Adrian Cantrill’s SAA-C02 study course, learn.cantrill.io, 75 minutes:
‘Advanced EC2’ section: ‘Boostrapping EC2 Using User Data’, ‘[DEMO] Boostrapping WordPress Directly and with CFN’, ‘Enhanced Bootstrapping with CFN’, ‘[DEMO] CFN-INIT and CFN Creation Policies’
I am now halfway through the SAA course. I have learned a lot, and there is much to learn. Today I have looked more deeply at the concept of boostrapping, and how it can be used to modify and personalize the initial launch state of an EC2 instance. There was also some discussion of the pros and cons of baking in configuration to an AMI vs. bootstrapping, and how the two approaches can be combined to streamline the process of starting an instance.
Also interesting was the discussion surrounding the use of the metadata urls (169.254 ‘repeating’/…/userdata) to inject user data into the code for and EC2 instance, and how user data is the thing that is used to bootstrap instances.
Going through the demo was really fun, implementing the bootstrapping concepts through creating EC2 instances using a .yaml file in CFN to implement the bootstrapping information when creating the stack. Using curl to see the userdata and cd’ing into /var/log and then running cat to output the logging information was more fun with Linux.
This was followed up by theory and implementation for boostrapping with CFN-INIT and creation policies, with the use of ‘signals’ to verify successful creation. I’m not going to comment on this much at present, as I grasped it enough to follow along but will require a couple of passes for it to become more comprehensible. One thing that was kind of revelatory was how the parameter fields changed when I created the init-enabled wordpress stack, and the option to create the username and password appeared in the stack configuration pages. Wild.
I am noticing that I’m becoming a little more familiar with the AWS landscape. Looking forward to what lies ahead.