I'm running several ETL flows in CDF/Nifi. The flows all involve writing some data to Iceberg tables. These flows are mostly running on a schedule that ranges from hourly to weekly (i.e., infrequent writes). Each data flow deployment has a few independent DAGs that all end with the PutIceberg processor, such that there are multiple separate ETL processes running at different intervals all in the same Nifi deployment.
The problem I see occurs pretty rarely (~once a month) and only for some deployments. Occasionally, the PutIceberg processor will error with 'Failed to acquire a SAS token' (see full error log below).
This will continue happening every time the processor runs unless I restart the flow and then it will run fine again. It seems to happen more often when the processor runs at a daily interval. My flows are using Nifi runtime 1.27.0.2.3.14.0-14 and I'm on CDP Public Cloud on Azure.
```
org.apache.hadoop.fs.azurebfs.contracts.exceptions.SASTokenProviderException: Failed to acquire a SAS token for create-file on [my-data-warehouse-bucket-and-table]/metadata/bb545710-14ea-4b07-b0f5-668978be4e8d-m1.avro due to org.apache.hadoop.security.AccessControlException: org.apache.ranger.raz.intg.RangerRazException: <!doctype html><html lang="en"><head><title>HTTP Status 401 ??? Unauthorized</title><style type="text/css">body {font-family:Tahoma,Arial,sans-serif;} h1, h2, h3, b {color:white;background-color:#525D76;} h1 {font-size:22px;} h2 {font-size:16px;} h3 {font-size:14px;} p {font-size:12px;} a {color:black;} .line {height:1px;background-color:#525D76;border:none;}</style></head><body><h1>HTTP Status 401 ??? Unauthorized</h1><hr class="line" /><p><b>Type</b> Status Report</p><p><b>Message</b> org.apache.hadoop.security.authentication.util.SignerException: Invalid signature</p><p><b>Description</b> The request has not been applied to the target resource because it lacks valid authentication credentials for that resource.</p><hr class="line" /><h3>Apache Tomcat/8.5.96</h3></body></html>; HttpStatus: 401
at org.apache.hadoop.fs.azurebfs.services.AbfsClient.appendSASTokenToQuery(AbfsClient.java:1233)
at org.apache.hadoop.fs.azurebfs.services.AbfsClient.appendSASTokenToQuery(AbfsClient.java:1199)
at org.apache.hadoop.fs.azurebfs.services.AbfsClient.createPath(AbfsClient.java:396)
at org.apache.hadoop.fs.azurebfs.AzureBlobFileSystemStore.conditionalCreateOverwriteFile(AzureBlobFileSystemStore.java:625)
at org.apache.hadoop.fs.azurebfs.AzureBlobFileSystemStore.createFile(AzureBlobFileSystemStore.java:568)
at org.apache.hadoop.fs.azurebfs.AzureBlobFileSystem.create(AzureBlobFileSystem.java:335)
at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:1177)
at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:1157)
at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:1046)
at org.apache.iceberg.hadoop.HadoopOutputFile.createOrOverwrite(HadoopOutputFile.java:85)
... 19 common frames omitted
```
