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From YouTube: OpenShift Coffee Break - Operators Series: Operator SDK

Description

Get your espresso ready for the OpenShift Coffee Break as we kick-off our new series on how to write Operators on Kubernetes! Today we welcome Dario Tranchitella, Kubernetes Engineer at Clastix, that will walk us through Operator SDK and how to create Kubernetes Operators.

Twitch: https://red.ht/twitch

A

Good morning, good morning, everyone welcome back to the openshift tv coffee break good morning. Everyone, I'm very happy today to start our weekly series about the openshift coffee break, I'm here with my friend andrea. How are you andrea.

B

A

B

A

London and I'm here with my friend taro, how are you taro.

C

Awesome. Thank you.

A

Oh nice cup um today we have a special guest, but before presenting our special guest and our topic, please uh enjoy your coffee, because this is the open cheese, coffee break um so welcome to dario tranquitela. That will kick off our new series about how to ride an operator on kubernetes hi dario. How are you.

D

Hi natalie, I'm really good thanks a lot really happy to be here.

A

So why we invited that or the people may think how, while you invite random people from the community and and they they start talking about everything um dalio um is experienced, passionate about kubernetes operators and actually it wrote an operator using operator sdk. So that's why we invited today him to share his uh experience with this tool and also to explain us a little bit how what is an operator, uh why we should write an operator on kubernetes and how we can make production grade operator that I said production uh word.

A

Did I write any alarm in your systems.

D

No, no, everything is fine, don't worry.

C

Production great, let's use the first hour to define production great.

D

Production way, production grade is v1 alpha, 1 api version. You know.

A

So folks, let me try if our macros in the chat works. I'm writing! Oh, that works also from here. So you see in the chat on your right. If you are from youtube or twitch um you, we use the chat to uh send the question to the to the people in our show. So if you have any question during the show, please uh send in the chat we will uh send all the questions to dario and that in need to also need to reply live uh of course, and dario is here.

A

Terror and andrea also for uh live demos, because this is mandatory for this show as usual. um Today we don't have jafar's. Jafar today was a busy. We will have it next, uh the next wednesday. So the first big news folks, is that the openshift coffee break now goes weekly. If you look at the openshift calendar and I'm sending the chat soon, you will see that now our we are weekly and we have a very cool schedule. There's the operator new operator uh series there, the database as a service series.

A

We have lots of people the next time we will have the red hack fest winner, so we're really excited to to be uh kind of uh promoted to a weekly show and after this uh wording, uh dario terror. Andrea. Do we want to start from the basis? So what is a kubernetes operator.

C

One more more important question: are we going to double our compensation since we have twice many shows now.

A

uh Well, I don't think so, but we can.

C

Zero, zero zero times two is still zero, so I think that we are fine, yeah yeah.

A

We we can check, we can. uh We can rise this concern, uh but I don't think so so dario coming back to the to the topic. What is an operator.

D

I had many discussions about that, because a lot of people say is well. An operator is just a new password to say that a custom controller you know, because sometimes we tend to miss that kubernetes is made of several components of several controllers.

D

When you deploy a service account when you deploy a role, binding and so on and so forth, there is a controller that is doing all the magic. So when you create the service account, you are going to get the secret with all this stuff containing it. So essentially there is a controller, but I wouldn't say that an operator is just a simple controller. Okay.

D

Why? This? Because uh we have always to remember that terminology is really important. When I operate the cluster, I'm an operator, okay, it means that I know all this stuff that is going on inside the cluster. I know the business logic, all the moving parts, and it means essentially that I'm creating all the domains, logic, all my business logic from the operator side. So from the human side, inside an application that could be a go operator, it could be a helm operator, an ansible operator and so on and so forth.

D

Whatever you want so essentially, I will say that the operator is the translation of a human form in a binary form of all the cluster management. So it's something uh more in advance than a simple controller deal with that.

A

It's good that you mentioned the word controller. I think dalio. We need to understand that kind of uh kubernetes uh kubernetes internals. uh Can we can you explain to to us to the audience? uh What is this concept of controller? Because I think this is really important to understand.

D

Sure sure, let's go from the basics, so uh when we spawn a part well, let's start from the beginning, so I would like to spawn an application on my cluster yeah. I can do that in many uh ways I can create a demon set. I can create a deployment. Sometimes all the hello world examples says that okay, you have to deploy your deployment, so it's much easier.

D

So when we deploy uh deployment, sorry for the word stroke, essentially, we are ending up with multiple resources. The final effect, the final result is going to be appalled inside the namespace, but that part uh is a direct consequence of a replica set.

D

So when we create the deployment we are getting a replica set and then the replica set is creating the part, it means that uh from the kubernetes control plane perspective, we have several components. We all know that we got scd and hd is our uh her, because we are containing all the information about the cluster state.

