prefect-server

prefect-server

Prefect server application bundle

Homepage: https://github.com/PrefectHQ

Installing the Chart

To install the chart with the release name prefect-server:

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

Prefect Configuration

Container Port // Port Forwarding

Without making any modifications to the values.yaml file, you can access the Prefect UI by port forwarding either the Server pod or service with the following command and visiting http:localhost:4200:

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

Note: If you choose to make modifications to either the server.prefectApiUrl or service.port, make sure to update the other value with the updated port!

Background Services Configuration

The Prefect server includes background services related to scheduling and cleanup. By default, these run in the same deployment as the web server, but they can be separated for better resource management and scalability.

To run background services in a separate deployment:

backgroundServices:
  runAsSeparateDeployment: true

This configuration is recommended when:

• You're experiencing database connection pool contention
• You need different scaling policies for the web server and background services
• You want to monitor and manage resource usage separately

PostgreSQL Configuration

Handling Connection Secrets

Using the bundled PostgreSQL chart

By default, Bitnami's PostgreSQL Helm Chart will be deployed. This is not intended for production use, and is only included to provide a functional proof of concept installation.

In this scenario, you'll need to provide either one of the following fields:

1. postgresql.auth.password: a password you want to set for the prefect user (default: prefect-rocks)

2. postgresql.auth.existingSecret: name of an existing secret in your cluster with the following field:

   • connection-string: fully-quallified connection string in the format of postgresql+asyncpg://{username}:{password}@{hostname}/{database}
     • username = postgresql.auth.username
     • hostname = <release-name>-postgresql.<release-namespace>:<postgresql.containerPorts.postgresql>
     • database = postgresql.auth.database

Two secrets are created when not providing an existing secret name:

1. prefect-server-postgresql-connection: used by the prefect-server deployment to connect to the postgresql database.

2. <release-name>-postgresql-0: defines the postgresql.auth.username's password on the postgresql server to allow successful authentication from the prefect server.

Using an external instance of PostgreSQL

If you want to disable the bundled PostgreSQL chart and use an external instance, provide the following configuration:

postgresql:
  enabled: false

secret:
  # Option 1: provide the name of an existing secret following the instructions above.
  create: false
  name: <existing secret name>

  # Option 2: provide the connection string details directly
  create: true
  username: myuser
  password: mypass
  host: myhost.com
  port: 1234
  database: mydb

Connecting with SSL configured

1. Mount the relevant certificate to /home/prefect/.postgresql so that it can be found by asyncpg. This is the default location postgresql expects per their documentation.

   server:
     extraVolumes:
       - name: db-ssl-secret
         secret:
           secretName: db-ssl-secret
           defaultMode: 384
     extraVolumeMounts:
       - name: db-ssl-secret
         mountPath: "/home/prefect/.postgresql"
         readOnly: true
   postgresql:
     enabled: false
     auth:
       existingSecret: external-db-connection-string

2. Create a secret to hold the ca certificate for the database with the key root.crt

   apiVersion: v1
   kind: Secret
   metadata:
     name: db-ssl-secret
   data:
     root.crt: BASE64ENCODECERTIFICATE=
   type: Opaque

3. Set the connection string in the existing secret following this format - ?ssl=verify-ca is cruicial:

   postgresql+asyncpg://{username}:{password}@{hostname}/{database}?ssl=verify-ca
   

SQLite Configuration

SQLite can be used as an alternative to PostgreSQL. As mentioned in the documentation on hosting Prefect, SQLite is only recommended for lightweight, single-server deployments.

To use SQLite for the database, provide the following configuration values:

postgresql:
  enabled: false
sqlite:
  enabled: true

More configuration options are available in values.yaml.

By default, a PersistentVolumeClaim persists the SQLite database file between Pod restarts.

Note that enabling SQLite enforces 1 replica in the Deployment, and disables the HorizontalPodAutoscaler.

