Confluent System Requirements

Hardware

On-Premises

The following machine recommendations are for installing individual Confluent Platform components:

Component	Nodes	Storage	Memory	CPU
Control Center (Legacy)-Normal mode	1	300 GB, preferably SSDs	32 GB RAM (JVM default 6 GB)	12 cores or more
Control Center (Legacy)-Reduced infrastructure mode	1	128 GB, preferably SSDs	8 GB RAM (JVM default 4 GB)	4 cores or more
Broker	3	12 X 1 TB disk. RAID 10 is optional Separate OS disks from Apache Kafka® storage	64 GB RAM	Dual 12 core sockets
Connect	2	Only required for installation	0.5 - 4 GB heap size depending on connectors	Typically not CPU- bound. More cores is better than faster cores.
Replicator		Same as Connect for nodes, storage, memory, and CPU. (See note below regarding AWS.)
ksqlDB	2	Use SSD. Sizing depends on the number of concurrent queries and the aggregation performed.	20 GB RAM	4 cores
REST Proxy	2	Only required for installation	1 GB overhead plus 64 MB per producer and 16 MB per consumer	16 cores to handle HTTP requests in parallel and background threads for consumers and producers.
Schema Registry	2	Only required for installation	1 GB heap size	Typically not CPU- bound. More cores is better than faster cores.
ZooKeeper	3-5	Transaction log: 512 GB Storage: 2 X 1 TB SATA, RAID 10 Each write to ZooKeeper must be persisted in the transaction log before the client gets an ack. Using SSD reduces the ZooKeeper write latency.	4 GB RAM	2-4 cores

• In the above table, the recommended CPU resource is in CPU units which are the same in all platforms. For example, if we recommend 12 CPUs for non-Kubernetes environment, the recommendation for Kubernetes environment would be 12 CPU units, as well.

• If you want to use RAID disks, the recommendation is:

  • RAID 1 and RAID 10: Preferred

  • RAID 0: 2nd preferred

  • RAID 5: Not recommended

Note

If deploying Confluent Platform on AWS VMs and running Replicator as a connector, be aware that VMs with burstable CPU types (T2, T3, T3a, and T4g) will not support high throughput streaming workloads. Replicator worker nodes running on these VMs experience throughput degradation due to credits expiring, making these VMs unsuitable for Confluent Platform nodes expected to run at elevated CPU levels for a sustained period of time, and supporting workloads that are above and beyond their baseline resource rates.

• For the requirements specific to Confluent for Kubernetes, see CFK Cluster Sizing.

Cloud

For information on Confluent Cloud support, see Supported Features for Confluent Cloud.

Software

Operating Systems

It is recommended that you run Confluent Platform across uniform OS, Confluent Platform, and JAVA versions.

Operating System	7.2.x	7.1.x	7.0.x	6.2.x	6.1.x	6.0.x	5.5.x	5.4.x	5.3.x
RHEL/CentOS 7.x (deprecated *)	yes	yes	yes	yes	yes	yes	yes	yes	yes
RHEL/CentOS 8.x	yes	yes	yes	yes	yes	yes	no	no	no
Debian 9 (stretch) (deprecated *)	yes	yes	yes	yes	yes	yes	yes	yes	yes
Debian 10 (buster)	yes	yes	yes	no	no	no	no	no	no
Ubuntu 16.04 LTS (xenial) (deprecated *)	yes	yes	yes	yes	yes	yes	yes	yes	yes
Ubuntu 18.04 LTS (bionic)	yes	yes	yes	yes	yes	yes	yes	yes	yes
Ubuntu 20.04 LTS (focal)	yes	yes	yes	no	no	no	no	no	no

^* Deprecated: Support for these OS versions are deprecated because they have reached their end of life. The OS is currently supported for Confluent Platform 7.2, but this support may be removed in a future release.

SELinux

Confluent Platform is supported on RHEL, CentOS, Debian and Ubuntu Linux Operating Systems. Confluent is not accountable for Security-Enhanced Linux (SELinux) policy development, support, or enforcement. If you experience issues running Confluent Platform with SELinux enabled on a supported Linux Operating System, contact your OS provider for assistance.

