List Openstack container’s options with the swift command-line client – capabilities command

First, you need to install

swift command-line utility

and second, install the command-line tool to manage your account: Install OpenStack swift client only
With the capabilities command you may discover the following important policy and limits of your account like:

  • Listing limits – how many files (objects) will be in the output when using list command.
  • The maximum file size, which is supported by the server.
  • Maximum files (objects) for deletion per a single request. How many files you can delete with a single request, which is very convinient to put thousands of files per one requests, not to initiate an http(s) connection for each file (object), which could be thousands of files, or even millions!
  • Additinal plugins (in terms of Openstack – middleware), which are supported
  • Maximum container name length

and many more.

In general, you will need:

  1. username (–os-username) – Username
  2. password (–os-password) – Password
  3. authentication url (–os-auth-url) – The URL address, which authorize your requests, it generates a security token for your operations. Always use https!
  4. tenant name (–os-tenant-name) – Tenant is like a project.

All of the above information should be available from your OpenStack administrator.
Here an example output of the capabalities command:

myuser@myserver:~$ swift --os-username myusr --os-tenant-name myusr --os-password mypass --os-auth-url https://auth01.example.com:5000/v2.0 capabilities
Core: swift
 Options:
  account_autocreate: True
  account_listing_limit: 20000
  allow_account_management: False
  container_listing_limit: 20000
  extra_header_count: 0
  max_account_name_length: 256
  max_container_name_length: 256
  max_file_size: 5368709122
  max_header_size: 8192
  max_meta_count: 90
  max_meta_name_length: 128
  max_meta_overall_size: 4096
  max_meta_value_length: 256
  max_object_name_length: 1024
  policies: [{'name': 'Policy-0', 'default': True}]
  strict_cors_mode: True
Additional middleware: bulk_delete
 Options:
  max_deletes_per_request: 20000
Additional middleware: bulk_upload
 Options:
  max_containers_per_extraction: 20000
  max_failed_extractions: 1000
Additional middleware: container_sync
 Options:
  realms: {}
Additional middleware: crossdomain
Additional middleware: formpost
Additional middleware: keystoneauth
Additional middleware: slo
 Options:
  max_manifest_segments: 1000
  max_manifest_size: 2097152
  min_segment_size: 1048576
Additional middleware: staticweb

You can see various middleware are activated with specific options – bulk_upload – to upload multiple files with one request (a list with files) and bulk_delete – to delete multiple files per one request and so on.

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