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June 08


Akka 2.6.6 Released with Split Brain Resolver

Dear hakkers,

We are excited to announce a new patch release of Akka 2.6, which includes Lightbend’s Split Brain Resolver. Notable changes relative to 2.6.5 include:

  • Split Brain Resolver is included in open source Akka Cluster. See below.
  • Kubernetes friendly SSLEngine provider. See below.
  • Fixes for TLS 1.3, #29111 and #29110.
  • New deployment guide for Kubernetes.
  • LZ4 compression alternative for Jackson serialization, thanks to @contrun, #27066.
  • Bug fix in Cluster Sharding that could cause allocation to remain on removed node, #29034.
  • EventSourcedBehavior.lastSequenceNumber was off by one in some cases, #28976.
  • Use CBOR in JacksonCborSerializer instead of JSON. Rolling update must go through 2.6.5 when upgrading to 2.6.6, see Rolling Updates notes.
  • Update to Protobuf 3.11.4 in Akka’s internal serialization #29014.
  • Documentation of context propagation in Akka Streams.

A total of 60 issues were closed since 2.6.5. The complete list can be found on the 2.6.6 milestone on github.

Split Brain Resolver

With the continued growth of Akka Cluster to power cloud native applications around the world, Lightbend has recognized that the timing is right to contribute the Split Brain Resolver to the open source core of Akka.

It is important to use a correct downing provider together with for example Akka Cluster Sharding. The Split Brain Resolver (SBR) makes the important decisions of what to do with crashed nodes, unhealthy nodes, and how to deal with network partitions.

The Kubernetes lease is also released as open source and included in Akka Management 1.0.8.

Watch this video about the Split Brain Resolver.

Kubernetes friendly SSLEngine provider

Akka 2.6.6 adds a new SSLEngine provider that is intended be used with Kubernetes infrastructure to facilitate distributing new certificates to pods without restarting them. Certificate rotation of Artery TCP connections is now supported without restarting the JVM. See rotating-keys-engine in reference.conf.

It also verifies that peers are part of the same Akka Cluster by comparing the subject names in the peer’s certificate with the name on the own certificate.


For this release we had the help of 21 committers – thank you all very much!

commits  added  removed
     26   7213      457 Patrik Nordwall
      9   2457      528 Ignasi Marimon-Clos
      9    663       59 Johan Andrén
      7    197      146 Johannes Rudolph
      6     75       10 Christopher Batey
      5    508      344 Enno
      5     14        8 yiksanchan
      4    130       23 Arnout Engelen
      4    102       24 Renato Cavalcanti
      2    216       32 contrun
      2    165       74 Nicolas Vollmar
      1    940      244 eyal farago
      1    449        0 XIAO Yang
      1    235        5 Helena Edelson
      1     95       75 kerr
      1     58       23 Yury Gribkov
      1      7        7 klappvisor
      1      3        1 László van den Hoek
      1      1        1 Ryan Braley
      1      1        1 Xavier GUIHOT
      1      1        1 Evgenii Ganchurin

The Akka core team is employed by Lightbend. If you’re looking to take your Akka systems to the next level, let’s set up a time to discuss our enterprise-grade expert support, self-paced education courses, and technology enhancements that help you manage, monitor and secure your Akka systems - from development to production.

Happy hakking!

– The Akka Team