APM agent TLS communication

TLS is disabled by default. When TLS is enabled for APM Server inbound communication, agents will verify the identity of the APM Server by authenticating its certificate.

When TLS is enabled, a certificate and corresponding private key are required. The certificate and private key can either be issued by a trusted certificate authority (CA) or be self-signed.

Use a self-signed certificate ¶

Step 1: Create a self-signed certificate ¶

The Elasticsearch distribution offers the certutil tool for the creation of self-signed certificates:

  1. Create a CA: ./bin/elasticsearch-certutil ca --pem. You’ll be prompted to enter the desired location of the output zip archive containing the certificate and the private key.
  2. Extract the contents of the CA archive.
  3. Create the self-signed certificate: ./bin/elasticsearch-certutil cert --ca-cert <path-to-ca-crt>/ca.crt --ca-key <path-to-ca-key>/ca.key --pem --name localhost
  4. Extract the certificate and key from the resulted zip archive.

Step 2: Configure the APM Server ¶

Enable TLS and configure the APM Server to point to the extracted certificate and key:

Enable TLS in the APM integration settings and use the SSL/TLS input settings to set the path to the server certificate and key.

The following is a basic APM Server SSL config with secure communication enabled. This will make APM Server serve HTTPS requests instead of HTTP.

			apm-server.ssl.enabled: true
apm-server.ssl.certificate: "/path/to/apm-server.crt"
apm-server.ssl.key: "/path/to/apm-server.key"

A full list of configuration options is available in SSL/TLS input settings.

Tip

If APM agents are authenticating themselves using a certificate that cannot be authenticated through known CAs (e.g. self signed certificates), use the ssl.certificate_authorities to set a custom CA. This will automatically modify the ssl.client_authentication configuration to require authentication.

Step 3: Configure APM agents ¶

When the APM server uses a certificate that is not chained to a publicly-trusted certificate (e.g. self-signed), additional configuration is required in the APM agent:

We do not recommend disabling APM agent verification of the server’s certificate, but it is possible:

Client certificate authentication ¶

APM Server does not require agents to provide a certificate for authentication, and there is no dedicated support for SSL/TLS client certificate authentication in Elastic’s backend agents.