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**Uma Mukkara:** I'll probably take a crack at it, and I think Karthik can give probably a better answer. I usually separate chaos and engineering as two different words in my mind. People always think chaos engineering is chaos. To me it's easy to introduce chaos. Of course, you have now better tools. It's faster to i... |
But failures do happen because something unexpected, untested has happened, and now we are looking at chaos engineering as a way to unearth those faults in a willful manner. So what is chaos engineering? In that sense it's when a fault happens, what should you look for? How do you actually search for a fault? So that's... |
The tools and the strategy design should go towards thinking more on the engineering side of "How can I avoid a certain loss?" or "How can I unearth a complex scenario or a complex faulty scenario?" and then I can split that scenario into multiple \[unintelligible 00:15:37.14\] And then that becomes easy, actually. So ... |
**Gerhard Lazu:** I'm really looking forward to Karthik's question, but before that, I would like to ask you, Uma, how do you look at a system? How do you look at the steady state of a system? What do you use? |
**Uma Mukkara:** \[15:57\] I would generally define the system in the minds of people who are the \[unintelligible 00:16:03.27\] and what keeps SREs and the management of the SREs up at night. So it's something that is closer to business criticality, the service. So that's what the system to me is. It is not really abo... |
So I would go ahead and define that map, and identify the criticality points, and then start thinking about manually to introduce a fault, what all will shake up, what can loosen up or what can fail, and who will wake up first before the customers start screaming too much. So that's what is the system in my view, where... |
**Gerhard Lazu:** So what I'm hearing is that not only you need to know all the services that make up a system, but also what does it mean for end users to be happy when it comes to using that system? So you define all the services that make the system, and also what does healthy mean for every single component in the ... |
**Uma Mukkara:** Yes. Again, it depends on how evolved or structured the system is. It's really about good dashboards, if you have, and you're using a good service-level object scheme, then you have a system that you are looking at. And if we're only measuring how often the faults are happening, and if you are really d... |
**Gerhard Lazu:** That is a great answer, very complete. A lot more comprehensive than I was expecting, but it was very, very good... Which comes back to Karthik. The question was - I know we talked a lot, so let's restate the question... The question was "What is chaos engineering in one short sentence?" |
**Karthik Satchitanand:** I think we are living in the times of the pandemic, so let's call it "Injecting harm to build your immunity." Just that instead of injecting harm into human beings, we're doing it on systems. So I would define chaos engineering as that. Uma made a good point about steady-state hypothesis - I t... |
So yes, I think chaos engineering is a lot about scientifically trying to understand or mapping user happiness to metrics and logs and events; steady state can be very diverse, and in today's age, that diversity has just increased. You could be talking about metrics, you could be talking about the availability of some ... |
\[20:17\] So I think yes, chaos engineering is about willful fault injection, like you mentioned, Gerhard. Artificially inducing faults in order to verify how the system is behaving, and have good means of identifying the \[unintelligible 00:20:30.16\] steady state, and checking whether it is within tolerable limits or... |
Then it's all about doing it continuously, then going back to the drawing board, fixing your application, business logic, or maybe your deployment practices, coming back and \[unintelligible 00:20:47.09\] proceeding with the next possible outage that you can think of. |
**Break**: \[20:54\] |
**Gerhard Lazu:** This doesn't happen often, but I was talking to one of our listeners, Patrick F. in Slack, and he has a question - more like a suggestion - which I think is a very good one to bring up in this interview, in this conversation, in this episode. Patrick is saying that he would love to hear about practici... |
**Karthik Satchitanand:** I think it makes sense, and I think this is especially true when you're trying to find out how good your security systems are. There's an entire new category, or a subcategory within chaos engineering for security chaos engineering, which people are trying to find out how reliable their system... |
I can relate a lot to Patrick when he says running things in the non-best practice way. You can run privileged containers, mount \[unintelligible 00:23:05.27\] and basically try and see how your system behaves; is it being called out? Do you have the right policies that restrict you from doing so? These are things that... |
Sometimes you would want to see what is the recovery time of your app. Let's say you were not running multiple replicas of an application; you were just going with a single replica, and there was a failure. You might want to figure out how best or how quickly you're able to recover. Maybe reschedule and bring up once a... |
\[24:00\] Sometimes you might want to run in modes that are not classified as the best practices. You would still learn a lot about your system by running that way. So that's something that should be done, but most probably on staging environments or development clusters, because you would not want to attempt this in p... |
**Gerhard Lazu:** Anything to add, Uma, to that? |
**Uma Mukkara:** Yeah, it's actually a very interesting question... You were saying Patrick is asking "Should we implement non-best practices or inefficient practices?" I'm saying the same thing when I say chaos is a best practice. It's a must-have. That really means that you in turn use non-best practices in productio... |
So your best practice is do everything right. Chaos engineering says "Break something. Don't assume that everything will happen." So the best practice is to have chaos engineering. That means the best practice is not to follow always the best practices that you are asked to follow. And the result of breaking things on ... |
So I would say he is 100% right, and he's just put it differently. We are putting chaos engineering as a more polished word, but it's an absolute thing. No one can tell everything will work well. |