Windows

Windows is not currently supported for Confluent Platform.

Windows 8.1 and later, as well as Windows 2016 and later, are supported by the C/C++ and .NET clients.

macOS

macOS 10.14 and later is supported for testing and development purposes only.

File descriptors

For the file descriptor requirement for Kafka, see File Descriptors and mmap.

ulimit

Control Center (Legacy) requires many open RocksDB files. Set the ulimit for the number of open files to a minimum value of 16384 using the ulimit -n command.

For the other Confluent Platform components, specifically Schema Registry and Replicator, you can leave the ulimit as the OS default.

RHEL with TLS

When installing Confluent Platform on RHEL8 with TLS encryption, you must add DH Key Size JVM Parameters for each component. For more information, see Strong crypto defaults in RHEL 8 and deprecation of weak crypto algorithms.

Set the following component-level environment variables to the argument:

• Control Center (Legacy): CONTROL_CENTER_OPTS=-Djdk.tls.ephemeralDHKeySize=2048

• Schema Registry: SCHEMA_REGISTRY_OPTS=-Djdk.tls.ephemeralDHKeySize=2048

• Kafka, ZooKeeper, and Connect: KAFKA_OPTS=-Djdk.tls.ephemeralDHKeySize=2048

• REST Proxy: KAFKAREST_OPTS=-Djdk.tls.ephemeralDHKeySize=2048

• ksqlDB: KSQL_OPTS=-Djdk.tls.ephemeralDHKeySize=2048

Java

Java 11 is recommended for this version of Confluent Platform.

Java 8 is now deprecated in Confluent Platform, and the support for Java 8 will be removed in Confluent Platform 8.0.

Use the latest released patch version of Java to ensure known security vulnerabilities are addressed.

Java 9 and 10 are not supported in Confluent Platform as those versions are short-term rapid release versions.

For more information about Java versions, see Java Version History.

You need to separately install the correct version of Java before you start the Confluent Platform installation process.

We recommend using the full JDK to help Confluent Support with troubleshooting and to provide better support when you experience issues with Confluent Platform.

OpenJDK, Zulu OpenJDK, Eclipse Temurin (formerly known as AdoptOpenJDK), and Oracle are supported with Confluent Platform.

If you have multiple JDKs installed, see also Java version requirements for the Confluent CLI.

Docker

Optional: Docker version 1.11 or later running on a supported operating system. This is required if you are installing Confluent Platform by using the Docker images.

Network

Control Center (Legacy) relies heavily on Kafka, so a fast and reliable network is important for performance. Modern datacenter networking speed of 1 GbE, 10 GbE should be sufficient.

Ports

The table below lists the network services and ports exposed as part of Confluent Platform.

All services listed below use the TCP protocol.

All ports listed below are the default ports, and in most cases you can configure each service to listen on a different port of your choice.

Ports that are indicated to be Internal Only need to be accessible by components within Confluent Platform, not by users or clients of the platform.

When deploying Confluent Platform, ensure that your networking rules allow for the required access to the various components and services.

Component and Service	Default Port	Internal Only?
ZooKeeper
Peer-to-peer communication	2888	Yes
Peer-to-peer communication	3888	Yes
Client access	2181	No
Client access via TLS	2182	No
Jolokia [*]	7770	No
Kafka Broker
Interbroker listener	9091	Yes
External listener	9092	No
Metadata Service (MDS)	8090	No
Confluent Server REST API	8090	No
Jolokia [*]	7771	No
(Standalone) REST Proxy	8082	No
Confluent Control Center (Legacy)	9021	No
Kafka Connect
REST API	8083	No
Jolokia [*]	7773	No
ksqlDB Server
REST API	8088	No
Jolokia [*]	7774	No
Schema Registry
REST API	8081	No
Jolokia [*]	7772	No

^[*] Reserve the Jolokia ports only when you deploy Confluent Platform using Ansible.

Synchronize time

Clock synchronization on each Kafka broker is required to ensure the full system functions correctly. For example, secure network communication with the brokers that rely on TLS certificate verification may fail if clocks are not synchronized. Clock synchronization can be achieved using utilities like ntpd that implement the Network Time Protocol (NTP).