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cluster-access.md

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Accessing the Cluster

Access the cluster using kubectl, continuous build pipelines, or other clients

If you've chosen to configure a public Load Balancer for your Kubernetes Master(s) (i.e. control_plane_subnet_access=public or control_plane_subnet_access=private and k8s_master_lb_access=public), you can interact with your cluster using kubectl, continuous build pipelines, or any other client over the Internet. A working kubeconfig can be found in the ./generated folder or generated on the fly using the kubeconfig Terraform output variable.

# warning: 0.0.0.0/0 is wide open. Consider limiting HTTPs ingress to smaller set of IPs.
$ terraform plan -var master_https_ingress=0.0.0.0/0
$ terraform apply -var master_https_ingress=0.0.0.0/0
# consider closing access off again using terraform apply -var master_https_ingress=10.0.0.0/16
$ export KUBECONFIG=`pwd`/generated/kubeconfig
$ kubectl cluster-info
$ kubectl get nodes

If you've chosen to configure a strictly private cluster (i.e. control_plane_subnet_access=private and k8s_master_lb_access=private), access to the cluster will be limited to the NAT instance(s) similar to how you would use a bastion host e.g.

$ terraform plan -var public_subnet_ssh_ingress=0.0.0.0/0
$ terraform apply -var public_subnet_ssh_ingress=0.0.0.0/0
$ terraform output ssh_private_key > generated/instances_id_rsa
$ chmod 600 generated/instances_id_rsa
$ scp -i generated/instances_id_rsa generated/instances_id_rsa opc@NAT_INSTANCE_PUBLIC_IP:/home/opc/
$ ssh -i generated/instances_id_rsa opc@NAT_INSTANCE_PUBLIC_IP
nat$ ssh -i /home/opc/instances_id_rsa opc@K8SMASTER_INSTANCE_PRIVATE_IP
master$ kubectl cluster-info
master$ kubectl get nodes

Note, for easier access, consider setting up an SSH tunnel between your local host and a NAT instance.

Access the cluster using Kubernetes Dashboard

Assuming kubectl has access to the Kubernetes Master Load Balancer, you can use kubectl proxy to access the Dashboard:

kubectl proxy &
open http://localhost:8001/ui

SSH into OCI Instances

If you've chosen to launch your control plane instance in public subnets (i.e. control_plane_subnet_access=public), you can open access SSH access to your master nodes by adding the following to your terraform.tfvars file:

# warning: 0.0.0.0/0 is wide open. remember to undo this.
etcd_ssh_ingress = "0.0.0.0/0"
master_ssh_ingress = "0.0.0.0/0"
worker_ssh_ingress = "0.0.0.0/0"
# Create local SSH private key file logging into OCI instances
$ terraform output ssh_private_key > generated/instances_id_rsa
# Retrieve public IP for etcd nodes
$ terraform output etcd_public_ips
# Log in as user opc to the OEL OS
$ ssh -i `pwd`/generated/instances_id_rsa opc@ETCD_INSTANCE_PUBLIC_IP
# Retrieve public IP for k8s masters
$ terraform output master_public_ips
$ ssh -i `pwd`/generated/instances_id_rsa opc@K8SMASTER_INSTANCE_PUBLIC_IP
# Retrieve public IP for k8s workers
$ terraform output worker_public_ips
$ ssh -i `pwd`/generated/instances_id_rsa opc@K8SWORKER_INSTANCE_PUBLIC_IP

If you've chosen to launch your control plane instance in private subnets (i.e. control_plane_subnet_access=private), you'll need to first SSH into a NAT instance, then to a worker, master, or etcd node:

$ terraform plan -var public_subnet_ssh_ingress=0.0.0.0/0
$ terraform apply -var public_subnet_ssh_ingress=0.0.0.0/0
$ terraform output ssh_private_key > generated/instances_id_rsa
$ chmod 600 generated/instances_id_rsa
$ terraform output nat_instance_public_ips
$ scp -i generated/instances_id_rsa generated/instances_id_rsa opc@NAT_INSTANCE_PUBLIC_IP:/home/opc/
$ ssh -i generated/instances_id_rsa opc@NAT_INSTANCE_PUBLIC_IP
nat$ ssh -i /home/opc/instances_id_rsa opc@PRIVATE_IP