**Gerhard Lazu:** I always keep going back to how many learnings I personally used to take from fire drills, or even Red Team Thinking. That was a very powerful one. But taking a step back and summarizing this - you tend to learn more from failures than from successes. So when you fail, there's a lot of learnings there... |
Okay, so that was a good one... Hopefully, Patrick got what -- well, not what he was expecting, but got something good out of this. Now, I would like us to go into a specific use case, and I keep bringing this one up... The Changelog.com application. We are in a unique position to be able to experiment and learn new th... |
**Karthik Satchitanand:** I think chaos engineering is as applicable and important for monolithic applications as they are for microservices. Sure, I think its adoption has been increased because of all this paradigm shift to microservices, and the fact that you have more possible failure points; the surface area for f... |
\[28:01\] In spite of being a monolith, there are some amount of dependencies that you would still have... Let's say infrastructural dependencies. We talked about databases being used as part of the stack; it's very much possible that the disks become slow, your writes become very slow, it's possible that you have spac... |
So this is something that you would still check, even if you were running a monolithic application. And that's true for a lot of other infrastructure components as well. When you do chaos engineering, there are two ways of deriving the scenarios to get started with chaos. One approach is a completely explorative approa... |
The other way of deriving scenarios is to look for data, historic data of what has gone wrong before, and what is the most problematic area. How many times did I have to grow my volume? How many times did I have to increase the CPU course on my system? When there was a lot of interest, a lot of reads, a lot of traffic,... |
So that pattern is common for both monolithic, as well as microservice applications... But the general concept of chaos engineering still applies here, too. It's just that the failures here might be more tied to the infrastructure, rather than something that you would think of in case of a microservices world, where th... |
**Gerhard Lazu:** So what tools could we use to do all those things? Is there a tool that you would recommend that we pick up and try simulating these scenarios, or faults, whatever you wanna call them? |
**Uma Mukkara:** Yeah, you were asking two creators of LitmusChaos project what they would use... Of course, we both recommend -- |
**Gerhard Lazu:** Maybe not LitmusChaos...? \[laughter\] It can happen... Unlikely, but... |
**Uma Mukkara:** If you want to run into real chaos in chaos engineering don't use Litmus, but if you want to stay organized in chaos engineering, you might choose Litmus. |
**Gerhard Lazu:** Okay. |
**Uma Mukkara:** Yeah, the idea of Litmus Chaos is to make sure that we provide a platform, not just an experiment. As I mentioned earlier, chaos engineering is real engineering. You go through managing the experiments, you're managing the steady-state hypothesis logic, and you keep changing it. You're not happy with w... |
\[31:42\] We needed a platform in our prior work life, that's when we looked for some good chaos engineering tools and started writing Litmus, and it became more widely adopted. I would say you can start with Litmus, and Litmus is just a chaos engineering platform... But for you at Changelog I would also recommend best... |
Then I would also say as a prerequisite you need to have good metrics, or a dashboard, even before you apply chaos engineering. Do you have a good monitoring system? Because when you actually do apply, it breaks, but then you need to be able to take care of observing what has gone wrong and "What do I do now?" |
So it all goes hand in hand, and discovery, reliability metrics, an observability system - all those things need to be in place, and then start with probably the backend, in infrastructure. And even though it's monolithic, you can still apply some service-level chaos such as push too much traffic into one of the servic... |
**Gerhard Lazu:** So when it comes to starting with the Litmus platform, I imagine we would need to have an account on this platform? It's not something that we would run, is that right? A litmus is a Kubernetes application. It's not SaaS. So it's a Kubernetes application, completely open source. it's a CNCF project. Y... |
You can run it on your existing Kubernetes, or spin up a small Kubernetes cluster to run Litmus. It is quite thin, but it is a Kubernetes distributed application. You can scale it up. If your hundreds of QA SREs are using a single instance of Litmus, it can scale up easily. |
**Gerhard Lazu:** Do you install it as a Helm chart? Is there like an operator that comes with its own CRDs? How does it get installed on Kubernetes? |
**Karthik Satchitanand:** Yes, you're right about that. You do have a Helm chart that helps to install the control plane of Litmus. As part of the setup process of the control plane you would go ahead and set up the account. The account is most probably about the users, who's going to do the chaos... |
\[35:53\] The next part is about the agent infrastructure. This is the environment you're going to actually do the experiments in. This can be the same place where you have the control plane installed. Uma mentioned that Litmus runs as a Kubernetes app... Or you could have other clusters in your fleet, where you want t... |
**Gerhard Lazu:** So I've seen somewhere - I don't remember where - Argo CD being somehow related to this as well... What is that relationship between Litmus and Argo CD? |
**Karthik Satchitanand:** We use Argo workflows as part of the chaos scenario construction. We chose Argo workflows for its flexibility to order or sequence faults in different ways \[unintelligible 00:37:10.13\] We've instrumented the Argo workflows with some Litmus intelligence. The containers that carry out the step... |
The Argo CD part - I'm sure you might have heard of it more around the GitOps support that Litmus offers. |
When we built Litmus, one of the things we wanted to do was somehow weave in the chaos engineering aspects into the standard GitOps flow that people are beginning to use... And people are trying to use GitOps to ensure the applications and infrastructure is maintaining a single source of truth, that is Git, and ensure ... |
Oftentimes we see that people who've upgraded applications in their environment \[unintelligible 00:38:17.22\] or they have deployed new infrastructure want to verify its sanity. And one means of verifying sanity is by performing some chaos experiments, along with a specific expectation of what's going to happen. And t... |
People want to do those sanity checks whenever they've upgraded their infrastructure or upgraded their applications, and it was done in a manual way, so we wanted to automate that and provide these users or this person with a main store on chaos experiments automatically when something is changed via the GitOps operato... |
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