> ## Documentation Index
> Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Custom Images
> Streamline deployments by bundling application code and server configuration into a single, ready-to-deploy image using tools like HashiCorp Packer.
Streamline your deployments by bundling application code and server configuration into a single, ready-to-deploy image. Tools like HashiCorp Packer automate the image-building process, producing fully configured artifacts for any environment.
Immutable images guarantee consistency, repeatability, and reliability across development, testing, and production.
## Why Use Custom Images?
| Benefit | Description |
| ----------- | --------------------------------------------------------------------------- |
| Consistency | Every environment runs the exact same image. |
| Speed | Pre-baked configurations reduce startup time. |
| Security | Reduce drift by disallowing manual changes to running instances. |
| Automation | Integrate with CI/CD pipelines for hands-off image creation and deployment. |
## Image-Building Tools
| Tool | Use Case | Example Command |
| ------------------ | ------------------------- | ------------------------------------------ |
| HashiCorp Packer | VM and cloud image builds | `packer build template.json` |
| Docker | Container images | `docker build -t myapp:latest .` |
| Custom AMI Scripts | AWS EC2 image automation | `aws ec2 create-image --instance-id i-123` |
## Sample Workflow
1. Define your machine configuration in Packer (or a Dockerfile).
2. Run the build command to generate an immutable image.
3. Push the image to your registry or cloud provider.
4. Deploy new instances using the updated image.
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Never modify a running image in place. Always build and deploy a new image for updates.
## Additional Resources
* [HashiCorp Packer Documentation](https://www.packer.io/docs)
* [Immutable Infrastructure—Martin Fowler](https://martinfowler.com/bliki/ImmutableServer.html)
* [Dockerfile Reference](https://docs.docker.com/engine/reference/builder/)