61 KiB
Configuring Keystone
man/keystone-manage man/keystone-all
Once Keystone is installed, it is configured via a primary
configuration file (etc/keystone.conf
), a PasteDeploy
configuration file (etc/keystone-paste.ini
), possibly a
separate logging configuration file, and initializing data into Keystone
using the command line client.
By default, Keystone starts a service on IANA-assigned port 35357. This may overlap with your system's ephemeral port range, so another process may already be using this port without being explicitly configured to do so. To prevent this scenario from occurring, it's recommended that you explicitly exclude port 35357 from the available ephemeral port range. On a Linux system, this would be accomplished by:
$ sysctl -w 'sys.net.ipv4.ip_local_reserved_ports=35357'
To make the above change persistent, net.ipv4.ip_local_reserved_ports = 35357 should
be added to /etc/sysctl.conf
or to
/etc/sysctl.d/keystone.conf
.
Starting and Stopping Keystone
Start Keystone services using the command:
$ keystone-all
Invoking this command starts up two wsgi.Server
instances, admin
(the administration API) and
main
(the primary/public API interface). Both services are
configured to run in a single process.
Stop the process using Control-C
.
Note
If you have not already configured Keystone, it may not start as expected.
Configuration Files
The Keystone configuration files are an ini
file format
based on Paste, a common system
used to configure Python WSGI based applications. The PasteDeploy
configuration entries (WSGI pipeline definitions) can be provided in a
separate keystone-paste.ini
file, while general and
driver-specific configuration parameters are in the primary
configuration file keystone.conf
. The primary configuration
file is organized into the following sections:
[DEFAULT]
- General configuration[assignment]
- Assignment system driver configuration[auth]
- Authentication plugin configuration[cache]
- Caching layer configuration[catalog]
- Service catalog driver configuration[credential]
- Credential system driver configuration[ec2]
- Amazon EC2 authentication driver configuration[endpoint_filter]
- Endpoint filtering extension configuration[endpoint_policy]
- Endpoint policy extension configuration[federation]
- Federation driver configuration[identity]
- Identity system driver configuration[identity_mapping]
- Identity mapping system driver configuration[kvs]
- KVS storage backend configuration[ldap]
- LDAP configuration options[memcache]
- Memcache configuration options[oauth1]
- OAuth 1.0a system driver configuration[os_inherit]
- Inherited role assignment extension[paste_deploy]
- Pointer to the PasteDeploy configuration file[policy]
- Policy system driver configuration for RBAC[revoke]
- Revocation system driver configuration[saml]
- SAML configuration options[signing]
- Cryptographic signatures for PKI based tokens[ssl]
- SSL configuration[stats]
- Stats system driver configuration[token]
- Token driver & token provider configuration[trust]
- Trust extension configuration
The Keystone primary configuration file is expected to be named
keystone.conf
. When starting Keystone, you can specify a
different configuration file to use with --config-file
. If
you do not specify a configuration file, Keystone will
look in the following directories for a configuration file, in
order:
~/.keystone/
~/
/etc/keystone/
/etc/
PasteDeploy configuration file is specified by the
config_file
parameter in [paste_deploy]
section of the primary configuration file. If the parameter is not an
absolute path, then Keystone looks for it in the same directories as
above. If not specified, WSGI pipeline definitions are loaded from the
primary configuration file.
Domain-specific Drivers
Note
This functionality is new in Juno.
Keystone supports the option (disabled by default) to specify identity driver configurations on a domain by domain basis, allowing, for example, a specific domain to have its own LDAP or SQL server. This is configured by specifying the following options:
[identity]
domain_specific_drivers_enabled = True
domain_config_dir = /etc/keystone/domains
Setting domain_specific_drivers_enabled
to
True
will enable this feature, causing Keystone to look in
the domain_config_dir
for config files of the form:
keystone.<domain_name>.conf
Options given in the domain specific configuration file will override those in the primary configuration file for the specified domain only. Domains without a specific configuration file will continue to use the options from the primary configuration file.
Note
Keystone does not support moving the contents of a domain (i.e. "it's" users and groups) from one backend to another, nor group membership across backend boundaries.
Note
Although Keystone supports multiple LDAP backends via domain specific configuration files, it currently only supports one SQL backend. This could be either the default driver or a single domain-specific backend, perhaps for storing service users in a predominantly LDAP installation.
Due to the need for user and group IDs to be unique across an OpenStack installation and for Keystone to be able to deduce which domain and backend to use from just a user or group ID, it dynamically builds a persistent identity mapping table from a public ID to the actual domain, local ID (within that backend) and entity type. The public ID is automatically generated by Keystone when it first encounters the entity. If the local ID of the entity is from a backend that does not guarantee to generate UUIDs, a hash algorithm will generate a public ID for that entity, which is what will be exposed by Keystone.
The use of a hash will ensure that if the public ID needs to be regenerated then the same public ID will be created. This is useful if you are running multiple keystones and want to ensure the same ID would be generated whichever server you hit.
While Keystone will dynamically maintain the identity mapping, including removing entries when entities are deleted via the Keystone, for those entities in backends that are managed outside of Keystone (e.g. a Read Only LDAP), Keystone will not know if entities have been deleted and hence will continue to carry stale identity mappings in its table. While benign, keystone provides an ability for operators to purge the mapping table of such stale entries using the keystone-manage command, for example:
$ keystone-manage mapping_purge --domain-name DOMAINA --local-id abc@de.com
A typical usage would be for an operator to obtain a list of those entries in an external backend that had been deleted out-of-band to Keystone, and then call keystone-manage to purge those entries by specifying the domain and local-id. The type of the entity (i.e. user or group) may also be specified if this is needed to uniquely identify the mapping.
