managing-tls-certificates（管理 tls 证书）

Managing TLS Certificates

Manages TLS certificates for CockroachDB clusters, covering CA certificate downloads, client certificate authentication setup, certificate rotation, and troubleshooting common SSL/TLS connection errors. Addresses both CockroachDB Cloud (always-on TLS) and self-hosted certificate lifecycle management.

When to Use This Skill

• Troubleshooting SSL/TLS connection errors from application clients (DBeaver, TypeORM, psql, Go, Python, Java)
• Setting up client certificate authentication on CockroachDB Cloud
• Uploading a custom Client CA to a Cloud cluster
• Rotating or renewing certificates (Cloud or self-hosted)
• Configuring mTLS for CDC changefeeds to Kafka
• Downloading or locating the CA certificate for a Cloud cluster

Prerequisites

CockroachDB Cloud:

• ccloud CLI authenticated (ccloud auth login)
• Cloud Console access for CA certificate download
• Cluster Admin role for client CA configuration

Self-hosted:

• cockroach cert CLI available
• Admin access to cluster nodes
• OpenSSL for certificate inspection and generation

Verify access:

# Cloud
ccloud auth whoami
ccloud cluster list

# Self-hosted — check existing certificates
cockroach cert list --certs-dir=<certs-directory>

Configuration Decisions

Before proceeding, determine the user's deployment model. Ask which option applies, then follow only the relevant sections below.

Decision 1 — Deployment model:

• CockroachDB Cloud: TLS is always on and the cluster CA is managed by Cockroach Labs. Follow Part 1 for CA download, client certificate auth, and Cloud certificate rotation.
• Self-hosted: Full manual certificate lifecycle management (CA, node, and client certificates). Follow Part 2 for certificate creation, rotation, and management.

Parts 3 (Troubleshooting) and 4 (mTLS for CDC) apply to both deployment models.

Steps

Part 1: CockroachDB Cloud TLS

Follow this part if the user selected CockroachDB Cloud in Decision 1.

CockroachDB Cloud enforces TLS on all connections. The cluster CA certificate is managed by Cockroach Labs.

1.1 Download the CA Certificate

The CA certificate is required by clients to verify the cluster's identity.

# Download via ccloud CLI
ccloud cluster cert <cluster-id>

# Or download from the Cloud Console:
# Cluster > Connect > Download CA Cert

The CA certificate is also available at: https://cockroachlabs.cloud/clusters/<cluster-id>/cert

Common CA cert locations after download:

• macOS: ~/.postgresql/root.crt
• Linux: ~/.postgresql/root.crt or /etc/cockroach-certs/ca.crt
• Windows: %APPDATA%\postgresql\root.crt

1.2 Configure Client Certificate Authentication

Client certificate auth provides mutual TLS (mTLS) — the client proves its identity via certificate instead of a password.

Step 1: Upload a Client CA to the cluster

The Client CA signs your client certificates. This is separate from the cluster's CA.

# Upload a Client CA certificate via ccloud CLI
ccloud cluster cert set-client-ca <cluster-id> --cert-file <client-ca.crt>

Step 2: Create a client certificate signed by your Client CA

# Generate a client key and certificate signing request
openssl genrsa -out client.<username>.key 2048
openssl req -new -key client.<username>.key \
  -out client.<username>.csr \
  -subj "/CN=<username>"

# Sign the CSR with your Client CA
openssl x509 -req -in client.<username>.csr \
  -CA client-ca.crt -CAkey client-ca.key \
  -CAcreateserial \
  -out client.<username>.crt \
  -days 365

Step 3: Connect using the client certificate

cockroach sql \
  --url "postgresql://<username>@<cluster-host>:26257/defaultdb?sslmode=verify-full&sslrootcert=<ca.crt>&sslcert=client.<username>.crt&sslkey=client.<username>.key"

See connection examples reference for client-specific connection strings.

1.3 Certificate Rotation (Cloud)

Client certificates should be rotated before expiry. The cluster CA certificate is managed by Cockroach Labs and rotated automatically.

Client certificate rotation:

1. Generate a new client certificate signed by the same Client CA (or a new Client CA)
2. Deploy the new certificate to application clients
3. Verify connections work with the new certificate
4. Remove the old certificate from application clients

Client CA rotation:

1. Generate a new Client CA
2. Upload the new Client CA to the cluster (supports multiple CAs during transition)
3. Issue new client certificates signed by the new CA
4. Deploy new client certificates to all applications
5. Remove the old Client CA after all clients have migrated

Part 2: Self-Hosted Certificate Management

Follow this part if the user selected Self-hosted in Decision 1.

