helm-s3 is a Helm plugin that provides Amazon S3 protocol support.

This allows you to have private or public Helm chart repositories hosted on Amazon S3. See this guide to get a detailed example use case overview.

The plugin supports both Helm v2 and v3.

Note

The documentation is available on website.

Table of contents

• Install
  • Docker Images
• Configuration
  • AWS Access
  • Helm version mode
• Usage
  • Init
  • Push
  • Delete
  • Reindex
• Uninstall
• Advanced Features
  • Relative chart URLs
  • Serving charts via HTTP
  • ACLs
  • Using alternative S3-compatible vendors
  • Using S3 bucket ServerSide Encryption
  • S3 bucket location
  • AWS SSO
• Additional Documentation
• Community and Related Projects
• Contributing
• License

Install

The installation itself is simple as:

$ helm plugin install https://github.com/hypnoglow/helm-s3.git

You can install a specific release version:

$ helm plugin install https://github.com/hypnoglow/helm-s3.git --version 0.16.2

To use the plugin, you do not need any special dependencies. The installer will download versioned release with prebuilt binary from github releases. However, if you want to build the plugin from source, or you want to contribute to the plugin, please see these instructions.

Docker Images

The plugin is also distributed as Docker images. Images are pushed to Docker Hub tagged with plugin release version and suffixed with Helm version. The image built from master branch is also available, note that it should be only used for playing and testing, it is strongly discouraged to use that image for production use cases. Refer to https://hub.docker.com/r/hypnoglow/helm-s3 for details and all available tags.

Configuration

AWS Access

To publish charts to buckets and to fetch from private buckets, you need to provide valid AWS credentials. You can do this in the same manner as for AWS CLI tool.

So, if you want to use the plugin and you are already using AWS CLI - you are good to go, no additional configuration required. Otherwise, follow the official guide to set up credentials.

To minimize security issues, remember to configure your IAM user policies properly. As an example, a setup can provide only read access for users, and write access for a CI that builds and pushes charts to your repository.

Example Read Only IAM policy

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "s3:ListBucket",
                "s3:GetObject"
            ],
            "Resource": [
                "arn:aws:s3:::bucket-name",
                "arn:aws:s3:::bucket-name/*"
            ]
        }
    ]
}

Example Read and Write IAM policy

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "files",
            "Effect": "Allow",
            "Action": [
                "s3:PutObjectAcl",
                "s3:PutObject",
                "s3:GetObjectAcl",
                "s3:GetObject",
                "s3:DeleteObject"
            ],
            "Resource": [
                "arn:aws:s3:::bucket-name/repository-name/*",
                "arn:aws:s3:::bucket-name/repository-name"
            ]
        },
        {
            "Sid": "bucket",
            "Effect": "Allow",
            "Action": "s3:ListBucket",
            "Resource": "arn:aws:s3:::bucket-name"
        }
    ]
}

Helm version mode

The plugin is able to detect if you are using Helm v2 or v3 automatically. If, for some reason, the plugin does not detect Helm version properly, you can set HELM_S3_MODE environment variable to value 2 or 3 to force the mode.

Demonstration

# We have Helm version 3:
$ helm version --short
v3.0.2+g19e47ee

# For some reason, the plugin detects Helm version badly:
$ helm s3 version --mode
helm-s3 plugin version: 0.9.2
Helm version mode: v2

# Force the plugin to operate in v3 mode:
$ HELM_S3_MODE=3 helm s3 version --mode
helm-s3 plugin version: 0.9.2
Helm version mode: v3

Usage

Note: example commands below are provided for Helm v3. If you still use Helm v2, see alternatives marked with a tip 💡.

For now let's omit the process of uploading repository index and charts to s3 and assume you already have your repository index.yaml file on s3 under path s3://bucket-name/charts/index.yaml and a chart archive epicservice-0.5.1.tgz under path s3://bucket-name/charts/epicservice-0.5.1.tgz.