Since public IDs are be regeneratable with the correct generator implementation, then, if the details of those entries that have been deleted are not available, then it is safe to simply bulk purge identity mappings periodically, for example:
$ keystone-manage mapping_purge --domain-name DOMAINA
will purge all the mappings for DOMAINA. The entire mapping table can be purged with the following command:
$ keystone-manage mapping_purge --all
Public ID Generators
Keystone supports a customizable public ID generator and it is
specified in the [identity_mapping]
section of the
configuration file. Keystone provides a sha256 generator as default,
which produces regeneratable public IDs. The generator algorithm for
public IDs is a balance between key size (i.e. the length of the public
ID), the probability of collision and, in some circumstances, the
security of the public ID. The maximum length of public ID supported by
Keystone is 64 characters, and the default generator (sha256) uses this
full capability. Since the public ID is what is exposed externally by
Keystone and potentially stored in external systems, some installations
may wish to make use of other generator algorithms that have a different
trade-off of attributes. A different generator can be installed by
configuring the following property:
generator
- identity mapping generator. Defaults tokeystone.identity.generators.sha256.Generator
Warning
Changing the generator may cause all existing public IDs to be become invalid, so typically the generator selection should be considered immutable for a given installation.
Authentication Plugins
Note
This feature is only supported by Keystone for the Identity API v3 clients.
Keystone supports authentication plugins and they are specified in
the [auth]
section of the configuration file. However, an
authentication plugin may also have its own section in the configuration
file. It is up to the plugin to register its own configuration
options.
methods
- comma-delimited list of authentication plugin names<plugin name>
- specify the class which handles to authentication method, in the same manner as one would specify a backend driver.
Keystone provides three authentication methods by default.
password
handles password authentication and
token
handles token authentication. external
is used in conjunction with authentication performed by a container web
server that sets the REMOTE_USER
environment variable. For
more details, refer to External Authentication
<external-auth>
.
How to Implement an Authentication Plugin
All authentication plugins must extend the
keystone.auth.core.AuthMethodHandler
class and implement
the authenticate()
method. The authenticate()
method expects the following parameters.
context
- Keystone's request contextauth_payload
- the content of the authentication for a given methodauth_context
- user authentication context, a dictionary shared by all plugins. It containsmethod_names
andextras
by default.method_names
is a list andextras
is a dictionary.
If successful, the authenticate()
method must provide a
valid user_id
in auth_context
and return
None
. method_name
is used to convey any
additional authentication methods in case authentication is for
re-scoping. For example, if the authentication is for re-scoping, a
plugin must append the previous method names into
method_names
. Also, a plugin may add any additional
information into extras
. Anything in extras
will be conveyed in the token's extras
field.
If authentication requires multiple steps, the
authenticate()
method must return the payload in the form
of a dictionary for the next authentication step.
If authentication is unsuccessful, the authenticate()
method must raise a keystone.exception.Unauthorized
exception.
Simply add the new plugin name to the methods
list along
with your plugin class configuration in the [auth]
sections
of the configuration file to deploy it.
If the plugin require addition configurations, it may register its own section in the configuration file.
Plugins are invoked in the order in which they are specified in the
methods
attribute of the authentication
request body. If multiple plugins are invoked, all plugins must succeed
in order to for the entire authentication to be successful. Furthermore,
all the plugins invoked must agree on the user_id
in the
auth_context
.
The REMOTE_USER
environment variable is only set from a
containing webserver. However, to ensure that a user must go through
other authentication mechanisms, even if this variable is set, remove
external
from the list of plugins specified in
methods
. This effectively disables external authentication.
For more details, refer to ExternalAuthentication <external-auth>
.
Token Persistence Driver
Keystone supports customizable token persistence drivers. These can
be specified in the [token]
section of the configuration
file. Keystone provides three non-test persistence backends. These can
be set with the [token]\driver
configuration option.
The drivers Keystone provides are:
keystone.token.persistence.backends.sql.Token
- The SQL-based (default) token persistence engine. This backend stores all token data in the same SQL store that is used for Identity/Assignment/etc.keystone.token.persistence.backends.memcache.Token
- The memcached based token persistence backend. This backend relies ondogpile.cache
and stores the token data in a set of memcached servers. The servers urls are specified in the[memcache]\servers
configuration option in the Keystone config.keystone.token.persistence.backends.memcache_pool.Token
- The pooled memcached token persistence engine. This backend supports the concept of pooled memcache client object (allowing for the re-use of the client objects). This backend has a number of extra tunable options in the[memcache]
section of the config.
Warning
It is recommended you use the
keystone.token.persistence.backend.memcache_pool.Token
backend instead of
keystone.token.persistence.backend.memcache.Token
as the
token persistence driver if you are deploying Keystone under eventlet
instead of Apache + mod_wsgi. This recommendation are due to known
issues with the use of thread.local
under eventlet that can
allow the leaking of memcache client objects and consumption of extra
sockets.
Token Provider
Keystone supports customizable token provider and it is specified in
the [token]
section of the configuration file. Keystone
provides both UUID and PKI token providers. However, users may register
their own token provider by configuring the following property.
provider
- token provider driver. Defaults tokeystone.token.providers.uuid.Provider
Note that token_format
in the [signing]
section is deprecated but still being supported for backward
compatibility. Therefore, if provider
is set to
keystone.token.providers.pki.Provider
,
token_format
must be PKI
. Conversely, if
provider
is
keystone.token.providers.uuid.Provider
,
token_format
must be UUID
.
For a customized provider, token_format
must not set to
PKI
or UUID
.
PKI or UUID?
UUID-based tokens are randomly generated opaque strings that are issued and validated by the identity service. They must be persisted by the identity service in order to be later validated, and revoking them is simply a matter of deleting them from the token persistence backend.
