Creating new Karpenter FAQ

website/content/en/docs/faq.md

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+---
+title: "FAQs"
+linkTitle: "FAQs"
+weight: 90
+---
+## General
+
+### How does a provisioner decide to manage a particular node?
+See [Configuring provisioners]({{< ref "/docs/concepts/#configuring-provisioners" >}}) for information on how Karpenter provisions and manages nodes.
+
+### What cloud providers are supported?
+AWS is the first cloud provider supported by Karpenter, although it is designed to be used with other cloud providers as well.
+See [[Cloud provider]({{< ref "/docs/concepts/#cloud-provider" >}}) for details.
+
+### Can I write my own cloud provider for Karpenter?
+Yes, but there is no documentation yet for it.
+Start with Karpenter's GitHub [cloudprovider](https://github.com/aws/karpenter/tree/main/pkg/cloudprovider) documentation to see how the AWS provider is built, but there are other sections of the code that will require changes too.
+
+### What operating system nodes does Karpenter deploy?
+By default, Karpenter uses Amazon Linux 2 images.
+
+### Can I provide my own custom operating system images?
+Karpenter allows you to create your own AWS AMIs using custom launch templates.
+See [Launch Templates and Custom Images]({{< ref "/docs/aws/launch-templates/" >}}) for details.
+
+### Can Karpenter deal with workloads for mixed architecture cluster (arm vs. amd)?
+Yes. Build and prepare custom arm images as described in [Launch Templates and Custom Images]({{< ref "/docs/aws/launch-templates/" >}}).
+Specify the desired architecture when you deploy workloads.
+
+### What RBAC access is required?
+All of the required RBAC rules can be found in the helm chart template.
+See the [rbac.yaml](https://github.com/aws/karpenter/blob/main/charts/karpenter/templates/controller/rbac.yaml) file for details.
+
+### Can I run Karpenter outside of a Kubernetes cluster?
+Yes, as long as the controller has network and IAM/RBAC access to the Kubernetes API and your provider API.
+
+## Compatibility
+
+### Which versions of Kubernetes does Karpenter support?
+Karpenter is tested with Kubernetes v1.19 and later.
+
+### What Kubernetes distributions are supported?
+Karpenter documents integration with a fresh install of the latest AWS Elastic Kubernetes Service (EKS).
+Existing EKS distributions can be used, but this use case has not yet been documented.
+Other Kubernetes distributions (KOPs, etc.) can be used, but setting up cloud provider permissions for those distributions has not been documented.
+
+### How does Karpenter interact with AWS node group features?
+Provisioners are designed to work alongside static capacity management solutions like EKS Managed Node Groups and EC2 Auto Scaling Groups.
+You can manage all capacity using provisioners, use a mixed model with dynamic and statically managed capacity, or use a fully static approach.
+We expect most users will use a mixed approach in the near term and provisioner-managed in the long term.
+
+
+### How does Karpenter interact with Kubernetes features?
+* Kubernetes Cluster Autoscaler: Karpenter can work alongside cluster autoscaler.
+See [Kubernetes cluster autoscaler]({{< ref "/docs/concepts/#kubernetes-cluster-autoscaler" >}}) for details.
+* Kubernetes Scheduler: Karpenter focuses on scheduling pods that the Kubernetes scheduler has marked as unschedulable.
+See [Scheduling]({{< ref "/docs/concepts/#scheduling" >}}) for details on how Karpenter interacts with the Kubernetes scheduler.
+
+## Provisioning
+### What features does the Karpenter provisioner support?
+See [Provisioner API]({{< ref "/docs/provisioner" >}}) for provisioner examples and descriptions of features.
+
+### Can I create multiple (team-based) provisioners on a cluster?
+Yes, provisioners can identify multiple teams based on labels.
+See [Provisioner API]({{< ref "/docs/provisioner" >}}) for details.
+
+### If multiple provisioners are defined, which will my pod use?
+
+By default, pods will use the rules defined by a provisioner named default.
+This is analogous to the default scheduler.
+To select an alternative provisioner, use the node selector `karpenter.sh/provisioner-name: alternative-provisioner`.
+You must either define a default provisioner or explicitly specify `karpenter.sh/provisioner-name node selector`.
+
+### Can I set total limits of CPU and memory for a provisioner?
+Yes, the setting is provider-specific.
+See examples in [Accelerators, GPU]({{< ref "/docs/aws/provisioning/#accelerators-gpu" >}}) Karpenter documentation.
+
+### Can I mix spot and on-demand EC2 run types?
+Yes, see [Example Provisioner Resource]({{< ref "/docs/provisioner/#example-provisioner-resource" >}}) for an example.
+
+### Can I restrict EC2 instance types?
+
+* Attribute-based requests are currently not possible.
+* You can select instances with special hardware, such as gpu.
+
+## Workloads
+
+### How can someone deploying pods take advantage of Karpenter?
+
+See [Application developer]({{< ref "/docs/concepts/#application-developer" >}}) for descriptions of how Karpenter matches nodes with pod requests.
+
+### How do I use Karpenter with the AWS load balancer controller?
+
+* Set the [ALB target type]({{< ref "https://kubernetes-sigs.github.io/aws-load-balancer-controller/v2.3/guide/ingress/annotations/#target-type" >}}) to IP mode for the pods.
+Use IP targeting if you want the pods to receive equal weight.
+Instance balancing could greatly skew the traffic being sent to a node without also managing host spread of the workload.
+* Set [readiness gate]({{< ref "https://kubernetes-sigs.github.io/aws-load-balancer-controller/v2.3/deploy/pod_readiness_gate/" >}}) on the namespace.
+The default is round robin at the node level.
+For Karpenter, not all nodes are equal.
+For example, each node will have different performance characteristics and a different number of pods running on it.
+A `t3.small` with three instances should not receive the same amount of traffic as a `m5.4xlarge` with dozens of pods.
+If you don't specify a spread at the workload level, or limit what instances should be picked, you could get the same amount of traffic sent to the `t3` and `m5`.
+
+### Can I use Karpenter with EBS disks per availability zone?
+Not yet.
+
+### Can I set `--max-pods` on my nodes?
+Not yet.
+
+## Deprovisioning
+### How does Karpenter deprovision nodes?
+See [Deprovisioning nodes]({{< ref "/docs/tasks/deprov-nodes" >}}) for information on how Karpenter deprovisions nodes.
+
+## Upgrading
+### How do I upgrade Karpenter?
+Karpenter is a controller that runs in your cluster, but it is not tied to a specific Kubernetes version, as the Cluster Autoscaler is.
+Use your existing upgrade mechanisms to upgrade your core add-ons in Kubernetes and keep Karpenter up to date on bug fixes and new features.