* Update from bootkube v0.6.2 to v0.7.0 * Use renamed terraform-render-bootkube. Renamed from bootkube-terraform to meet Terraform Module requirements
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AWS
In this tutorial, we'll create a Kubernetes v1.7.7 cluster on AWS.
We'll declare a Kubernetes cluster in Terraform using the Typhoon Terraform module. On apply, a VPC, gateway, subnets, auto-scaling groups of controllers and workers, network load balancers for controllers and workers, and security groups will be created.
Controllers and workers are provisioned to run a kubelet
. A one-time bootkube bootstrap schedules etcd
, apiserver
, scheduler
, controller-manager
, and kube-dns
on controllers and runs kube-proxy
and flannel
or calico
on each node. A generated kubeconfig
provides kubectl
access to the cluster.
!!! warning "Alpha" Typhoon Kubernetes clusters on AWS are marked as "alpha".
!!! warning "Disabled" Clusters do not use EC2 instances with elevated IAM roles. Kubernetes AWS integrations are not enabled.
Requirements
- AWS Account and IAM credentials
- AWS Route53 DNS Zone (registered Domain Name or delegated subdomain)
- Terraform v0.10.1+ and terraform-provider-ct installed locally
Terraform Setup
Install Terraform v0.10.1 on your system.
$ terraform version
Terraform v0.10.1
Add the terraform-provider-ct plugin binary for your system.
wget https://github.com/coreos/terraform-provider-ct/releases/download/v0.2.0/terraform-provider-ct-v0.2.0-linux-amd64.tar.gz
tar xzf terraform-provider-ct-v0.2.0-linux-amd64.tar.gz
sudo mv terraform-provider-ct-v0.2.0-linux-amd64/terraform-provider-ct /usr/local/bin/
Add the plugin to your ~/.terraformrc
.
providers {
ct = "/usr/local/bin/terraform-provider-ct"
}
Read concepts to learn about Terraform, modules, and organizing resources. Change to your infrastructure repository (e.g. infra
).
cd infra/clusters
Provider
Login to your AWS IAM dashboard and find your IAM user. Select "Security Credentials" and create an access key. Save the id and secret to a file that can be referenced in configs.
[default]
aws_access_key_id = xxx
aws_secret_access_key = yyy
Configure the AWS provider to use your access key credentials in a providers.tf
file.
provider "aws" {
region = "eu-central-1"
shared_credentials_file = "/home/user/.config/aws/credentials"
}
Additional configuration options are described in the aws
provider docs.
!!! tip
Regions are listed in docs or with aws ec2 describe-regions
.
Cluster
Define a Kubernetes cluster using the module aws/container-linux/kubernetes
.
module "aws-tempest" {
source = "git::https://github.com/poseidon/typhoon//aws/container-linux/kubernetes"
cluster_name = "tempest"
# AWS
dns_zone = "aws.example.com"
dns_zone_id = "Z3PAABBCFAKEC0"
controller_count = 1
controller_type = "t2.small"
worker_count = 2
worker_type = "t2.small"
ssh_authorized_key = "ssh-rsa AAAAB3Nz..."
# bootkube
asset_dir = "/home/user/.secrets/clusters/tempest"
}
Reference the variables docs or the variables.tf source.
ssh-agent
Initial bootstrapping requires bootkube.service
be started on one controller node. Terraform uses ssh-agent
to automate this step. Add your SSH private key to ssh-agent
.
ssh-add ~/.ssh/id_rsa
ssh-add -L
!!! warning
terrafrom apply
will hang connecting to a controller if ssh-agent
does not contain the SSH key.
Apply
Initialize the config directory if this is the first use with Terraform.
terraform init
Get or update Terraform modules.
$ terraform get # downloads missing modules
$ terraform get --update # updates all modules
Get: git::https://github.com/poseidon/typhoon (update)
Get: git::https://github.com/poseidon/bootkube-terraform.git?ref=v0.7.0 (update)
Plan the resources to be created.
$ terraform plan
Plan: 98 to add, 0 to change, 0 to destroy.
Apply the changes to create the cluster.
$ terraform apply
...
module.aws-tempest.null_resource.bootkube-start: Still creating... (10m50s elapsed)
module.aws-tempest.null_resource.bootkube-start: Still creating... (11m0s elapsed)
module.aws-tempest.null_resource.bootkube-start: Creation complete after 11m8s (ID: 3961816482286168143)
Apply complete! Resources: 98 added, 0 changed, 0 destroyed.
In 10-20 minutes, the Kubernetes cluster will be ready.
!!! bug "" Typhoon clusters on AWS take much longer to create than clusters on other platforms. This is related to DNS resolution time to the ASG, which will be resolved in a future version that uses static controllers.