PKI-based tokens are Cryptographic Message Syntax (CMS) strings that can be verified offline using keystone's public signing key. The only reason for them to be persisted by the identity service is to later build token revocation lists (explicit lists of tokens that have been revoked), otherwise they are theoretically ephemeral. PKI tokens should therefore have much better scaling characteristics (decentralized validation). They are base-64 encoded (and are therefore not URL-friendly without encoding) and may be too long to fit in either headers or URLs if they contain extensive service catalogs or other additional attributes.
Warning
Both UUID and PKI-based tokens are bearer tokens, meaning that they must be protected from unnecessary disclosure to prevent unauthorized access.
The current architectural approaches for both UUID and PKI-based tokens have pain points exposed by environments under heavy load (search bugs and blueprints for the latest details and potential solutions).
Caching Layer
Keystone supports a caching layer that is above the configurable
subsystems (e.g. token
, identity
, etc).
Keystone uses the dogpile.cache
library which allows for flexible cache backends. The majority of the
caching configuration options are set in the [cache]
section. However, each section that has the capability to be cached
usually has a caching
boolean value that will toggle
caching for that specific section. The current default behavior is that
subsystem caching is enabled, but the global toggle is set to
disabled.
[cache]
configuration
section:
enabled
- enables/disables caching across all of keystonedebug_cache_backend
- enables more in-depth logging from the cache backend (get, set, delete, etc)backend
- the caching backend module to use e.g.dogpile.cache.memcached
Note
A given
backend
must be registered withdogpile.cache
before it can be used. The default backend is theKeystone
no-op backend (keystone.common.cache.noop
). If caching is desired a different backend will need to be specified. Current functional backends are:dogpile.cache.memcached
- Memcached backend using the standard python-memcached librarydogpile.cache.pylibmc
- Memcached backend using the pylibmc librarydogpile.cache.bmemcached
- Memcached using python-binary-memcached library.dogpile.cache.redis
- Redis backenddogpile.cache.dbm
- local DBM file backenddogpile.cache.memory
- in-memory cachekeystone.cache.mongo
- MongoDB as caching backendkeystone.cache.memcache_pool
- An eventlet safe implementation ofdogpile.cache.memcached
.-
This implementation also provides client connection re-use.
Warning
dogpile.cache.memory
is not suitable for use outside of unit testing as it does not cleanup it's internal cache on cache expiration, does not provide isolation to the cached data (values in the store can be inadvertently changed without extra layers of data protection added), and does not share cache between processes. This means that caching and cache invalidation will not be consistent or reliable when usingKeystone
and thedogpile.cache.memory
backend under any real workload.Warning
Do not use
dogpile.cache.memcached
backend if you are deploying Keystone under eventlet. There are known issues with the use ofthread.local
under eventlet that can allow the leaking of memcache client objects and consumption of extra sockets.
expiration_time
- int, the default length of time to cache a specific value. A value of0
-
indicates to not cache anything. It is recommended that the
enabled
option be used to disable cache instead of setting this to0
.
backend_argument
- an argument passed to the backend when instantiated-
backend_argument
should be specified once per argument to be passed to the back end and in the format of<argument name>:<argument value>
. e.g.:backend_argument = host:localhost
proxies
- comma delimited list of ProxyBackends e.g.my.example.Proxy, my.example.Proxy2
- Current Keystone systems that have caching capabilities:
-
token
-
The token system has a separate
cache_time
configuration option, that can be set to a value above or below the globalexpiration_time
default, allowing for different caching behavior from the other systems inKeystone
. This option is set in the[token]
section of the configuration file.The Token Revocation List cache time is handled by the configuration option
revocation_cache_time
in the[token]
section. The revocation list is refreshed whenever a token is revoked. It typically sees significantly more requests than specific token retrievals or token validation calls.
assignment
-
The assignment system has a separate
cache_time
configuration option, that can be set to a value above or below the globalexpiration_time
default, allowing for different caching behavior from the other systems inKeystone
. This option is set in the[assignment]
section of the configuration file.Currently
assignment
has caching forproject
,domain
, androle
specific requests (primarily around the CRUD actions). Caching is currently not implemented on grants. The list (list_projects
,list_domains
, etc) methods are not subject to caching.Warning
Be aware that if a read-only
assignment
backend is in use, the cache will not immediately reflect changes on the back end. Any given change may take up to thecache_time
(if set in the[assignment]
section of the configuration) or the globalexpiration_time
(set in the[cache]
section of the configuration) before it is reflected. If this type of delay (when using a read-onlyassignment
backend) is an issue, it is recommended that caching be disabled onassignment
. To disable caching specifically onassignment
, in the[assignment]
section of the configuration setcaching
toFalse
.
- For more information about the different backends (and configuration options):
-
- dogpile.cache.backends.memory
- dogpile.cache.backends.memcached
- dogpile.cache.backends.redis
- dogpile.cache.backends.file
- :py
keystone.common.cache.backends.mongo
Certificates for PKI
PKI stands for Public Key Infrastructure. Tokens are documents, cryptographically signed using the X509 standard. In order to work correctly token generation requires a public/private key pair. The public key must be signed in an X509 certificate, and the certificate used to sign it must be available as Certificate Authority (CA) certificate. These files can be generated either using the keystone-manage utility, or externally generated.
keystone-manage pki_setup
is a development tool. We
recommend that you do not use keystone-manage pki_setup
in
a production environment. In production, an external CA should be used
instead. This is because the CA secret key should generally be kept
apart from the token signing secret keys so that a compromise of a node
does not lead to an attacker being able to generate valid signed
Keystone tokens. This is a low probability attack vector, as compromise
of a Keystone service machine's filesystem security almost certainly
means the attacker will be able to gain direct access to the token
backend.
The files need to be in the locations specified by the top level
Keystone configuration file as specified in the above section.
