If you are in the business of developing and running web applications there's a lot overlap between dev and ops in terms of knowledge. If you have to troublesho

If you are in the business of developing and running web applications there's a lot overlap between dev and ops in terms of knowledge. If you have to troubleshoot something you need to know HTTP Headers, CORS and related topics. Who is in charge when the latest update of Chrome breaks your clients' websites? Wearing both hats certainly helped us fixing stuff easier by inserting headers through HAProxy although our regular job is programming. What about performance optimization? Can that slow SQL query be fixed through tuning the MySQL server or maybe just rewrite the code?