AWS provides a complete monitoring engine called CloudWatch; it works with metrics – including custom, user-provided metrics – and is able to raise alarms when any such metric crosses a certain threshold. This is the tool that is used for all perfomance monitoring tasks within AWS.
This text will cover a monitoring scenario regarding deploying an arbitrary appplication to the cloud and being able to determine what causes the performance limits to be met, be it the application code itself or resource limits enforced by Amazon.
Scenario
Let’s assume that one has just started using Amazon Web Services and is deploying applications on free tier or other general purpose (T2) instances. One learns that the general purpose instances work with “credits” that allow dealing with short spikes through performance bursting – but once the credits are exhausted the performance is reverted to some baseline. All the particular details do not make a lot of sense but one needs to know if the application can meet the desired service limits with this setup.
The big data repository known as Chef Server is manipulated with a tool called knife. The general (simplified) syntax for this tool is:
$ knife category command item
The category can be one of: environment, client, node, data bag, cookbook, … The full list can be found here.
The command (usually) is one of create, list, show, edit or delete. There are more commands, though, depending on what is being requested through knife.
On the cheat sheat itself, let’s start with some classics:
I just got myself LPIC-1 certified (verify). I’ll try to address a few issues here, if anybody else wants to do it and doesn’t know how.
Introduction
The LPIC-1 is granted upon passing 2 exams:
Exam 101 – more theoretically oriented, with many general questions.
Exam 102 – more practically oriented, with an emphasis on Scripting, Networking and Security.
The exams can be passed in any order, the certification is automatically granted upon passing both. Also, in order to get certified on the subsequent levels, you need to already have the lower level certification at hand. That is, for one of the LPIC-3 certifications you need to pass a total of 5 exams, in any order.
Logistics
The “official way” of taking exams is through a Pearson VUE test center. You need to first purchase an exam voucher (EUR 150 approx, might fluctuate with exchange rates) and then go take the exam on a computer in a controlled setup.
The “alternate way” is to attend a conference where pen/paper exams are offered. In Europe you may want to register your seat on this site, then attend that particular event. The cost for taking the exam in such setup is lower and may be the way to go if you plan to attend the conference for other reasons than taking the exams alone.
I have personally taken both 101 and 102 exams during the FOSDEM 2016 event in Bruxelles, Belgium, on January 30 and 31st.