Additionally, the private key should only be readable by the system user
that will run Keystone. The values that specify where to read the
certificates are under the [signing]
section of the
configuration file. The configuration values are:
token_format
- Determines the algorithm used to generate tokens. Can be eitherUUID
orPKI
. Defaults toPKI
. This option must be used in conjunction withprovider
configuration in the[token]
section.certfile
- Location of certificate used to verify tokens. Default is/etc/keystone/ssl/certs/signing_cert.pem
keyfile
- Location of private key used to sign tokens. Default is/etc/keystone/ssl/private/signing_key.pem
ca_certs
- Location of certificate for the authority that issued the above certificate. Default is/etc/keystone/ssl/certs/ca.pem
ca_key
- Default is/etc/keystone/ssl/private/cakey.pem
key_size
- Default is2048
valid_days
- Default is3650
Signing Certificate Issued by External CA
You may use a signing certificate issued by an external CA instead of generated by keystone-manage. However, certificate issued by external CA must satisfy the following conditions:
- all certificate and key files must be in Privacy Enhanced Mail (PEM) format
- private key files must not be protected by a password
When using signing certificate issued by an external CA, you do not
need to specify key_size
, valid_days
and
ca_key
as they will be ignored.
The basic workflow for using a signing certificate issued by an external CA involves:
- Request Signing Certificate from External CA
- Convert certificate and private key to PEM if needed
- Install External Signing Certificate
Request Signing Certificate from External CA
One way to request a signing certificate from an external CA is to first generate a PKCS #10 Certificate Request Syntax (CRS) using OpenSSL CLI.
First create a certificate request configuration file (e.g.
cert_req.conf
):
[ req ]
default_bits = 2048
default_keyfile = keystonekey.pem
default_md = default
prompt = no
distinguished_name = distinguished_name
[ distinguished_name ]
countryName = US
stateOrProvinceName = CA
localityName = Sunnyvale
organizationName = OpenStack
organizationalUnitName = Keystone
commonName = Keystone Signing
emailAddress = keystone@openstack.org
Then generate a CRS with OpenSSL CLI. Do not encrypt the generated private key. Must use the -nodes option.
For example:
$ openssl req -newkey rsa:2048 -keyout signing_key.pem -keyform PEM -out signing_cert_req.pem -outform PEM -config cert_req.conf -nodes
If everything is successfully, you should end up with
signing_cert_req.pem
and signing_key.pem
. Send
signing_cert_req.pem
to your CA to request a token signing
certificate and make sure to ask the certificate to be in PEM format.
Also, make sure your trusted CA certificate chain is also in PEM
format.
Install External Signing Certificate
Assuming you have the following already:
signing_cert.pem
- (Keystone token) signing certificate in PEM formatsigning_key.pem
- corresponding (non-encrypted) private key in PEM formatcacert.pem
- trust CA certificate chain in PEM format
Copy the above to your certificate directory. For example:
$ mkdir -p /etc/keystone/ssl/certs
$ cp signing_cert.pem /etc/keystone/ssl/certs/
$ cp signing_key.pem /etc/keystone/ssl/certs/
$ cp cacert.pem /etc/keystone/ssl/certs/
$ chmod -R 700 /etc/keystone/ssl/certs
Make sure the certificate directory is root-protected.
If your certificate directory path is different from the default
/etc/keystone/ssl/certs
, make sure it is reflected in the
[signing]
section of the configuration file.
Service Catalog
Keystone provides two configuration options for your service catalog.
SQL-based Service Catalog
(sql.Catalog
)
A dynamic database-backed driver fully supporting persistent configuration.
keystone.conf
example:
[catalog]
driver = keystone.catalog.backends.sql.Catalog
Note
A template_file does not need to be defined for the sql.Catalog driver.
To build your service catalog using this driver, see the built-in help:
$ keystone
$ keystone help service-create
$ keystone help endpoint-create
You can also refer to an example in Keystone (tools/sample_data.sh).
File-based Service
Catalog (templated.Catalog
)
The templated catalog is an in-memory backend initialized from a
read-only template_file
. Choose this option only if you
know that your service catalog will not change very much over time.
Note
Attempting to manage your service catalog using keystoneclient
commands (e.g. keystone endpoint-create
) against this
driver will result in HTTP 501 Not Implemented
errors. This
is the expected behavior. If you want to use these commands, you must
instead use the SQL-based Service Catalog driver.
keystone.conf
example:
[catalog]
driver = keystone.catalog.backends.templated.Catalog
template_file = /opt/stack/keystone/etc/default_catalog.templates
The value of template_file
is expected to be an absolute
path to your service catalog configuration. An example
template_file
is included in Keystone, however you should
create your own to reflect your deployment.
Another such example is available in devstack (files/default_catalog.templates).
Logging
Logging is configured externally to the rest of Keystone. Configure
the path to your logging configuration file using the
[DEFAULT] log_config
option of keystone.conf
.
If you wish to route all your logging through syslog, set the
[DEFAULT] use_syslog
option.
A sample log_config
file is included with the project at
etc/logging.conf.sample
. Like other OpenStack projects,
Keystone uses the Python logging module,
which includes extensive configuration options for choosing the output
levels and formats.
Monitoring
Keystone provides some basic request/response monitoring statistics out of the box.
Enable data collection by defining a stats_monitoring
filter and including it at the beginning of any desired WSGI
pipelines:
[filter:stats_monitoring]
paste.filter_factory = keystone.contrib.stats:StatsMiddleware.factory
[pipeline:public_api]
pipeline = stats_monitoring [...] public_service
Enable the reporting of collected data by defining a
stats_reporting
filter and including it near the end of
your admin_api
WSGI pipeline (After *_body
middleware and before *_extension
filters is
recommended):
[filter:stats_reporting]
paste.filter_factory = keystone.contrib.stats:StatsExtension.factory
[pipeline:admin_api]
pipeline = [...] json_body stats_reporting ec2_extension [...] admin_service
Query the admin API for statistics using:
$ curl -H 'X-Auth-Token: ADMIN' http://localhost:35357/v2.0/OS-STATS/stats
Reset collected data using:
$ curl -H 'X-Auth-Token: ADMIN' -X DELETE http://localhost:35357/v2.0/OS-STATS/stats
SSL
Keystone may be configured to support SSL and 2-way SSL out-of-the-box. The X509 certificates used by Keystone can be generated by keystone-manage or obtained externally and configured for use with Keystone as described in this section. Here is the description of each of them and their purpose:
Types of certificates
cacert.pem
: Certificate Authority chain to validate against.ssl_cert.pem
: Public certificate for Keystone server.middleware.pem
: Public and private certificate for Keystone middleware/client.cakey.pem
: Private key for the CA.ssl_key.pem
: Private key for the Keystone server.
