Deploy Kubernetes (K8s) on Amazon AWS using mixed on-demand and spot instances
Published in
12 min readApr 14, 2022
Deploy in a few minutes an high available Kubernetes cluster on Amazon AWS using mixed on-demand and spot instances.
Please note, this is only an example on how to Deploy a Kubernetes cluster. For a production environment you should use EKS or ECS.
The scope of this repo is to show all the AWS components needed to deploy a high available K8s cluster.
Requirements
- Terraform - Terraform is an open-source infrastructure as code software tool that provides a consistent CLI workflow to manage hundreds of cloud services. Terraform codifies cloud APIs into declarative configuration files.
- Amazon AWS Account - Amazon AWS account with billing enabled
- kubectl - The Kubernetes command-line tool (optional)
- aws cli optional
You need also:
- one VPC with private and public subnets
- one ssh key already uploaded on your AWS account
- one bastion host to reach all the private EC2 instances
For VPC and bastion host you can refer to this repository.
Infrastructure overview
The final infrastructure will be made by:
- two autoscaling group, one for the kubernetes master nodes and one for the worker nodes
- two launch template, used by the asg
- one internal load balancer (L4) that will route traffic to Kubernetes servers
- one external load balancer (L7) that will route traffic to Kubernetes workers
- one security group that will allow traffic from the VPC subnet CIDR on all the k8s ports (kube api, nginx ingress node port etc)
- one security group that will allow traffic from all the internet into the public load balancer (L7) on port 80 and 443
- one S3 bucket, used to store the cluster join certificates
- one IAM role, used to allow all the EC2 instances in the cluster to write on the S3 bucket, used to share the join certificates
- one certificate used by the public LB, stored on AWS ACM. The certificate is a self signed certificate.
Kubernetes setup
The installation of K8s id done by kubeadm. In this installation Containerd is used as CRI and flannel is used as CNI.
You can optionally install Nginx ingress controller and Longhorn.
To install Nginx ingress set the variable install_nginx_ingress to yes (default no). To install longhorn set the variable install_longhorn to yes (default no). NOTE if you don’t install the nginx ingress, the public Load Balancer and the SSL certificate won’t be deployed.
In this installation is used a S3 bucket to store the join certificate/token. At the first startup of the instance, if the cluster does not exist, the S3 bucket is used to get the join certificates/token.
Before you start
Note that this tutorial uses AWS resources that are outside the AWS free tier, so be careful!
Project setup
Clone this repo and go in the example/ directory:
git clone https://github.com/garutilorenzo/k8s-aws-terraform-cluster
cd k8s-aws-terraform-cluster/example/Now you have to edit the main.tf file and you have to create the terraform.tfvars file. For more detail see AWS provider setup and Pre flight checklist.
Or if you prefer you can create an new empty directory in your workspace and create this three files:
- terraform.tfvars
- main.tf
- provider.tf
The main.tf file will look like:
variable "AWS_ACCESS_KEY" {}variable "AWS_SECRET_KEY" {}variable "environment" {
default = "staging"
}variable "AWS_REGION" {
default = "<YOUR_REGION>"
}module "k8s-cluster" {
ssk_key_pair_name = "<SSH_KEY_NAME>"
uuid = "<GENERATE_UUID>"
environment = var.environment
vpc_id = "<VPC_ID>"
vpc_private_subnets = "<PRIVATE_SUBNET_LIST>"
vpc_public_subnets = "<PUBLIC_SUBNET_LIST>"
vpc_subnet_cidr = "<SUBNET_CIDR>"
PATH_TO_PUBLIC_LB_CERT = "<PAHT_TO_PUBLIC_LB_CERT>"
PATH_TO_PUBLIC_LB_KEY = "<PAHT_TO_PRIVATE_LB_CERT>"
install_nginx_ingress = true
source = "github.com/garutilorenzo/k8s-aws-terraform-cluster"
}output "k8s_dns_name" {
value = module.k8s-cluster.k8s_dns_name
}output "k8s_server_private_ips" {
value = module.k8s-cluster.k8s_server_private_ips
}output "k8s_workers_private_ips" {
value = module.k8s-cluster.k8s_workers_private_ips
}
For all the possible variables see Pre flight checklist
The provider.tf will look like:
provider "aws" {
region = var.AWS_REGION
access_key = var.AWS_ACCESS_KEY
secret_key = var.AWS_SECRET_KEY
}The terraform.tfvars will look like:
AWS_ACCESS_KEY = "xxxxxxxxxxxxxxxxx"
AWS_SECRET_KEY = "xxxxxxxxxxxxxxxxx"Now we can init terraform with:
terraform initInitializing modules...
