# How to resolve the below unassigned shards?

**URL:** <https://discuss.elastic.co/t/how-to-resolve-the-below-unassigned-shards/268037>\
**Category:** Elasticsearch\
**Created:** [March 23, 2021, 4:36am UTC](https://discuss.elastic.co/t/how-to-resolve-the-below-unassigned-shards/268037 "2021-03-23T04:36:23Z")\
**Posts on this page:** 7\
**Page:** 1

<div class="post-metadata">

**Author:** ![Jax\_dev](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/jax_dev/32/79117_2.png) [@Jax\_dev](https://discuss.elastic.co/u/Jax_dev)\
**Post date:** [March 23, 2021, 4:36am UTC](https://discuss.elastic.co/t/how-to-resolve-the-below-unassigned-shards/268037/1 "2021-03-23T04:36:23Z")

</div>

How do I resolve the below unassigned shards ?

What exactly happened - one of the node in the cluster was down for 2days and I bought the node back again.

After above issue - I could see shards got unassigned.

Again I have bought down another node because of disk space issue, allocation is not happening for few shards. I dont want this node back again, as I have added another alternative node.

`_cluster/allocation/explain?pretty`

output:

```
{
    "index": "prodtemp",
    "shard": 0,
    "primary": false,
    "current_state": "unassigned",
    "unassigned_info": {
        "reason": "NODE_LEFT",
        "at": "2021-03-20T19:27:19.950Z",
        "details": "node_left [4cZwIGYbTYe5YTMQpg1fBg]",
        "last_allocation_status": "no_attempt"
    },
    "can_allocate": "no",
    "allocate_explanation": "cannot allocate because allocation is not permitted to any of the nodes",
    "node_allocation_decisions": [
        {
            "node_id": "xxxxxxxxxxxxxxxxxxxx",
            "node_name": "xxxxxxxxxxx",
            "transport_address": "xx.xx.1.xx:9300",
            "node_attributes": {
                "ml.machine_memory": "33731194880",
                "xpack.installed": "true",
                "transform.node": "true",
                "ml.max_open_jobs": "20"
            },
            "node_decision": "no",
            "deciders": [
                {
                    "decider": "node_version",
                    "decision": "NO",
                    "explanation": "cannot allocate replica shard to a node with version [7.9.2] since this is older than the primary version [7.11.2]"
                }
            ]
        },
        {
            "node_id": "xxxxxxxxxxxxxx",
            "node_name": "yyyyyyyyyyyyy",
            "transport_address": "xx.xx.1.xxx:9300",
            "node_attributes": {
                "ml.machine_memory": "33731170304",
                "ml.max_open_jobs": "20",
                "xpack.installed": "true",
                "transform.node": "true"
            },
            "node_decision": "no",
            "deciders": [
                {
                    "decider": "node_version",
                    "decision": "NO",
                    "explanation": "cannot allocate replica shard to a node with version [7.10.1] since this is older than the primary version [7.11.2]"
                }
            ]
        },
        {
            "node_id": "xxxxxxx",
            "node_name": "zzzzzzzzzzzzz",
            "transport_address": "xx.xxx.1.xx:9300",
            "node_attributes": {
                "ml.machine_memory": "33731194880",
                "ml.max_open_jobs": "20",
                "xpack.installed": "true",
                "transform.node": "true"
            },
            "node_decision": "no",
            "deciders": [
                {
                    "decider": "node_version",
                    "decision": "NO",
                    "explanation": "cannot allocate replica shard to a node with version [7.9.2] since this is older than the primary version [7.11.2]"
                }
            ]
        },
        {
            "node_id": "xx55555",
            "node_name": "aaaaaaaaaaaaaa",
            "transport_address": "xx.xxx.1.xx:9300",
            "node_attributes": {
                "ml.machine_memory": "33731174400",
                "ml.max_open_jobs": "20",
                "xpack.installed": "true",
                "ml.max_jvm_size": "21474836480",
                "transform.node": "true"
            },
            "node_decision": "no",
            "deciders": [
                {
                    "decider": "same_shard",
                    "decision": "NO",
                    "explanation": "a copy of this shard is already allocated to this node [[prodtempcstempdata][0], node[lwFqKkuPQPm3_UYN9DU9VQ], [P], s[STARTED], a[id=w-uD-aw_RvWCYG47uvR88w]]"
                }
            ]
        }
    ]
}
```

---

<div class="post-metadata">

**Author:** ![Christian\_Dahlqvist](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/christian_dahlqvist/32/4617_2.png) [@Christian\_Dahlqvist](https://discuss.elastic.co/u/Christian_Dahlqvist)\
**Post date:** [March 23, 2021, 4:39am UTC](https://discuss.elastic.co/t/how-to-resolve-the-below-unassigned-shards/268037/2 "2021-03-23T04:39:58Z")

</div>

It looks like all nodes in your cluster are not running exactly the same version of Elasticsearch and that a shard on a newer node can not be replicated to an older one. Upgrade any older nodes to the same version as the newest one in the cluster.