Add your repository:

$ helm repo add coolcharts s3://bucket-name/charts

Now you can use it as any other Helm chart repository. Try:

$ helm search coolcharts
NAME                       	VERSION	  DESCRIPTION
coolcharts/epicservice	    0.5.1     A Helm chart.

💡 For Helm v2, use helm search coolcharts.

To install the chart:

$ helm install coolchart/epicservice --version "0.5.1"

Fetching also works:

$ helm pull coolchart/epicservice --version "0.5.1"

💡 For Helm v2, use helm fetch.

Alternatively:

$ helm pull s3://bucket-name/charts/epicservice-0.5.1.tgz

Init

To create a new repository, use init:

$ helm s3 init s3://bucket-name/charts

This command generates an empty index.yaml and uploads it to the S3 bucket under /charts key.

To work with this repo by its name, first you need to add it using native helm command:

$ helm repo add mynewrepo s3://bucket-name/charts

Push

Now you can push your chart to this repo:

$ helm s3 push ./epicservice-0.7.2.tgz mynewrepo

You may want to push the chart with relative URL, see Relative chart URLs.

On push, both remote and local repo indexes are automatically updated (that means you don't need to run helm repo update).

Your pushed chart is available:

$ helm search repo mynewrepo
NAME                    VERSION	 DESCRIPTION
mynewrepo/epicservice   0.7.2    A Helm chart.

💡 For Helm v2, use helm search mynewrepo.

Note that the plugin denies push when the chart with the same version already exists in the repository. This behavior is intentional. It is useful, for example, in CI automated pushing: if someone forgets to bump chart version - the chart would not be overwritten. However, in some cases you want to replace existing chart version. To do so, add --force flag to a push command:

$ helm s3 push --force ./epicservice-0.7.2.tgz mynewrepo

To see other available options, use --help flag:

$ helm s3 push --help

Delete

To delete specific chart version from the repository:

$ helm s3 delete epicservice --version 0.7.2 mynewrepo

As always, both remote and local repo indexes updated automatically.

The chart is deleted from the repo:

$ helm search repo mynewrepo/epicservice
No results found

💡 For Helm v2, use helm search mynewrepo/epicservice

Reindex

If your repository somehow became inconsistent or broken, you can use reindex to recreate the index in accordance with the charts in the repository.

$ helm s3 reindex mynewrepo

You may want to reindex the repo with relative chart URLs, see Relative chart URLs.

Uninstall

$ helm plugin remove s3

Thank you for using the plugin! 👋

Advanced Features

Relative chart URLs

Charts can be push-ed with --relative flag so their URLs in the index file will be relative to your repository root. This can be useful in various scenarios, e.g. serving charts via HTTP, serving charts from replicated buckets, etc.

Also, you can run reindex command with --relative flag to make all chart URLs relative in an existing repository.

Serving charts via HTTP

You can enable HTTP access to your S3 bucket and serve charts via HTTP URLs, so your repository users won't have to install this plugin.

To do this, you need your charts to have relative URLs in the index. See Relative chart URLs.

Example of setting up a public repo using Virtual hosting of buckets

1. Create S3 bucket named example-bucket in EU (Frankfurt) eu-central-1 region.

2. Go to "Permissions", edit Bucket Policy:

   {
     "Version": "2012-10-17",
     "Statement": [
       {
         "Effect": "Allow",
         "Principal": "*",
         "Action": [
           "s3:ListBucket",
           "s3:GetObject"
          ],
         "Resource": [
           "arn:aws:s3:::example-bucket",
           "arn:aws:s3:::example-bucket/*"
         ]
       }
     ]
   }
   

3. Initialize repository:

   $ helm s3 init s3://example-bucket
   Initialized empty repository at s3://example-bucket
   

4. Add repository:

   $ helm repo add example-bucket s3://example-bucket
   "example-bucket" has been added to your repositories
   

5. Create demo chart:

   $ helm create petstore
   Creating petstore
   
   $ helm package petstore --version 1.0.0
   Successfully packaged chart and saved it to: petstore-1.0.0.tgz
   

6. Push chart:

   $ helm s3 push ./petstore-1.0.0.tgz --relative
   Successfully uploaded the chart to the repository.
   

