Azure Synapse runtimes

Apache Spark pools in Azure Synapse use runtimes to tie together essential component versions such as Azure Synapse optimizations, packages, and connectors with a specific Apache Spark version. Each runtime will be upgraded periodically to include new improvements, features, and patches.

When you create a serverless Apache Spark pool, you will have the option to select the corresponding Apache Spark version. Based on this, the pool will come pre-installed with the associated runtime components and packages. The runtimes have the following advantages:

  • Faster session startup times
  • Tested compatibility with specific Apache Spark versions
  • Access to popular, compatible connectors and open-source packages


  • Maintenance updates will be automatically applied to new sessions for a given serverless Apache Spark pool.
  • You should test and validate that your applications run properly when using new runtime versions.


Log4j 1.2.x security patches

Open-source Log4j library version 1.2.x has several known CVEs (Common Vulnerabilities and Exposures), as described here.

On all Synapse Spark Pool runtimes, we have patched the Log4j 1.2.17 JARs to mitigate the following CVEs: CVE-2019-1751, CVE-2020-9488, CVE-2021-4104, CVE-2022-23302, CVE-2022-2330, CVE-2022-23307

The applied patch works by removing the following files which are required to invoke the vulnerabilities:

  • org/apache/log4j/net/SocketServer.class
  • org/apache/log4j/net/SMTPAppender.class
  • org/apache/log4j/net/JMSAppender.class
  • org/apache/log4j/net/JMSSink.class
  • org/apache/log4j/jdbc/JDBCAppender.class
  • org/apache/log4j/chainsaw/*

While the above classes were not used in the default Log4j configurations in Synapse, it is possible that some user application could still depend on it. If your application needs to use these classes, use Library Management to add a secure version of Log4j to the Spark Pool. Do not use Log4j version 1.2.17, as it would be reintroducing the vulnerabilities.

Supported Azure Synapse runtime releases

The following table lists the runtime name, Apache Spark version, and release date for supported Azure Synapse Runtime releases.

Runtime name Release date Release stage End of life announcement date End of life effective date
Azure Synapse Runtime for Apache Spark 3.3 Nov 17, 2022 Public Preview - -
Azure Synapse Runtime for Apache Spark 3.2 July 8, 2022 GA July 8, 2023 July 8, 2024
Azure Synapse Runtime for Apache Spark 3.1 May 26, 2021 LTS January 26, 2023 January 26, 2024
Azure Synapse Runtime for Apache Spark 2.4 December 15, 2020 End of Life Announced (EOLA) July 29, 2022 July 28, 2023

Runtime release stages

For the complete runtime for Apache Spark lifecycle and support policies, refer to Synapse runtime for Apache Spark lifecycle and supportability.

Runtime patching

Azure Synapse runtime for Apache Spark patches are rolled out monthly containing bug, feature and security fixes to the Apache Spark core engine, language environments, connectors and libraries.

The patch policy differs based on the runtime lifecycle stage:

  1. Generally Available (GA) runtime: Receive no upgrades on major versions (i.e. 3.x -> 4.x). And will upgrade a minor version (i.e. 3.x -> 3.y) as long as there are no deprecation or regression impacts.
  2. Preview runtime: No major version upgrades unless strictly necessary. Minor versions (3.x -> 3.y) will be upgraded to add latest features to a runtime.
  3. Long Term Support (LTS) runtime will be patched with security fixes only.
  4. End of life announced (EOLA) runtime will not have bug and feature fixes. Security fixes will be backported based on risk assessment.