---

<div class="post-metadata">

**Author:** ![Jax\_dev](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/jax_dev/32/79117_2.png) [@Jax\_dev](https://discuss.elastic.co/u/Jax_dev)\
**Post date:** [March 23, 2021, 5:01am UTC](https://discuss.elastic.co/t/how-to-resolve-the-below-unassigned-shards/268037/3 "2021-03-23T05:01:58Z")

</div>

> [@Christian\_Dahlqvist](#):
>
> newest

I could see the following version:  
node 1:  
"version" : {  
"number" : "7.10.1",  
"build\_flavor" : "default",  
"build\_type" : "deb",  
"build\_hash" : "xxxxxxxxxxxxxxxxxxx",  
"build\_date" : "2020-12-05T01:00:33.671820Z",  
"build\_snapshot" : false,  
"lucene\_version" : "8.7.0",  
"minimum\_wire\_compatibility\_version" : "6.8.0",  
"minimum\_index\_compatibility\_version" : "6.0.0-beta1"

node 2:  
"version" : {  
"number" : "7.9.2",  
"build\_flavor" : "default",  
"build\_type" : "deb",  
"build\_hash" : "xxxxxxxxxxxxxxfffffff",  
"build\_date" : "2020-09-23T00:45:33.626720Z",  
"build\_snapshot" : false,  
"lucene\_version" : "8.6.2",  
"minimum\_wire\_compatibility\_version" : "6.8.0",  
"minimum\_index\_compatibility\_version" : "6.0.0-beta1"  
},

node 3:

```
  "version" : {
    "number" : "7.9.2",
    "build_flavor" : "default",
    "build_type" : "deb",
    "build_hash" : "fffffffffffffffff",
    "build_date" : "2020-09-23T00:45:33.626720Z",
    "build_snapshot" : false,
    "lucene_version" : "8.6.2",
    "minimum_wire_compatibility_version" : "6.8.0",
    "minimum_index_compatibility_version" : "6.0.0-beta1"
  },

```

node 4:

```
 "version" : {
    "number" : "7.11.2",
    "build_flavor" : "default",
    "build_type" : "deb",
    "build_hash" : "4fffffffffffdddddd",
    "build_date" : "2021-03-06T05:54:38.141101Z",
    "build_snapshot" : false,
    "lucene_version" : "8.7.0",
    "minimum_wire_compatibility_version" : "6.8.0",
    "minimum_index_compatibility_version" : "6.0.0-beta1"
  },

```

Primary is in node 4 - Should I upgrade other nodes to the same version ? Is there anyway that I could manually allocate shards without upgrading the version.

Because we don't want the down time as this is production system with heavy traffic.

Also please share the recommended approach to upgrade the Elasticsearch version without loosing the data, if this is mandatory step to follow.

---

<div class="post-metadata">

**Author:** ![Christian\_Dahlqvist](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/christian_dahlqvist/32/4617_2.png) [@Christian\_Dahlqvist](https://discuss.elastic.co/u/Christian_Dahlqvist)\
**Post date:** [March 23, 2021, 5:17am UTC](https://discuss.elastic.co/t/how-to-resolve-the-below-unassigned-shards/268037/4 "2021-03-23T05:17:14Z")

</div>

All nodes need to be upgraded to exactly the same version. Primary shards on a newer node can not be replicated to an older node in any way as Lucene can not read shards created on newer versions.

---

<div class="post-metadata">

**Author:** ![Jax\_dev](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/jax_dev/32/79117_2.png) [@Jax\_dev](https://discuss.elastic.co/u/Jax_dev)\
**Post date:** [March 23, 2021, 5:20am UTC](https://discuss.elastic.co/t/how-to-resolve-the-below-unassigned-shards/268037/5 "2021-03-23T05:20:03Z")

</div>

> [@Christian\_Dahlqvist](#):
>
> All nodes need to be upgraded to exactly the same version. Primary shards on a newer node can not be replicated to an older node in any way as Lucene can not read shards created on newer versions.

Ok understood.

Is there any recommended approach to upgrade the version in other 3 nodes in the cluster without loosing data ?

Any API available to upgrade version ?

Please share documentation if any to upgrade version safely.

---

<div class="post-metadata">

**Author:** ![Christian\_Dahlqvist](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/christian_dahlqvist/32/4617_2.png) [@Christian\_Dahlqvist](https://discuss.elastic.co/u/Christian_Dahlqvist)\
**Post date:** [March 23, 2021, 5:22am UTC](https://discuss.elastic.co/t/how-to-resolve-the-below-unassigned-shards/268037/6 "2021-03-23T05:22:03Z")

</div>

I would recommend you perform [a rolling upgrade](https://www.elastic.co/guide/en/elasticsearch/reference/7.11/rolling-upgrades.html) one node at a time.

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [April 20, 2021, 5:22am UTC](https://discuss.elastic.co/t/how-to-resolve-the-below-unassigned-shards/268037/7 "2021-04-20T05:22:53Z")

</div>

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