To make our lives easier as cloud system administrators, we can automate the creation of instances. We can also automate the installation of applications & code on those instances.
Each instance includes meta data (which is shown in the details pane of your EC2 dashboard).
- Launch a new instance
- Enable public IP
- Click advanced details
- In here type:
yum install -y httpd
service httpd startWhat this will do is it will touch the file ‘test1’ and then install apache httpd server & set it running.
- Launch your instance
- type in ‘sudo su-‘ to run as a root user
lsHere you should see test1 as a response (as per your bash script instructions)
- Next, open ‘security groups’
- Edit the inbound rules on the security group to enable HTTP
- You can view meta data
curl http://169.254.169.254/latest/meta-dataThis gives you all the meta data about the instance. You can search a piece of meta data by just adding to the end of that statement. e,g, /public-ipv4
- You can also see the user data and the scripts passed at launch
You can set your automated code to download code from a git repository and install multiple applications. This can also be applied to multiple servers at once (e.g. you could launch 10 servers sharing the same config).
The cloud.cfg file (found in etc/cloud) holds the configuration for the system. This runs at instance creation, not at instance start.
This article was brought to you by Netshock. Netshock aim to provide technology guides and insight to our readers