D

Then we got the api server, so the rest api that we are using to interact with the control plane. We got the scheduler and then we got also a component that is named controller manager and this controller manager is a huge monolith. Full of controllers and all these controllers are watching uh for some actions. So when we are creating a resource in our hcd or I would say in our backing storage, uh these controllers are going to take uh these requests and translating in other resources.

D

So when we create the deployment, the controller deployment is going to create the replica set and the replica set is going to create finally deposed. So these are a sort of binaries, I would say, not operator, because otherwise we could um create some confusion there, but they are watching for some resources and applying to the desired state. So translating from the imperative way of saying, I would like to get this stuff. That is going to be persistent story in scd and then translated in some other resources.

A

Well, thanks daddy this. This was very, very helpful to understand internals in the while you were speaking, I I put in the chat some links to the kubernetes operator pattern, kubernetes components because you mentioned at etcd. You mentioned the controller, so I think it's very good to understand how they work, but thanks for this explanation, because uh this, I think, is the introduction to everything no um and uh dario before you go in in depth. I want to do unchanged here.

A

So, if you see since we're talking about operator, let me put this new background here. Okay, so now I'm ready to talk about kubernetes operators and uh yeah. That was a little joke. I was planning, but it's cool, because uh also we will share the link uh to download this uh ebook for free about kubernetes operators. But today, here we're here, daddy for live demos live show. So the first thing I don't know andre. If you have a question for this introduction about the internals um before.

A

If, if you don't have a question about those internals, uh I think we can go to the first step dario. So uh we understood the the the the introduction uh now we would like to understand uh why operators for building a new operator and and how to do it, but first terror, andrea. Any any question for this internals.

C

That that was spot on, because it's not easy to explain what happens in kubernetes cluster people know port services and everything, but what is actually happening there. So it's it's not easy to explain, and that was a really good one.

B

And yes, I think that maybe maybe one one thing that could be added to that is uh that you have the freedom to decide how you would implement it by by coding it, and you have choices on how you code it.

D

Yeah absolutely, I was missing also another example. That could be more easy to understand because I was you know um when we deal with kubernetes, sometimes I'm feeling uh the toughness the fact of the knowledge, because I know a lot of stuff. I know a lot of internals, so maybe it's better to try to explain also controllers with a simpler example. So we have a pot. Okay, that's great! A pod is made of several containers.

D

We got c groups and spaces volume mounts and so on and so forth, but parts they got also some ip addresses. Okay, let's keep it uh for single ip. No, so let's avoid dual suck okay. uh How can we get the traffic to that port? It means that we have an endpoint resource, so it means that we got a controller and that's the endpoint slice or the endpoint controller that is watching for parts getting their eyepiece and then finally updating to the point resource. So we can get traffic from other services to the pods.

D

So it's much, maybe it's much better explaining how controllers are working and yeah andre you're, totally right, so controllers are doing stuff for the government stuff. Okay, instead operator is something that you can craft. I would say it's craftsmanship.

A

Yeah thanks um and I would like to also remember uh remember the people in the chat and uh that see more people are coming. If you have any question to that, please send in to the chat. So we will we. We have the chance to reply your question this uh hour, uh but I know that you that there will be more and more question while you kind of uh hands on so when you are ready. Let me know- and I can we can start in in the in the deep dive.

D

Sure sure so, let's go for the code or do you would like to get also a sort of brief introduction? Why I'm here explaining why operators are so important, yeah.

A

Please please, uh and do you want with your, do you want to share anything or um or or not? Do you any any.

D

Well, well, uh we can start with the code because you know I really love the code. So it's pretty that's simple.

A

Okay, another one, only one thing: dario: uh can you please increase the font, absolutely.

D

A

So the people- because this is an embedded window, so the the people can see thanks. I.

B

Guess yeah yeah.

D

So writing an operator is really simple, because what you have to do is to pick a human form, put it in front of the terminal and say operate the cluster, no joke support. So we are lucky enough because we got a lot of stuff out there. My first experience writing operator was using the sample controller. Although you're saying dario, you just told us that controllers are not operators well you're right, but it's the starting point and a lot of tools are out there. We got cube builder, we got operator sdk. We got also cap.

D

If I remember correctly the name, so you can write whatever you want in whatever language you will like and honestly uh during these years I felt very good with operator sdk for several reasons. I had also experience with keybuilder, but I guess that operator sdk is good enough, because in the end uh is not so much opinionated I mean uh the operator is not just code. Well, it's code, but it's more a pattern behind that. uh I still remember that chorus were the inventors of the operator pattern and what is an operator pattern?

D

So essentially you got a request. Reconcile request and you're watching uh the current state and moving it towards the desired state. So it's a reconciliation loop, something that we already know in kubernetes, because uh it's the core concept behind beretus. uh There is a drift in the configuration. I apply all the changes to reach out to the desired state.

