
Steps
Secure Docker Daemon using HTTPS
Step 1 - Generate Server SSL Certificate
First create a public key.
openssl genrsa -aes256 -out ca-key.pem 2048
Enter a password for the public key. This creates a file called ca-key.pem.
Generate server key.
openssl genrsa -out server-key.pem 4096
This generates server-key.pem.
Generate certificate. Set the subject to the hostname.
openssl req -subj "/CN=$HOST" -sha256 -new -key server-key.pem -out server.csr
This creates server.csr.
The server will use ca-key.pem and server-key.pem. These will also be used to create and sign keys allowing clients to access the Docker daemon.