- k8s-cluster in ..Initializing the backend...Initializing provider plugins...
- Finding latest version of hashicorp/template...
- Finding latest version of hashicorp/aws...
- Installing hashicorp/template v2.2.0...
- Installed hashicorp/template v2.2.0 (signed by HashiCorp)
- Installing hashicorp/aws v4.9.0...
- Installed hashicorp/aws v4.9.0 (signed by HashiCorp)Terraform has created a lock file .terraform.lock.hcl to record the provider
selections it made above. Include this file in your version control repository
so that Terraform can guarantee to make the same selections by default when
you run "terraform init" in the future.Terraform has been successfully initialized!You may now begin working with Terraform. Try running "terraform plan" to see
any changes that are required for your infrastructure. All Terraform commands
should now work.If you ever set or change modules or backend configuration for Terraform,
rerun this command to reinitialize your working directory. If you forget, other
commands will detect it and remind you to do so if necessary.
Generate self signed SSL certificate for the public LB (L7)
NOTE If you already own a valid certificate skip this step and set the correct values for the variables: PATH_TO_PUBLIC_LB_CERT and PATH_TO_PUBLIC_LB_KEY
We need to generate the certificates (sel signed) for our public load balancer (Layer 7). To do this we need openssl, open a terminal and follow this step:
Generate the key:
openssl genrsa 2048 > privatekey.pem
Generating RSA private key, 2048 bit long modulus (2 primes)
.......+++++
...............+++++
e is 65537 (0x010001)Generate the a new certificate request:
openssl req -new -key privatekey.pem -out csr.pem
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:IT
State or Province Name (full name) [Some-State]:Italy
Locality Name (eg, city) []:Brescia
Organization Name (eg, company) [Internet Widgits Pty Ltd]:GL Ltd
Organizational Unit Name (eg, section) []:IT
Common Name (e.g. server FQDN or YOUR name) []:testlb.domainexample.com
Email Address []:email@you.comPlease enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:
Generate the public CRT:
openssl x509 -req -days 365 -in csr.pem -signkey privatekey.pem -out public.crt
Signature ok
subject=C = IT, ST = Italy, L = Brescia, O = GL Ltd, OU = IT, CN = testlb.domainexample.com, emailAddress = email@you.com
Getting Private keyThis is the final result:
lscsr.pem privatekey.pem public.crt
Now set the variables:
- PATH_TO_PUBLIC_LB_CERT: ~/full_path/public.crt
- PATH_TO_PUBLIC_LB_KEY: ~/full_path/privatekey.pem
AWS provider setup
Follow the prerequisites step on this link. In your workspace folder or in the examples directory of this repo create a file named terraform.tfvars:
AWS_ACCESS_KEY = "xxxxxxxxxxxxxxxxx"
AWS_SECRET_KEY = "xxxxxxxxxxxxxxxxx"Pre flight checklist
Once you have created the terraform.tfvars file edit the main.tf file (always in the example/ directory) and set the following variables.
Deploy
We are now ready to deploy our infrastructure. First we ask terraform to plan the execution with:
terraform plan...
...
+ name = "k8s-sg"
+ name_prefix = (known after apply)
+ owner_id = (known after apply)
+ revoke_rules_on_delete = false
+ tags = {
+ "Name" = "sg-k8s-cluster-staging"
+ "environment" = "staging"
+ "provisioner" = "terraform"
+ "scope" = "k8s-cluster"
+ "uuid" = "xxxxx-xxxxx-xxxx-xxxxxx-xxxxxx"
}
+ tags_all = {
+ "Name" = "sg-k8s-cluster-staging"
+ "environment" = "staging"
+ "provisioner" = "terraform"
+ "scope" = "k8s-cluster"
+ "uuid" = "xxxxx-xxxxx-xxxx-xxxxxx-xxxxxx"
}
+ vpc_id = "vpc-xxxxxx"
}Plan: 25 to add, 0 to change, 0 to destroy.Changes to Outputs:
+ k8s_dns_name = (known after apply)
+ k8s_server_private_ips = [
+ (known after apply),
]
+ k8s_workers_private_ips = [
+ (known after apply),
]Note: You didn't use the -out option to save this plan, so Terraform can't guarantee to take exactly these actions if you run "terraform apply" now.
now we can deploy our resources with:
terraform apply...+ tags_all = {
+ "Name" = "sg-k8s-cluster-staging"
+ "environment" = "staging"
+ "provisioner" = "terraform"
+ "scope" = "k8s-cluster"
+ "uuid" = "xxxxx-xxxxx-xxxx-xxxxxx-xxxxxx"
}
+ vpc_id = "vpc-xxxxxxxx"
}Plan: 25 to add, 0 to change, 0 to destroy.Changes to Outputs:
+ k8s_dns_name = (known after apply)
+ k8s_server_private_ips = [
+ (known after apply),
]
+ k8s_workers_private_ips = [
+ (known after apply),
]Do you want to perform these actions?
