rke2
is lightweight, easy to use, and has minimal dependencies. As such, there is a tremendous amount of flexibility for deployments that can be tailored to best suit you and your organization's needs.
This repository is inteded to clearly demonstrate one method of deploying rke2
in a highly available, resilient, scalable, and simple method on AWS. It is by no means the only supported solution for running rke2
on AWS.
We highly recommend you use the modules in this repository as stepping stones in solutions that meet the needs of your workflow and organization. If you have suggestions or areas of improvements, we would love to hear them!
Changes have been introduced as of March 2023 that are not compatible with user-defined environments. Please make note of and test the following changes before deploying into your environments:
-rke2 user is no longer being installed by default for both servers and agents. -cloud-init runcmd scripts have been re-numbered as follows:
- 00_pre.sh
- 10_download.sh
- 20_rke2.sh
- 99_post.sh
If you are using additional cloud-init scripts, ensure that their numbering will run in the order you expect. -When setting the 'asg' variable, you now must also set the 'termination_policy' value.
This repository contains 2 terraform modules intended for user consumption:
# Provision rke2 server(s) and controlplane loadbalancer
module "rke2" {
source = "git::https://github.com/rancherfederal/rke2-aws-tf.git"
name = "quickstart"
vpc_id = "vpc-###"
subnets = ["subnet-###"]
ami = "ami-###"
}
# Provision Auto Scaling Group of agents to auto-join cluster
module "rke2_agents" {
source = "git::https://github.com/rancherfederal/rke2-aws-tf.git//modules/agent-nodepool"
name = "generic"
vpc_id = "vpc-###"
subnets = ["subnet-###"]
ami = "ami-###"
# Required input sourced from parent rke2 module, contains configuration that agents use to join existing cluster
cluster_data = module.rke2.cluster_data
}
For more complete options, fully functioning examples are provided in the examples/
folder to meet the various use cases of rke2
clusters on AWS, ranging from:
examples/quickstart
: bare minimum rke2 server/agent cluster, start here!examples/cloud-enabled
: aws cloud aware rke2 cluster
The deployment model of this repository is designed to feel very similar to the major cloud providers kubernetes distributions.
It revolves around provisioning the following:
- Nodepools: Self-bootstrapping and auto-joining groups of EC2 instances
- AWS NLB: Controlplane static address
This iac leverages the ease of use of rke2
to provide a simple sshless bootstrapping process for sets of cluster nodes, known as nodepools
. Both the servers and agents within the cluster are simply one or more Auto Scaling Groups (ASG) with the necessary minimal userdata required for either creating or joining an rke2
cluster.
Upon ASG boot, every node will:
- Install the
rke2
self-extracting binary from https://get.rke2.io - Fetch the
rke2
cluster token from a secure secrets store (s3) - Initialize or join an
rke2
cluster
The most basic deployment involves a server nodepool
. However, most deployments will see a server nodepool
with one or more logical groups of agent
nodepools. These are typically separated based of node labels, workload functions, instance types, or any physical/logical separation of nodes.
This repository contains 2 primary modules that users are expected to consume:
rke2
:
The primary rke2
cluster component. Defining this is mandatory, and will provision a control plane load balancer (AWS NLB) and a server nodepool.
agent-nodepool
Optional (but recommended) cluster component to create agent nodepools that will auto-join the cluster created using the rke2
module. This is the primary method for defining nodes in which cluster workloads will run.
Since it is bad practice to store sensitive information in userdata, s3 is used as a secure secrets store that is commonly available in all instantiations of AWS is used for storing and fetching the token
. Provisioned nodes will fetch the token
from the appropriate secrets store via the awscli
before attempting to join a cluster.
This module has a mininmum dependency on being able to fetch the cluster join token from an S3 bucket. By default, the bucket, token, roles, and minimum policies will be created for you. For restricted environments unable to create IAM Roles or Policies, you can specify an existing IAM Role that the instances will assume instead. Note that when going this route, you must be sure the IAM role specified has the minimum required policies to fetch the cluster token from S3. The required and optional policies are defined below:
Required policies are created by default, but are specified below if you are using a custom IAM role.
Servers and agents need to be able to fetch the cluster join token
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": "s3:GetObject",
"Resource": "arn:<aws-region>:s3:<aws-region>:<aws-account>:<bucket>:<object>"
}
]
}
Note: The S3 bucket will be dynamically created during cluster creation, in order to pre create an iam policy that points to this bucket, the use of wildcards is recommended.
For example: s3:::us-gov-west-1:${var.cluster_name}-*
Servers need to be able to query instances within their autoscaling group for "leader election".
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Resource": "*",
"Action": [
"autoscaling:DescribeAutoScalingGroups",
"autoscaling:DescribeAutoScalingInstances"
]
}
]
}
Optional policies have the option of being created by default, but are specified below if you are using a custom IAM role.