D

So with the operator pattern, we can get everything that we want, so we can put our business logic and it means that we can do in several ways. We can write our code and honestly, I really love that way, because I'm a former software engineer- or at least I'm I'm still a software engineer, because uh it's like a mark, you cannot get out of that, but you can also break the cluster using hand using your ansible.

D

It really depends on the scope of your operator, so operator. Sdk is really good at uh doing this stuff because it says you can use hansible, you can use um whatever you want, so you can write your code. So I'm feeling very good about that. So how to write that. So, obviously we need our binary. It can be downloaded by.

C

Dario one one, quick question: if you, because at the end of the day operator, is just young files and container in the cluster just simplified and you can create operator without the sdk, how much the sdk sdk helps you to do that. If you compare that simple operator, sdk takes x amount of time. So how how much more it would take without the sdk.

D

uh A lot of time, honestly, uh it's a question more. Regarding software development, I would say, because uh it's a common question that we I faced several times across my career when I was working in our companies that were saying so, should we use a framework or should we build our framework and it's a matter of payoff. You know, because uh you can create your framework, that's good enough, but there is a downside, and the downside is that you have fully ownership of that project.

D

So it means that you have to break upgrade it uh the doing bug, 3-h, doing implementations and so on and so forth, and also providing documentation and ramp up for new developers, because it's something that is not public, or at least it couldn't be public.

D

Instead, if you go for something that is a sort of standard or something that is provided by the community like operator, sdk is much easier because there are plenty of examples. There is a community uh it's much more easier. Also. Regarding the debugging uh across my career, I had also the pain to debug others, the others operators and the best way to do that is to looking at the code. Okay, because code doesn't lie so when.

A

D

A

Lie I like this, can we can we have a caption called? Doesn't live, that's true by the way.

D

Because uh when I have to try to understand what's going on, if I open a project that has been scaffolded using operator sdk, I can easily jump out to the section where I think the bug is or if I have to check out the api types or I have to check out. Also, I don't know the example, the examples of the custom resource definition, it's that simple, otherwise, will be a pain because you know it's like creating a a new protocol. There are plenty of protocols all day, all of them sucks all of them suck.

D

So, let's create a new protocol. Well, it's not the kind of way of working. So uh I hope I replicate your question.

C

Yeah, that was just just the audience understand that the aztec is this really an sdk that helps you to get started.

D

C

D

That simple, that's simple: okay,.

A

Sebby in the.

D

A

Now, with operator sdk, you can also scaffold the quercus java operator project. This is true and we will see in the next episode on second march, the second, but uh that this is also introduced. The concept so right now we're seeing we are scaffolding, a new operator, but is it language specific?

A

uh Can I develop my operator in any programming language, or is there any preferred programming language.

D

Well, actually, with operator sdk, you have to write everything in go and I would say that uh I had several questions regarding, should we use go or python or java and so on and so forth? And honestly it really depends. But I understand that saying it really depends. uh Doesn't answer any questions, so I will try to elaborate a bit more. So if your team is mostly focused on java or python or whatever language you prefer, I don't think that the payoff is positive. Switching over go okay, because that will require a huge mind.

D

New mindset of developing, uh I really hate when I see python code that has been wrote in a different way in not not in the pythonic way. You know, and the same also applies for goal when I see go that has been written by people that works mostly in java.

D

I will I don't know, I don't know if I can say bad words, but that would be really bad bad bad. So, let's try always to focus on your knowledge. So if you would like to extend kubernetes- and you know, go you can use operator sdk, otherwise you can use whatever you want. I don't think that the runtime here is uh is the silver ballot. Okay, the real silver palette is translating all your business logic inside the operator, because the operator is just a tool.

D

The runtime gog java python or whatever you will like to use, is just a tool. It really depends how you implement this stuff.

D

Gotcha yeah great great anyway, keep in mind that operator sdk is scaffolding. Project single! I really love go honestly. I really love some stuff go. Sometimes I miss some features but keep in mind that that's really cool and since you were talking also regarding uh quarkus, I just wanted to point out this because keep in mind that operator sdk allows.

C

D

uh To put some plugins here so um so you.

A

Can pick your kind of uh programming, language or tools like I see, ansible, helm, customize and and quarkus, so you can scaffold a new project using one of this programming, language or framework.

D

Well, keep in mind that these plugins is something that has been inherited by cube builder, because there is a long story behind the cooperation between operator, sdk and cube builder uh keybuilder, if I recall correctly, was one of the first project that was working on developing operators.

D

So at that time I was working for a company and I was in the middle of choicing. Should we go for cube builder or should we go for operator sdk and I did some proof of concept in both frameworks.

