Helm

You can use Helm to manage a self-hosted Prefect server and a worker.

Prerequisites

A Kubernetes cluster
Install the Helm CLI

Deploy a server with Helm

Configuring ingress or publicly exposing Prefect from the cluster is business dependent and not covered in this tutorial. For details on Ingress configuration, consult the Kubernetes documentation.

Add the Prefect Helm repository:

helm repo add prefect https://prefecthq.github.io/prefect-helm
helm repo update

Create a namespace

Create a new namespace for this tutorial (all commands will use this namespace):

kubectl create namespace prefect
kubectl config set-context --current --namespace=prefect

Deploy the server

For a customized deployment, first create a server-values.yaml file for the server (see values.yaml template):

server:
  basicAuth:
    enabled: true
    existingSecret: server-auth-secret

Create a secret for the API basic authentication username and password:

kubectl create secret generic server-auth-secret \
  --namespace prefect --from-literal auth-string='admin:password123'

Install the server:

helm install prefect-server prefect/prefect-server \
  --namespace prefect \
  -f server-values.yaml

Expected output:

NAME: prefect-server
LAST DEPLOYED: Tue Mar  4 09:08:07 2025
NAMESPACE: prefect
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
Run the following command to port-forward the UI to your localhost:
$ kubectl --namespace prefect port-forward svc/prefect-server 4200:4200

Visit http://localhost:4200 to use Prefect!

Access the Prefect UI:

kubectl --namespace prefect port-forward svc/prefect-server 4200:4200

Open localhost:4200 in your browser. If using basic authentication, sign in with admin:password123.

Deploy a worker with Helm

To connect a worker to your self-hosted Prefect server in the same cluster:

Create a worker-values.yaml file for the worker (see values.yaml template):

worker:
  apiConfig: selfHostedServer
  config:
    workPool: kube-test
  selfHostedServerApiConfig:
    apiUrl: http://prefect-server.prefect.svc.cluster.local:4200/api

Install the worker:

helm install prefect-worker prefect/prefect-worker \
  --namespace prefect \
  -f worker-values.yaml

Create a worker-values.yaml file for the worker (see values.yaml template):

worker:
  apiConfig: selfHostedServer
  config:
    workPool: kube-test
  selfHostedServerApiConfig:
    apiUrl: http://prefect-server.prefect.svc.cluster.local:4200/api
    basicAuth:
      enabled: true
      existingSecret: worker-auth-secret

Create a secret for the API basic authentication username and password:

kubectl create secret generic worker-auth-secret \
  --namespace prefect --from-literal auth-string='admin:password123'

Install the worker:

helm install prefect-worker prefect/prefect-worker \
  --namespace prefect \
  -f worker-values.yaml

Expected output:

Release "prefect-worker" has been installed. Happy Helming!
NAME: prefect-worker
LAST DEPLOYED: Tue Mar  4 11:26:21 2025
NAMESPACE: prefect
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:

Cleanup

To uninstall the self-hosted Prefect server and Prefect worker:

helm uninstall prefect-worker
helm uninstall prefect-server

Troubleshooting

If you see this error:

Error from server (BadRequest): container "prefect-server" in pod "prefect-server-7c87b7f7cf-sgqj2" is waiting to start: CreateContainerConfigError

Run kubectl events and confirm that the authString is correct.

If you see this error:

prefect.exceptions.PrefectHTTPStatusError: Client error '401 Unauthorized' for url 'http://prefect-server.prefect.svc.cluster.local:4200/api/work_pools/kube-test'
Response: {'exception_message': 'Unauthorized'}
For more information check: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/401
An exception occurred.

Ensure basicAuth is configured in the worker-values.yaml file.

If you see this error:

File "/usr/local/lib/python3.11/site-packages/httpcore/_backends/anyio.py", line 113, in connect_tcp
  with map_exceptions(exc_map):
File "/usr/local/lib/python3.11/contextlib.py", line 158, in __exit__
  self.gen.throw(typ, value, traceback)
File "/usr/local/lib/python3.11/site-packages/httpcore/_exceptions.py", line 14, in map_exceptions
  raise to_exc(exc) from exc
httpcore.ConnectError: [Errno -2] Name or service not known

Ensure the PREFECT_API_URL environment variable is properly templated by running the following command:

helm template prefect-worker prefect/prefect-worker -f worker-values.yaml

The URL format should look like the following:

http://prefect-server.prefect.svc.cluster.local:4200/api

If the worker is not in the same cluster and namespace, the precise format will vary.

For additional troubleshooting and configuration, review the Prefect Worker Helm Chart.

Get started

Tutorials

Develop

Deploy

Automate

Operate

Migrate

Prerequisites

Deploy a server with Helm

Add the Prefect Helm repository:

Create a namespace

Deploy the server

Create a secret for the API basic authentication username and password:

Install the server:

Access the Prefect UI:

Deploy a worker with Helm

Install the worker:

Create a secret for the API basic authentication username and password:

Install the worker:

Cleanup

Troubleshooting

Get started

Tutorials

Develop

Deploy

Automate

Operate

Migrate

​Prerequisites

​Deploy a server with Helm

​Add the Prefect Helm repository:

​Create a namespace

​Deploy the server

Create a secret for the API basic authentication username and password:

Install the server:

​Access the Prefect UI:

​Deploy a worker with Helm

Install the worker:

Create a secret for the API basic authentication username and password:

Install the worker:

​Cleanup

​Troubleshooting

Prerequisites

Deploy a server with Helm

Add the Prefect Helm repository:

Create a namespace

Deploy the server

Access the Prefect UI:

Deploy a worker with Helm

Cleanup

Troubleshooting