# Vault

Vault is a tool for securely accessing secrets. A secret is anything that you want to tightly control access to, such as API keys, passwords, certificates, and more. Vault provides a unified interface to any secret, while providing tight access control and recording a detailed audit log. For more information, please see:

-	[Vault documentation](https://www.vaultproject.io/)
-	[Vault on GitHub](https://github.com/hashicorp/vault)

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# Using the Container

We chose Alpine as a lightweight base with a reasonably small surface area for security concerns, but with enough functionality for development and interactive debugging.

Vault always runs under [dumb-init](https://github.com/Yelp/dumb-init), which handles reaping zombie processes and forwards signals on to all processes running in the container. This binary is built by HashiCorp and signed with our [GPG key](https://www.hashicorp.com/security.html), so you can verify the signed package used to build a given base image.

Running the Vault container with no arguments will give you a Vault server in [development mode](https://www.vaultproject.io/docs/concepts/dev-server.html). The provided entry point script will also look for Vault subcommands and run `vault` with that subcommand. For example, you can execute `docker run vault status` and it will run the `vault status` command inside the container. The entry point also adds some special configuration options as detailed in the sections below when running the `server` subcommand. Any other command gets `exec`-ed inside the container under `dumb-init`.

The container exposes two optional `VOLUME`s:

-	`/vault/logs`, to use for writing persistent audit logs. By default nothing is written here; the `file` audit backend must be enabled with a path under this directory.
-	`/vault/file`, to use for writing persistent storage data when using the`file` data storage plugin. By default nothing is written here (a `dev` server uses an in-memory data store); the `file` data storage backend must be enabled in Vault's configuration before the container is started.

The container has a Vault configuration directory set up at `/vault/config` and the server will load any HCL or JSON configuration files placed here by binding a volume or by composing a new image and adding files. Alternatively, configuration can be added by passing the configuration JSON via environment variable `VAULT_LOCAL_CONFIG`.

## Memory Locking and 'setcap'

The container will attempt to lock memory to prevent sensitive values from being swapped to disk and as a result must have `--cap-add=IPC_LOCK` provided to `docker run`. Since the Vault binary runs as a non-root user, `setcap` is used to give the binary the ability to lock memory. With some Docker storage plugins in some distributions this call will not work correctly; it seems to fail most often with AUFS. The memory locking behavior can be disabled by setting the `SKIP_SETCAP` environment variable to any non-empty value.

## Running Vault for Development

```console
$ docker run --cap-add=IPC_LOCK -d --name=dev-vault %%IMAGE%%
```

This runs a completely in-memory Vault server, which is useful for development but should not be used in production.

When running in development mode, two additional options can be set via environment variables:

-	`VAULT_DEV_ROOT_TOKEN_ID`: This sets the ID of the initial generated root token to the given value
-	`VAULT_DEV_LISTEN_ADDRESS`: This sets the IP:port of the development server listener (defaults to 0.0.0.0:8200)

As an example:

```console
$ docker run --cap-add=IPC_LOCK -e 'VAULT_DEV_ROOT_TOKEN_ID=myroot' -e 'VAULT_DEV_LISTEN_ADDRESS=0.0.0.0:1234' %%IMAGE%%
```

## Running Vault in Server Mode

```console
$ docker run --cap-add=IPC_LOCK -e 'VAULT_LOCAL_CONFIG={"backend": {"file": {"path": "/vault/file"}}, "default_lease_ttl": "168h", "max_lease_ttl": "720h"}' %%IMAGE%% server
```

This runs a Vault server using the `file` storage backend at path `/vault/file`, with a default secret lease duration of one week and a maximum of 30 days.

Note the `--cap-add=IPC_LOCK`: this is required in order for Vault to lock memory, which prevents it from being swapped to disk. This is highly recommended. In a non-development environment, if you do not wish to use this functionality, you must add `"disable_mlock: true"` to the configuration information.

At startup, the server will read configuration HCL and JSON files from `/vault/config` (any information passed into `VAULT_LOCAL_CONFIG` is written into `local.json` in this directory and read as part of reading the directory for configuration files). Please see Vault's [configuration documentation](https://www.vaultproject.io/docs/config/index.html) for a full list of options.

Since 0.6.3 this container also supports the `VAULT_REDIRECT_INTERFACE` and `VAULT_CLUSTER_INTERFACE` environment variables. If set, the IP addresses used for the redirect and cluster addresses in Vault's configuration will be the address of the named interface inside the container (e.g. `eth0`).