/k3saws

Low-cost, secure, scalable, and feature-complete kubernetes in AWS via k3s

Primary LanguageHCLApache License 2.0Apache-2.0

cloudk3s

Kubernetes in AWS with k3s deployed via terraform. Save costs (compared to EKS) without compromising scalability or features.

Requirements

Deploy

cd terraform/

# customize settings.auto.tfvars

# init and apply
terraform init
terraform apply

Features

  • offline or online
    • cluster functions without direct internet access
    • container image mirror via ecr with:
      • pull-through-cache for images @
      • any other public image using codebuild (var.container_images)
        • supports multi-arch
        • see terraform/settings.auto.tfvars => container_images[]
  • multiple scaling configurations
    • create any number of node groups
    • define the following components per node group, including the control-plane
      • node count (min/max)
      • instance type
      • arch/accelerated (arm64, x86_64, gpu)
      • local storage
    • availability zones
  • IRSA (IAM roles for Service Accounts) support
    • OIDC endpoint enrollment via s3 bucket static page
    • lambda manages aws identity provider
    • example: ./terraform/manifests/irsa.yaml after apply
  • interact with cluster API via SSM PortForwardSession
    • post-apply: ./terraform/connect.sh, see example image
    • works with kubectl, helm, k9s, lens, etc.
  • strongly enforced encryption + access management
    • at-rest:
      • 8 independent kms keys (codebuild, cloudwatch, ec2, ecr, lambda, s3, sns, ssm)
      • tailored kms key, bucket, iam, and trust policies
    • in-transit:
      • IPSec via Cilium
      • Cilium network policies
  • included charts:
    • aws-cloud-controller
    • aws-efs-csi-controller
    • cilium cni w/ ipsec and base network policies
    • nvidia-device-plugin for GPU-accelerated instances
    • external-dns (req. var.nat_gateways = true)

Known Bugs + Fixes

  • aws-efs-csi-driver
    • bug: official helm chart does not support passing mounts + envvars
      • mounts + envvars are required for non-eks IRSA, e.g: see ./terraform/templates/irsa.yaml.tftpl
      • fix: granted control-plane nodes' iam instance profile the permissions required for efs
  • aws-load-balancer-controller
    • bug: nodes (ec2 instances) are not attached to associated nlb target group(s)
      • likely related to cni being non-native (cilium instead of eni)
      • fix: used aws ccm's native lb controller
  • external-dns
    • bug: use of route53 requires internet egress
      • route53 has no regional endpoints (therefore no vpc endpoint support)
      • fix: added option to enable a nat gateway
    • bug: kubernetes-sigs/external-dns' helm chart does not support serviceaccount automountServiceAccountToken
      • the token must be mounted for non-eks IRSA, e.g: see ./terraform/templates/irsa.yaml.tftpl
      • fix: used bitnami/charts's external-dns w/ .Values.serviceAccount.automountServiceAccountToken: true
        • this introduces another bug
    • bug: bitnami/external-dns container image only supports x86_64
      • node architecture may be arm64
      • fix: used ghcr.io/zcube/bitnami-compat/external-dns which supports multi-arch

Output

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