open-nomad/website/content/docs/job-specification/env.mdx

---
layout: docs
page_title: env Block - Job Specification
description: |-
  The "env" block configures a list of environment variables to populate the
  task's environment before starting.
---

# `env` Block

<Placement groups={['job', 'group', 'task', 'env']} />

The `env` block configures a list of environment variables to populate the
task's environment before starting.

```hcl
job "docs" {
  group "example" {
    task "server" {
      env {
        my_key = "my-value"
      }
    }
  }
}
```

## `env` Parameters

The "parameters" for the `env` block can be any key-value. The keys and values
are both of type `string`, but they can be specified as other types. They will
automatically be converted to strings. Invalid characters such as dashes (`-`)
will be converted to underscores.

## `env` Examples

The following examples only show the `env` blocks. Remember that the
`env` block is only valid in the placements listed above.

### Coercion

This example shows the different ways to specify key-value pairs. Internally,
these values will be stored as their string representation. No type information
is preserved.

```hcl
env {
  key   = 1.4
  key   = "1.4"

  key = true
  key = "1"
  key = 1
}
```

### Interpolation

This example shows using [Nomad interpolation][interpolation] to populate
environment variables.

```hcl
env {
  NODE_CLASS = "${node.class}"
}
```

### Environment variables with dots

Environment variables that aren't valid HCLv2 identifiers, like ones containing `.`, require an alternative map assignment syntax.

```hcl
env = {
  "discovery.type" = "single-node"
}
```

### Dynamic Environment Variables

Nomad also supports populating dynamic environment variables from data stored in
HashiCorp Consul and Vault. To use this feature please see the documentation on
the [`template` block][template-env].

[interpolation]: /nomad/docs/runtime/interpolation 'Nomad interpolation'
[template-env]: /nomad/docs/job-specification/template#environment-variables 'Nomad template Block'