D

And finally, I went for operator sdk for several reasons, but we are in a good spot right now, because after some efforts, they started in 2019. If I recall correctly, uh a sort of fusion, a sort of cooperation between cube builder and operator, sdk started with a deep integration, so uh just to say that these are cube. Builders plugins and these plugins are really useful.

D

If you would like to scaffold the code according to your needs, so in the end with operator, sdk you're ending with creating go codes, but with the plugins uh you have the chance to scaffold the code according to best practices for your strategy.

D

So, as you can see here, we got goku builder, v2 and v3.

B

D

If you, I never use quarkus honestly, because you know uh I don't like java, but it's just a matter of taste, but if you would like to implement the your operator uh with um more opinions away for quarkus, you just need to use the plugin, so the generated code is going to be scaffolded according to your uh scaffolding strategy and, what's really cool, is that you can also use create your own plugins, because what I really love regarding kubernetes and besides also operator, is that if you would like to extend the capabilities of kubernetes like custom resources or extended api servers, it's that simple.

D

Absolutely that's simple!.

A

That's amazing what you say so basically this is a plugable interface. If I want to write my let's say rust uh operator, sdk plugin, I can just uh create this plugin and insert in this architecture.

D

I don't know honestly how to do that, because I'm just working with bergo's stuff and I'm feeling comfortable with this but yeah.

A

D

The version three yeah I I also worked with the v2, but um is.

A

There any difference between v2 v3.

D

Yeah yeah, I remember that because I converted capsule, that is, our multi-tenancy operators, classics from v2 and to b3, and it has been a pain honestly, but I survived that I lost my hair. Well, not joking.

A

You you were having a blonde long, hair yeah.

D

Yeah, just joking, but yeah you can convert that there were. There was also a guide regarding how to translate from v2 to b3, because uh I still remember that in v2 there were many int functions in go so keep in mind that go provides several ways to group your code. You got the modules or, I would say the packages and each package provides a way to initialize it.

D

Okay and this init function is going to be executed when you are importing your package and there are some linters or some metal interstate discard the use of init functions. So it's really cool that starting from v3. uh We don't have any more in it. I would say that it's just a matter of styling stuff. There are no huge side effects. Besides the fact that init functions are just function, you don't have uh error handling, so it's really tough to manage the error handling. But you know uh it's just a matter of style.

B

I would say.

D

That, if you will, if you will start writing your operator uh going for the latest version, is safe and.

B

A

D

A

A newbie uh I want to start creating my operator. I I is that the default option yeah.

D

Okay: okay, it's the default! One! Don't worry, don't worry, uh as I show you early so when we run operator sdk, we got all this stuff saying we can do a lot of stuff. We got the bundle clean up completion create. So what we are going to do right now is to focus on the init, so we have to initialize a new project. Otherwise we cannot do anything else, okay. So what I do every time that I issue a comment. I read the redmi or the hub, so how can I do that?

D

I have to issue operator sdk. If I would like to, I can also set the plugins and then we got the domain and the owner so keep in mind that right now, uh with these uh statements, we are creating go code, but we are scaffolding, just the operators. So to do that, I'm going to issue operator, sdk init and then let's go for reflex.

D

I would like to put the domain so the domain for groups so domain. I would say that we could use the default one my domain and then we have to set also the license. Let's, for let's go for the apache 2, the owner, the owner, I'm going to say my github account from ethereum and the product name project name, I will say my operator and then we have to set also the project version.

D

I am referring to the gospel folding, the version of q builder, so the free, the latest one is good enough, and finally, we have also to set also our repository.

D

Let's go for github.com from tyrion, my operator. Okay, with this, what we are going to do is to get a scaffolding of all the resources that have been created. So, as you can see, we got the docker file, the gomod hack main make file and project. So this is our starting point at this point. What I would suggest is to perform it in it. It commit everything. First comment: okay or initial, commit uh what.

A

Git first approach: what what then, what's the name of this, this approach.

D

uh I don't know the name, but I really love also why I'm coding to see the div, the git div, to understand. What's going on, because since we are talking about scaffolding, uh sometimes you are missing the focus on what operator sdk is going to do so just to show with all the people I'm going to do to do that, so it was within it yeah. So it come. Oh, let me check yeah. We have to add everything, get comment and, let's say.

A

That is a shortcut g, a a you have.

D

Because I I face so many outages issues, so every second is very important, so I got a lot of aliases. So gaa is good at all. Okay,.

A

D

Is git status and gc is good comet.

A

Maybe you can share your aliases, your bash analysis to the as.

D

Well, these are the default one offered by zsh, but I got another one that I really love, that is kill p and hill p is to kill a pod with grace period equals to zero and force, because sometimes you are ending up with pods that are out there in waiting state terminating saying and oh my gosh. I have to wait. No, no, no! No! I'm in production! I have to kill everything so yeah.

