Azure repository creation issue in 7.10.2

(I'm using this image: amazon/opendistro-for-elasticsearch:1.13.2)

Following the docs on setting up an azure repository:

  1. Added storage account name and key and reloaded settings (Azure Repository | Elasticsearch Plugins and Integrations [7.10] | Elastic)
# on the elasticsearch node; I have one node in this test cluster
bin/elasticsearch-keystore add azure.client.default.account
bin/elasticsearch-keystore add azure.client.default.key
curl -X POST "localhost:9200/_nodes/reload_secure_settings"
  1. Tried to register the Azure repository using the simplest settings (Repository settings | Elasticsearch Plugins and Integrations [7.10] | Elastic)
# on the elasticsearch node
curl -X PUT "localhost:9200/_snapshot/my_backups_repository" -H 'Content-Type: application/json' -d '{
  "type": "azure"
}'

Getting

{
  "error": {
    "root_cause": [
      {
        "type": "repository_verification_exception",
        "reason": "[my_backups_repository] path  is not accessible on master node"
      }
    ],
    "type": "repository_verification_exception",
    "reason": "[my_backups_repository] path  is not accessible on master node",
    "caused_by": {
      "type": "null_pointer_exception",
      "reason": "Cannot invoke \"String.length()\" because \"host\" is null"
    }
  },
  "status": 500
}

and in the logs I see

[2021-09-10T13:50:42,456][WARN ][r.suppressed             ] [elasticsearch-0] path: /_snapshot/my_backups_repository, params: {repository=my_backups_repository}
org.elasticsearch.repositories.RepositoryVerificationException: [my_backups_repository] path  is not accessible on master node
	at org.elasticsearch.repositories.blobstore.BlobStoreRepository.startVerification(BlobStoreRepository.java:1276) ~[elasticsearch-7.10.2.jar:7.10.2]
	at org.elasticsearch.repositories.RepositoriesService$3.doRun(RepositoriesService.java:268) ~[elasticsearch-7.10.2.jar:7.10.2]
	at org.elasticsearch.common.util.concurrent.ThreadContext$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:743) [elasticsearch-7.10.2.jar:7.10.2]
	at org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:37) [elasticsearch-7.10.2.jar:7.10.2]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) [?:?]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) [?:?]
	at java.lang.Thread.run(Thread.java:832) [?:?]
Caused by: java.lang.NullPointerException: Cannot invoke "String.length()" because "host" is null
	at com.microsoft.azure.storage.core.Utility.isHostDnsName(Utility.java:533) ~[?:?]
	at com.microsoft.azure.storage.core.Utility.determinePathStyleFromUri(Utility.java:521) ~[?:?]
	at com.microsoft.azure.storage.StorageUri.<init>(StorageUri.java:71) ~[?:?]
	at com.microsoft.azure.storage.core.PathUtility.appendPathToUri(PathUtility.java:124) ~[?:?]
	at com.microsoft.azure.storage.core.PathUtility.appendPathToUri(PathUtility.java:108) ~[?:?]
	at com.microsoft.azure.storage.blob.CloudBlobContainer.<init>(CloudBlobContainer.java:169) ~[?:?]
	at com.microsoft.azure.storage.blob.CloudBlobClient.getContainerReference(CloudBlobClient.java:123) ~[?:?]
	at org.elasticsearch.repositories.azure.AzureBlobStore.writeBlob(AzureBlobStore.java:333) ~[?:?]
	at org.elasticsearch.repositories.azure.AzureBlobContainer.writeBlob(AzureBlobContainer.java:115) ~[?:?]
	at org.elasticsearch.repositories.azure.AzureBlobContainer.writeBlobAtomic(AzureBlobContainer.java:123) ~[?:?]
	at org.elasticsearch.repositories.blobstore.BlobStoreRepository.startVerification(BlobStoreRepository.java:1271) ~[elasticsearch-7.10.2.jar:7.10.2]
	... 6 more

Can't figure out what host might refer to. Are there more settings I need to provide?

opendistro is an aws project, you may need to ask them on their support forums.

However, did you create a custom container or are you using the default?

I tried both the default container (elasticsearch-snapshots based on what the docs say) and a custom container (backups)

# checking that the containers exist
az storage container list --account-name xyz -o table      
Name                     Lease Status    Last Modified
-----------------------  --------------  -------------------------
backups                                  2021-08-19T11:22:07+00:00
elasticsearch-snapshots                  2021-09-13T13:26:02+00:00
PUT _snapshot/my_backups_repository
{
  "type": "azure"
}

PUT _snapshot/my_backups_repository
{
  "type": "azure",
  "settings": {
    "container": "backups",
  }
}

You might need to ask the opendistro devs then sorry.

So turns out I had a typo in the container name. After fixing that, everything works. Just leaving this here in case anybody else has the same problem as Cannot invoke \"String.length()\" because \"host\" is null is not the clearest error message.