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Connect to ClickHouse over HTTP

DevOpsPad talks to ClickHouse through its HTTP interface, not the native TCP protocol. Use port 8123 for plain HTTP or 8443 with Use TLS with certificate verification turned on. ClickHouse Cloud uses 8443 with TLS.

The same adapter works for self-hosted servers and ClickHouse Cloud. Every request is sent with readonly=1, so the server itself rejects writes. See ClickHouse read-only queries.

Add the connection

  1. Click New connection and choose ClickHouse. The port starts at 8123.
  2. Enter a Connection name and an Environment label.
  3. Enter the Host without http:// or https://, for example clickhouse.internal or abc123.eu-central-1.aws.clickhouse.cloud.
  4. Set the Port: 8123 for HTTP, 8443 for HTTPS.
  5. Enter the Username and Password. They are sent with HTTP basic authentication. The password is stored in the OS keychain.
  6. Optionally enter a default Database. Leave it blank to use the server’s default database for that user.
  7. Turn on Use TLS with certificate verification for port 8443.
  8. Click Test connection. DevOpsPad runs SELECT 1. Then click Save connection.
Setup Port TLS
Self-hosted, plain HTTP 8123 Off
Self-hosted, HTTPS 8443 (or your configured https_port) On
ClickHouse Cloud 8443 On

Through an SSH tunnel

If ClickHouse only listens on a private network, enable Connect through SSH tunnel and set the host and port as the SSH server sees them, for example 127.0.0.1:8123. HTTP proxy environment variables are bypassed for tunneled requests. With TLS turned on, the certificate is still verified against the host name you entered, so use a name that matches the server certificate. See the SSH tunnel overview.

Troubleshooting

  • “Cannot reach ClickHouse HTTP interface; check the host, port, and TLS setting”: the request did not get an HTTP response. Check that you used the HTTP port, not 9000, and that TLS matches the port.
  • ClickHouse HTTP <status>: …: ClickHouse answered with an error. The text after the status code comes from the server, for example a wrong user name or password.
  • Redirects: DevOpsPad does not follow HTTP redirects. Point it at the ClickHouse endpoint directly, not at a load balancer that redirects.

Limits

  • Only the HTTP interface is supported. The native protocol, inserts and other mutations are not available.
  • Custom CA certificates are not configurable yet. TLS uses the system trust store.
  • Each request has a 20-second HTTP timeout and a server-side max_execution_time of 15 seconds.

Frequently asked questions

Does DevOpsPad use the ClickHouse native protocol on port 9000?

No. DevOpsPad only uses the HTTP interface, on port 8123 or 8443 with TLS. The native TCP protocol is not supported yet.

How do I connect to ClickHouse Cloud?

Use your service host name, port 8443 and turn on Use TLS with certificate verification. Enter the user and password from the Cloud console.