A

I see taro is laughing and also crying, so maybe he's thinking about any part that couldn't delete the battle. Do you do you fly you're having this kit first approach.

C

Of of course, but about killing ports, yeah, maybe kill n, also so killing a namespace when you have a finalizer rating something and you try to find out what is its waiting. So maybe I need to create a shortcut for that. Also.

D

Yeah yeah patching the namespace, removing finalizers or at this.

B

D

I will say that we could create all scenarios to ssh the control plane, connect to hcd and removing the key of the namespace will be much much better. Just joking, you know, but it's pretty easy.

C

Yeah ocrs hcd of that cd, yeah yeah, okay,.

A

Anyway, before uh luca in the chat were saying, the way the operator looks like inside kubernetes might be a technical details, but it's very important to understand the concept of reconciliation, loop and decided state versus actual state. So this is what what daddy was saying mentioning. I think that we will go into again into reconciliation loop, but yeah, but that is the main topic. So thanks luca for your note in the chat.

D

Yeah yeah, thank you so much so, uh let's commit so git commit, I will say, git commit and let's go for initial commit yeah. We got our operator. Everything has been committed, so we are on master. So let's take a look also to what we have right now. So I hope that you are familiar with go in case. You are not that's, not a big problem, so we got a godmode file, so go mod file, and here it is so essentially we got our module.

D

That is github.com from affiliate on my operator and if you recall correctly, it's the one that I couldn't where. Where are you here? It is so essentially this repo is going to be used here. We are using a go version. 1.16 uh doesn't matter because this has been scaffolding. This way you can use, go 1.17.

D

In fact, I'm using that and we got some dependencies. So we got api machinery, we got the client go and the controller runtime uh keep in mind that operator sdk.

D

I I don't want to say bad words regarding operator sdk, but operator. Sdk is just a scaffolding tool. Okay, because we have to pay kudos, we have to say thank you a lot of thanks honestly to the controller and time special interest group, because essentially the operator components are managed by this special interest group, or rather, I will say by this library, by this module or whatever you would like to call them. Since we are in the go context, I would say in this module, so we are using the 0.10.

D

I don't remember the first time I used that I used them. It was maybe 0.4.

A

Well, you remember also the the versions yeah.

D

Yeah memory, zero for.

A

X, uh do you recall your dependency version in your in your head blackout? So I don't think that.

D

Yeah, I remember honestly because I was.

C

What is a dependency.

B

D

I got a dependency on kubernetes, but yeah. I never told them to my wife, but I guess she is suspecting something anyway yeah. I remember my dependencies because I had so many issues while I was trying to upgrade from back and forth from a version. So that's the reason why I'm remembering that, anyway, with the go modules, it's a sort of package.log in node.js, or rather composer.json in php or whatever you would like to use to lock your dependencies. This is not the log file.

D

Obviously, the log file is stored in go.some, where we got everything yeah pretty nice ashes, arches cool actually everywhere. But what I would like to get uh more focus is the project file. Okay, because with project file, what I really love is the fact that we are storing in a declarative way how we are structuring our operator. So essentially, uh we are storing the version, and this is really cool to understand. Also for newcomers that are we using version, 2 version 3, which plugins are we using or not?

D

What's the project name, the repository the layout and the domain, since these are essential, also when we are generating types and apis? Why api and types, because the main difference between a controller and an operator is that the controller is managing the kubernetes resources, so deployment services, uh endpoints config maps secrets whatever you want. Sometimes I call them the default resources. I know that maybe the name is not the right one, but I'm referring to the apis offered by default by the api server. The operator instead is managing custom resource definitions crds.

D

So essentially we are translating a crd, something that is not standard in kubernetes to create something not directly, but sometimes we create something inside of the kubernetes cluster. So we are translating this crd, this custom resource definition instance in something that is going to be deployed inside the cluster. So uh since uh I recall there was a question regarding luca about the operator patterns on and so forth, yeah. It's also regarding uh the pattern behind that, but also keep in mind that the operator to be classified like an operator must manage also custom resource definitions.

D

Otherwise, will be a simple controller. A custom controller, okay and with that said, I guess that we can also take a look to what we have here. So I will start also from the make file.

D

Let's go for vi, so there is a plenty of stuff here, honestly, uh a lot a lot of targets, but this is really cool because um I hope you all love makes file honestly. I love them because it's old school automation- and I really love that, although I I'm pretty young- I guess so, but with the make file, we got a lot of stuff because essentially we have all the management of our operators so how to deploy an operator.

D

We have to build the binary. We have to build the docker image. We have to build the manifest we have to install the manifest. We have also to manage the full life cycle of the operator, so installing and uninstalling- and everything is here in this- make file. Obviously it's just a scaffolded one uh for capsule, for example, we extended it a little bit, um but it's really cool, because you don't have to write on your own. It's only automated uh it's all generated.