Maintainers

Name	Email	Url
jamiezieziula	[email protected]
jimid27	[email protected]
parkedwards	[email protected]
mitchnielsen	[email protected]

Requirements

Repository	Name	Version
https://charts.bitnami.com/bitnami	common	2.27.0
https://charts.bitnami.com/bitnami	postgresql	12.12.10

Values

Key	Type	Default	Description
backgroundServices.affinity	object	{}	affinity for background-services pod assignment
backgroundServices.containerSecurityContext.allowPrivilegeEscalation	bool	false	set background-services containers' security context allowPrivilegeEscalation
backgroundServices.containerSecurityContext.capabilities	object	{}	set background-services container's security context capabilities
backgroundServices.containerSecurityContext.readOnlyRootFilesystem	bool	true	set background-services containers' security context readOnlyRootFilesystem
backgroundServices.containerSecurityContext.runAsNonRoot	bool	true	set background-services containers' security context runAsNonRoot
backgroundServices.containerSecurityContext.runAsUser	int	1001	set background-services containers' security context runAsUser
backgroundServices.debug	bool	false	enable background-services debug mode
backgroundServices.env	list	[]	array with environment variables to add to background-services container
backgroundServices.extraContainers	list	[]	additional sidecar containers
backgroundServices.extraEnvVarsCM	string	""	name of existing ConfigMap containing extra env vars to add to background-services pod
backgroundServices.extraEnvVarsSecret	string	""	name of existing Secret containing extra env vars to add to background-services pod
backgroundServices.extraVolumeMounts	list	[]	array with extra volumeMounts for the background-services pod
backgroundServices.extraVolumes	list	[]	array with extra volumes for the background-services pod
backgroundServices.livenessProbe.config.failureThreshold	int	3	The number of consecutive failures allowed before considering the probe as failed.
backgroundServices.livenessProbe.config.initialDelaySeconds	int	10	The number of seconds to wait before starting the first probe.
backgroundServices.livenessProbe.config.periodSeconds	int	10	The number of seconds to wait between consecutive probes.
backgroundServices.livenessProbe.config.successThreshold	int	1	The minimum consecutive successes required to consider the probe successful.
backgroundServices.livenessProbe.config.timeoutSeconds	int	5	The number of seconds to wait for a probe response before considering it as failed.
backgroundServices.livenessProbe.enabled	bool	false
backgroundServices.loggingLevel	string	"WARNING"
backgroundServices.nodeSelector	object	{}	node labels for background-services pod assignment
backgroundServices.podAnnotations	object	{}	extra annotations for background-services pod
backgroundServices.podLabels	object	{}	extra labels for background-services pod
backgroundServices.podSecurityContext.fsGroup	int	1001	set background-services pod's security context fsGroup
backgroundServices.podSecurityContext.runAsNonRoot	bool	true	set background-services pod's security context runAsNonRoot
backgroundServices.podSecurityContext.runAsUser	int	1001	set background-services pod's security context runAsUser
backgroundServices.priorityClassName	string	""	priority class name to use for the background-services pods; if the priority class is empty or doesn't exist, the background-services pods are scheduled without a priority class
backgroundServices.readinessProbe.config.failureThreshold	int	3	The number of consecutive failures allowed before considering the probe as failed.
backgroundServices.readinessProbe.config.initialDelaySeconds	int	10	The number of seconds to wait before starting the first probe.
backgroundServices.readinessProbe.config.periodSeconds	int	10	The number of seconds to wait between consecutive probes.
backgroundServices.readinessProbe.config.successThreshold	int	1	The minimum consecutive successes required to consider the probe successful.
backgroundServices.readinessProbe.config.timeoutSeconds	int	5	The number of seconds to wait for a probe response before considering it as failed.
backgroundServices.readinessProbe.enabled	bool	false
backgroundServices.resources.limits	object	{"cpu":"1","memory":"1Gi"}	the requested limits for the background-services container
backgroundServices.resources.requests	object	{"cpu":"500m","memory":"512Mi"}	the requested resources for the background-services container
backgroundServices.revisionHistoryLimit	int	10	the number of old ReplicaSets to retain to allow rollback
backgroundServices.runAsSeparateDeployment	bool	false	Run background services (like scheduling) in a separate deployment.
backgroundServices.serviceAccount.annotations	object	{}	additional service account annotations (evaluated as a template)
