Azure Blob Storage

Azure Blob Storage is a Microsoft-managed service providing cloud storage for a variety of use cases. You can use Azure Blob Storage with Flink for reading and writing data as well in conjunction with the streaming state backends

You can use Azure Blob Storage objects like regular files by specifying paths in the following format:

  1. wasb://<your-container>@$<your-azure-account>.blob.core.windows.net/<object-path>
  3. // SSL encrypted access
  4. wasbs://<your-container>@$<your-azure-account>.blob.core.windows.net/<object-path>

See below for how to use Azure Blob Storage in a Flink job:

  1. // Read from Azure Blob storage
  2. env.readTextFile("wasb://<your-container>@$<your-azure-account>.blob.core.windows.net/<object-path>");
  4. // Write to Azure Blob storage
  5. stream.writeAsText("wasb://<your-container>@$<your-azure-account>.blob.core.windows.net/<object-path>")
  7. // Use Azure Blob Storage as FsStatebackend
  8. env.setStateBackend(new FsStateBackend("wasb://<your-container>@$<your-azure-account>.blob.core.windows.net/<object-path>"));

Shaded Hadoop Azure Blob Storage file system

To use flink-azure-fs-hadoop, copy the respective JAR file from the opt directory to the plugins directory of your Flink distribution before starting Flink, e.g.

  1. mkdir ./plugins/azure-fs-hadoop
  2. cp ./opt/flink-azure-fs-hadoop-1.12.0.jar ./plugins/azure-fs-hadoop/

flink-azure-fs-hadoop registers default FileSystem wrappers for URIs with the wasb:// and wasbs:// (SSL encrypted access) scheme.

Credentials Configuration

Hadoop’s Azure Filesystem supports configuration of credentials via the Hadoop configuration as outlined in the Hadoop Azure Blob Storage documentation. For convenience Flink forwards all Flink configurations with a key prefix of fs.azure to the Hadoop configuration of the filesystem. Consequentially, the azure blob storage key can be configured in flink-conf.yaml via:

  1. fs.azure.account.key.<account_name>.blob.core.windows.net: <azure_storage_key>

Alternatively, the filesystem can be configured to read the Azure Blob Storage key from an environment variable AZURE_STORAGE_KEY by setting the following configuration keys in flink-conf.yaml.

  1. fs.azure.account.keyprovider.<account_name>.blob.core.windows.net: org.apache.flink.fs.azurefs.EnvironmentVariableKeyProvider