Ghost blog on Google Kubernetes Engine and B2 Cloud Storage

I've recently been migrating my infrastructures to GCP and one of the most critical services I've been running is Ghost. Previously, I ran Ghost with:

• a tiny cloud VPS
• Docker Compose, which runs a MariaDB instance as well
• a local volume to /var/lib/ghost/content
• a custom theme that I upload manually every time I made a change

Obviously this is one of the worst setup I could've had. Non-scalable, not fault-tolerant, and troublesome just to customise the theme files. I came up with:

• making the theme files built-in to the Ghost container images
• using Backblaze B2 for the image storage
  • and using it with Cloudflare Workers saves a lot of money!

That means no more persistent storage volumes. Money saved again. Here's how!

First of all. Making the Ghost Dockerfile.

# from https://gist.github.com/22phuber/76c282d18ec0db166aa1aa3812217e1e

# stage
FROM ghost:3-alpine as ghost-storage-adapter-s3
WORKDIR $GHOST_INSTALL/current
RUN yarn add "ghost-storage-adapter-s3"

# build
FROM ghost:3-alpine
COPY --chown=node:node --from=ghost-storage-adapter-s3 $GHOST_INSTALL/current/node_modules $GHOST_INSTALL/current/node_modules
COPY --chown=node:node --from=ghost-storage-adapter-s3 $GHOST_INSTALL/current/node_modules/ghost-storage-adapter-s3 $GHOST_INSTALL/current/core/server/adapters/storage/s3

ADD --chown=node:node src ./content.orig/themes/default

This grabs official ghost:3-alpine as base image, installs Amazon S3 storage adapter for Ghost and copies ./src, the theme files, to ./content.orig/themes/default, which will be later automatically copied to ./content/themes/default.

The Kubernetes manifest file will look like this:

apiVersion: v1
kind: Service
metadata:
  name: ghost

spec:
  ports:
    - protocol: TCP
      name: web
      port: 2368
  selector:
    app: ghost
layout: layouts/post.njk
---
kind: Deployment
apiVersion: apps/v1
metadata:
  name: ghost
  labels:
    app: ghost

spec:
  replicas: 1
  selector:
    matchLabels:
      app: ghost
  template:
    metadata:
      labels:
        app: ghost
    spec:
      containers:
        - name: ghost
          image: YOUR_DOCKER_IMAGE_URL_AND_TAG
          ports:
            - name: web
              containerPort: 2368
          resources:
            limits:
              memory: "256Mi"
              cpu: "250m"
          env:
            - name: url
              value: "https://blog.birkhoff.me"
            - name: database__client
              value: "mysql"
            - name: database__connection__user
              value: "ghost"
            - name: database__connection__password
              value: "ghost"
            - name: database__connection__database
              value: "ghost"
            - name: mail__transport
              value: "SMTP"
            - name: mail__from
              value: "'Birkhoff\'s Blog' <no-reply@blog.birkhoff.me>"
            - name: mail__options__service
              value: "Mailgun"
            - name: mail__options__port
              value: "2525"
            - name: mail__options__auth__user
              value: "smtp_user@mailgun.com"
            - name: mail__options__auth__pass
              value: "some_password_here"
            - name: storage__active
              value: "s3"
            - name: storage__s3__accessKeyId
              value: "AWS_ACCESS_KEY_ID" # B2 keyID
            - name: storage__s3__secretAccessKey
              value: "AWS_SECRET_ACCESS_KEY" # B2 applicationKey
            - name: storage__s3__region
              value: "AWS_DEFAULT_REGION" # e.g.: us-west-001 for s3.us-west-001.backblazeb2.com
            - name: storage__s3__bucket
              value: "GHOST_STORAGE_ADAPTER_S3_PATH_BUCKET" # B2 bucket name
            - name: storage__s3__endpoint
              value: "GHOST_STORAGE_ADAPTER_S3_ENDPOINT" # s3.us-west-001.backblazeb2.com
            - name: storage__s3__assetHost
              value: "GHOST_STORAGE_ADAPTER_S3_ASSET_HOST" # the image URL host on the website

Obviously you need a way to manage the secrets, which I will not cover here. For S3 compatible API docs, check out https://help.backblaze.com/hc/en-us/articles/360047425453. Moreover, I use GitLab CI to automate the process, but that is totally of personal preference.

Before deploying, export your old website data on Ghost admin panel. You will need to run another MySQL or some relational database on your K8s cluster as well. I tried Google Cloud SQL, but somehow they charged me ~30 USD for under 200 hours. So I decided to manage a MySQL instance on my own.