Terraform will perform the actions described above.
Only 'yes' will be accepted to approve.Enter a value: yes...
...Apply complete! Resources: 25 added, 0 changed, 0 destroyed.Outputs:k8s_dns_name = "k8s-ext-<REDACTED>.elb.amazonaws.com"
k8s_server_private_ips = [
tolist([
"172.x.x.x",
"172.x.x.x",
"172.x.x.x",
]),
]
k8s_workers_private_ips = [
tolist([
"172.x.x.x",
"172.x.x.x",
"172.x.x.x",
]),
]
Now on one master node you can check the status of the cluster with:
ssh -j bastion@<BASTION_IP> ubuntu@172.x.x.xWelcome to Ubuntu 20.04.4 LTS (GNU/Linux 5.13.0-1021-aws x86_64)* Documentation: https://help.ubuntu.com
* Management: https://landscape.canonical.com
* Support: https://ubuntu.com/advantageSystem information as of Wed Apr 13 12:41:52 UTC 2022System load: 0.52 Processes: 157
Usage of /: 17.8% of 19.32GB Users logged in: 0
Memory usage: 11% IPv4 address for cni0: 10.244.0.1
Swap usage: 0% IPv4 address for ens3: 172.68.4.2370 updates can be applied immediately.Last login: Wed Apr 13 12:40:32 2022 from 172.68.0.6
ubuntu@i-04d089ed896cfafe1:~$ sudo su -root@i-04d089ed896cfafe1:~# kubectl get nodes
NAME STATUS ROLES AGE VERSION
i-0033b408f7a1d55f3 Ready control-plane,master 3m33s v1.23.5
i-0121c2149821379cc Ready <none> 4m16s v1.23.5
i-04d089ed896cfafe1 Ready control-plane,master 4m53s v1.23.5
i-072bf7de2e94e6f2d Ready <none> 4m15s v1.23.5
i-09b23242f40eabcca Ready control-plane,master 3m56s v1.23.5
i-0cb1e2e7784768b22 Ready <none> 3m57s v1.23.5root@i-04d089ed896cfafe1:~# kubectl get ns
NAME STATUS AGE
default Active 5m18s
ingress-nginx Active 111s # <- ingress controller ns
kube-node-lease Active 5m19s
kube-public Active 5m19s
kube-system Active 5m19s
longhorn-system Active 109s # <- longhorn nsroot@i-04d089ed896cfafe1:~# kubectl get pods --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
ingress-nginx ingress-nginx-admission-create-v2fpx 0/1 Completed 0 2m33s
ingress-nginx ingress-nginx-admission-patch-54d9f 0/1 Completed 0 2m33s
ingress-nginx ingress-nginx-controller-7fc8d55869-cxv87 1/1 Running 0 2m33s
kube-system coredns-64897985d-8cg8g 1/1 Running 0 5m46s
kube-system coredns-64897985d-9v2r8 1/1 Running 0 5m46s
kube-system etcd-i-0033b408f7a1d55f3 1/1 Running 0 4m33s
kube-system etcd-i-04d089ed896cfafe1 1/1 Running 0 5m42s
kube-system etcd-i-09b23242f40eabcca 1/1 Running 0 5m
kube-system kube-apiserver-i-0033b408f7a1d55f3 1/1 Running 1 (4m30s ago) 4m30s
kube-system kube-apiserver-i-04d089ed896cfafe1 1/1 Running 0 5m46s
kube-system kube-apiserver-i-09b23242f40eabcca 1/1 Running 0 5m1s
kube-system kube-controller-manager-i-0033b408f7a1d55f3 1/1 Running 0 4m36s
kube-system kube-controller-manager-i-04d089ed896cfafe1 1/1 Running 1 (4m50s ago) 5m49s
kube-system kube-controller-manager-i-09b23242f40eabcca 1/1 Running 0 5m1s
kube-system kube-flannel-ds-7c65s 1/1 Running 0 5m2s
kube-system kube-flannel-ds-bb842 1/1 Running 0 4m10s