Note that you may choose whatever names you want for these certificates, or combine the public/private keys in the same file if you wish. These certificates are just provided as an example.
Configuration
To enable SSL modify the etc/keystone.conf file accordingly under the [ssl] section. SSL configuration example using the included sample certificates:
[ssl]
enable = True
certfile = <path to keystone.pem>
keyfile = <path to keystonekey.pem>
ca_certs = <path to ca.pem>
ca_key = <path to cakey.pem>
cert_required = False
enable
: True enables SSL. Defaults to False.certfile
: Path to Keystone public certificate file.keyfile
: Path to Keystone private certificate file. If the private key is included in the certfile, the keyfile maybe omitted.ca_certs
: Path to CA trust chain.cert_required
: Requires client certificate. Defaults to False.
When generating SSL certificates the following values are read
key_size
: Key size to create. Defaults to 1024.valid_days
: How long the certificate is valid for. Defaults to 3650 (10 years).ca_key
: The private key for the CA. Defaults to/etc/keystone/ssl/certs/cakey.pem
.cert_subject
: The subject to set in the certificate. Defaults to /C=US/ST=Unset/L=Unset/O=Unset/CN=localhost. When setting the subject it is important to set CN to be the address of the server so client validation will succeed. This generally means having the subject be at least /CN=<keystone ip>
Generating SSL certificates
Certificates for secure HTTP communication can be generated by:
$ keystone-manage ssl_setup
This will create a private key, a public key and a certificate that will be used to encrypt communications with keystone. In the event that a Certificate Authority is not given a testing one will be created.
It is likely in a production environment that these certificates will
be created and provided externally. Note that ssl_setup
is
a development tool and is only recommended for developments environment.
We do not recommend using ssl_setup
for production
environments.
User CRUD
Keystone provides a user CRUD filter that can be added to the
public_api pipeline. This user crud filter allows users to use a HTTP
PATCH to change their own password. To enable this extension you should
define a user_crud_extension filter, insert it after the
*_body
middleware and before the
public_service
app in the public_api WSGI pipeline in
keystone-paste.ini
e.g.:
[filter:user_crud_extension]
paste.filter_factory = keystone.contrib.user_crud:CrudExtension.factory
[pipeline:public_api]
pipeline = stats_monitoring url_normalize token_auth admin_token_auth xml_body json_body debug ec2_extension user_crud_extension public_service
Each user can then change their own password with a HTTP PATCH :
$ curl -X PATCH http://localhost:5000/v2.0/OS-KSCRUD/users/<userid> -H "Content-type: application/json" \
"X_Auth_Token: <authtokenid>" -d '{"user": {"password": "ABCD", "original_password": "DCBA"}}' -H
In addition to changing their password all of the users current tokens will be deleted (if the backend used is SQL)
Inherited Role Assignment Extension
Keystone provides an optional extension that adds the capability to
assign roles to a domain that, rather than affect the domain itself, are
instead inherited to all projects owned by that domain. This extension
is disabled by default, but can be enabled by including the following in
keystone.conf
:
[os_inherit]
enabled = True
Token Binding
Token binding refers to the practice of embedding information from external authentication providers (like a company's Kerberos server) inside the token such that a client may enforce that the token only be used in conjunction with that specified authentication. This is an additional security mechanism as it means that if a token is stolen it will not be usable without also providing the external authentication.
To activate token binding you must specify the types of
authentication that token binding should be used for in
keystone.conf
e.g.:
[token]
bind = kerberos
Currently only kerberos
is supported.
To enforce checking of token binding the
enforce_token_bind
parameter should be set to one of the
following modes:
disabled
disable token bind checkingpermissive
enable bind checking, if a token is bound to a mechanism that is unknown to the server then ignore it. This is the default.strict
enable bind checking, if a token is bound to a mechanism that is unknown to the server then this token should be rejected.required
enable bind checking and require that at least 1 bind mechanism is used for tokens.named enable bind checking and require that the specified authentication mechanism is used. e.g.:
[token] enforce_token_bind = kerberos
Do not set
enforce_token_bind = named
as there is not an authentication mechanism callednamed
.
Limiting the number of entities returned in a collection
Keystone provides a method of setting a limit to the number of
entities returned in a collection, which is useful to prevent overly
long response times for list queries that have not specified a
sufficiently narrow filter. This limit can be set globally by setting
list_limit
in the default section of
keystone.conf
, with no limit set by default. Individual
driver sections may override this global value with a specific limit,
for example:
[assignment]
list_limit = 100
If a response to list_{entity}
call has been truncated,
then the response status code will still be 200 (OK), but the
truncated
attribute in the collection will be set to
true
.
Sample Configuration Files
The etc/
folder distributed with Keystone contains
example configuration files for each Server application.
etc/keystone.conf.sample
etc/keystone-paste.ini
etc/logging.conf.sample
etc/default_catalog.templates
Keystone API protection with Role Based Access Control (RBAC)
Like most OpenStack projects, Keystone supports the protection of its APIs by defining policy rules based on an RBAC approach. These are stored in a JSON policy file, the name and location of which is set in the main Keystone configuration file.
