Amazon EKS Operations

Internal

• Amazon Elastic Kubernetes Service
• aws-iam-authenticator
• kubectl
• eksctl

Create a Cluster

Create Cluster

Cluster Information

Cluster Status

aws eks [--region us-east-1] describe-cluster --name example-cluster --query "cluster.status"

"ACTIVE"

If the right region is configured in the profile, there is no need to be specified.

Cluster Endpoint

aws eks [--region us-east-1] describe-cluster --name example-cluster --query "cluster.endpoint" --output text

https://FDXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX.gr0.us-east-1.eks.amazonaws.com

If the right region is configured in the profile, there is no need to be specified.

Cluster Certificate Authority

aws eks [--region us-east-1] describe-cluster --name example-cluster --query "cluster.certificateAuthority.data" --output text

LS0t...LQo=

If the right region is configured in the profile, there is no need to be specified.

Connect to an EKS Cluster with kubectl

https://docs.aws.amazon.com/eks/latest/userguide/getting-started-eksctl.html

Update .kube/config with the EKS cluster definition as follows:

aws eks [--region us-east-1] update-kubeconfig --name example-eks-cluster [--alias <context-alias>] [--role-arn arn:aws:iam::999999999999:role/some-role]

This command constructs a Kubernetes context with pre-populated server and certificate authority data values for the cluster specified by name. If the right region is configured in the profile, there is no need to be specified. If no alias is used, the default name of the context is the cluster ARN. The result is to add a new context to .kube/config:

Added new context arn:aws:eks:us-east-1:999999999999:cluster/example-eks-cluster to /Users/testuser/.kube/config

If no --role-arn option is specified for the aws eks command, kubectl context is configured to accesses the EKS cluster with the default AWS CLI IAM user identity at the time of aws eks execution. This identity can be obtained with aws sts get-caller-identity. The IAM identity associated with the context can be changed with the --role-arn option. If the --role-arn option is specified, the Kubernetes context will be configured as such that it will not be necessary to explicitly assume the role; kubectl operations in the correct context will simply work. Note that the IAM role used for --role-arn is NOT the cluster service role, but a completely different role altogether.

For more details on how the IAM user or role identity is linked to a specific set of RBAC permissions, see:

EKS API Server User Management and Access Control

Building upon this capability, it is possible to create two different Kuberenetes context that imply to different sets of RBAC permission on the Kubernetes clusters:

aws eks update-kubeconfig --name example-eks-cluster --alias access-with-cluster-admin-permissions --role-arn arn:aws:iam::999999999999:role/eks-clusterrole-cluster-admin
aws eks update-kubeconfig --name example-eks-cluster --alias access-with-limited-permissions --role-arn arn:aws:iam::999999999999:role/eks-clusterrole-limited-permissions

Switching between Kubernetes contexts is done with kubectl config use-context:

kubectl config use-context access-with-cluster-admin-permissions

kubectl config current-context
access-with-cluster-admin-permissions

kubectl config use-context access-with-limited-permissions 

kubectl config current-context
access-with-limited-permissions

Allowing Additional Users to Access the Cluster

https://docs.aws.amazon.com/eks/latest/userguide/add-user-role.html

Allow IAM Role Access

Individual AWS users (authenticating as particular IAM Users) can be allowed access if an IAM role is "allowed" access to the Kubernetes cluster by associating it with RBAC roles or groups, and then the IAM role is configured to allow IAM users to assume it. This is the preferred solution, because different roles can be associated with different cluster permissions, and the same user can access the cluster with different permissions, by just using a different role.

1. Create an IAM role dedicated to cluster access, as described here: Create a Role to Delegate Permission to an IAM User.

2. Update aws-auth ConfigMap to allow the IAM role to access the Kubernetes cluster. This is done by associating it with a specific set of RBAC permissions, denoted by a group or Kubernetes role:

kubectl -n kube-system edit cm aws-auth

apiVersion: v1
kind: ConfigMap
metadata:
  name: aws-auth
  namespace: kube-system
data:
  mapRoles: |
    - rolearn: arn:aws:iam::...
      username: system:node:{{EC2PrivateDNSName}}
      groups:
      - system:bootstrappers
      - system:nodes
    - rolearn: arn:aws:iam::999999999999:role/playground-eks-cluster-admin
      groups:
      - system:masters

Allow Individual IAM User Access

Configuring individual user access directly in aws-auth ConfigMap is less preferable than using an IAM role for access, for reasons explained in that section.

TODO https://docs.aws.amazon.com/eks/latest/userguide/getting-started-eksctl.html

Associate an IAM Role with a Kubernetes User

1. Create an IAM role dedicated to cluster access, as described here: Create a Role to Delegate Permission to an IAM User. Use the following convention when naming it:

<cluster-name>-eks-namespaced-edit-role

2. Edit aws-auth ConfigMap and associate the IAM role with a Kubernetes User:

kubectl -n kube-system edit cm aws-auth

kind: ConfigMap
data:
  mapRoles: |
    - rolearn: arn:aws:iam::836860439671:role/eks-clusterrole-edit
      username: eks-clusterrole-edit

Load Balancer Troubleshooting

https://aws.amazon.com/premiumsupport/knowledge-center/eks-load-balancers-troubleshooting/