Does Ruby on Rails Work With Kubernetes?
Ruby on Rails runs excellently on Kubernetes with proper containerization and configuration management.
Quick Facts
How Ruby on Rails Works With Kubernetes
Rails applications deploy to Kubernetes by packaging the entire framework stack into Docker containers. The stateless nature of modern Rails (with external databases and caching layers) aligns perfectly with Kubernetes's container orchestration model. Developers create a Dockerfile that installs Ruby, gems, and the Rails application, then Kubernetes manages pod scheduling, scaling, and rollouts. Rails' asset pipeline and database migrations require careful consideration—precompilation happens in the container build stage, and migrations run as init containers or Jobs before deployment. The developer experience is smooth: you write Rails code normally, containerize it once, and Kubernetes handles the operational complexity of multiple replicas, load balancing, and self-healing. Most production Rails deployments on Kubernetes use Sidekiq or similar for background jobs, which scales naturally with pod replicas.
Best Use Cases
Dockerfile and Kubernetes Deployment for Rails
docker build -t myapp:latest . && kubectl apply -f deployment.yaml# Dockerfile
FROM ruby:3.2-slim as builder
WORKDIR /app
COPY Gemfile Gemfile.lock ./
RUN bundle install --without development test
FROM ruby:3.2-slim
WORKDIR /app
COPY --from=builder /usr/local/bundle /usr/local/bundle
COPY . .
RUN bundle exec rake assets:precompile
EXPOSE 3000
CMD ["bundle", "exec", "rails", "server", "-b", "0.0.0.0"]
---
# deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: rails-app
spec:
replicas: 3
selector:
matchLabels:
app: rails-app
template:
metadata:
labels:
app: rails-app
spec:
containers:
- name: rails
image: myapp:latest
ports:
- containerPort: 3000
env:
- name: RAILS_ENV
value: "production"
- name: DATABASE_URL
valueFrom:
secretKeyRef:
name: db-secret
key: url
livenessProbe:
httpGet:
path: /health
port: 3000
initialDelaySeconds: 30
periodSeconds: 10Known Issues & Gotchas
Database connection pooling exhaustion when horizontal pod autoscaling creates many replicas
Fix: Use PgBouncer or similar connection pooler as a sidecar, or implement connection pool size limits in database.yml based on expected replica count
Rails tmp/ and log/ directories not persisting across pod restarts, causing disk space issues in containers
Fix: Configure ephemeral volumes or ensure logs stream to stdout/stderr for container logging drivers to capture
Secret management complexity with database passwords and API keys in environment variables
Fix: Use Kubernetes Secrets with sealed-secrets or external-secrets operator rather than storing in ConfigMaps
Asset precompilation in multi-stage builds increases image size significantly
Fix: Use multi-stage Docker builds to separate build dependencies from runtime, or serve assets from CDN
Alternatives
- •Django + Kubernetes: Python alternative with similar containerization patterns but heavier framework
- •Node.js/Express + Kubernetes: Lighter alternative with better resource efficiency for I/O-bound workloads
- •Rails on managed services (Heroku, Cloud Run): Skip Kubernetes complexity but lose portability and control
Resources
Related Compatibility Guides
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