Using aws ecr with backup

Question

Pulumi · Accepted Answer

When you're dealing with AWS Elastic Container Registry (ECR), having a backup strategy is crucial to ensure that your Docker images are safe and available even if the original ECR repository becomes unavailable or corrupted. AWS ECR does not provide a direct built-in backup feature, but you can effectively create a backup by replicating the images from one ECR repository to another, potentially across different regions for added redundancy.

Here's how to achieve ECR backup using AWS ECR replication feature:

1. **Create an ECR Repository**: This repository will hold your Docker images.
2. **Configure a Replication Rule**: Set up a replication rule to copy images from the primary repository to a backup repository.
3. **Enable Image Scanning**: Optionally, you can enable image scanning on push to scan for vulnerabilities whenever an image is pushed to your repository.
4. **Apply Lifecycle Policies**: Lifecycle policies can help manage your images by defining rules which automatically clean up outdated images.

Below is a Pulumi program that demonstrates this process by creating two repositories and setting up replication between them. We will be using the high-level `awsx` package to work with ECR because it simplifies some of the boilerplate code you would have to write otherwise.

### The Pulumi TypeScript Program

Let's dive into the TypeScript code to implement this:

```typescript
import * as aws from "@pulumi/aws";
import * as awsx from "@pulumi/awsx";

// Create the primary ECR repository where your Docker images will be pushed originally.
const primaryRepo = new awsx.ecr.Repository("primaryRepo", {
    imageScanningConfiguration: {
        // Enable scanning whenever an image is pushed.
        scanOnPush: true,
    },
});

// Create a secondary ECR repository, which will serve as a backup.
const backupRepo = new awsx.ecr.Repository("backupRepo", {
    imageScanningConfiguration: {
        scanOnPush: true, // Enable scanning for the backup as well.
    },
});

// Create a replication configuration to replicate images from the primary to the backup repository.
const replicationRule = new aws.ecr.ReplicationConfiguration("replicationRule", {
    replicationConfiguration: {
        // Define replication rules.
        rules: [{
            destinations: [{
                // Specify the region and ARN of the backup repository.
                region: backupRepo.repository.region,
                registryId: backupRepo.repository.registryId,
            }],
            repositoryFilters: [{
                // Only replicate images matching this filter.
                filterType: "PREFIX_MATCH",
                filter: "backup/",
            }],
        }],
    },
}, {dependsOn: [primaryRepo, backupRepo]});

// Export the repository URLs, which can be used to push/pull Docker images.
export const primaryRepositoryUrl = primaryRepo.repository.repositoryUrl;
export const backupRepositoryUrl = backupRepo.repository.repositoryUrl;
```

This Pulumi program sets up two ECR repositories: a primary one where you'd push your Docker images and a backup repository where images will be replicated to. The `awsx.ecr.Repository` resource is used because it wraps `aws.ecr.Repository` with additional capabilities like lifecycle policies and simplified input handling.

Additionally, the replication rule is set up to replicate only images from the primary repository with a specific prefix (`backup/` in this case). You can adjust the `repositoryFilters` to match your naming conventions for the images that need backing up.

Don't forget that you need to have the Pulumi CLI installed and AWS credentials configured to run this program. Once ready, you can use `pulumi up` in your CLI to deploy this configuration.

### Further Considerations

- **Cross-Region Replication**: For even better fault tolerance, consider setting your backup repository in a different AWS region. Adjust the `region` property within the replication rule's `destinations`.
- **Lifecycle Policies**: These can be added to the repository resource to automatically clean up old, unused images based on certain criteria such as age or count.

Remember, while replication provides a level of redundancy, it's not a substitute for a comprehensive disaster recovery plan, as it won't protect against corruption of the images that are already replicated. Ensure to have a proper CI/CD workflow that could rebuild and push these images if required.