Each Keystone v3 API has a line in the policy file which dictates what level of protection is applied to it, where each line is of the form:
<api name>: <rule statement> or <match statement>
where:
<rule statement>
can contain
<rule statement>
or
<match statement>
<match statement>
is a set of identifiers that
must match between the token provided by the caller of the API and the
parameters or target entities of the API call in question. For
example:
"identity:create_user": [["role:admin", "domain_id:%(user.domain_id)s"]]
Indicates that to create a user you must have the admin role in your token and in addition the domain_id in your token (which implies this must be a domain scoped token) must match the domain_id in the user object you are trying to create. In other words, you must have the admin role on the domain in which you are creating the user, and the token you are using must be scoped to that domain.
Each component of a match statement is of the form:
<attribute from token>:<constant> or <attribute related to API call>
The following attributes are available
Attributes from token: user_id, the domain_id or project_id depending on the scope, and the list of roles you have within that scope
Attributes related to API call: Any parameters that are passed into the API call are available, along with any filters specified in the query string. Attributes of objects passed can be referenced using an object.attribute syntax (e.g. user.domain_id). The target objects of an API are also available using a target.object.attribute syntax. For instance:
"identity:delete_user": [["role:admin", "domain_id:%(target.user.domain_id)s"]]
would ensure that the user object that is being deleted is in the same domain as the token provided.
Every target object has an id and a name available as target.<object>.id and target.<object>.name. Other attributes are retrieved from the database and vary between object types. Moreover, some database fields are filtered out (e.g. user passwords).
List of object attributes:
- role:
-
- target.role.id
- target.role.name
- user:
-
- target.user.default_project_id
- target.user.description
- target.user.domain_id
- target.user.enabled
- target.user.id
- target.user.name
- group:
-
- target.group.description
- target.group.domain_id
- target.group.id
- target.group.name
- domain:
-
- target.domain.enabled
- target.domain.id
- target.domain.name
- project:
-
- target.project.description
- target.project.domain_id
- target.project.enabled
- target.project.id
- target.project.name
The default policy.json file supplied provides a somewhat basic example of API protection, and does not assume any particular use of domains. For multi-domain configuration installations where, for example, a cloud provider wishes to allow administration of the contents of a domain to be delegated, it is recommended that the supplied policy.v3cloudsample.json is used as a basis for creating a suitable production policy file. This example policy file also shows the use of an admin_domain to allow a cloud provider to enable cloud administrators to have wider access across the APIs.
A clean installation would need to perhaps start with the standard policy file, to allow creation of the admin_domain with the first users within it. The domain_id of the admin domain would then be obtained and could be pasted into a modified version of policy.v3cloudsample.json which could then be enabled as the main policy file.
Preparing your deployment
Step 1: Configure keystone.conf
Ensure that your keystone.conf
is configured to use a
SQL driver:
[identity]
driver = keystone.identity.backends.sql.Identity
You may also want to configure your [sql]
settings to
better reflect your environment:
[sql]
connection = sqlite:///keystone.db
idle_timeout = 200
Note
It is important that the database that you specify be different from the one containing your existing install.
Step 2: Sync your new, empty database
You should now be ready to initialize your new database without error, using:
$ keystone-manage db_sync
To test this, you should now be able to start
keystone-all
and use the Keystone Client to list your
tenants (which should successfully return an empty list from your new
database):
$ keystone --os-token ADMIN --os-endpoint http://127.0.0.1:35357/v2.0/ tenant-list
+----+------+---------+
| id | name | enabled |
+----+------+---------+
+----+------+---------+
Note
We're providing the default OS_SERVICE_TOKEN and OS_SERVICE_ENDPOINT
values from keystone.conf
to connect to the Keystone
service. If you changed those values, or deployed Keystone to a
different endpoint, you will need to change the provided command
accordingly.
Initializing Keystone
keystone-manage
is designed to execute commands that
cannot be administered through the normal REST API. At the moment, the
following calls are supported:
db_sync
: Sync the database.db_version
: Print the current migration version of the database.mapping_purge
: Purge the identity mapping table.pki_setup
: Initialize the certificates used to sign tokens.saml_idp_metadata
: Generate identity provider metadata.ssl_setup
: Generate certificates for SSL.token_flush
: Purge expired tokens
Invoking keystone-manage
by itself will give you
additional usage information.
The private key used for token signing can only be read by its owner.
This prevents unauthorized users from spuriously signing tokens.
keystone-manage pki_setup
Should be run as the same system
user that will be running the Keystone service to ensure proper
ownership for the private key file and the associated certificates.
Adding Users, Tenants, and Roles with python-keystoneclient
Users, tenants, and roles must be administered using admin
credentials. There are two ways to configure
python-keystoneclient
to use admin credentials, using the
either an existing token or password credentials.
Authenticating with a Token
Note
If your Keystone deployment is brand new, you will need to use this
authentication method, along with your
[DEFAULT] admin_token
.
To use Keystone with a token, set the following flags:
--os-endpoint OS_SERVICE_ENDPOINT
: allows you to specify the Keystone endpoint to communicate with. The default endpoint ishttp://localhost:35357/v2.0
--os-token OS_SERVICE_TOKEN
: your service token
To administer a Keystone endpoint, your token should be either belong
to a user with the admin
role, or, if you haven't created
one yet, should be equal to the value defined by
[DEFAULT] admin_token
in your
keystone.conf
.
You can also set these variables in your environment so that they do not need to be passed as arguments each time:
$ export OS_SERVICE_ENDPOINT=http://localhost:35357/v2.0
$ export OS_SERVICE_TOKEN=ADMIN
Authenticating with a Password
To administer a Keystone endpoint, the following user referenced
below should be granted the admin
role.