kube-system kube-flannel-ds-q27gs 1/1 Running 0 5m21s
kube-system kube-flannel-ds-sww7p 1/1 Running 0 5m3s
kube-system kube-flannel-ds-z8h5p 1/1 Running 0 5m38s
kube-system kube-flannel-ds-zrwdq 1/1 Running 0 5m22s
kube-system kube-proxy-6rbks 1/1 Running 0 5m2s
kube-system kube-proxy-9npgg 1/1 Running 0 5m21s
kube-system kube-proxy-px6br 1/1 Running 0 5m3s
kube-system kube-proxy-q9889 1/1 Running 0 4m10s
kube-system kube-proxy-s5qnv 1/1 Running 0 5m22s
kube-system kube-proxy-tng4x 1/1 Running 0 5m46s
kube-system kube-scheduler-i-0033b408f7a1d55f3 1/1 Running 0 4m27s
kube-system kube-scheduler-i-04d089ed896cfafe1 1/1 Running 1 (4m50s ago) 5m58s
kube-system kube-scheduler-i-09b23242f40eabcca 1/1 Running 0 5m1s
longhorn-system csi-attacher-6454556647-767p2 1/1 Running 0 115s
longhorn-system csi-attacher-6454556647-hz8lj 1/1 Running 0 115s
longhorn-system csi-attacher-6454556647-z5ftg 1/1 Running 0 115s
longhorn-system csi-provisioner-869bdc4b79-2v4wx 1/1 Running 0 115s
longhorn-system csi-provisioner-869bdc4b79-4xcv4 1/1 Running 0 114s
longhorn-system csi-provisioner-869bdc4b79-9q95d 1/1 Running 0 114s
longhorn-system csi-resizer-6d8cf5f99f-dwdrq 1/1 Running 0 114s
longhorn-system csi-resizer-6d8cf5f99f-klvcr 1/1 Running 0 114s
longhorn-system csi-resizer-6d8cf5f99f-ptpzb 1/1 Running 0 114s
longhorn-system csi-snapshotter-588457fcdf-dlkdq 1/1 Running 0 113s
longhorn-system csi-snapshotter-588457fcdf-p2c7c 1/1 Running 0 113s
longhorn-system csi-snapshotter-588457fcdf-p5smn 1/1 Running 0 113s
longhorn-system engine-image-ei-fa2dfbf0-bkwhx 1/1 Running 0 2m7s
longhorn-system engine-image-ei-fa2dfbf0-cqq9n 1/1 Running 0 2m8s
longhorn-system engine-image-ei-fa2dfbf0-lhjjc 1/1 Running 0 2m7s
longhorn-system instance-manager-e-542b1382 1/1 Running 0 119s
longhorn-system instance-manager-e-a5e124bb 1/1 Running 0 2m4s
longhorn-system instance-manager-e-acb2a517 1/1 Running 0 2m7s
longhorn-system instance-manager-r-11ab6af6 1/1 Running 0 119s
longhorn-system instance-manager-r-5b82fba2 1/1 Running 0 2m4s
longhorn-system instance-manager-r-c2561fa0 1/1 Running 0 2m6s
longhorn-system longhorn-csi-plugin-4br28 2/2 Running 0 113s
longhorn-system longhorn-csi-plugin-8gdxf 2/2 Running 0 113s
longhorn-system longhorn-csi-plugin-wc6tt 2/2 Running 0 113s
longhorn-system longhorn-driver-deployer-7dddcdd5bb-zjh4k 1/1 Running 0 2m31s
longhorn-system longhorn-manager-cbsh7 1/1 Running 0 2m31s
longhorn-system longhorn-manager-d2t75 1/1 Running 1 (2m9s ago) 2m31s
longhorn-system longhorn-manager-xqlfv 1/1 Running 1 (2m9s ago) 2m31s
longhorn-system longhorn-ui-7648d6cd69-tc6b9 1/1 Running 0 2m31s
Public LB check
We can now test the public load balancer, nginx ingress controller and the security group ingress rules. On your local PC run:
curl -k -v https://k8s-ext-<REDACTED>.elb.amazonaws.com/
* Trying 34.x.x.x:443...