D

uh You don't have to do anything so if I would like to test, I just need to issue make test end of the story, and obviously we got some prerequisites like creating manifest generating the code generation part performing the fmt vt. These are sort of linters and scaffolding also the m test.

D

So this is really cool and just suggestion from my side. Let's use as much as you can. The make five. Oh.

A

The great return on the make file great to hear you know.

C

A

C

But that's actually interesting, since that you can just basically put it as an let's say: github action and run everything in there based on your comments, and you don't have to build it locally and push it. So it's it's kind of cool. You have everything ready like.

D

C

When you're using sdk, you save a lot of time.

D

Yeah, keep in mind that actually we are using on capsule the make file also to scaffold the end-to-end test suite, because since it's an operator to manage multi-tenancy, uh we would like to test with real kubernetes also because we have to ensure a compatibility matrix. So we have to test on kubernetes, 1.16, 17, 18, 19, 20 and so on and so forth, and using the make file is really cool because you have to write your github action say, make end to end slash the version end of the story and also from the developer experience.

D

uh If a new developer is developing something for capsule. What he has to do is just to issue that make target end of the story, otherwise will be a pain, so the ci stuff.

A

There's a comment in the chat that luca is saying that the operator doesn't have only to manage kubernetes resources but also manage external resources, and he was pointing out to the cloudflare operator example.

D

Yeah yeah, that's true, in fact. uh Maybe I I used the right words, but I was trying to say that the operator can manage or not kubernetes resources, because there is something really cool project out there like the cloudflare one, although I never use that, but also take a look to. I don't remember the name: uh crossplane playing okay with first plane, you're creating customers. Well, you have plenty of custom resources, mostly for infrastructure staff that are generating stuff outside of your kubernetes cluster.

D

So I would like to get the postgres sql database match on azure or whatever you want. You just need to create the instance and there you go obviously maybe will be helpful. Also having additional resources, like I don't know the secrets uh containing the connection string to that possible sequel. But you know, I hope that you get uh the point about that, but yeah, that's really cool.

A

Yeah, that's cool and also that, since you mentioned we're there, there's a new operator we are building here in redat was called. uh Is a service called the red that uh um open uh uh database access roda? uh So basically it connects is an operator that connects the deployment, your deployment to a database as a service uh on some third-party sas. So the database is elsewhere.

A

Your your pods are in the cluster, but they are connected and the operators make sure this connection uh uh is uh exists and uh it works out of the box. So yeah uh thanks luca for your um your point.

C

That sounds almost like a smooth operator.

B

A

Yeah good operator, like.

D

A

We don't have the right to send music. We can only send that music you see at the beginning, but that would be a really nice thing to do. A spoof operator smooth.

D

Operator and I would say uh just for a reference force ferrari, because if you're following ferrari formula one, you know carlos signs always said smooth operator ah anyway. Sorry, sorry, forza ferrari, anyway. uh At the same time, let's go also to take a look to the code, because this is really cool. Okay, I'm using beam, you know, but I got also goland. So maybe it's not! No! No, let's not talk about uh other tools. So let's use vi okay.

D

So this is our main goal and, as you can see here, we got several stuff like this. Keep builder scaffolding, ports, and this is the proof that there is a huge connection between operator, sdk and cube builder. So you can take a look to the documentation of q builder and you will see that will be appliable also for operator sdk. So what is going to do could be the scaffolding ports, since the operator needs to manage custom resource definitions.

D

We have to import that in our code base- and this is just a marker- because when we are creating a new api type- and we will see that uh this is going to be imported here in a automated way and the same applies also here. Unfortunately, we still have some heat functions.

D

That's not a big problem honestly, but just to show that uh you know, let's be pragmatic, so we got a plenty of stuff and what I really love also regarding controller manager- and I guess that was the question by taro- should we write our operators on our own or using uh sdks or libraries and so on and so forth.

D

I will say that, uh thanks to the controller manager and the controller and time special interest group, we could get a manager of our custom controller that is managing a custom resource definition, and so it's going to be the final operator that got everything bundled it. So it means that I got metrics.

D

I got the web book servers. I got the indexers. I got everything that is really good to write operators. Okay, we will uh have also the opportunity to see everything anyway, uh just to show you uh our operator is going to be managed by a manager. So essentially we are listening on a specific port, and this is a port. You will ask me: why do we have a port here? Well with web books? We need web books and then we got several options, but it's pretty straightforward.

D

I mean, uh if you try to take a look uh to this code. You see that we got several slack, so we are accepting some flags to this binary. We are setting the logger, we are initializing our manager and then we are adding some health probes and then finally, we are starting the manager end of the story. It's pretty that simple, and with that said, uh I would like just to add also a note regarding the web.

