data/public-ipv4");
?>- If you feel curious you can see what other metadata you can get via http://169.254.169.254 here: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instancedata-data-retrieval.html