* TCP_NODELAY set
* Connected to k8s-ext-<REDACTED>.elb.amazonaws.com (34.x.x.x) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
* CAfile: /etc/ssl/certs/ca-certificates.crt
CApath: /etc/ssl/certs
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / ECDHE-RSA-AES128-GCM-SHA256
* ALPN, server accepted to use h2
* Server certificate:
* subject: C=IT; ST=Italy; L=Brescia; O=GL Ltd; OU=IT; CN=testlb.domainexample.com; emailAddress=email@you.com
* start date: Apr 11 08:20:12 2022 GMT
* expire date: Apr 11 08:20:12 2023 GMT
* issuer: C=IT; ST=Italy; L=Brescia; O=GL Ltd; OU=IT; CN=testlb.domainexample.com; emailAddress=email@you.com
* SSL certificate verify result: self signed certificate (18), continuing anyway.
* Using HTTP2, server supports multi-use
* Connection state changed (HTTP/2 confirmed)
* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
* Using Stream ID: 1 (easy handle 0x55c6560cde10)
> GET / HTTP/2
> Host: k8s-ext-<REDACTED>.elb.amazonaws.com
> user-agent: curl/7.68.0
> accept: */*
>
* Connection state changed (MAX_CONCURRENT_STREAMS == 128)!
< HTTP/2 404
< date: Tue, 12 Apr 2022 10:08:18 GMT
< content-type: text/html
< content-length: 146
< strict-transport-security: max-age=15724800; includeSubDomains
<
<html>
<head><title>404 Not Found</title></head>
<body>
<center><h1>404 Not Found</h1></center>
<hr><center>nginx</center>
</body>
</html>
* Connection #0 to host k8s-ext-<REDACTED>.elb.amazonaws.com left intact404 is a correct response since the cluster is empty.
Deploy a sample stack
We use the same stack used in this repository. This stack need longhorn and nginx ingress.
To test all the components of the cluster we can deploy a sample stack. The stack is composed by the following components:
- MariaDB
- Nginx
- Wordpress
Each component is made by: one deployment and one service. Wordpress and nginx share the same persistent volume (ReadWriteMany with longhorn storage class). The nginx configuration is stored in four ConfigMaps and the nginx service is exposed by the nginx ingress controller.
Deploy the resources with:
kubectl apply -f https://raw.githubusercontent.com/garutilorenzo/k3s-oci-cluster/master/deployments/mariadb/all-resources.yml
kubectl apply -f https://raw.githubusercontent.com/garutilorenzo/k3s-oci-cluster/master/deployments/nginx/all-resources.yml
kubectl apply -f https://raw.githubusercontent.com/garutilorenzo/k3s-oci-cluster/master/deployments/wordpress/all-resources.ymlNOTE to install WP and reach the wp-admin path you have to edit the nginx deployment and change this line:
env:
- name: SECURE_SUBNET
value: 8.8.8.8/32 # change-meand set your public ip address.
To check the status:
root@i-04d089ed896cfafe1:~# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
mariadb-6cbf998bd6-s98nh 1/1 Running 0 2m21s 10.244.2.13 i-072bf7de2e94e6f2d <none> <none>
nginx-68b4dfbcb6-s6zfh 1/1 Running 0 19s 10.244.1.12 i-0121c2149821379cc <none> <none>
wordpress-558948b576-jgvm2 1/1 Running 0 71s 10.244.3.14 i-0cb1e2e7784768b22 <none> <none>root@i-04d089ed896cfafe1:~# kubectl get deployments
NAME READY UP-TO-DATE AVAILABLE AGE
mariadb 1/1 1 1 2m32s
nginx 1/1 1 1 30s
wordpress 1/1 1 1 82sroot@i-04d089ed896cfafe1:~# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 14m
mariadb-svc ClusterIP 10.108.78.60 <none> 3306/TCP 2m43s
nginx-svc ClusterIP 10.103.145.57 <none> 80/TCP 41s
wordpress-svc ClusterIP 10.103.49.246 <none> 9000/TCP 93s
Now you are ready to setup WP, open the LB public ip and follow the wizard. NOTE nginx and the Kubernetes Ingress rule are configured without virthual host/server name.
To clean the deployed resources:
kubectl delete -f https://raw.githubusercontent.com/garutilorenzo/k3s-oci-cluster/master/deployments/mariadb/all-resources.yml
kubectl delete -f https://raw.githubusercontent.com/garutilorenzo/k3s-oci-cluster/master/deployments/nginx/all-resources.yml
kubectl delete -f https://raw.githubusercontent.com/garutilorenzo/k3s-oci-cluster/master/deployments/wordpress/all-resources.ymlClean up
Before destroy all the infrastructure DELETE all the object in the S3 bucket.
terraform destroy
