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IntroductionCustom container images Defining ImagesPrivate registriesFast pull from registryGPUs and other resources GPU accelerationUsing CUDA on ModalReserving CPU and memoryScaling out Scaling outInput concurrencyBatch processingJob queuesDynamic batching (beta)Scheduling and cron jobsDeployment Apps, Functions, and entrypointsManaging deploymentsInvoking deployed functionsContinuous deploymentRunning untrusted code in FunctionsSecrets and environment variables SecretsEnvironment variablesWeb endpoints Web endpointsStreaming endpointsWeb endpoint URLsRequest timeoutsProxy Auth TokensNetworking TunnelsProxies (beta)Cluster networkingData sharing and storage Passing local dataVolumesStoring model weightsCloud bucket mountsDictsQueuesDataset ingestionSandboxes SandboxesRunning commandsNetworking and securityFile accessSnapshotsPerformance Cold start performanceMemory SnapshotGeographic latencyReliability and robustness Failures and retriesPreemptionTimeoutsGPU healthTroubleshootingSecurity and privacyIntegrations Using OIDC to authenticate with external servicesConnecting Modal to your Datadog accountConnecting Modal to your OpenTelemetry providerOkta SSOSlack notifications (beta)Workspace & account settings WorkspacesEnvironmentsModal user account setupService usersOther topics Modal 1.0 migration guideFile and project structureDeveloping and debuggingDeveloping Modal code with LLMsJupyter notebooksAsynchronous API usageGlobal variablesRegion selectionContainer lifecycle hooksParametrized functionsS3 Gateway endpointsGPU Metrics

Environment variables

The Modal runtime sets several environment variables during initialization. The keys for these environment variables are reserved and cannot be overridden by your Function or Sandbox configuration.

These variables provide information about the containers’s runtime environment.

Container runtime environment variables

The following variables are present in every Modal container:

  • MODAL_CLOUD_PROVIDER — Modal executes containers across a number of cloud providers (AWS, GCP, OCI). This variable specifies which cloud provider the Modal container is running within.
  • MODAL_IMAGE_ID — The ID of the modal.Image used by the Modal container.
  • MODAL_REGION — This will correspond to a geographic area identifier from the cloud provider associated with the Modal container (see above). For AWS, the identifier is a “region”. For GCP it is a “zone”, and for OCI it is an “availability domain”. Example values are us-east-1 (AWS), us-central1 (GCP), us-ashburn-1 (OCI).
  • MODAL_TASK_ID — The ID of the container running the Modal Function or Sandbox.

Function runtime environment variables

The following variables are present in containers running Modal Functions:

  • MODAL_ENVIRONMENT — The name of the Modal Environment the container is running within.
  • MODAL_IS_REMOTE - Set to ‘1’ to indicate that Modal Function code is running in a remote container.
  • MODAL_IDENTITY_TOKEN — An OIDC token encoding the identity of the Modal Function.

Sandbox environment variables

The following variables are present within modal.Sandbox instances.

  • MODAL_SANDBOX_ID — The ID of the Sandbox.

Container image environment variables

The container image layers used by a modal.Image may set environment variables. These variables will be present within your container’s runtime environment. For example, the debian_slim image sets the GPG_KEY variable.

To override image variables or set new ones, use the .env method provided by modal.Image.