Spinnaker rollout strategy Kubernetes vs Istio - kubernetes

I am new to Spinnaker and when using the UI (with Spinnaker for GCP), it says for rollout strategies
Allow Spinnaker to associate each ReplicaSet deployed in this stage with one or more Services and manage traffic based on your selected rollout strategy options.
Does this mean that its rollout strategies are "only" Kubernetes-Replicaset based, but doesn't have support for, for example, Istio Traffic Management and Virtual Services? (or does the UI only offer limited option, compared to, say, an API)
Probably the same question can be asked for canary analysis?

Related

Kubernetes: How to manage multiple separate deployments of the same app

We're migrating our app's deployments from using VMs to Kubernetes and as my knowledge of Kubernetes is very limited, I'm lost how I could set up deployment for multiple clients.
Right now we have a separate VM for each client but how to separate the clients in Kubernetes in a way that will be cost and resource efficient and easy to manage?
I managed to create dev and staging environments using namespaces and this is working great.
To update dev and staging deployment I just use kubectl apply -f <file> --namespace staging.
Now I need to deploy app to production for several clients (50+). They should be completely separate from each other (using separate environment variables and secrets) while code should be the same. And I don't know what is the best way to achieve that.
Could you please hint me what is the right way for that in Kubernetes?
You can use Kustomize. It provides purely declarative approach to configuration customization to manage an arbitrary number of distinctly customized Kubernetes configurations.
https://github.com/kubernetes-sigs/kustomize/tree/master/examples
one (or a set of namespaces) by customer
kustomize has a very good patterns system to handle generic configuration and several adaptation by clients
use NetworkPolicy to isolate network between clients

Can i only change one pod in kubernetes?

I only want to deploy one pod in k8s.
For example, I deploy several pods in one pool with the same codes, but I only want to change one pod to do some test. Can it be done?
What you're describing in your question is actually the closest to what we call Canary Deployment.
In a nutshell Canary Deployment (also known as Canary Release) is a technique that allows you to reduce potential risk of introducing in production a new software version that may be corrupted. It is achieved by rolling out the change only to a small subset of servers ( in Kubernetes it may be just one pod ) before deploying it to the entire infrastructure and making it available to everybody.
If you decide e.g. to deploy one more pod using new image version and you've got already working deployment consisting let's say of 3 replicas, only 25 % of traffic will be routed to the new pod. Once you decide the test was successful you may continue rolling out the update to other pods.
Here you can find an article describing in detail how you can perform such kind of deployment on Kubernetes.
It's actually similar approach to Blue-Green Deployment already mentioned by #Malathi and has a lot in common with it.
Perhaps you meant Blue-Green Deployments.
The common release process involves, adding new pods with the latest release and perhaps expose a certain percent of the traffic to be routed to the new release pod. If everything goes well you can remove the old pods with old release and replace them with new pods with the new release.
This article talks of blue-green deployments with Kubernetes.
It is also possible to use service mesh-like istio with Kubernetes for advanced blue-green deployments such as redirect traffic to a new release based on header values or cookies.

Deploying multiple versions of the same software in Kubernetes

I'm planning to migrate the deployment process from a traditional deployment tool (Octopus) to Kubernetes and as my knowledge of Kubernetes is very limited, I'm lost how I could set up deployment for multiple clients. I have a CMS-like web-site and I need to deploy it to dev/stage/production for several clients (different servers). Could you please hint me what is the right abstraction for that in Kubernetes?
Option 1 (the easiest): Kubernetes namespace.
Create different namespaces for dev/stage/production. Install same name/label resources there and they will not overlap.
Option 2: Helm chart with the release name tied to every resource. Example chart https://github.com/helm/charts/tree/master/stable/wordpress. When you do this https://github.com/helm/charts/blob/master/stable/wordpress/templates/deployment.yaml#L19 resource references do not overlap even in the same namespace.
Option 3: Do both at time :)

Kubernetes Continuous Deployment

I know continuous deployment can be done via spinnaker like Blue/Green, Canary Deployment etc
but my question how does it differ from other GitOps tools like WeaveWorks Flux ?
Does both solve the same problem ? or Do we need both tools in conjunction ?
As mentioned in "The GitOps Pipeline - Part 2"
Weave Flux is a tool that automates the staging and release of containers to Kubernetes, as well as services, deployments, network policies and even Istio routing rules. Flux is therefore ‘glue’ that maps all the relationships between code, services and running clusters.
It can be seen as a leaner, Kubernetes-native alternative to Spinnaker.

Is it safe/right to deploy Spinnaker to same kubernetes cluster which Spinnaker will manage?

I cannot find any articles answering question: Is it safe/right to deploy Spinnaker to same Kubernetes cluster which Spinnaker will manage? Mainly I mean for production, HA deployments.
I think the architectures of Spinnaker and Kubernetes compliment each other very well, and running Spinnaker in the same K8s cluster it is managing is definitely safe.
As per your comment in #mdirkse's answer, there is a codelab, which is official Spinnaker documentation, that explains how to create a set of basic pipelines for deploying code from a Github repo to a production Kubernetes cluster in the form of a Docker container.
In this documentation, it specifically states the following:
We will be deploying Spinnaker to the same Kubernetes cluster it will be managing. ...
Not sure if this is exactly what you are looking for though.
I'm not sure about "right", but I'd definitely say that it is safe to run Spinnaker on the same Kubernetes cluster that it manages, if you set it up right. Kubernetes (and Docker) gives you all the tools you need to properly separate Spinnaker from the other things running on the cluster (namespaces, quotas, node affinities etc). Indeed the whole point of Kubernetes is to be able to easily run software in an HA/fault tolerant way, and since Spinnaker consists of a collection of stateless microservices it really plays to the strenghts of k8s.