Kube-Ghost

A minimal configuration for running Ghost on Kubernetes/K3s.

Setup

In line with keeping the project as lean as possible we will be using K3s but most of the underlying concepts can be applied to a Kubernetes cluster as well.

Bootstrapping the cluster

• For the sake of this exercise the cluster was spun on Linode. There may be some edge cases that are not covered here when using a different cloud provider.
• Two nodes were used : 1 master and 1 agent/worker node.

1. Copy the bootstrap.sh script to the node you want to use as the master and run it as follows :

$ ./bootstrap.sh master

2. Once the master node is ready, copy the bootstrap.sh script to the node you want to use as the agent/worker and run it as follows :

$ ./bootstrap.sh agent-1 <node-public-ip> <k3s-token>

The k3s token can be found at /var/lib/rancher/k3s/server/node-token on the master node.

Deploy the nginx ingress controller

1. To install using helm run the following command :

$ helm upgrade --install --namespace ingress-nginx --repo https://kubernetes.github.io/ingress-nginx ingress-nginx ingress-nginx --create-namespace

Setup infrastructure for the Ghost application

• Attach a volume to the worker node for Ghost content stored at /var/lib/ghost/content.
• Use a managed or self-managed MySQL database.

For the purpose of this exercise a 20GB Volume and a managed database in Linode were used.

Install cert-manager

• We will use it to create auto-renewing certificates for the ghost application issued by LetsEncrypt.

$ kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.8.0/cert-manager.yaml

Install the Ghost application.

1. Fill in the database credentials in ghost/config.yaml and ghost/ghost-secret.txt.
2. Fill in the API token for your DNS provider (in this case DigitalOcean) in ghost/do-access-token.txt. This will be used by the issuer to solve the DNS01 challenge, essentially proving that you control the DNS for the domain you are trying to request a certificate for.
3. Fill in the domains for which you wish to generate the cert in ghost/cert.yaml.
4. Deploy :

$ kubectl apply -k -f ghost/k8s/

You can read more about the various YAMLs applied here.