# Multiple nodes of one cluster on one runner

**URL:** <https://discuss.elastic.co/t/multiple-nodes-of-one-cluster-on-one-runner/131355>\
**Category:** Elastic Cloud Enterprise (ECE)\
**Created:** [May 10, 2018, 8:38pm UTC](https://discuss.elastic.co/t/multiple-nodes-of-one-cluster-on-one-runner/131355 "2018-05-10T20:38:22Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![jmtrc](https://avatars.discourse-cdn.com/v4/letter/j/c37758/32.png) [@jmtrc](https://discuss.elastic.co/u/jmtrc)\
**Post date:** [May 10, 2018, 8:38pm UTC](https://discuss.elastic.co/t/multiple-nodes-of-one-cluster-on-one-runner/131355/1 "2018-05-10T20:38:22Z")

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I have a cluster in ECE with two nodes/two zones setup. The ECE has several spare runners are available. It works normally as expected. But I noticed that two nodes were assigned to one runner in a given zone.

Is it right that ECE may deploy multiple nodes of one cluster to one single runner? This is a concern that the cluster may loose more than one node due to runner issue which seems to be risky.

Thank you.

Jin.

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**Author:** ![Yuri](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/yuri/32/52458_2.png) [@Yuri](https://discuss.elastic.co/u/Yuri)\
**Post date:** [May 11, 2018, 2:50pm UTC](https://discuss.elastic.co/t/multiple-nodes-of-one-cluster-on-one-runner/131355/2 "2018-05-11T14:50:27Z")

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Hi Jin,  
you're right that in this particular topology you will lose two instances if allocator (runner) goes down. However, ECE sets up the cluster the way that shard replicas cannot be allocated to an instance that is running on the same allocator (runner). This topology is primarily used if you need more than 64Gb (32Gb heap + 32Gb kernel) of memory per availability zone. 64Gb is the maximum memory that makes sense to use per instance ([see why](https://www.elastic.co/guide/en/elasticsearch/guide/master/_limiting_memory_usage.html)). Therefore, if you need, for example, 256Gb per AZ and 3 AZ, you should provision 4 64Gb nodes in every AZ.

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [May 25, 2018, 2:50pm UTC](https://discuss.elastic.co/t/multiple-nodes-of-one-cluster-on-one-runner/131355/3 "2018-05-25T14:50:29Z")

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