Define which Pods use AWS Fargate when launched - Amazon EKS
Fargate profile componentsFargate profile wildcardsCreate a Fargate profileeksctlAWS Management Console

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Define which Pods use AWS Fargate when launched

Important

AWS Fargate with Amazon EKS isn’t available in AWS GovCloud (US-East) and AWS GovCloud (US-West).

Before you schedule Pods on Fargate in your cluster, you must define at least one Fargate profile that specifies which Pods use Fargate when launched.

As an administrator, you can use a Fargate profile to declare which Pods run on Fargate. You can do this through the profile’s selectors. You can add up to five selectors to each profile. Each selector must contain a namespace. The selector can also include labels. The label field consists of multiple optional key-value pairs. Pods that match a selector are scheduled on Fargate. Pods are matched using a namespace and the labels that are specified in the selector. If a namespace selector is defined without labels, Amazon EKS attempts to schedule all the Pods that run in that namespace onto Fargate using the profile. If a to-be-scheduled Pod matches any of the selectors in the Fargate profile, then that Pod is scheduled on Fargate.

If a Pod matches multiple Fargate profiles, you can specify which profile a Pod uses by adding the following Kubernetes label to the Pod specification: eks.amazonaws.com/fargate-profile: my-fargate-profile . The Pod must match a selector in that profile to be scheduled onto Fargate. Kubernetes affinity/anti-affinity rules do not apply and aren’t necessary with Amazon EKS Fargate Pods.

When you create a Fargate profile, you must specify a Pod execution role. This execution role is for the Amazon EKS components that run on the Fargate infrastructure using the profile. It’s added to the cluster’s Kubernetes Role Based Access Control (RBAC) for authorization. That way, the kubelet that runs on the Fargate infrastructure can register with your Amazon EKS cluster and appear in your cluster as a node. The Pod execution role also provides IAM permissions to the Fargate infrastructure to allow read access to Amazon ECR image repositories. For more information, see Amazon EKS Pod execution IAM role.

Fargate profiles can’t be changed. However, you can create a new updated profile to replace an existing profile, and then delete the original.

Note

Any Pods that are running using a Fargate profile are stopped and put into a pending state when the profile is deleted.

If any Fargate profiles in a cluster are in the DELETING status, you must wait until after the Fargate profile is deleted before you create other profiles in that cluster.

Note

Fargate does not currently support Kubernetes topologySpreadConstraints.

Amazon EKS and Fargate spread Pods across each of the subnets that’s defined in the Fargate profile. However, you might end up with an uneven spread. If you must have an even spread, use two Fargate profiles. Even spread is important in scenarios where you want to deploy two replicas and don’t want any downtime. We recommend that each profile has only one subnet.

Fargate profile components

The following components are contained in a Fargate profile.

Pod execution role

When your cluster creates Pods on AWS Fargate, the kubelet that’s running on the Fargate infrastructure must make calls to AWS APIs on your behalf. For example, it needs to make calls to pull container images from Amazon ECR. The Amazon EKS Pod execution role provides the IAM permissions to do this.

When you create a Fargate profile, you must specify a Pod execution role to use with your Pods. This role is added to the cluster’s Kubernetes Role-based access control (RBAC) for authorization. This is so that the kubelet that’s running on the Fargate infrastructure can register with your Amazon EKS cluster and appear in your cluster as a node. For more information, see Amazon EKS Pod execution IAM role.

Subnets

The IDs of subnets to launch Pods into that use this profile. At this time, Pods that are running on Fargate aren’t assigned public IP addresses. Therefore, only private subnets with no direct route to an Internet Gateway are accepted for this parameter.

Selectors

The selectors to match for Pods to use this Fargate profile. You might specify up to five selectors in a Fargate profile. The selectors have the following components:

  • Namespace – You must specify a namespace for a selector. The selector only matches Pods that are created in this namespace. However, you can create multiple selectors to target multiple namespaces.

  • Labels – You can optionally specify Kubernetes labels to match for the selector. The selector only matches Pods that have all of the labels that are specified in the selector.

