cockroach cert

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To secure your CockroachDB cluster's inter-node and client-node communication, you need to provide a Certificate Authority (CA) certificate that has been used to sign keys and certificates (SSLs) for:

• Nodes
• Clients
• DB Console (optional)

To create these certificates and keys, use the cockroach cert commands with the appropriate subcommands and flags, use openssl commands, or use a custom CA (for example, a public CA or your organizational CA).

How security certificates work

1. Using the cockroach cert command, you create a CA certificate and key and then node and client certificates that are signed by the CA certificate. Since you need access to a copy of the CA certificate and key to create node and client certs, it's best to create everything in one place.

2. You then upload the appropriate node certificate and key and the CA certificate to each node, and you upload the appropriate client certificate and key and the CA certificate to each client.

3. When nodes establish contact to each other, and when clients establish contact to nodes, they use the CA certificate to verify each other's identity.

Subcommands

Certificate directory

When using cockroach cert to create node and client certificates, you will need access to a local copy of the CA certificate and key. It is therefore recommended to create all certificates and keys in one place and then distribute node and client certificates and keys appropriately. For the CA key, be sure to store it somewhere safe and keep a backup; if you lose it, you will not be able to add new nodes or clients to your cluster. For a tutorial of this process, see Manual Deployment.

Required keys and certificates

The create-* subcommands generate the CA certificate and all node and client certificates and keys in a single directory specified by the --certs-dir flag, with the files named as follows:

Node key and certificates

Client key and certificates

Optionally, if you have a certificate issued by a public CA to securely access the DB Console, you need to place the certificate and key (ui.crt and ui.key respectively) in the directory specified by the --certs-dir flag. For more information, refer to Use a UI certificate and key to access the DB Console.

Note the following:

• By default, the node.crt is multi-functional, as in the same certificate is used for both incoming connections (from SQL and DB Console clients, and from other CockroachDB nodes) and for outgoing connections to other CockroachDB nodes. To make this possible, the node.crt created using the cockroach cert command has CN=node and the list of IP addresses and DNS names listed in Subject Alternative Name field.

• The CA key is never loaded automatically by cockroach commands, so it should be created in a separate directory, identified by the --ca-key flag.

Key file permissions

To reduce the likelihood of a malicious user or process accessing a certificate key (files ending in ".key"), we require that the certificate key be owned by one of the following system users:

• The user that the CockroachDB process runs as.
• The system root user (not to be confused with the CockroachDB root user) and the group that the CockroachDB process runs in.

For example, if running the CockroachDB process as a system user named cockroach, we can use the id cockroach command to list each group the cockroach user is a member of:

id cockroach
uid=1000(cockroach) gid=1000(cockroach) groups=1000(cockroach),1000(cockroach)

In the output, we can see that the system user cockroach is in the cockroach group (with the group ID or gid 1000).

If the key file is owned by the system root user (who has user ID 0), CockroachDB won't be able to read it unless it has permission to read because of its group membership. Because we know that CockroachDB user is a member of the cockroach group, we can allow CockroachDB to read the key by changing the group owner of the key file to the cockroach group. We then give the group read permissions by running chmod. Notice that the others group has no permissions (the 0 of 740). Only the cockroach user, a member of the cockroach group, or the system root user has permission to read the key.

sudo chgrp cockroach ui.key
sudo chmod 0740 ui.key

However, if the ui.key file is owned by the cockroach system user, CockroachDB ignores the group ownership of the file, and requires that the permissions only allow the cockroach system user to interact with it (0700 or rwx------).

Note the following:

• When running in Kubernetes, you will not be able to change the user that owns a certificate file mounted from a Secret or another Volume, but you will be able to override the group by setting the fsGroup flag in a Pod or Container's Security Context. In our example above, you would set fsGroup to "1000". You will also need to set the key's "mode" using the mode flag on individual items or the defaultMode flag if applying to the entire secret.

• This check can be disabled by setting the environment variable COCKROACH_SKIP_KEY_PERMISSION_CHECK to true.

Synopsis

Create the CA certificate and key:

$ cockroach cert create-ca \
 --certs-dir=[path-to-certs-directory] \
 --ca-key=[path-to-ca-key]

Create a node certificate and key:

$ cockroach cert create-node \
 [node-hostname] \
 [node-other-hostname] \
 [node-yet-another-hostname] \
 [hostname-in-wildcard-notation] \
 --certs-dir=[path-to-certs-directory] \
 --ca-key=[path-to-ca-key]

Create a client certificate and key:

$ cockroach cert create-client \
 [username] \
 --certs-dir=[path-to-certs-directory] \
 --ca-key=[path-to-ca-key]

List certificates and keys:

$ cockroach cert list \
 --certs-dir=[path-to-certs-directory]

View help:

$ cockroach cert --help

$ cockroach cert <subcommand> --help

Flags

The cert command and subcommands support the following general-use and logging flags.