7. The bucket is public and chart repo is set up. Now users can use the repo without the need to install helm-s3 plugin.

   Add HTTP repo:

   $ helm repo add example-bucket-http https://example-bucket.s3.eu-central-1.amazonaws.com/
   "example-bucket-http" has been added to your repositories
   

   Search and download charts:

   $ helm search repo example-bucket-http
   NAME                            CHART VERSION	APP VERSION	DESCRIPTION
   example-bucket-http/petstore	1.0.0       	1.16.0     	A Helm chart for Kubernetes
   
   $ helm pull example-bucket-http/petstore --version 1.0.0
   

ACL

In use cases where you share a repo across multiple AWS accounts, you may want the ability to define object ACLs to allow charts to persist their permissions across accounts. To do so, add the flag --acl="ACL_POLICY". The list of ACLs can be found here:

$ helm s3 push --acl="bucket-owner-full-control" ./epicservice-0.7.2.tgz mynewrepo

Note that if you do use ACL, you need to add --acl flag for all commands, even for 'delete', because the index file is still updated when you remove a chart.

You can also set the default ACL be setting the S3_ACL environment variable.

Timeout

The default timeout for all commands is 5 minutes. This is an opinionated default to be suitable for MFA use, among other things.

If you don't use MFA, it may be reasonable to lower the timeout for most commands, e.g. to 10 seconds. In contrast, in cases where you want to reindex a big repository with thousands of charts, you definitely want to increase the timeout.

Example:

$ helm s3 push --timeout=10s ./epicservice-0.7.2.tgz mynewrepo

Using alternative S3-compatible vendors

The plugin assumes Amazon S3 by default. However, it can work with any S3-compatible object storage, like minio, DreamObjects and others. To configure the plugin to work alternative S3 backend, just define AWS_ENDPOINT (and optionally AWS_DISABLE_SSL if you play with Minio locally):

$ export AWS_ENDPOINT=localhost:9000
$ export AWS_DISABLE_SSL=true

See these integration tests that use local minio docker container for a complete example.

Using S3 bucket ServerSide Encryption

To enable S3 SSE, export environment variable AWS_S3_SSE and set it to desired type, e.g. AES256.

S3 bucket location

The plugin will look for the bucket in the region inferred by the environment. This can be controlled by exporting one of HELM_S3_REGION, AWS_REGION or AWS_DEFAULT_REGION, in order of precedence.

Since v0.11.0 the plugin supports dynamic S3 bucket region retrieval, so in most cases you don't need to provide the region. The plugin will detect it automatically and work without issues.

AWS SSO

The plugin supports AWS IAM Identity Center (aka AWS SSO) authentication.

To use AWS SSO, make sure you configured it via AWS CLI:

$ aws configure sso
SSO session name (Recommended): my-sso
SSO start URL [None]: https://my-sso-portal.awsapps.com/start
SSO region [None]: us-east-1
SSO registration scopes [None]: sso:account:access

...

CLI default client Region [None]: us-east-1
CLI default output format [None]:
CLI profile name [...]: YOUR-PROFILE-NAME

Then, set AWS_PROFILE environment variable to the profile name you used in the previous step:

$ export AWS_PROFILE=YOUR-PROFILE-NAME

Now you can use the plugin as usual.

Additional Documentation

Additional documentation is available in the docs directory. This currently includes:

• Estimated usage cost calculation
• Best Practices for organizing your repositories.

Community and Related Projects

• Helm | Related Projects and Documentation
• Set up a Helm v3 chart repository in Amazon S3 - AWS Prescriptive Guidance
• Deploy Kubernetes resources and packages using Amazon EKS and a Helm chart repository in Amazon S3 - AWS Prescriptive Guidance
• Chart sources - Flux Helm Operator
• How to create a Helm chart repository using Amazon S3

Contributing

Contributions are welcome. Please see these instructions that will help you to develop the plugin.

License

MIT