Encrypting Communication between Web Node and Compute Node in Linux

This article walks you through the steps for encrypting the traffic between web nodes and compute nodes in Linux using self-signed certificates. If a compute node is inside the web node's trust boundary, then encryption of this piece isn't needed. However, if the compute node resides outside of the trust boundary, consider using the compute node certificate to encrypt the traffic between the web node and compute node. As a prerequisite, you can spin a 1-webnode-1-computenode enterprise configuration using ARM Template from here.

For Single Compute Node, use IP Address as Certificate Subject Name.

For multiple compute nodes, use DNS Suffix as Certificate Subject Name. 

Example: say you have 2 compute nodes CN1.contoso.microsoft.com, CN2.contoso.microsoft.com, certificate subject name will be CN=contoso.microsoft.com.

 cd /etc/ssl/certs
openssl genrsa -out privateKey.pem 2048
openssl req -new -x509 -key privateKey.pem -out publicCert.pem -days 3650 -nodes -subj "/CN=10.0.1.4"
openssl x509 -noout -hash -in publicCert.pem
ln -s publicCert.pem 0c73457b.0

 apt-get install -y nginx

 yum clean all
yum makecache fast
yum -y install https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
yum install -y nginx

 yum install -y epel-release
yum install -y nginx

Location of nginx.conf
Ubuntu: /etc/nginx/sites-enabled/default
RedHat and CentOS: /etc/nginx/nginx.conf

Modify the file in above location to the following contents :

 server {
    listen 443 ssl;
    ssl_certificate /etc/ssl/certs/publicCert.pem;
    ssl_certificate_key /etc/ssl/private/privateKey.pem;
    server_name _;
    location / {
        proxy_pass https://127.0.0.1:12805/;
    }
}

 service nginx start
update-rc.d nginx defaults

 systemctl start nginx
systemctl enable nginx
iptables –flush

 systemctl start nginx
systemctl enable nginx

Launch the administrator's utility and restart the compute node

 curl https://10.0.1.4/status

Should give a response like this:

 {
 "statusCode": 0,
 "components": null,
 "details": {
     "rMaxPoolSize": 500,
     "rActiveShellCount": 0,
     "rCurrentPoolSize": 5,
     "rCanOpenShell": "True",
     "apiVersion": "1.0",
     "logPath": "/usr/lib64/microsoft-r/rserver/o16n/9.1.0/Microsoft.RServer.ComputeNode/logs"
 }
}

Copy paste the publicCert.pem and certificate authority into /etc/ssl/certs

 scp root@10.0.1.4:/etc/ssl/certs/publicCert.pem /etc/ssl/certs
scp root@10.0.1.4:/etc/ssl/certs/0c73457b.0 /etc/ssl/certs

Open appsettings.json and modify the URIs :

 "Uris": {
    "Values": [ "https://10.0.1.4" ]
}

NOTE: If you have multiple compute nodes, make sure to enter all compute nodes information in the URI values. For example:

 "Uris": {
    "Values": [ "https://CN1.contoso.microsoft.com", "https://CN2.contoso.microsoft.com" ]
}

Launch the administrator's utility and restart the web node.

Verify the configuration by running diagnostic test on the web node.

NOTE:  Self-Signed Certificates are NOT recommended for production usage. Please obtain certificate from Trusted Certificate Authorities for production usage.

• Anonymous
  October 17, 2017
  I executed curl command, but using self certification, I got the following error message.curl: (60) Peer's certificate issuer has been marked as not trusted by the user.More details here: http://curl.haxx.se/docs/sslcerts.htmlcurl performs SSL certificate verification by default, using a "bundle" of Certificate Authority (CA) public keys (CA certs). If the default bundle file isn't adequate, you can specify an alternate file using the --cacert option.If this HTTPS server uses a certificate signed by a CA represented in the bundle, the certificate verification probably failed due to a problem with the certificate (it might be expired, or the name might not match the domain name in the URL).If you'd like to turn off curl's verification of the certificate, use the -k (or --insecure) option.
• Anonymous
  November 21, 2017
  Hi DataplatJP, does curl -k work ? Or you can try turning off ssl verification in nginx configuration file like this : location / { proxy_pass http://127.0.0.1:12805/; proxy_ssl_verify off; }