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Kubernetes on Openstack with Terraform
Provision a Kubernetes cluster with Terraform on Openstack.
Status
This will install a Kubernetes cluster on an Openstack Cloud. It is tested on a OpenStack Cloud provided by BlueBox and should work on most modern installs of OpenStack that support the basic services.
There are some assumptions made to try and ensure it will work on your openstack cluster.
- floating-ips are used for access
- you already have a suitable OS image in glance
- you already have both an internal network and a floating-ip pool created
- you have security-groups enabled
Requirements
Terraform
Terraform will be used to provision all of the OpenStack resources required to run Docker Swarm. It is also used to deploy and provision the software requirements.
Prep
OpenStack
Ensure your OpenStack credentials are loaded in environment variables. This is how I do it:
$ source ~/.stackrc
You will need two networks before installing, an internal network and an external (floating IP Pool) network. The internet network can be shared as we use security groups to provide network segregation. Due to the many differences between OpenStack installs the Terraform does not attempt to create these for you.
By default Terraform will expect that your networks are called internal and
external. You can change this by altering the Terraform variables network_name and floatingip_pool.
A full list of variables you can change can be found at variables.tf.
All OpenStack resources will use the Terraform variable cluster_name (
default example) in their name to make it easier to track. For example the
first compute resource will be named example-kubernetes-1.
Terraform
Ensure your local ssh-agent is running and your ssh key has been added. This step is required by the terraform provisioner:
$ eval $(ssh-agent -s)
$ ssh-add ~/.ssh/id_rsa
Ensure that you have your Openstack credentials loaded into Terraform environment variables. Likely via a command similar to:
$ echo Setting up Terraform creds && \
export TF_VAR_username=${OS_USERNAME} && \
export TF_VAR_password=${OS_PASSWORD} && \
export TF_VAR_tenant=${OS_TENANT_NAME} && \
export TF_VAR_auth_url=${OS_AUTH_URL}
Provision a Kubernetes Cluster on OpenStack
terraform apply -state=contrib/terraform/openstack/terraform.tfstate contrib/terraform/openstack
openstack_compute_secgroup_v2.k8s_master: Creating...
description: "" => "example - Kubernetes Master"
name: "" => "example-k8s-master"
rule.#: "" => "<computed>"
...
...
Apply complete! Resources: 9 added, 0 changed, 0 destroyed.
The state of your infrastructure has been saved to the path
below. This state is required to modify and destroy your
infrastructure, so keep it safe. To inspect the complete state
use the `terraform show` command.
State path: contrib/terraform/openstack/terraform.tfstate
Make sure you can connect to the hosts:
$ ansible -i contrib/terraform/openstack/hosts -m ping all
example-k8s_node-1 | SUCCESS => {
"changed": false,
"ping": "pong"
}
example-etcd-1 | SUCCESS => {
"changed": false,
"ping": "pong"
}
example-k8s-master-1 | SUCCESS => {
"changed": false,
"ping": "pong"
}
if it fails try to connect manually via SSH ... it could be somthing as simple as a stale host key.
Deploy kubernetes:
$ ansible-playbook --become -i contrib/terraform/openstack/hosts cluster.yml
clean up:
$ terraform destroy
Do you really want to destroy?
Terraform will delete all your managed infrastructure.
There is no undo. Only 'yes' will be accepted to confirm.
Enter a value: yes
...
...
Apply complete! Resources: 0 added, 0 changed, 12 destroyed.