Self-hosted CockroachDB requires manual certificate lifecycle management for the CA, node, and client certificates.

2.1 Initialize the Certificate Authority

# Create the CA certificate and key
cockroach cert create-ca \
  --certs-dir=certs \
  --ca-key=my-safe-directory/ca.key

2.2 Create Node Certificates

# Create a node certificate for each node
cockroach cert create-node \
  <node-hostname> \
  <node-ip> \
  localhost \
  127.0.0.1 \
  --certs-dir=certs \
  --ca-key=my-safe-directory/ca.key

2.3 Create Client Certificates

# Create a client certificate for root user
cockroach cert create-client root \
  --certs-dir=certs \
  --ca-key=my-safe-directory/ca.key

# Create a client certificate for an application user
cockroach cert create-client <username> \
  --certs-dir=certs \
  --ca-key=my-safe-directory/ca.key

2.4 Certificate Rotation (Self-Hosted)

# Check certificate expiry
cockroach cert list --certs-dir=certs

# Or with OpenSSL
openssl x509 -in certs/node.crt -noout -enddate

Rotation process:

1. Generate new certificates using the existing CA (or rotate the CA first)
2. Copy new certificates to each node
3. Reload certificates (SIGHUP — no downtime required): kill -SIGHUP $(pgrep cockroach)
4. Verify nodes are serving the new certificates

Part 3: Troubleshooting SSL/TLS Errors

See troubleshooting reference for a comprehensive error guide.

Common Errors and Quick Fixes

"x509: certificate signed by unknown authority"

• Client does not trust the cluster's CA certificate
• Fix: Download the correct CA certificate and set sslrootcert in the connection string

"SSL SYSCALL error: EOF detected"

• Connection terminated unexpectedly during TLS handshake
• Fix: Check network connectivity, firewall rules, and that the correct port (26257) is used

"tls: bad certificate"

• Client certificate rejected by the server
• Fix: Verify the client certificate is signed by a CA the cluster trusts (Client CA must be uploaded)

"certificate has expired"

• Client or server certificate has passed its expiry date
• Fix: Rotate the expired certificate (see rotation steps above)

Diagnostic Commands

# Inspect a certificate
openssl x509 -in cert.crt -text -noout

# Verify certificate chain
openssl verify -CAfile ca.crt client.crt

# Test TLS connection to cluster
openssl s_client -connect <host>:26257 -CAfile ca.crt

# Check certificate expiry date
openssl x509 -in cert.crt -noout -enddate

Part 4: mTLS for CDC Changefeeds to Kafka

CockroachDB CDC changefeeds can use mTLS to authenticate to Kafka brokers.

-- Create a changefeed with mTLS authentication to Kafka
CREATE CHANGEFEED FOR TABLE orders
  INTO 'kafka://<kafka-broker>:9093?tls_enabled=true&ca_cert=<base64-ca>&client_cert=<base64-cert>&client_key=<base64-key>'
  WITH updated, resolved;

Preparing certificates for changefeed URI:

# Base64 encode certificates for use in changefeed URI
cat ca.crt | base64 -w 0    # Linux
cat ca.crt | base64          # macOS

cat client.crt | base64 -w 0
cat client.key | base64 -w 0

Safety Considerations

Do not:

• Delete the CA private key — it is required for signing new certificates
• Upload an expired CA certificate
• Remove a Client CA while clients still depend on it
• Disable TLS on production clusters (CockroachDB Cloud does not allow this)

Rollback

Cloud — Client CA issues:

1. If a new Client CA was uploaded incorrectly, upload the correct CA
2. If client certificates are rejected, revert to password authentication temporarily
3. Contact CockroachDB support if the cluster CA needs intervention

Self-hosted — Certificate issues:

1. Restore previous certificates from backup
2. Reload certificates: kill -SIGHUP $(pgrep cockroach)
3. If CA was rotated, ensure all nodes and clients have the new CA

References

Skill references:

• Client connection examples — Connection strings for common clients
• TLS troubleshooting guide — Common SSL/TLS errors and fixes

Related skills:

• auditing-cloud-cluster-security — Run a full security posture audit
• configuring-sso-and-scim — SSO as an alternative to certificate-based auth

Official CockroachDB Documentation:

• Transport Layer Security (TLS)
• Authentication
• Client Connection Parameters
• cockroach cert Commands
• Rotate Security Certificates
• Cloud Certificate Management
• CDC Kafka Sink