# How to upgrade a cluster

**URL:** <https://discuss.elastic.co/t/how-to-upgrade-a-cluster/19158>\
**Category:** Elasticsearch\
**Created:** [August 8, 2014, 6:54am UTC](https://discuss.elastic.co/t/how-to-upgrade-a-cluster/19158 "2014-08-08T06:54:55Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![xzer\_LR](https://avatars.discourse-cdn.com/v4/letter/x/2acd7d/32.png) [@xzer\_LR](https://discuss.elastic.co/u/xzer_LR)\
**Post date:** [August 8, 2014, 6:54am UTC](https://discuss.elastic.co/t/how-to-upgrade-a-cluster/19158/1 "2014-08-08T06:54:55Z")

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I am upgrading a cluster in version 1.0.3 to 1.2.3 and I am confused by  
something.

According to the description at  
here: [http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/setup-upgrade.html](http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/setup-upgrade.html)  
I can disable the allocation before I started the upgrading process.

Then I disabled the allocation at first, after that I upgrade one of my  
node to 1.2.3, then restart the elasticsearch, I saw the node join  
the existing cluster well, but the upgraded node was keeping blank without  
any shards recognized, since the allocation has been  
disabled, the other nodes in old version did not do any reshard too. But  
according to the document I parsed above, it says that even  
I disable the allocation, " With shard reallocation disabled, the nodes  
will join the cluster with their indices intact"

I guess that if I proceed to upgrade the left nodes, all the shards will  
become unavailable since the restarted node does not recognize existing  
shards  
when allocation is disabled, thus I stopped my operation after the first  
node was upgraded.

My question is how I can upgrade my nodes with allocation disabled? Is it a  
bug? If I have to upgrade all the nodes with allocation enabling, it seems  
that  
a vast amount of unnecessary IO for resharding will occur.

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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:** [July 6, 2017, 1:10am UTC](https://discuss.elastic.co/t/how-to-upgrade-a-cluster/19158/2 "2017-07-06T01:10:02Z")

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