Create a custom DNS alias by setting up a reverse proxy

Learn how to set up a custom DNS alias for your instance using a reverse proxy

Custom DNS alias by setting up reverse proxy

In this knowledgebase article, we will walk you through how you can set up a custom DNS alias for your ClickHouse Cloud instance through the use of a reverse proxy such as Nginx for ClickHouse native client.

Create a self-signed certificate

This step is not needed if you are using signed certificates.

Create a self-signed certificate with the domain name of your choice. In this example we will use a domain name xyz-customdomain.com and create a certificate called MyCertificate.crt. Refer to “Create SSL certificates” for further details.

Add the certificate to /etc/clickhouse-client/config.xml:

<clickhouse>
    <openSSL>
        <client>
            <loadDefaultCAFile>false</loadDefaultCAFile>
            <caConfig>/etc/ssl/certs/MyCertificate.crt</caConfig>
            <cacheSessions>true</cacheSessions>
            <disableProtocols>sslv2,sslv3</disableProtocols>
            <preferServerCiphers>true</preferServerCiphers>
            <invalidCertificateHandler>
                <name>RejectCertificateHandler</name>
            </invalidCertificateHandler>
        </client>
    </openSSL>
</clickhouse>

Update Nginx configuration

Add the following in your nginx.conf file:

proxy_ssl_name xyz.us-west-2.aws.clickhouse.cloud;
proxy_ssl_server_name on;

stream {
    upstream stream_backend {
         server xyz.us-west-2.aws.clickhouse.cloud:9440;
    }

    server {
        listen                9440 ssl;
        proxy_pass            stream_backend;

        ssl_certificate       /etc/ssl/certs/MyCertificate.crt;
        ssl_certificate_key   /etc/ssl/certs/MyKey.key;
        ssl_protocols         SSLv3 TLSv1 TLSv1.1 TLSv1.2;
        ssl_ciphers           HIGH:!aNULL:!MD5;
        ssl_session_cache     shared:SSL:20m;
        ssl_session_timeout   4h;
        ssl_handshake_timeout 30s;
	proxy_ssl on;
	proxy_ssl_trusted_certificate /etc/ssl/certs/isrgrootx1.pem;
	proxy_ssl_session_reuse on;
        proxy_ssl_verify on;
	proxy_ssl_name xyz.us-west-2.aws.clickhouse.cloud;
	proxy_ssl_server_name on;
    }
}

Where isrgrootx1.pem is the root certificate for ClickHouse Cloud which you can download here.

Update hosts file

The following step is not needed if you are using your own domain controllers

Add the following to your /etc/hosts file on the Nginx server:

/etc/hosts

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost6 localhost6.localdomain6
10.X.Y.Z  xyz-customdomain.com

Where 10.X.Y.Z is the IP address of your specific Nginx box.

Connect to Cloud using alias

You are now ready to connect using your custom alias:

clickhouse-client --host xyz.customdomain.com --secure --password 'xxxxxxx'
ClickHouse client version 23.12.1.428 (official build).
Connecting to xyz.customdomain.com:9440 as user default.
Connected to ClickHouse server version 23.9.2.

clickhouse-cloud :)