--os_username OS_USERNAME
: Name of your user--os_password OS_PASSWORD
: Password for your user--os_tenant_name OS_TENANT_NAME
: Name of your tenant--os_auth_url OS_AUTH_URL
: URL of your Keystone auth server, e.g.http://localhost:35357/v2.0
You can also set these variables in your environment so that they do not need to be passed as arguments each time:
$ export OS_USERNAME=my_username
$ export OS_PASSWORD=my_password
$ export OS_TENANT_NAME=my_tenant
Example usage
keystone
is set up to expect commands in the general
form of keystone
command
argument
, followed by flag-like keyword arguments to
provide additional (often optional) information. For example, the
command user-list
and tenant-create
can be
invoked as follows:
# Using token auth env variables
$ export OS_SERVICE_ENDPOINT=http://127.0.0.1:35357/v2.0/
$ export OS_SERVICE_TOKEN=secrete_token
$ keystone user-list
$ keystone tenant-create --name=demo
# Using token auth flags
$ keystone --os-token=secrete --os-endpoint=http://127.0.0.1:35357/v2.0/ user-list
$ keystone --os-token=secrete --os-endpoint=http://127.0.0.1:35357/v2.0/ tenant-create --name=demo
# Using user + password + tenant_name env variables
$ export OS_USERNAME=admin
$ export OS_PASSWORD=secrete
$ export OS_TENANT_NAME=admin
$ keystone user-list
$ keystone tenant-create --name=demo
# Using user + password + tenant_name flags
$ keystone --os_username=admin --os_password=secrete --os_tenant_name=admin user-list
$ keystone --os_username=admin --os_password=secrete --os_tenant_name=admin tenant-create --name=demo
For additional examples refer to CLI Examples.
Removing Expired Tokens
In the SQL backend expired tokens are not automatically removed. These tokens can be removed with:
$ keystone-manage token_flush
The memcache backend automatically discards expired tokens and so flushing is unnecessary and if attempted will fail with a NotImplemented error.
Configuring the LDAP Identity Provider
As an alternative to the SQL Database backing store, Keystone can use a directory server to provide the Identity service. An example Schema for OpenStack would look like this:
dn: dc=openstack,dc=org
dc: openstack
objectClass: dcObject
objectClass: organizationalUnit
ou: openstack
dn: ou=Projects,dc=openstack,dc=org
objectClass: top
objectClass: organizationalUnit
ou: groups
dn: ou=Users,dc=openstack,dc=org
objectClass: top
objectClass: organizationalUnit
ou: users
dn: ou=Roles,dc=openstack,dc=org
objectClass: top
objectClass: organizationalUnit
ou: roles
The corresponding entries in the Keystone configuration file are:
[ldap]
url = ldap://localhost
user = dc=Manager,dc=openstack,dc=org
password = badpassword
suffix = dc=openstack,dc=org
use_dumb_member = False
allow_subtree_delete = False
user_tree_dn = ou=Users,dc=openstack,dc=org
user_objectclass = inetOrgPerson
project_tree_dn = ou=Projects,dc=openstack,dc=org
project_objectclass = groupOfNames
role_tree_dn = ou=Roles,dc=openstack,dc=org
role_objectclass = organizationalRole
The default object classes and attributes are intentionally simplistic. They reflect the common standard objects according to the LDAP RFCs. However, in a live deployment, the correct attributes can be overridden to support a preexisting, more complex schema. For example, in the user object, the objectClass posixAccount from RFC2307 is very common. If this is the underlying objectclass, then the uid field should probably be uidNumber and username field either uid or cn. To change these two fields, the corresponding entries in the Keystone configuration file are:
[ldap]
user_id_attribute = uidNumber
user_name_attribute = cn
There is a set of allowed actions per object type that you can modify depending on your specific deployment. For example, the users are managed by another tool and you have only read access, in such case the configuration is:
[ldap]
user_allow_create = False
user_allow_update = False
user_allow_delete = False
project_allow_create = True
project_allow_update = True
project_allow_delete = True
role_allow_create = True
role_allow_update = True
role_allow_delete = True
There are some configuration options for filtering users, tenants and roles, if the backend is providing too much output, in such case the configuration will look like:
[ldap]
user_filter = (memberof=CN=openstack-users,OU=workgroups,DC=openstack,DC=org)
project_filter =
role_filter =
In case that the directory server does not have an attribute enabled of type boolean for the user, there is several configuration parameters that can be used to extract the value from an integer attribute like in Active Directory:
[ldap]
user_enabled_attribute = userAccountControl
user_enabled_mask = 2
user_enabled_default = 512
In this case the attribute is an integer and the enabled attribute is listed in bit 1, so the if the mask configured user_enabled_mask is different from 0, it gets the value from the field user_enabled_attribute and it makes an ADD operation with the value indicated on user_enabled_mask and if the value matches the mask then the account is disabled.
It also saves the value without mask to the user identity in the attribute enabled_nomask. This is needed in order to set it back in case that we need to change it to enable/disable a user because it contains more information than the status like password expiration. Last setting user_enabled_mask is needed in order to create a default value on the integer attribute (512 = NORMAL ACCOUNT on AD)
In case of Active Directory the classes and attributes could not match the specified classes in the LDAP module so you can configure them like:
[ldap]
user_objectclass = person
user_id_attribute = cn
user_name_attribute = cn
user_mail_attribute = mail
user_enabled_attribute = userAccountControl
user_enabled_mask = 2
user_enabled_default = 512
user_attribute_ignore = tenant_id,tenants
project_objectclass = groupOfNames
project_id_attribute = cn
project_member_attribute = member
project_name_attribute = ou
project_desc_attribute = description
project_enabled_attribute = extensionName
project_attribute_ignore =
role_objectclass = organizationalRole
role_id_attribute = cn
role_name_attribute = ou
role_member_attribute = roleOccupant
role_attribute_ignore =
Debugging LDAP
For additional information on LDAP connections, performance (such as
slow response time), or field mappings, setting debug_level
in the [ldap] section is used to enable debugging:
debug_level = 4095
This setting in turn sets OPT_DEBUG_LEVEL in the underlying python library. This field is a bit mask (integer), and the possible flags are documented in the OpenLDAP manpages. Commonly used values include 255 and 4095, with 4095 being more verbose.
