Enable TLS for DM Connections

This document describes how to enable encrypted data transmission for DM connections, including connections between the DM-master, DM-worker, and dmctl components, and connections between DM and the upstream or downstream database.

Enable encrypted data transmission between DM-master, DM-worker, and dmctl

This section introduces how to enable encrypted data transmission between DM-master, DM-worker, and dmctl.

Configure and enable encrypted data transmission

Prepare certificates.
It is recommended to prepare a server certificate for DM-master and DM-worker separately. Make sure that the two components can authenticate each other. You can choose to share one client certificate for dmctl.
To generate self-signed certificates, you can use openssl, cfssl and other tools based on openssl, such as easy-rsa.
If you choose openssl, you can refer to generating self-signed certificates.
Configure certificates.
Note
You can configure DM-master, DM-worker, and dmctl to use the same set of certificates.
- DM-master
  Configure in the configuration file or command-line arguments:
```
ssl-ca = "/path/to/ca.pem"
ssl-cert = "/path/to/master-cert.pem"
ssl-key = "/path/to/master-key.pem"
```
- DM-worker
  Configure in the configuration file or command-line arguments:
```
ssl-ca = "/path/to/ca.pem"
ssl-cert = "/path/to/worker-cert.pem"
ssl-key = "/path/to/worker-key.pem"
```
- dmctl
  After enabling encrypted transmission in a DM cluster, if you need to connect to the cluster using dmctl, specify the client certificate. For example:
```
./dmctl --master-addr=127.0.0.1:8261 --ssl-ca /path/to/ca.pem --ssl-cert /path/to/client-cert.pem --ssl-key /path/to/client-key.pem
```

Verify component caller's identity

The Common Name is used for caller verification. In general, the callee needs to verify the caller's identity, in addition to verifying the key, the certificates, and the CA provided by the caller. For example, DM-worker can only be accessed by DM-master, and other visitors are blocked even though they have legitimate certificates.

To verify component caller's identity, you need to mark the certificate user identity using Common Name (CN) when generating the certificate, and to check the caller's identity by configuring the Common Name list for the callee.

DM-master
Configure in the configuration file or command-line arguments:
```
cert-allowed-cn = ["dm"]
```
DM-worker
Configure in the configuration file or command-line arguments:
```
cert-allowed-cn = ["dm"]
```

Reload certificates

To reload the certificates and the keys, DM-master, DM-worker, and dmctl reread the current certificates and the key files each time a new connection is created.

When the files specified by ssl-ca, ssl-cert or ssl-key are updated, restart DM components to reload the certificates and the key files and reconnect with each other.

Enable encrypted data transmission between DM components and the upstream or downstream database

This section introduces how to enable encrypted data transmission between DM components and the upstream or downstream database.

Enable encrypted data transmission for upstream database

Configure the upstream database, enable the encryption support, and set the server certificate. For detailed operations, see Using encrypted connections.
Set the MySQL client certificate in the source configuration file:
Note
Make sure that all DM-master and DM-worker components can read the certificates and the key files via specified paths.
```
from:
    security:
        ssl-ca: "/path/to/mysql-ca.pem"
        ssl-cert: "/path/to/mysql-cert.pem"
        ssl-key: "/path/to/mysql-key.pem"
```

Enable encrypted data transmission for downstream TiDB

Configure the downstream TiDB to use encrypted connections. For detailed operatons, refer to Configure TiDB to use encrypted connections.

Set the TiDB client certificate in the task configuration file:

Note

Make sure that all DM-master and DM-worker components can read the certificates and the key files via specified paths.

target-database:
    security:
        ssl-ca: "/path/to/tidb-ca.pem"
        ssl-cert: "/path/to/tidb-client-cert.pem"
        ssl-key: "/path/to/tidb-client-key.pem"