Hi, Spark standalone mode does not use or rely on ZooKeeper by default. The Spark master and workers communicate directly with each other without using ZooKeeper. However, it appears that in your case you are relying on ZooKeeper to provide high availability for your standalone cluster. By configuring Spark to use ZooKeeper for leader election, you can ensure that there is always a Spark master running, even if one of the ZooKeeper servers goes down.
To use ZooKeeper for high availability in Spark standalone mode, you need to configure the following properties: spark.deploy.recoveryMode: Set to ZOOKEEPER to enable high availability spark.deploy.zookeeper.url: The ZooKeeper cluster URL Now the Spark master shuts down when a Zookeeper instance is down because it loses its leadership. Zookeeper uses a leader election algorithm to ensure that there is always a single leader in the cluster. When a Zookeeper instance goes down, the remaining Zookeeper instances will elect a new leader. The original master that was down never comes up because it has lost its state. The Spark master stores its state in Zookeeper. When the Zookeeper instance that the master was connected to goes down, the master loses its state. This means that the master cannot restart without losing data. To avoid this problem, you can run multiple Spark masters in high availability mode. This means that you will have at least two Spark masters running at all times. When a Zookeeper instance goes down, the remaining Spark masters will continue to run and serve applications. As stated, to run Spark masters in high availability mode, you will need to configure the spark.deploy.recoveryMode property to ZOOKEEPER. You will also need to configure the spark.deploy.zookeeper.url property to point to your Zookeeper cluster. HTH, Mich Talebzadeh, Distinguished Technologist, Solutions Architect & Engineer London United Kingdom Mich Talebzadeh (Ph.D.) | LinkedIn <https://www.linkedin.com/in/michtalebzadeh/> https://en.everybodywiki.com/Mich_Talebzadeh Disclaimer: Use it at your own risk. Any and all responsibility for any loss, damage or destruction of data or any other property which may arise from relying on this email's technical content is explicitly disclaimed. The author will in no case be liable for any monetary damages arising from such loss, damage or destruction. Mich Talebzadeh, Distinguished Technologist, Solutions Architect & Engineer London United Kingdom view my Linkedin profile <https://www.linkedin.com/in/mich-talebzadeh-ph-d-5205b2/> https://en.everybodywiki.com/Mich_Talebzadeh *Disclaimer:* Use it at your own risk. Any and all responsibility for any loss, damage or destruction of data or any other property which may arise from relying on this email's technical content is explicitly disclaimed. The author will in no case be liable for any monetary damages arising from such loss, damage or destruction. On Mon, 6 Nov 2023 at 15:19, Kaustubh Ghode <kaustubhgh...@gmail.com> wrote: > I am using spark-3.4.1 I have a setup with three ZooKeeper servers, Spark > master shuts down when a Zookeeper instance is down a new master is elected > as leader and the cluster is up. But the original master that was down > never comes up. can you please help me with this issue? > > Stackoverflow link:- https://stackoverflow.com/questions/77431515 > > Thanks, > Kaustubh >
