CloudFormation is the core functionality provided by Amazon Web Services in the area of expressing infrastructure as code. One can write the infrastructure design in either JSON and YAML (with similar syntax keywords); there is also a template designer that may help in putting together the infrastructure elements and their dependencies. The particular details of each resource being defined must be coded out, though.
There are no limitations on the types of resources that can be brought up, as far as I noticed – each resource type provided by Amazon can be coded and subsequently created and provisioned. One can also define an explicit order (e.g. some resource to be created before another), apart from the implicit order that can be deduced (e.g. if an EC2 instance is defined with a IAM Role, the role is always created before the instance). The revert process is also clean: deleting the CloudFormation stack does delete everything created by the stack itself; nothing gets left behind.
Note: The first 2 episodes of the interview series can be found here and here.
Question 1:
The interviewer comes in and hands you the following ls -la listing:
# ls -la total 108 dr-xr-x---. 7 root root 4096 Sep 5 07:16 . dr-xr-xr-x. 22 root root 4096 Sep 1 17:43 .. -rw-------. 1 root root 15432 Sep 5 06:36 .bash_history -rw-r--r--. 1 root root 18 May 20 2009 .bash_logout -rw-r--r--. 1 root root 176 May 20 2009 .bash_profile -rw-r--r--. 1 root root 176 Sep 23 2004 .bashrc -rw-r--r-- 1 root root 0 Sep 5 07:16 -f ...
They say the -f file must go; would you please delete it?
Amazon CloudWatch is the monitoring tool for all the Amazon Cloud services. It offers both White Box and Black Box monitoring for services managed by Amazon and can be extended to work with user-generated monitoring data.
This text covers the integration of a simple MySQL monitoring script with Amazon CloudWatch.
MySQL Monitoring
Let’s assume that we want to monitor the number of active connections to the MySQL server and have an indication on when this figure becomes close to the maximal value defined in the configuration file (max_connections). In order to be portable, we may want to also report this value to the monitoring engine, even if it’s unlikely that a change may occur without explicit human intervention.
MySQL provides 3 numeric figures we may be interested in: