certutil

The certutil command simplifies the creation of certificates for use with Transport Layer Security (TLS) in the Elastic Stack.

bin/x-pack/certutil
(
(ca [--ca-dn <name>] [--days <n>] [--pem])

| (cert ([--ca <file_path>] | [--ca-cert <file_path> --ca-key <file_path>])
[--ca-dn <name>] [--ca-pass <password>] [--days <n>]
[--dns <domain_name>] [--in <input_file>] [--ip <ip_addresses>]
[--keep-ca-key] [--multiple] [--name <file_name>] [--pem])

| (csr [--dns <domain_name>] [--in <input_file>] [--ip <ip_addresses>]
[--name <file_name>])

[-E <KeyValuePair>] [--keysize <bits>] [--out <file_path>]
[--pass <password>]
)
[-h, --help] ([-s, --silent] | [-v, --verbose])

You can specify one of the following modes: ca, cert, csr. The certutil command also supports a silent mode of operation to enable easier batch operations.

The ca mode generates a new certificate authority (CA). By default, it produces a single PKCS#12 output file, which holds the CA certificate and the private key for the CA. If you specify the --pem parameter, the command generates a zip file, which contains the certificate and private key in PEM format.

You can subsequently use these files as input for the cert mode of the command.

The cert mode generates X.509 certificates and private keys. By default, it produces a single certificate and key for use on a single instance.

To generate certificates and keys for multiple instances, specify the --multiple parameter, which prompts you for details about each instance. Alternatively, you can use the --in parameter to specify a YAML file that contains details about the instances.

An instance is any piece of the Elastic Stack that requires a TLS or SSL certificate. Depending on your configuration, Elasticsearch, Logstash, Kibana, and Beats might all require a certificate and private key. The minimum required information for an instance is its name, which is used as the common name for the certificate. The instance name can be a hostname value or a full distinguished name. If the instance name would result in an invalid file or directory name, you must also specify a file name in the --name command parameter or in the filename field in an input YAML file.

You can optionally provide IP addresses or DNS names for each instance. If neither IP addresses nor DNS names are specified, the Elastic stack products cannot perform hostname verification and you might need to configure the verfication_mode security setting to certificate only. For more information about this setting, see Security settings.

All certificates that are generated by this command are signed by a CA. You can provide your own CA with the --ca or --ca-cert parameters. Otherwise, the command automatically generates a new CA for you. For more information about generating a CA, see the CA mode of this command.

By default, the cert mode produces a single PKCS#12 output file which holds the instance certificate, the instance private key, and the CA certificate. If you specify the --pem parameter, the command generates PEM formatted certificates and keys and packages them into a zip file. Likewise if you chose to generate output for multiple instances, the command produces a zip file.

The csr mode generates certificate signing requests (CSRs) that you can send to a trusted certificate authority to obtain signed certificates. The signed certificates must be in PEM or PKCS#12 format to work with X-Pack security.

By default, the command produces a single CSR for a single instance.

To generate CSRs for multiple instances, specify the --multiple parameter, which prompts you for details about each instance. Alternatively, you can use the --in parameter to specify a YAML file that contains details about the instances.

The cert mode produces a single zip file which contains the CSRs and the private keys for each instance. Each CSR is provided as a standard PEM encoding of a PKCS#10 CSR. Each key is provided as a PEM encoding of an RSA private key.

The following command generates a CA certificate and private key in PKCS#12 format:

bin/x-pack/certutil ca

You are prompted for an output filename and a password. Alternatively, you can specify the --out and --pass parameters.

You can then generate X.509 certificates and private keys by using the new CA. For example:

bin/x-pack/certutil cert --ca elastic-stack-ca.p12

You are prompted for the CA password and for an output filename and password. Alternatively, you can specify the --ca-pass, --out, and --pass parameters.

By default, this command generates a file called elastic-certificates.p12, which you can copy to the relevant configuration directory for each Elastic product that you want to configure. For more information, see Setting Up TLS on a Cluster.

To use the silent mode of operation, you must create a YAML file that contains information about the instances. It must match the following format:

instances:
  - name: "node1" 
    ip: 
      - "192.0.2.1"
    dns: 
      - "node1.mydomain.com"
  - name: "node2"
    ip:
      - "192.0.2.2"
      - "198.51.100.1"
  - name: "node3"
  - name: "node4"
    dns:
      - "node4.mydomain.com"
      - "node4.internal"
  - name: "CN=node5,OU=IT,DC=mydomain,DC=com"
    filename: "node5" 

When your YAML file is ready, you can use the certutil command to generate certificates or certificate signing requests. Simply use the --in parameter to specify the location of the file. For example:

bin/x-pack/certutil cert --silent --in instances.yml --out test1.zip --pass testpassword

This command generates a compressed test1.zip file. After you decompress the output file, there is a directory for each instance that was listed in the instances.yml file. Each instance directory contains a single PKCS#12 (.p12) file, which contains the instance certificate, instance private key, and CA certificate.

You an also use the YAML file to generate certificate signing requests. For example:

bin/x-pack/certutil csr --silent --in instances.yml --out test2.zip --pass testpassword

This command generates a compressed file, which contains a directory for each instance. Each instance directory contains a certificate signing request (*.csr file) and private key (*.key file).