page_title: Docker HTTPS Setup
page_description: How to set Docker up with https
page_keywords: docker, example, https, daemon

# Running Docker with https

By default, Docker runs via a non-networked Unix socket. It can also
optionally communicate using a HTTP socket.

If you need Docker to be reachable via the network in a safe manner, you can
enable TLS by specifying the `tlsverify` flag and pointing Docker's
`tlscacert` flag to a trusted CA certificate.

In daemon mode, it will only allow connections from clients
authenticated by a certificate signed by that CA. In client mode, it
will only connect to servers with a certificate signed by that CA.

> **Warning**: 
> Using TLS and managing a CA is an advanced topic. Please familiarize yourself
> with OpenSSL, x509 and TLS before using it in production.

> **Warning**:
> These TLS commands will only generate a working set of certificates on Linux.
> Mac OS X comes with a version of OpenSSL that is incompatible with the 
> certificates that Docker requires.

## Create a CA, server and client keys with OpenSSL

First, initialize the CA serial file and generate CA private and public
keys:

    $ echo 01 > ca.srl
    $ openssl genrsa -des3 -out ca-key.pem 2048
    $ openssl req -new -x509 -days 365 -key ca-key.pem -out ca.pem

Now that we have a CA, you can create a server key and certificate
signing request (CSR). Make sure that "Common Name" (i.e. server FQDN or YOUR
name) matches the hostname you will use to connect to Docker:

    $ openssl genrsa -des3 -out server-key.pem 2048
    $ openssl req -subj '/CN=<Your Hostname Here>' -new -key server-key.pem -out server.csr

Next we're going to sign the key with our CA:

    $ openssl x509 -req -days 365 -in server.csr -CA ca.pem -CAkey ca-key.pem \
      -out server-cert.pem

For client authentication, create a client key and certificate signing
request:

    $ openssl genrsa -des3 -out client-key.pem 2048
    $ openssl req -subj '/CN=client' -new -key client-key.pem -out client.csr

To make the key suitable for client authentication, create an extensions
config file:

    $ echo extendedKeyUsage = clientAuth > extfile.cnf

Now sign the key:

    $ openssl x509 -req -days 365 -in client.csr -CA ca.pem -CAkey ca-key.pem \
      -out client-cert.pem -extfile extfile.cnf

Finally, you need to remove the passphrase from the client and server key:

    $ openssl rsa -in server-key.pem -out server-key.pem
    $ openssl rsa -in client-key.pem -out client-key.pem

Now you can make the Docker daemon only accept connections from clients
providing a certificate trusted by our CA:

    $ sudo docker -d --tlsverify --tlscacert=ca.pem --tlscert=server-cert.pem --tlskey=server-key.pem \
      -H=0.0.0.0:2376

To be able to connect to Docker and validate its certificate, you now
need to provide your client keys, certificates and trusted CA:

    $ docker --tlsverify --tlscacert=ca.pem --tlscert=client-cert.pem --tlskey=client-key.pem \
      -H=dns-name-of-docker-host:2376

> **Note**:
> Docker over TLS should run on TCP port 2376.

> **Warning**: 
> As shown in the example above, you don't have to run the `docker` client 
> with `sudo` or the `docker` group when you use certificate
> authentication. That means anyone with the keys can give any
> instructions to your Docker daemon, giving them root access to the
> machine hosting the daemon. Guard these keys as you would a root
> password!

## Secure By Default

If you want to secure your Docker client connections by default, you can move the files
to the `.docker` directory in your home directory. Set the `DOCKER_HOST` variable as well.

    $ cp ca.pem ~/.docker/ca.pem
    $ cp client-cert.pem ~/.docker/cert.pem
    $ cp client-key.pem ~/.docker/key.pem
    $ export DOCKER_HOST=tcp://:2376

Then you can just run docker with the `--tlsverify` option.

    $ docker --tlsverify ps

## Other modes

If you don't want to have complete two-way authentication, you can run
Docker in various other modes by mixing the flags.

### Daemon modes

 - `tlsverify`, `tlscacert`, `tlscert`, `tlskey` set: Authenticate clients
 - `tls`, `tlscert`, `tlskey`: Do not authenticate clients

### Client modes

 - `tls`: Authenticate server based on public/default CA pool
 - `tlsverify`, `tlscacert`: Authenticate server based on given CA
 - `tls`, `tlscert`, `tlskey`: Authenticate with client certificate, do not
   authenticate server based on given CA
 - `tlsverify`, `tlscacert`, `tlscert`, `tlskey`: Authenticate with client
   certificate and authenticate server based on given CA

The client will send its client certificate if found, so you just need
to drop your keys into `~/.docker/<ca, cert or key>.pem`. Alternatively, if you
want to store your keys in another location, you can specify that location
using the environment variable `DOCKER_CONFIG`.

    $ export DOCKER_CONFIG=${HOME}/.dockers/zone1/
    $ docker --tlsverify ps