Migrating from k8s-alpha CLI to Terraform
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The k8s-alpha CLI is deprecated. On March 31st, 2020, it will be removed from the linode-cli. After March 31, 2020, you will no longer be able to create or manage clusters created by the k8s-alpha CLI plugin, however, you will still be able to successfully manage your clusters using the Kubernetes Terraform installer for Linode Instances.
In This Guide
You will use the Kubernetes Terraform installer for Linode Instances to continue to manage and support clusters created using the k8s-alpha CLI plugin following the EOL date and beyond. You will learn how to:
- Manage clusters created with the k8s-alpha CLI following its deprecation.
- Delete clusters using Terraform.
- Create clusters using Terraform.
Manage k8s-alpha Clusters
The k8s-alpha CLI plugin was based on
Terraform. As a result, it created a number of Terraform configuration files whenever it created a cluster. These Terraform files are found within the .k8s-alpha-linode
directory. You can change into this directory using the following syntax:
cd $HOME/.k8s-alpha-linode
If you list the contents of this directory, you will see a subdirectory for each of the clusters you’ve created with the k8s-alpha CLI plugin. For any of your clusters, contents of these subdirectories will be as follows:
drwxr-xr-x 5 username staff 160 Dec 11 08:10 .terraform
-rw-r--r-- 1 username staff 705 Dec 11 08:10 cluster.tf
-rw-r--r-- 1 username staff 5456 Dec 11 08:14 example-cluster.conf
-rw-r--r-- 1 username staff 5488 Dec 11 08:16 example-cluster_new.conf
drwxr-xr-x 3 username staff 96 Dec 11 08:10 terraform.tfstate.d
- Both of the
.conf
files are kubeconfig files for this cluster. terraform.tfstate.d
is a Terraform state directory..terraform
is a hidden directory which contains Terraform configuration files.cluster.tf
is the Terraform module file. This is the most important file here because it will allow you to scale, upgrade, and delete your cluster.
NoteFor more information regarding these files and directories and their contents, see our Beginner’s Guide to Terraform
Scale a Cluster
Open
cluster.tf
with the text editor of your choice. The contents will be similar to the following:- File: cluster.tf
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variable "server_type_node" { default = "g6-standard-2" } variable "nodes" { default = 3 } variable "server_type_master" { default = "g6-standard-2" } variable "region" { default = "us-east" } variable "ssh_public_key" { default = "/Users/username/.ssh/id_rsa.pub" } module "k8s" { source = "git::https://github.com/linode/terraform-linode-k8s.git?ref=for-cli" linode_token = "<your api token>" linode_group = "kabZmZ3TA0r-mycluster" server_type_node = "${var.server_type_node}" nodes = "${var.nodes}" server_type_master = "${var.server_type_master}" region = "${var.region}" ssh_public_key = "${var.ssh_public_key}" }
To scale your cluster, edit the value of the
nodes
variable. To resize the number of nodes from3
to5
, make the following edit and save your changes:variable "nodes" { default = 5 }
Once your edit is made, move back to the
/.k8s-alpha-linode/clustername
directory and apply your changes with Terraform:terraform apply
Note
You may need to use the original Terraform version used to deploy the cluster (either Terraform 0.11.X or Terraform 0.12.X). If you do not, you will see syntax errors.Once this is completed, you’ll see a prompt reviewing your changes and asking if you would like to accept them. To proceed, type
yes
and Terraform will proceed to make the changes. This process may take a few moments.Note
When prompted, you may notice that one item in your plan is marked asdestroy
. This is generally a “null resource” or a local script execution and is not indicative of an unintended change.After Terraform has finished, your cluster will be resized. To confirm, enter the following command to list all nodes in your cluster, replacing the string
mycluster
with the name of the cluster you edited:kubectl --kubeconfig=mycluster.conf get nodes
The output will then list an entry for each node:
kubectl --kubeconfig=mycluster.conf get nodes NAME STATUS ROLES AGE VERSION mycluster-master-1 Ready master 21m v1.13.6 mycluster-node-1 Ready <none> 18m v1.13.6 mycluster-node-2 Ready <none> 18m v1.13.6 mycluster-node-3 Ready <none> 18m v1.13.6 mycluster-node-4 Ready <none> 4m26s v1.13.6 mycluster-node-5 Ready <none> 4m52s v1.13.6
Upgrade a Cluster
You may have noticed that the Terraform module file, cluster.tf
, refers to a specific branch or git commit hash referencing the remote Kubernetes Terraform installer for Linode Instances module on GitHub. The following section will outline how to upgrade your cluster to the latest version.
For example, your source
variable may have a value that points to the git branch ref for-cli
. To perform an upgrade this must point to the latest commit history hash.
