# openssl_dhparam – Generate OpenSSL Diffie-Hellman Parameters

New in version 2.5.

- Synopsis

- Requirements

- Parameters

- See Also

- Examples

- Return Values

- Status

## Synopsis

- This module allows one to (re)generate OpenSSL DH-params.

- This module uses file common arguments to specify generated file permissions.

- Please note that the module regenerates existing DH params if they don’t match the module’s options. If you are concerned that this could overwrite your existing DH params, consider using the backup option.

## Requirements

The below requirements are needed on the host that executes this module.

- OpenSSL

## Parameters

Parameter | Choices/Defaults | Comments
--- | --- | ---
attributes string |  | The attributes the resulting file or directory should have. To get supported flags look at the man page for chattr on the target system. This string should contain the attributes in the same order as the one displayed by lsattr. The `=` operator is assumed as default, otherwise `+` or `-` operators need to be included in the string. aliases: attr

backup
boolean
added in 2.8

Choices:
- no ←
- yes

Create a backup file including a timestamp so you can get the original DH params back if you overwrote them with new ones by accident.

force
boolean

Choices:
- no ←
- yes

Should the parameters be regenerated even it it already exists.

group string |  | Name of the group that should own the file/directory, as would be fed to chown.

mode
string

The permissions the resulting file or directory should have.
For those used to /usr/bin/chmod remember that modes are actually octal numbers. You must either add a leading zero so that Ansible's YAML parser knows it is an octal number (like `0644` or `01777`) or quote it (like `'644'` or `'1777'`) so Ansible receives a string and can do its own conversion from string into number.
Giving Ansible a number without following one of these rules will end up with a decimal number which will have unexpected results.
As of Ansible 1.8, the mode may be specified as a symbolic mode (for example, `u+rwx` or `u=rw,g=r,o=r`).

owner string |  | Name of the user that should own the file/directory, as would be fed to chown.
path path / required |  | Name of the file in which the generated parameters will be saved.
selevel string | Default: "s0" | The level part of the SELinux file context. This is the MLS/MCS attribute, sometimes known as the `range`. When set to `_default`, it will use the `level` portion of the policy if available.
serole string |  | The role part of the SELinux file context. When set to `_default`, it will use the `role` portion of the policy if available.
setype string |  | The type part of the SELinux file context. When set to `_default`, it will use the `type` portion of the policy if available.
seuser string |  | The user part of the SELinux file context. By default it uses the `system` policy, where applicable. When set to `_default`, it will use the `user` portion of the policy if available.
size integer | Default: 4096 | Size (in bits) of the generated DH-params.

state
string

Choices:
- absent
- present ←

Whether the parameters should exist or not, taking action if the state is different from what is stated.

unsafe_writes
boolean

Choices:
- no ←
- yes

Influence when to use atomic operation to prevent data corruption or inconsistent reads from the target file.
By default this module uses atomic operations to prevent data corruption or inconsistent reads from the target files, but sometimes systems are configured or just broken in ways that prevent this. One example is docker mounted files, which cannot be updated atomically from inside the container and can only be written in an unsafe manner.
This option allows Ansible to fall back to unsafe methods of updating files when atomic operations fail (however, it doesn't force Ansible to perform unsafe writes).
IMPORTANT! Unsafe writes are subject to race conditions and can lead to data corruption.

## See Also

See also

openssl_certificate – Generate and/or check OpenSSL certificates

  The official documentation on the openssl_certificate module.

openssl_csr – Generate OpenSSL Certificate Signing Request (CSR)

  The official documentation on the openssl_csr module.

openssl_pkcs12 – Generate OpenSSL PKCS#12 archive

  The official documentation on the openssl_pkcs12 module.

openssl_privatekey – Generate OpenSSL private keys

  The official documentation on the openssl_privatekey module.

openssl_publickey – Generate an OpenSSL public key from its private key

  The official documentation on the openssl_publickey module.

## Examples

    - name: Generate Diffie-Hellman parameters with the default size (4096 bits)
      openssl_dhparam:
        path: /etc/ssl/dhparams.pem

    - name: Generate DH Parameters with a different size (2048 bits)
      openssl_dhparam:
        path: /etc/ssl/dhparams.pem
        size: 2048

    - name: Force regenerate an DH parameters if they already exist
      openssl_dhparam:
        path: /etc/ssl/dhparams.pem
        force: yes

## Return Values

Common return values are documented here, the following are the fields unique to this module:

Key | Returned | Description
--- | --- | ---
backup_file string | changed and if backup is `yes` | Name of backup file created. Sample: /path/to/dhparams.pem.2019-03-09@11:22~
filename string | changed or success | Path to the generated Diffie-Hellman parameters. Sample: /etc/ssl/dhparams.pem
size integer | changed or success | Size (in bits) of the Diffie-Hellman parameters. Sample: 4096

## Status

- This module is not guaranteed to have a backwards compatible interface. [preview]

- This module is maintained by the Ansible Community. [community]

### Authors

- Thom Wiggers (@thomwiggers)

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