Warning
Enabling debug_level
will negatively impact
performance.
Enabled Emulation
Some directory servers do not provide any enabled attribute. For
these servers, the user_enabled_emulation
and
project_enabled_emulation
attributes have been created.
They are enabled by setting their respective flags to True. Then the
attributes user_enabled_emulation_dn
and
project_enabled_emulation_dn
may be set to specify how the
enabled users and projects (tenants) are selected. These attributes work
by using a groupOfNames
and adding whichever users or
projects (tenants) that you want enabled to the respective group. For
example, this will mark any user who is a member of
enabled_users
as enabled:
[ldap]
user_enabled_emulation = True
user_enabled_emulation_dn = cn=enabled_users,cn=groups,dc=openstack,dc=org
The default values for user and project (tenant) enabled emulation DN
is cn=enabled_users,$user_tree_dn
and
cn=enabled_tenants,$project_tree_dn
respectively.
Secure Connection
If you are using a directory server to provide the Identity service, it is strongly recommended that you utilize a secure connection from Keystone to the directory server. In addition to supporting ldaps, Keystone also provides Transport Layer Security (TLS) support. There are some basic configuration options for enabling TLS, identifying a single file or directory that contains certificates for all the Certificate Authorities that the Keystone LDAP client will recognize, and declaring what checks the client should perform on server certificates. This functionality can easily be configured as follows:
[ldap]
use_tls = True
tls_cacertfile = /etc/keystone/ssl/certs/cacert.pem
tls_cacertdir = /etc/keystone/ssl/certs/
tls_req_cert = demand
A few points worth mentioning regarding the above options. If both tls_cacertfile and tls_cacertdir are set then tls_cacertfile will be used and tls_cacertdir is ignored. Furthermore, valid options for tls_req_cert are demand, never, and allow. These correspond to the standard options permitted by the TLS_REQCERT TLS option.
Read Only LDAP
Many environments typically have user and group information in directories that are accessible by LDAP. This information is for read-only use in a wide array of applications. Prior to the Havana release, we could not deploy Keystone with read-only directories as backends because Keystone also needed to store information such as projects, roles, domains and role assignments into the directories in conjunction with reading user and group information.
Keystone now provides an option whereby these read-only directories
can be easily integrated as it now enables its identity entities (which
comprises users, groups, and group memberships) to be served out of
directories while assignments (which comprises projects, roles, role
assignments, and domains) are to be served from a different Keystone
backend (i.e. SQL). To enable this option, you must have the following
keystone.conf
options set:
[identity]
driver = keystone.identity.backends.ldap.Identity
[assignment]
driver = keystone.assignment.backends.sql.Assignment
With the above configuration, Keystone will only lookup identity
related information such users, groups, and group membership from the
directory, while assignment related information will be provided by the
SQL backend. Also note that if there is an LDAP Identity, and no
assignment backend is specified, the assignment backend will default to
LDAP. Although this may seem counterintuitive, it is provided for
backwards compatibility. Nonetheless, the explicit option will always
override the implicit option, so specifying the options as shown above
will always be correct. Finally, it is also worth noting that whether or
not the LDAP accessible directory is to be considered read only is still
configured as described in a previous section above by setting values
such as the following in the [ldap]
configuration
section:
[ldap]
user_allow_create = False
user_allow_update = False
user_allow_delete = False
Connection Pooling
Various LDAP backends in Keystone use a common LDAP module to interact with LDAP data. By default, a new connection is established for LDAP operations. This can become highly expensive when TLS support is enabled which is a likely configuraton in enterprise setup. Re-using of connectors from a connection pool drastically reduces overhead of initiating a new connection for every LDAP operation.
Keystone now provides connection pool support via configuration. This change will keep LDAP connectors alive and re-use for subsequent LDAP operations. A connection lifespan is going to be configurable with other pooling specific attributes. The change is made in LDAP handler layer logic which is primarily responsible for LDAP connection and shared common operations.
In LDAP identity driver, Keystone authenticates end user by LDAP bind
with user DN and provided password. These kind of auth binds can fill up
the pool pretty quickly so a separate pool is provided for those end
user auth bind calls. If a deployment does not want to use pool for
those binds, then it can disable pooling selectively by
use_auth_pool
as false. If a deployment wants to use pool
for those auth binds, then use_auth_pool
needs to be true.
For auth pool, a different pool size (auth_pool_size
) and
connection lifetime (auth_pool_connection_lifetime
) can be
specified. With enabled auth pool, its connection lifetime should be
kept short so that pool frequently re-binds the connection with provided
creds and works reliably in end user password change case. When
use_pool
is false (disabled), then auth pool configuration
is also not used.
Connection pool configuration is added in [ldap]
configuration section:
[ldap]
# Enable LDAP connection pooling. (boolean value)
use_pool=false
# Connection pool size. (integer value)
pool_size=10
# Maximum count of reconnect trials. (integer value)
pool_retry_max=3
# Time span in seconds to wait between two reconnect trials.
# (floating point value)
pool_retry_delay=0.1
# Connector timeout in seconds. Value -1 indicates indefinite wait for
# response. (integer value)
pool_connection_timeout=-1
# Connection lifetime in seconds. (integer value)
pool_connection_lifetime=600
# Enable LDAP connection pooling for end user authentication. If use_pool
# is disabled, then this setting is meaningless and is not used at all.
# (boolean value)
use_auth_pool=false
# End user auth connection pool size. (integer value)
auth_pool_size=100
# End user auth connection lifetime in seconds. (integer value)
auth_pool_connection_lifetime=60