- Put
kubeconfig
: will upload the kubeconfig to the appropriate S3 bucket - AWS Cloud Enabled Cluster: will configure
rke2
to self provision certain cloud resources, see here for more info - AWS Cluster Autoscaler: will configure
rke2
to autoscale based off kubernetes resource requests
Name | Version |
---|---|
terraform | >= 1.3 |
aws | >= 4.6, <= 5.22 |
cloudinit | >= 2 |
random | >= 3 |
Name | Version |
---|---|
aws | >= 4.6, <= 5.22 |
cloudinit | >= 2 |
random | >= 3 |
Name | Source | Version |
---|---|---|
cp_lb | ./modules/nlb | n/a |
iam | ./modules/policies | n/a |
init | ./modules/userdata | n/a |
servers | ./modules/nodepool | n/a |
statestore | ./modules/statestore | n/a |
Name | Type |
---|---|
aws_iam_role_policy.aws_autoscaler | resource |
aws_iam_role_policy.aws_ccm | resource |
aws_iam_role_policy.aws_required | resource |
aws_iam_role_policy.get_token | resource |
aws_iam_role_policy.put_kubeconfig | resource |
aws_security_group.cluster | resource |
aws_security_group.server | resource |
aws_security_group_rule.cluster_egress | resource |
aws_security_group_rule.cluster_shared | resource |
aws_security_group_rule.server_cp | resource |
aws_security_group_rule.server_cp_supervisor | resource |
random_password.token | resource |
random_string.uid | resource |
aws_iam_policy_document.aws_autoscaler | data source |
aws_iam_policy_document.aws_ccm | data source |
aws_iam_policy_document.aws_required | data source |
aws_iam_role.provided | data source |
cloudinit_config.this | data source |
Name | Description | Type | Default | Required |
---|---|---|---|---|
ami | Server pool ami | string |
n/a | yes |
associate_public_ip_address | n/a | bool |
null |
no |
awscli_url | URL for awscli zip file | string |
"https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" |
no |
block_device_mappings | Server pool block device mapping configuration | map(string) |
{ |
no |
ccm_external | Set kubelet arg 'cloud-provider-name' value to 'external'. Requires manual install of CCM. | bool |
false |
no |
cluster_name | Name of the rkegov cluster to create | string |
n/a | yes |
controlplane_access_logs_bucket | Bucket name for logging requests to control plane load balancer | string |
"disabled" |
no |
controlplane_allowed_cidrs | Server pool security group allowed cidr ranges | list(string) |
[ |
no |
controlplane_enable_cross_zone_load_balancing | Toggle between controlplane cross zone load balancing | bool |
true |
no |
controlplane_internal | Toggle between public or private control plane load balancer | bool |
true |
no |
create_acl | Toggle creation of ACL for statestore bucket | bool |
true |
no |
download | Toggle best effort download of rke2 dependencies (rke2 and aws cli), if disabled, dependencies are assumed to exist in $PATH | bool |
true |
no |
enable_autoscaler | Toggle enabling policies required for cluster autoscaler to work | bool |
false |
no |
enable_ccm | Toggle enabling the cluster as aws aware, this will ensure the appropriate IAM policies are present | bool |
false |
no |
extra_block_device_mappings | Used to specify additional block device mapping configurations | list(map(string)) |
[] |
no |
extra_cloud_config_config | extra config to append to cloud-config | string |
"" |
no |
extra_security_group_ids | List of additional security group IDs | list(string) |
[] |
no |
iam_instance_profile | Server pool IAM Instance Profile, created if left blank (default behavior) | string |
"" |
no |
iam_permissions_boundary | If provided, the IAM role created for the servers will be created with this permissions boundary attached. | string |
null |
no |
instance_type | Server pool instance type | string |
"t3a.medium" |
no |
lb_subnets | List of subnet IDs to create load balancer in | list(string) |
null |
no |
metadata_options | Instance Metadata Options | map(any) |
{ |
no |
post_userdata | Custom userdata to run immediately after rke2 node attempts to join cluster | string |
"" |
no |
pre_userdata | Custom userdata to run immediately before rke2 node attempts to join cluster, after required rke2, dependencies are installed | string |
"" |
no |
rke2_channel | Channel to use for RKE2 server nodepool | string |
null |
no |
rke2_config | Server pool additional configuration passed as rke2 config file, see https://docs.rke2.io/install/install_options/server_config for full list of options | string |
"" |
no |
rke2_install_script_url | URL for RKE2 install script | string |
"https://get.rke2.io" |
no |
rke2_start | Start/Stop value for the rke2-server/agent service. This will prevent the service from starting until the next reboot. True=start, False= don't start. | bool |
true |
no |
rke2_version | Version to use for RKE2 server nodepool | string |
null |
no |
servers | Number of servers to create | number |
3 |
no |
spot | Toggle spot requests for server pool | bool |
false |
no |
ssh_authorized_keys | Server pool list of public keys to add as authorized ssh keys | list(string) |
[] |
no |
statestore_attach_deny_insecure_transport_policy | Toggle for enabling s3 policy to reject non-SSL requests | bool |
true |
no |
subnets | List of subnet IDs to create nodes in | list(string) |
n/a | yes |
suspended_processes | List of processes to suspend in the autoscaling service | list(string) |
[] |
no |
tags | Map of tags to add to all resources created | map(string) |
{} |
no |
termination_policies | List of policies to decide how the instances in the Auto Scaling Group should be terminated | list(string) |
[ |
no |
unique_suffix | Enables/disables generation of a unique suffix to cluster name | bool |
true |
no |
unzip_rpm_url | URL path to unzip rpm | string |
"" |
no |
vpc_id | VPC ID to create resources in | string |
n/a | yes |
wait_for_capacity_timeout | How long Terraform should wait for ASG instances to be healthy before timing out. | string |
"10m" |
no |
Name | Description |
---|---|
cluster_data | Map of cluster data required by agent pools for joining cluster, do not modify this |
cluster_name | Name of the rke2 cluster |
cluster_sg | Security group shared by cluster nodes, this is different than nodepool security groups |
iam_instance_profile | IAM instance profile attached to server nodes |
iam_role | IAM role of server nodes |
iam_role_arn | IAM role arn of server nodes |
kubeconfig_path | n/a |
server_nodepool_arn | n/a |
server_nodepool_id | n/a |
server_nodepool_name | n/a |
server_sg | n/a |
server_url | n/a |