Verify
Install kubectl on your system. Use the generated kubeconfig
credentials to access the Kubernetes cluster and list nodes.
$ KUBECONFIG=/home/user/.secrets/clusters/tempest/auth/kubeconfig
$ kubectl get nodes
NAME STATUS AGE VERSION
ip-10-0-12-221 Ready 34m v1.7.7+coreos.0
ip-10-0-19-112 Ready 34m v1.7.7+coreos.0
ip-10-0-4-22 Ready 34m v1.7.7+coreos.0
List the pods.
$ kubectl get pods --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system calico-node-1m5bf 2/2 Running 0 34m
kube-system calico-node-7jmr1 2/2 Running 0 34m
kube-system calico-node-bknc8 2/2 Running 0 34m
kube-system etcd-operator-2287495111-br512 1/1 Running 1 34m
kube-system kube-apiserver-4mjbk 1/1 Running 0 34m
kube-system kube-controller-manager-3597210155-j2jbt 1/1 Running 1 34m
kube-system kube-controller-manager-3597210155-j7g7x 1/1 Running 0 34m
kube-system kube-dns-1187388186-wx1lg 3/3 Running 0 34m
kube-system kube-etcd-0000 1/1 Running 0 32m
kube-system kube-etcd-network-checkpointer-dt5pt 1/1 Running 0 34m
kube-system kube-proxy-14wxv 1/1 Running 0 34m
kube-system kube-proxy-9vxh2 1/1 Running 0 34m
kube-system kube-proxy-sbbsh 1/1 Running 0 34m
kube-system kube-scheduler-3359497473-5plhf 1/1 Running 0 34m
kube-system kube-scheduler-3359497473-r7zg7 1/1 Running 1 34m
kube-system pod-checkpointer-4kxtl 1/1 Running 0 34m
kube-system pod-checkpointer-4kxtl-ip-10-0-12-221 1/1 Running 0 33m
Going Further
Learn about version pinning, maintenance, and addons.
!!! note
On Container Linux clusters, install the container-linux-update-operator
addon to coordinate reboots and drains when nodes auto-update. Otherwise, updates may not be applied until the next reboot.
Variables
Required
Name | Description | Example |
---|---|---|
cluster_name | Unique cluster name (prepended to dns_zone) | "tempest" |
dns_zone | AWS Route53 DNS zone | "aws.example.com" |
dns_zone_id | AWS Route53 DNS zone id | "Z3PAABBCFAKEC0" |
ssh_authorized_key | SSH public key for ~/.ssh_authorized_keys | "ssh-rsa AAAAB3NZ..." |
os_channel | Container Linux AMI channel | stable, beta, alpha |
asset_dir | Path to a directory where generated assets should be placed (contains secrets) | "/home/user/.secrets/clusters/tempest" |
DNS Zone
Clusters create a DNS A record ${cluster_name}.${dns_zone}
to resolve a network load balancer backed by controller instances. This FQDN is used by workers and kubectl
to access the apiserver. In this example, the cluster's apiserver would be accessible at tempest.aws.example.com
.
You'll need a registered domain name or subdomain registered in a AWS Route53 DNS zone. You can set this up once and create many clusters with unqiue names.
resource "aws_route53_zone" "zone-for-clusters" {
name = "aws.example.com."
}
Reference the DNS zone id with "${aws_route53_zone.zone-for-clusters.zone_id}"
.
!!! tip "" If you have an existing domain name with a zone file elsewhere, just carve out a subdomain that can be managed on Route53 (e.g. aws.mydomain.com) and update nameservers.
Optional
Name | Description | Default | Example |
---|---|---|---|
controller_count | Number of controllers (i.e. masters) | 1 | 1 |
controller_type | Controller EC2 instance type | "t2.small" | "t2.medium" |
worker_count | Number of workers | 1 | 3 |
worker_type | Worker EC2 instance type | "t2.small" | "t2.medium" |
disk_size | Size of the EBS volume in GB | "40" | "100" |
networking | Choice of networking provider | "calico" | "calico" or "flannel" |
network_mtu | CNI interface MTU (calico only) | 1480 | 8981 |
host_cidr | CIDR range to assign to EC2 instances | "10.0.0.0/16" | "10.1.0.0/16" |
pod_cidr | CIDR range to assign to Kubernetes pods | "10.2.0.0/16" | "10.22.0.0/16" |
service_cidr | CIDR range to assgin to Kubernetes services | "10.3.0.0/16" | "10.3.0.0/24" |
Check the list of valid instance types.
!!! tip "MTU"
If your EC2 instance type supports Jumbo frames (most do), we recommend you change the network_mtu
to 8991! You will get better pod-to-pod bandwidth.