General

Logging

By default, this command logs messages to stderr. This includes events with WARNING severity and higher.

If you need to troubleshoot this command's behavior, you can customize its logging behavior.

Examples

Create the CA certificate and key pair

1. Create two directories:

   $ mkdir certs
   

   $ mkdir my-safe-directory
   

   • certs: You'll generate your CA certificate and all node and client certificates and keys in this directory and then upload some of the files to your nodes.
   • my-safe-directory: You'll generate your CA key in this directory and then reference the key when generating node and client certificates. After that, you'll keep the key safe and secret; you will not upload it to your nodes.

2. Generate the CA certificate and key:

   $ cockroach cert create-ca \
   --certs-dir=certs \
   --ca-key=my-safe-directory/ca.key
   

   $ ls -l certs
   

   total 8
   -rw-r--r--  1 maxroach  maxroach  1.1K Jul 10 14:12 ca.crt
   

Create the certificate and key pairs for nodes

1. Generate the certificate and key for the first node:

   $ cockroach cert create-node \
   node1.example.com \
   node1.another-example.com \
   *.dev.another-example.com \
   --certs-dir=certs \
   --ca-key=my-safe-directory/ca.key
   

   $ ls -l certs
   

   total 24
   -rw-r--r--  1 maxroach  maxroach  1.1K Jul 10 14:12 ca.crt
   -rw-r--r--  1 maxroach  maxroach  1.2K Jul 10 14:16 node.crt
   -rw-------  1 maxroach  maxroach  1.6K Jul 10 14:16 node.key
   

2. Upload certificates to the first node:

   # Create the certs directory:
   $ ssh <username>@<node1 address> "mkdir certs"
   

   # Upload the CA certificate and node certificate and key:
   $ scp certs/ca.crt \
   certs/node.crt \
   certs/node.key \
   <username>@<node1 address>:~/certs
   

3. Delete the local copy of the first node's certificate and key:

   $ rm certs/node.crt certs/node.key
   

   Note:

   This is necessary because the certificates and keys for additional nodes will also be named node.crt and node.key As an alternative to deleting these files, you can run the next cockroach cert create-node commands with the --overwrite flag.

4. Create the certificate and key for the second node:

   $ cockroach cert create-node \
   node2.example.com \
   node2.another-example.com \
   --certs-dir=certs \
   --ca-key=my-safe-directory/ca.key
   

   $ ls -l certs
   

   total 24
   -rw-r--r--  1 maxroach  maxroach  1.1K Jul 10 14:12 ca.crt
   -rw-r--r--  1 maxroach  maxroach  1.2K Jul 10 14:17 node.crt
   -rw-------  1 maxroach  maxroach  1.6K Jul 10 14:17 node.key
   

5. Upload certificates to the second node:

   # Create the certs directory:
   $ ssh <username>@<node2 address> "mkdir certs"
   

   # Upload the CA certificate and node certificate and key:
   $ scp certs/ca.crt \
   certs/node.crt \
   certs/node.key \
   <username>@<node2 address>:~/certs
   

6. Repeat steps 3 - 5 for each additional node.

Create the certificate and key pair for a client

$ cockroach cert create-client \
maxroach \
--certs-dir=certs \
--ca-key=my-safe-directory/ca.key

$ ls -l certs

total 40
-rw-r--r--  1 maxroach  maxroach  1.1K Jul 10 14:12 ca.crt
-rw-r--r--  1 maxroach  maxroach  1.1K Jul 10 14:13 client.maxroach.crt
-rw-------  1 maxroach  maxroach  1.6K Jul 10 14:13 client.maxroach.key
-rw-r--r--  1 maxroach  maxroach  1.2K Jul 10 14:17 node.crt
-rw-------  1 maxroach  maxroach  1.6K Jul 10 14:17 node.key

List certificates and keys

$ cockroach cert list \
--certs-dir=certs

Certificate directory: certs
+-----------------------+---------------------+---------------------+------------+--------------------------------------------------------+-------+
|         Usage         |  Certificate File   |      Key File       |  Expires   |                         Notes                          | Error |
+-----------------------+---------------------+---------------------+------------+--------------------------------------------------------+-------+
| Certificate Authority | ca.crt              |                     | 2027/07/18 | num certs: 1                                           |       |
| Node                  | node.crt            | node.key            | 2022/07/14 | addresses: node2.example.com,node2.another-example.com |       |
| Client                | client.maxroach.crt | client.maxroach.key | 2022/07/14 | user: maxroach                                         |       |
+-----------------------+---------------------+---------------------+------------+--------------------------------------------------------+-------+
(3 rows)

See also

• Security overview
• Authentication
• Client Connection Parameters
• Rotate Security Certificates
• Manual Deployment
• Orchestrated Deployment
• Local Deployment
• cockroach Commands Overview

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