backgroundServices.serviceAccount.create	bool	true	specifies whether a service account should be created
backgroundServices.serviceAccount.name	string	""	the name of the service account to use. if not set and create is true, a name is generated using the common.names.fullname template with "-background-services" appended
backgroundServices.tolerations	list	[]	tolerations for background-services pod assignment
commonAnnotations	object	{}	annotations to add to all deployed objects
commonLabels	object	{}	labels to add to all deployed objects
fullnameOverride	string	"prefect-server"	fully override common.names.fullname
global.prefect.env	list	[]	array with environment variables to add to all deployments
global.prefect.image.prefectTag	string	"3-latest"	prefect image tag (immutable tags are recommended)
global.prefect.image.pullPolicy	string	"IfNotPresent"	prefect image pull policy
global.prefect.image.pullSecrets	list	[]	prefect image pull secrets
global.prefect.image.repository	string	"prefecthq/prefect"	prefect image repository
global.prefect.prefectApiHost	string	"0.0.0.0"	sets PREFECT_SERVER_API_HOST
global.prefect.prefectApiUrl	string	"http://localhost:4200/api"	sets PREFECT_API_URL
ingress.annotations	object	{}	additional annotations for the Ingress resource. To enable certificate autogeneration, place here your cert-manager annotations.
ingress.className	string	""	IngressClass that will be used to implement the Ingress (Kubernetes 1.18+)
ingress.enabled	bool	false	enable ingress record generation for server
ingress.extraHosts	list	[]	an array with additional hostname(s) to be covered with the ingress record
ingress.extraPaths	list	[]	an array with additional arbitrary paths that may need to be added to the ingress under the main host
ingress.extraRules	list	[]	additional rules to be covered with this ingress record
ingress.extraTls	list	[]	an array with additional tls configuration to be added to the ingress record
ingress.host.hostname	string	"prefect.local"	default host for the ingress record
ingress.host.path	string	"/"	default path for the ingress record
ingress.host.pathType	string	"ImplementationSpecific"	ingress path type
ingress.selfSigned	bool	false	create a TLS secret for this ingress record using self-signed certificates generated by Helm
ingress.servicePort	string	"server-svc-port"	port for the ingress' main path
ingress.tls	bool	false	enable TLS configuration for the host defined at ingress.host.hostname parameter
nameOverride	string	""	partially overrides common.names.name
namespaceOverride	string	""	fully override common.names.namespace
postgresql.auth.database	string	"server"	name for a custom database
postgresql.auth.enablePostgresUser	bool	false	determines whether an admin user is created within postgres
postgresql.auth.password	string	"prefect-rocks"	password for the custom user. Ignored if auth.existingSecret with key password is provided
postgresql.auth.username	string	"prefect"	name for a custom user
postgresql.enabled	bool	true	enable use of bitnami/postgresql subchart
postgresql.image.tag	string	"14.13.0"	Version tag, corresponds to tags at https://hub.docker.com/r/bitnami/postgresql/
postgresql.primary.initdb.user	string	"postgres"	specify the PostgreSQL username to execute the initdb scripts
postgresql.primary.persistence.enabled	bool	false	enable PostgreSQL Primary data persistence using PVC
secret.create	bool	true	whether to create a Secret containing the PostgreSQL connection string
secret.database	string	""	database for the PostgreSQL connection string
secret.host	string	""	host for the PostgreSQL connection string
secret.name	string	""	name for the Secret containing the PostgreSQL connection string To provide an existing Secret, provide a name and set create=false
secret.password	string	""	password for the PostgreSQL connection string
secret.port	string	""	port for the PostgreSQL connection string
secret.username	string	""	username for the PostgreSQL connection string
server.affinity	object	{}	affinity for server pods assignment
server.autoscaling.enabled	bool	false	enable autoscaling for server
server.autoscaling.maxReplicas	int	100	maximum number of server replicas
server.autoscaling.minReplicas	int	1	minimum number of server replicas
server.autoscaling.targetCPU	int	80	target CPU utilization percentage
server.autoscaling.targetMemory	int	80	target Memory utilization percentage
server.containerSecurityContext.allowPrivilegeEscalation	bool	false	set server containers' security context allowPrivilegeEscalation
server.containerSecurityContext.capabilities	object	{}	set server container's security context capabilities
server.containerSecurityContext.readOnlyRootFilesystem	bool	true	set server containers' security context readOnlyRootFilesystem