Visit the branch of the Terraform module you’re using on Github. Note the commit history and copy the latest hash by clicking on the clipboard next to the hash of the most recent commit. At the time of this writing, the most recent hash is as follows:
5e68ff7beee9c36aa4a4f5599f3973f753b1cd9e
Edit
cluster.tf
to prepare for the upgrade. Update the following section using the hash you copied to appear as follows:- File: cluster.tf
1
source = "git::https://github.com/linode/terraform-linode-k8s.git?ref=5e68ff7beee9c36aa4a4f5599f3973f753b1cd9e"
To apply these changes, re-initialize the module by running the following command:
terraform init
Once this has completed, apply your changes with the following command:
terraform apply
Note
Depending on the changes that have been configured, you may or may not see the upgrade perform actions. For example, in this case, because the only change was to the Kubernetes version, no actions were taken.
Delete a Cluster
To destroy a cluster, navigate to the directory containing your cluster’s files, and enter the terraform destroy
command:
cd ~/.k8s-alpha-linode/mycluster
terraform destroy
Terraform will prompt you to confirm the action, and on confirmation will proceed to destroy all associated resources. If this process is interrupted for any reason, you can run the command again at any time to complete the process.
Create a Cluster
Create a new directory to house the new cluster’s configuration files in the
~/.k8s-alpha-linode
directory. In this example the cluster name ismynewcluster
:cd ~/.k8s-alpha-linode mkdir mynewcluster
Create a Terraform module file in this new directory called
cluster.tf
with your desired configuration. Replace the values for the variablesssh_public_key
andlinode_token
with your own unique values and feel free to change the configuration values for the cluster itself. The example configuration below will create a cluster with a 4GB master, with a node pool with three 4GB Linodes, hosted in the us-east region:- File: cluster.tf
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variable "server_type_node" { default = "g6-standard-2" } variable "nodes" { default = 3 } variable "server_type_master" { default = "g6-standard-2" } variable "region" { default = "us-east" } variable "ssh_public_key" { default = "/Users/username/.ssh/id_rsa.pub" } module "k8s" { source = "git::https://github.com/linode/terraform-linode-k8s.git?ref=for-cli" linode_token = "<your api token>" linode_group = "mynewcluster" server_type_node = "${var.server_type_node}" nodes = "${var.nodes}" server_type_master = "${var.server_type_master}" region = "${var.region}" ssh_public_key = "${var.ssh_public_key}" }
Initialize and apply your new Terraform configuration:
terraform workspace new mynewcluster terraform init terraform apply
When prompted, review your changes and enter
yes
to continue.Once completed, you’ll see a kubeconfig file,
mynewcluster.conf
, in this directory.To complete your deployment, you will use this kubeconfig file and export it using the following syntax:
export KUBECONFIG=$(pwd)/mynewcluster.conf kubectl get pods --all-namespaces
Once completed, you should see your new cluster active and available with similar output:
NAMESPACE NAME READY STATUS RESTARTS AGE kube-system calico-node-4kp2d 2/2 Running 0 22m kube-system calico-node-84fj7 2/2 Running 0 21m kube-system calico-node-nnns7 2/2 Running 0 21m kube-system calico-node-xfkvs 2/2 Running 0 23m kube-system ccm-linode-c66gk 1/1 Running 0 23m kube-system coredns-54ff9cd656-jqszt 1/1 Running 0 23m kube-system coredns-54ff9cd656-zvgbd 1/1 Running 0 23m kube-system csi-linode-controller-0 3/3 Running 0 23m kube-system csi-linode-node-2tbcd 2/2 Running 0 21m kube-system csi-linode-node-gfvgx 2/2 Running 0 21m kube-system csi-linode-node-lbt5s 2/2 Running 0 21m kube-system etcd-mynewcluster-master-1 1/1 Running 0 22m kube-system external-dns-d4cfd5855-25x65 1/1 Running 0 23m kube-system kube-apiserver-mynewcluster-master-1 1/1 Running 0 22m kube-system kube-controller-manager-mynewcluster-master-1 1/1 Running 0 22m kube-system kube-proxy-29sgx 1/1 Running 0 21m kube-system kube-proxy-5w78s 1/1 Running 0 22m kube-system kube-proxy-7ptxp 1/1 Running 0 21m kube-system kube-proxy-7v8pr 1/1 Running 0 23m kube-system kube-scheduler-mynewcluster-master-1 1/1 Running 0 22m kube-system kubernetes-dashboard-57df4db6b-rtzvm 1/1 Running 0 23m kube-system metrics-server-68d85f76bb-68bl5 1/1 Running 0 23m
More Information
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