Both containers and virtual machines (VMs) provide isolated environments, but they work differently. Let's explore when to use each.
Virtual Machines:
Docker Containers:
Aspect | Containers | Virtual Machines |
---|---|---|
Startup Time | Seconds | Minutes |
Size | MBs | GBs |
Performance | Near-native | Some overhead |
Isolation | Process-level | Hardware-level |
Security | Good | Better |
Containers are ideal for:
Example use case:
FROM node:18-alpine
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
EXPOSE 3000
CMD ["npm", "start"]
VMs are better for:
Many organizations use both:
# Container startup
docker run -d nginx # < 1 second
# VM startup
virsh start ubuntu-vm # 30-60 seconds
Choose containers for application deployment and microservices. Choose VMs when you need strong isolation or different operating systems. Often, the best solution combines both technologies.