D

Why we need web book because keep in mind that the customer resource definitions are going to be installed using um a resource, and this resource is a sort of open api specification, be free. Okay, and with that said, we don't have so much control on the validation of data okay, and it means that if we would like to put in place some specific validations like you can use, I don't know uh even or odd numbers or just uh the fibonacci uh scheme. uh You have to implement your own validation and this validation is.

A

Now tell me now tell me the fibonacci scheme. Please start with the series.

A

Accept the challenge one yeah.

D

Oh, my gosh, oh my gosh, uh it's a test. Are you trying to hire me for reddit.

A

D

I have to apply maybe anyway um just trying to say that if you would like to put something uh a validation, a custom validation, you need web book and web book are really important, also for the kubernetes ecosystem. We all know, I guess open policy agent. We know kiverno. There are plenty of resources out there that are using the dynamic admission control and so validating the books, or also imitating the books to perform assault, a sort of policy enforcement on your cluster.

D

This policy enforcement could be also applied to your customer resource for the validation or whatever you would like to achieve, but since time is running out like the new song, I don't know if you remember that, but I was playing a lot of muse music. uh Let's take a look also to how to create my custom resource definition. So we got a comment and the command is create and we got the create api.

D

We got also the webhook so a web book for an api resource. What I'm going to say is: okay, let's create the api and it says create results, but um I don't like this stuff: let's go for h. So, uh where is the hub? So we got operator sdk create api, okay and we can specify the group and the version and the kind okay. Let's go for the example the. So we are sticking to that.

D

Oh my gosh, let me copy that.

D

So take a look at this, so we are defining a group that is going to be named sheep, a version and a kind and just to show. What are we referring to? Is that every time that we have a custom resource definition, we got some special fees like api version.

D

And kind okay and the api version is always made of um three parts. So we got the group, the group and the version and the kind this is from the code perspective, but in the yaml definition we got these two fields, so the group could be my group, slash v1 and the kind could be my kind or kind. My kind would be better.

D

So essentially we are designing the metadata of our customer resource and in fact, if we, if we try to create that, we got also some inputs like would you like to create a resource? Obviously, yes and the controller?

D

Obviously yes, and here we are so what I'm referring regarding the controller, uh keep in mind that this could be uh a bit disturbing, because we are trying to implement an operator and we are talking about controller, but the controller in this case is referring to the manager controller, the one that we saw. uh It was red at ma. Oh my gosh, uh it was documents read out my operator vi, main.

D

Mgr yeah I'm referring to this one, so we got a manager that is managing several controllers and each controller is controlling a custom resource definition and with that said, let's take a look and yeah. We got everything. So, as you can see here, we got a lot of stuff. We got some make targets that are creating. We got new files and in fact, if we try to issue git status gst, we got some uh changes and some untracked files. So let's go for the git beef ah yeah gd is good.

A

So I don't know if you know alessio from the chat alessio greg, he said, dario, everyone hates your shot shortcut.

D

Yeah yeah, I know that I know that anyway, as you can see here uh when we create a new project, a new api.

D

These apis are going to be injected inside the project and it's really cool, because taking a look at taking a look to the project, I can understand which custom resource are going to be managed by this operator and obviously we got also a lot of stuff regarding the go mode, and this is more interesting because if we take a look to the main, take a look here, so we got the cube builder scaffolding, ports. So we got our um pointer, our keybuild pointer.

D

It is saying we have to add something new, so we are adding ship better one and we got also the controllers. So, instead of doing this manually, that could be error prone. I just need to issue my command using operator sdk, and the same also applies for the util time registering. uh This is required by because we are not using the ah it's also a long discussion regarding the client to interact with the api server. So we have to register the scheme.

D

Otherwise, we cannot interact with the api and finally, since we got our manager, we got our controller where we are injecting our client from the manager we scheme from the manager, and we are setting up that, uh keep in mind that this is weird because, as you can see, we are generating the controller then setting up with the manager but injecting the manager. Inside of that. So um it's a bit tricky, but it's working. uh It's something that honestly, I don't like so much.

D

Recording the scaffolding by operation sdk, but you know uh it's working, it's good enough, so I'm not complaining about that, and mostly what's really cool is that we got also uh new files like this one. We got api v1 beta1 and we got our create types. So with that said, uh it's not a very sdk, but it's keybuilder that is managed by operator sdk. This is doing all the magic. So essentially we got our package, our versioning. We got our spec our status and also the list struct.

D

All this stuff must be managed by the controller or rather by the manager, in order to install everything and being able to get update, delete patch and list custom resources like this way in this way- and we got also a lot of great fights like this one- uh that that generated difficulty.

