System: SSH Agent

The ssh-agent service allows adding multiple keys (including the ones protected with a passphrase) to a single pool of SSH keys, which can be shared across multiple projects. It runs an SSH agent process whose Unix socket is mounted into your project’s cli container by default.

The default SSH keys (~/.ssh/id_rsa, ~/.ssh/id_dsa, ~/.ssh/id_ecdsa, ~/.ssh/id_ed25519) are loaded into the agent automatically. On macOS and Windows, this happens when the Docksal VM is (re)started, on Linux, whenever fin project start is used.

Alternatively, you can run the ssh-agent service in a proxy mode, where your host’s SSH agent is passed through to all containers that talk to the ssh-agent service. This can be useful for CI where SSH keys are managed inside an SSH agent, or if you already have an SSH agent up and running that you would like to reuse.

Command Line Reference

See fin help ssh-key for more information and usage guidelines.

$ fin help ssh-key
Manage SSH keys loaded into Docksal

  Private SSH keys loaded into the secure docksal-ssh-agent service are accessible to all project containers.
  This allows containers to connect to the external SSH servers that require SSH keys
  without a need to copy over the key into the container every time.
  Default keys id_rsa/id_dsa/id_ecdsa/id_ed25519 are loaded automatically on every project start.

Usage: fin ssh-key <command> [params]

  add [key-name] [--quiet] 	Add a private SSH key from $HOME/.ssh by file name
                           	Adds all default keys (id_rsa/id_dsa/id_ecdsa/id_ed25519) if no file name is given.
                           	Suppress key already loaded notifications if --quiet option specified.
  ls                       	List SSH keys loaded in the docksal-ssh-agent
  rm                       	Remove all keys from the docksal-ssh-agent
  new [key-name]           	Generate a new SSH key pair

  fin ssh-key add          	Loads all SSH keys with default names: id_rsa/id_dsa/id_ecdsa from $HOME/.ssh/
  fin ssh-key server_rsa   	Loads the key stored in $HOME/.ssh/server_id_rsa into the agent
  fin ssh-key new server2_rsa	Generates a new SSH key pair in ~/.ssh/server2_id_rsa

Automatically Add Keys

Adding SSH keys automatically whenever Docksal project is started can be done by defining special variable(s) within the $HOME/.docksal/docksal.env file. All variables should be prefixed with SECRET_SSH_KEY_ plus the identifier of the SSH key. After that has been done, restart your project with fin project restart, and the keys will be added.

For example, assuming you have a private SSH key $HOME/.ssh/acquia_key, you would define a variable:


When creating the variable use the file name within $HOME/.ssh/ directory as the variable value. NOTE: the private key should be referenced, not the public one.

Manually Add Keys

To add a key manually, run fin ssh-key add <key_filename> and it will be manually loaded. NOTE: this key will only be available to the containers until the next ssh-agent restart.

Using the host’s SSH agent

The default behavior for the ssh-agent service is to manage SSH keys itself. There are two ways to enable SSH agent pass-through:

  • When running Docksal as part of a CI job, set the environment variable CI to 1. This will result in ssh-agent starting in proxy mode by default.
  • By setting the environment variable DOCKSAL_SSH_AGENT_USE_HOST to 1. This will explictly enable proxy mode. Set it by running fin config set --global DOCKSAL_SSH_AGENT_USE_HOST=1 followed by fin system reset ssh-agent.

On Linux, ssh-agent is able to directly mount your host SSH agent’s Unix socket into the container.

On Windows and macOS, the socat utility is used to convert your local Unix socket to a TCP-endpoint and back again. To do so, a local port configured by the DOCKSAL_SSH_PROXY_PORT environment variable (defaults to 30001) is opened.

Caution: if other users have local access to your system, they could connect to this port and use your keys. The port is only opened on an internal network interface and is not accessible from your LAN. Use with care!