Fargate profile wildcards

In addition to characters allowed by Kubernetes, you’re allowed to use \* and ? in the selector criteria for namespaces, label keys, and label values:

  • * represents none, one, or multiple characters. For example, prod* can represent prod and prod-metrics.

  • ? represents a single character (for example, value? can represent valuea). However, it can’t represent value and value-a, because ? can only represent exactly one character.

These wildcard characters can be used in any position and in combination (for example, prod*, *dev, and frontend*?). Other wildcards and forms of pattern matching, such as regular expressions, aren’t supported.

If there are multiple matching profiles for the namespace and labels in the Pod spec, Fargate picks up the profile based on alphanumeric sorting by profile name. For example, if both profile A (with the name beta-workload) and profile B (with the name prod-workload) have matching selectors for the Pods to be launched, Fargate picks profile A (beta-workload) for the Pods. The Pods have labels with profile A on the Pods (for example, eks.amazonaws.com/fargate-profile=beta-workload).

If you want to migrate existing Fargate Pods to new profiles that use wildcards, there are two ways to do so:

  • Create a new profile with matching selectors, then delete the old profiles. Pods labeled with old profiles are rescheduled to new matching profiles.

  • If you want to migrate workloads but aren’t sure what Fargate labels are on each Fargate Pod, you can use the following method. Create a new profile with a name that sorts alphanumerically first among the profiles on the same cluster. Then, recycle the Fargate Pods that need to be migrated to new profiles.

Create a Fargate profile

This section describes how to create a Fargate profile. You also must have created a Pod execution role to use for your Fargate profile. For more information, see Amazon EKS Pod execution IAM role. Pods that are running on Fargate are only supported on private subnets with NAT gateway access to AWS services, but not a direct route to an Internet Gateway. This is so that your cluster’s VPC must have private subnets available.

You can create a profile with the following:

eksctl

To create a Fargate profile with eksctl

Create your Fargate profile with the following eksctl command, replacing every example value with your own values. You’re required to specify a namespace. However, the --labels option isn’t required.

eksctl create fargateprofile \
    --cluster my-cluster \
    --name my-fargate-profile \
    --namespace my-kubernetes-namespace \
    --labels key=value

You can use certain wildcards for my-kubernetes-namespace and key=value labels. For more information, see Fargate profile wildcards.

AWS Management Console

To create a Fargate profile with AWS Management Console

  1. Open the Amazon EKS console.

  2. Choose the cluster to create a Fargate profile for.

  3. Choose the Compute tab.

  4. Under Fargate profiles, choose Add Fargate profile.

  5. On the Configure Fargate profile page, do the following:

    1. For Name, enter a unique name for your Fargate profile, such as my-profile.

    2. For Pod execution role, choose the Pod execution role to use with your Fargate profile. Only the IAM roles with the eks-fargate-pods.amazonaws.com service principal are shown. If you don’t see any roles listed, you must create one. For more information, see Amazon EKS Pod execution IAM role.

    3. Modify the selected Subnets as needed.

      Note

      Only private subnets are supported for Pods that are running on Fargate.

    4. For Tags, you can optionally tag your Fargate profile. These tags don’t propagate to other resources that are associated with the profile, such as Pods.

    5. Choose Next.

  6. On the Configure Pod selection page, do the following:

    1. For Namespace, enter a namespace to match for Pods.

      • You can use specific namespaces to match, such as kube-system or default.

      • You can use certain wildcards (for example, prod-*) to match multiple namespaces (for example, prod-deployment and prod-test). For more information, see Fargate profile wildcards.

    2. (Optional) Add Kubernetes labels to the selector. Specifically, add them to the one that the Pods in the specified namespace need to match.

      • You can add the label infrastructure: fargate to the selector so that only Pods in the specified namespace that also have the infrastructure: fargate Kubernetes label match the selector.

      • You can use certain wildcards (for example, key?: value?) to match multiple namespaces (for example, keya: valuea and keyb: valueb). For more information, see Fargate profile wildcards.

    3. Choose Next.

  7. On the Review and create page, review the information for your Fargate profile and choose Create.

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