D

Okay, since we don't have um generic single, we are coping with uh code generation, so this is mandatory in order to interact also with some uh uh utilities offered by the kubernetes got the code base. So the deep cutting deep copy method must be implemented, otherwise would be a pain, and with that said, uh we are ready, because in the end we scaffolded an operator just the code base. We scaffolded an api in less than, I would say, 30 minutes and honestly, it's absolutely mesmerizing.

D

When I was working at my first operator implementation.

D

I did everything on my own and I spent a lot of days and it was full of bug absolutely full of back and what's really cool is that we got also test and it's really important having tests, especially when you are writing operator.

D

I would say that tests are uh absolutely important when you're developing software, but especially with operators test.

A

Driven development.

D

Oh, no, I'm not I'm not particular, no, I'm not a big fan of that honestly. Don't know, I guess, because I'm not so good at developing, so I'm I'm not trying to. uh I don't like the tdd honestly, but I prefer the end to end honestly just a matter of taste by the way.

A

Yeah, that's uh that's how I think a philosophy I don't know terror or andrea, which philosophy you follow. Tdd, not dddd, just test not.

C

I have I don't write box methodology, so I don't have to test anything because there is no bugs.

C

Yeah, I agree with tdd, it is kind of usually you create the logic, and then you write test cases that work, and then you have dvd. It always goes a wrong way around and it never works. So end-to-end testing is the thing that you you should be doing.

B

Well, uh I agree with the ted approach when it's possible.

A

B

So a couple of questions, though, because what we're basically running out of time.

A

B

Or maybe that could be the topic for another for another session operators? um How do you actually implement the control?

B

How do you actually determine what data you need and where you get it, get it from from changes in the resource definition, for example, and then, and how do you check if uh changes need to be to be made.

A

B

A

Andrea spoiler, at our next episode, no.

D

Yeah a little bit a little bit yeah. I think that, by the way, when I try to design a custom resource definition, I would say that too long did the red it's the specification.

D

It's writing the right specification and writing. The right specification is like writing apis because keep in mind that custom resource definitions are going to be used like apis. Whenever we interact with the api server, essentially, we are doing both uh put post patch get resources so uh starting from the beginning, with the right approach with the right struct and everything else is absolutely mandatory, and what I really love from kubernetes itself is that when you make mistakes like oh my gosh, I totally forgot this.

D

I don't know this field or this feature you can cope with annotations. I know that a lot of people ate annotations but at the same time also using operators. Since you are the owner of your custom resource, you can use versioning and that's really really cool, because with versioning you can create new features without any breaking change.

D

But it's a long topic. We can talk about that.

A

Definitely definitely dario. So thanks for this uh thanks for this session. Well, we basically scaffolded the new operator in uh 20 minutes or 15 minutes uh talking about also your git alice's. I think it was really 15 minutes. It was great, so this was an example on how to scaffold the new operator and and it's part of our new series about how to write an operators or just writing operators on kubernetes.

A

So this was the first episode and I'm really happy that you explained very good either the internals of kubernetes, then the internals of the operators, how to scaffold the new operator and how to create that the first skeleton of a new app to answer. Also the question from andrea.

A

We will have a second episode uh again with dario, because we like how he explained the things it's really good um and how what we should take, what we should put in in the controller um in this controller and uh right now we're we're we are going out of time. So I would like to close up everything uh with what we we've seen. So we we, we have the uh this overview on operator.

A

Sdk dario is the outer on a operator uh which is the capsule operator, so you can see what it made live with operator sdk. It created the capsule operator, which is a an operator for bringing multi-tenancy in kubernetes. He also presented it on kubecon last time. So uh please check out the repo I put in the chat and let me also leave some other appointments today. Openshift tv is live. You can check uh the the live streaming today. uh What we have in the shadow we will come back uh andrea.

A

uh We will come back again uh next wednesday, uh wednesday. uh The ninth, uh together with the winners of the red that act fest we we're gonna, celebrate them um for the operator series. We come back on march, the second with sebby uh and another people person from our engineering talking about the outright operator, also in java with the quercus uh plugin, and then we come back with dario again where we will uh sync on on the next appointment where we want to implement the second part of this uh operator.

A

uh I think I I've shared everything. Do you have any final uh thought uh things to say: andrea dario,.

D

Write your code write your operators and, oh.

A

C

A

C

This was the this is perfect for the explaining the need. This answered my question about why the sdk perfect.

A

That was the reason of this episode, I'm glad we we reached this goal and happy the audience also enjoyed uh this episode. uh The episode is gonna be recorded at the same link. You have either in youtube, and it's going to be available also on twitch, if you are following from twitch so folks, thank you for joining us today was really a pleasure to have you. uh Our next appointment is always an openshift to be on the schedule you have in the chat or with the openshift coffee break.

A

We will come back next wednesday 10 a.m here at openshift24 tv. So, thanks to uh thank you all. Thank you. Thank you. Everyone ciao talk soon, ciao.

B