8.10. Secure Internal Communication#
The Presto cluster can be configured to use secured communication. Communication between Presto nodes can be secured with SSL/TLS.
Requests between Presto nodes are authenticated using a shared secret. For secure internal communication, the shared secret must be configured on all nodes in the cluster:
A large random key is recommended, and can be generated with the following Linux command:
openssl rand 512 | base64
Internal SSL/TLS configuration#
SSL/TLS is configured in the
config.properties file. The SSL/TLS on the
worker and coordinator nodes are configured using the same set of properties.
Every node in the cluster must be configured. Nodes that have not been
configured, or are configured incorrectly, are not able to communicate with
other nodes in the cluster.
To enable SSL/TLS for Presto internal communication, do the following:
Disable HTTP endpoint.
You can enable HTTPS, while leaving HTTP enabled. In most cases this is a security hole. If you are certain you want to use this configuration, you should consider using an firewall to limit access to the HTTP endpoint to only those hosts that should be allowed to use it.
Configure the cluster to communicate using the fully qualified domain name (fqdn) of the cluster nodes. This can be done in either of the following ways:
If the DNS service is configured properly, we can just let the nodes introduce themselves to the coordinator using the hostname taken from the system configuration (
It is also possible to specify each node’s fully-qualified hostname manually. This is different for every host. Hosts should be in the same domain to make it easy to create the correct SSL/TLS certificates. e.g.:
Generate a Java Keystore File. Every Presto node must be able to connect to any other node within the same cluster. It is possible to create unique certificates for every node using the fully-qualified hostname of each host, create a keystore that contains all the public keys for all of the hosts, and specify it for the client (see step #8 below). In most cases it is simpler to use a wildcard in the certificate as shown below.
keytool -genkeypair -alias example.com -keyalg RSA -keystore keystore.jks Enter keystore password: Re-enter new password: What is your first and last name? [Unknown]: *.example.com What is the name of your organizational unit? [Unknown]: What is the name of your organization? [Unknown]: What is the name of your City or Locality? [Unknown]: What is the name of your State or Province? [Unknown]: What is the two-letter country code for this unit? [Unknown]: Is CN=*.example.com, OU=Unknown, O=Unknown, L=Unknown, ST=Unknown, C=Unknown correct? [no]: yes Enter key password for <presto> (RETURN if same as keystore password):
Distribute the Java Keystore File across the Presto cluster.
Enable the HTTPS endpoint.
http-server.https.enabled=true http-server.https.port=<https port> http-server.https.keystore.path=<keystore path> http-server.https.keystore.key=<keystore password>
Change the discovery uri to HTTPS.
discovery.uri=https://<coordinator fqdn>:<https port>
Configure the internal communication to require HTTPS.
Configure the internal communication to use the Java keystore file.
internal-communication.https.keystore.path=<keystore path> internal-communication.https.keystore.key=<keystore password>
Performance with SSL/TLS enabled#
Enabling encryption impacts performance. The performance degradation can vary based on the environment, queries, and concurrency.
For queries that do not require transferring too much data between the Presto
SELECT count(*) FROM table, the performance impact is negligible.
However, for CPU intensive queries which require a considerable amount of data to be transferred between the nodes (for example, distributed joins, aggregations and window functions, which require repartitioning), the performance impact can be considerable. The slowdown may vary from 10% to even 100%+, depending on the network traffic and the CPU utilization.
Advanced Performance Tuning#
In some cases, changing the source of random numbers improves performance significantly.
By default, TLS encryption uses the
/dev/urandom system device as a source of entropy.
This device has limited throughput, so on environments with high network bandwidth
(e.g. InfiniBand), it may become a bottleneck. In such situations, it is recommended to try
to switch the random number generator algorithm to
SHA1PRNG, by setting it via
http-server.https.secure-random-algorithm property in
config.properties on the coordinator
and all of the workers:
Be aware that this algorithm takes the initial seed from
/dev/random device. For environments that do not have enough entropy to seed
SHAPRNG algorithm, the source can be changed to
by adding the
java.security.egd property to