Enable TLS Between TiDB Components

This document describes how to enable encrypted data transmission between components within a TiDB cluster. Once enabled, encrypted transmission is used between the following components:

Communication between TiDB, TiKV, PD, and TiFlash
TiDB Control and TiDB; TiKV Control and TiKV; PD Control and PD
Internal communication within each TiDB, TiKV, PD, and TiFlash cluster

Currently, it is not supported to only enable encrypted transmission of some specific components.

Configure and enable encrypted data transmission

Prepare certificates.
It is recommended to prepare a server certificate for TiDB, TiKV, and PD separately. Make sure that these components can authenticate each other. The Control tools of TiDB, TiKV, and PD can choose to share one client certificate.
You can use tools like openssl, easy-rsa and cfssl to generate self-signed certificates.
If you choose openssl, you can refer to generating self-signed certificates.

Configure certificates.

To enable mutual authentication among TiDB components, configure the certificates of TiDB, TiKV, and PD as follows.

TiDB

Configure in the configuration file or command-line arguments:

[security]
# Path of the file that contains list of trusted SSL CAs for connection with cluster components.
cluster-ssl-ca = "/path/to/ca.pem"
# Path of the file that contains X509 certificate in PEM format for connection with cluster components.
cluster-ssl-cert = "/path/to/tidb-server.pem"
# Path of the file that contains X509 key in PEM format for connection with cluster components.
cluster-ssl-key = "/path/to/tidb-server-key.pem"

TiKV

Configure in the configuration file or command-line arguments, and set the corresponding URL to https:

[security]
## The path for certificates. An empty string means that secure connections are disabled.
# Path of the file that contains a list of trusted SSL CAs. If it is set, the following settings `cert_path` and `key_path` are also needed.
ca-path = "/path/to/ca.pem"
# Path of the file that contains X509 certificate in PEM format.
cert-path = "/path/to/tikv-server.pem"
# Path of the file that contains X509 key in PEM format.
key-path = "/path/to/tikv-server-key.pem"

Configure in the configuration file or command-line arguments, and set the corresponding URL to https:

[security]
## The path for certificates. An empty string means that secure connections are disabled.
# Path of the file that contains a list of trusted SSL CAs. If it is set, the following settings `cert_path` and `key_path` are also needed.
cacert-path = "/path/to/ca.pem"
# Path of the file that contains X509 certificate in PEM format.
cert-path = "/path/to/pd-server.pem"
# Path of the file that contains X509 key in PEM format.
key-path = "/path/to/pd-server-key.pem"

TiFlash (New in v4.0.5)

Configure in the tiflash.toml file, and change the http_port item to https_port:

[security]
## The path for certificates. An empty string means that secure connections are disabled.
# Path of the file that contains a list of trusted SSL CAs. If it is set, the following settings `cert_path` and `key_path` are also needed.
ca_path = "/path/to/ca.pem"
# Path of the file that contains X509 certificate in PEM format.
cert_path = "/path/to/tiflash-server.pem"
# Path of the file that contains X509 key in PEM format.
key_path = "/path/to/tiflash-server-key.pem"

Configure in the tiflash-learner.toml file:

[security]
# Path of the file that contains a list of trusted SSL CAs. If it is set, the following settings `cert_path` and `key_path` are also needed.
ca-path = "/path/to/ca.pem"
# Path of the file that contains X509 certificate in PEM format.
cert-path = "/path/to/tiflash-server.pem"
# Path of the file that contains X509 key in PEM format.
key-path = "/path/to/tiflash-server-key.pem"

TiCDC

Configure in the configuration file：

[security]
ca-path = "/path/to/ca.pem"
cert-path = "/path/to/cdc-server.pem"
key-path = "/path/to/cdc-server-key.pem"

Alternatively, configure in the command-line arguments and set the corresponding URL to https:

cdc server --pd=https://127.0.0.1:2379 --log-file=ticdc.log --addr=0.0.0.0:8301 --advertise-addr=127.0.0.1:8301 --ca=/path/to/ca.pem --cert=/path/to/ticdc-cert.pem --key=/path/to/ticdc-key.pem

Now, encrypted transmission among TiDB components is enabled.

Note

After enabling encrypted transmission in a TiDB cluster, if you need to connect to the cluster using tidb-ctl, tikv-ctl, or pd-ctl, specify the client certificate. For example:

./tidb-ctl -u https://127.0.0.1:10080 --ca /path/to/ca.pem --ssl-cert /path/to/client.pem --ssl-key /path/to/client-key.pem

tiup ctl:v<CLUSTER_VERSION> pd -u https://127.0.0.1:2379 --cacert /path/to/ca.pem --cert /path/to/client.pem --key /path/to/client-key.pem

./tikv-ctl --host="127.0.0.1:20160" --ca-path="/path/to/ca.pem" --cert-path="/path/to/client.pem" --key-path="/path/to/clinet-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, TiKV can only be accessed by TiDB, 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 when generating the certificate, and to check the caller's identity by configuring the Common Name list for the callee.

Note

Currently the cert-allowed-cn configuration item of the PD can only be set to one value. Therefore, the commonName of all authentication objects must be set to the same value.

TiDB
Configure in the configuration file or command-line arguments:
```
[security]
cluster-verify-cn = ["TiDB"]
```
TiKV
Configure in the configuration file or command-line arguments:
```
[security]
cert-allowed-cn = ["TiDB"]
```
PD
Configure in the configuration file or command-line arguments:
```
[security]
cert-allowed-cn = ["TiDB"]
```
TiFlash (New in v4.0.5)
Configure in the tiflash.toml file or command-line arguments:
```
[security]
cert_allowed_cn = ["TiDB"]
```
Configure in the tiflash-learner.toml file:
```
[security]
cert-allowed-cn = ["TiDB"]
```

Reload certificates

If your TiDB cluster is deployed in a local data center, to reload the certificates and keys, TiDB, PD, TiKV, TiFlash, TiCDC, and all kinds of clients reread the current certificates and key files each time a new connection is created, without restarting the TiDB cluster.
If your TiDB cluster is deployed on your own managed cloud, make sure that the issuance of TLS certificates is integrated with the certificate management service of the cloud provider. The TLS certificates of the TiDB, PD, TiKV, TiFlash, and TiCDC components can be automatically rotated without restarting the TiDB cluster.

Certificate validity

You can customize the validity period of TLS certificates for each component in a TiDB cluster. For example, when using OpenSSL to issue and generate TLS certificates, you can set the validity period via the days parameter. For more information, see Generate self-signed certificates.

Enable TLS Between TiDB Components

Configure and enable encrypted data transmission

Verify component caller's identity

Reload certificates

Certificate validity

See also

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