server.containerSecurityContext.runAsNonRoot	bool	true	set server containers' security context runAsNonRoot
server.containerSecurityContext.runAsUser	int	1001	set server containers' security context runAsUser
server.debug	bool	false	enable server debug mode
server.env	list	[]	array with environment variables to add to server deployment
server.extraArgs	list	[]	array with extra Arguments for the server container to start with
server.extraContainers	list	[]	additional sidecar containers
server.extraEnvVarsCM	string	""	name of existing ConfigMap containing extra env vars to add to server nodes
server.extraEnvVarsSecret	string	""	name of existing Secret containing extra env vars to add to server nodes
server.extraVolumeMounts	list	[]	array with extra volumeMounts for the server pod
server.extraVolumes	list	[]	array with extra volumes for the server pod
server.livenessProbe.config.failureThreshold	int	3	The number of consecutive failures allowed before considering the probe as failed.
server.livenessProbe.config.initialDelaySeconds	int	10	The number of seconds to wait before starting the first probe.
server.livenessProbe.config.periodSeconds	int	10	The number of seconds to wait between consecutive probes.
server.livenessProbe.config.successThreshold	int	1	The minimum consecutive successes required to consider the probe successful.
server.livenessProbe.config.timeoutSeconds	int	5	The number of seconds to wait for a probe response before considering it as failed.
server.livenessProbe.enabled	bool	false
server.loggingLevel	string	"WARNING"
server.nodeSelector	object	{}	node labels for server pods assignment
server.podAnnotations	object	{}	extra annotations for server pod
server.podLabels	object	{}	extra labels for server pod
server.podSecurityContext.fsGroup	int	1001	set server pod's security context fsGroup
server.podSecurityContext.runAsNonRoot	bool	true	set server pod's security context runAsNonRoot
server.podSecurityContext.runAsUser	int	1001	set server pod's security context runAsUser
server.priorityClassName	string	""	priority class name to use for the server pods; if the priority class is empty or doesn't exist, the server pods are scheduled without a priority class
server.readinessProbe.config.failureThreshold	int	3	The number of consecutive failures allowed before considering the probe as failed.
server.readinessProbe.config.initialDelaySeconds	int	10	The number of seconds to wait before starting the first probe.
server.readinessProbe.config.periodSeconds	int	10	The number of seconds to wait between consecutive probes.
server.readinessProbe.config.successThreshold	int	1	The minimum consecutive successes required to consider the probe successful.
server.readinessProbe.config.timeoutSeconds	int	5	The number of seconds to wait for a probe response before considering it as failed.
server.readinessProbe.enabled	bool	false
server.replicaCount	int	1	number of server replicas to deploy
server.resources.limits	object	{"cpu":"1","memory":"1Gi"}	the requested limits for the server container
server.resources.requests	object	{"cpu":"500m","memory":"512Mi"}	the requested resources for the server container
server.revisionHistoryLimit	int	10	the number of old ReplicaSets to retain to allow rollback
server.tolerations	list	[]	tolerations for server pods assignment
server.uiConfig.enabled	bool	true	set PREFECT_UI_ENABLED; enable the UI on the server
server.uiConfig.prefectUiApiUrl	string	""	sets PREFECT_UI_API_URL
server.uiConfig.prefectUiStaticDirectory	string	"/ui_build"	sets PREFECT_UI_STATIC_DIRECTORY
server.uiConfig.prefectUiUrl	string	""	sets PREFECT_UI_URL
service.annotations	object	{}
service.clusterIP	string	""	service Cluster IP
service.externalTrafficPolicy	string	"Cluster"	service external traffic policy
service.extraPorts	list	[]
service.nodePort	string	""	service port if defining service as type nodeport
service.port	int	4200	service port
service.targetPort	int	4200	target port of the server pod; also sets PREFECT_SERVER_API_PORT
service.type	string	"ClusterIP"	service type
serviceAccount.annotations	object	{}	additional service account annotations (evaluated as a template)
serviceAccount.create	bool	true	specifies whether a service account should be created
serviceAccount.name	string	""	the name of the service account to use. if not set and create is true, a name is generated using the common.names.fullname template
sqlite.enabled	bool	false	enable use of the embedded SQLite database
sqlite.persistence.enabled	bool	true	enable SQLite data persistence using PVC
sqlite.persistence.size	string	"1Gi"	size for the PVC
sqlite.persistence.storageClassName	string	""	storage class name for the PVC

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Autogenerated from chart metadata using helm-docs v1.13.1