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Table of Contents

Status

Current state:  DraftAccepted - 2.6.0 contains describe and alter functionality, resolve is pending for a future release.

Discussion thread: TODO here

JIRA: TODO KAFKA-7740

Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).

Motivation

Quota management via Admin Client has gone through a couple drafts of proposals (KIP-248, KIP-422). While improvements have been made to the Admin interface for configuration handling, fitting quotas into the API hasn't been clean is awkward as they don't fit the natural key-value pairing, nor is the configuration output expressive enough to return all useful information. Therefore, it'd be beneficial to have a quota-native API for managing quotas, which would offer an intuitive and less error-prone interface, convey additional useful information beyond what the configuration APIs could offerprovide, and provide enable for future extensibility as quotas types are added or evolved.

Background

Quotas By default, quotas are currently defined in terms of a user and client ID, where the user acts as a specific an opaque principal name, and the client ID as a more generic group identifier. When setting quotas, an administrator has flexibility in how it specifies the user and client ID for which the quota applies to, where the user and client ID may be specifically named, indicated as the a default, or omitted entirely. Since there's multiple ways to specify quotas, a hierarchy structure for which quotas apply must be appliedquotas have flexible configurations, there is a method for resolving the quotas that apply to a request: a hierarchy structure is used, where the most specific , defined quota will be matched to a request's user and client ID.

As represented by the current ZK node structure, the order in which quotas are matched are as follows. Note , from highest priority to lowest (note <user> is a specified user principal, <client-id> is a specified client ID, and <default> is a special default user/client ID that matches to all users or clients IDs.):

        /config/users/<user>/clients/<client-id>
        /config/users/<user>/clients/<default>
        /config/users/<user>
        /config/users/<default>/clients/<client-id>
        /config/users/<default>/clients/<default>
        /config/users/<default>
        /config/clients/<client-id>
        /config/clients/<default>

As such, reasoning around quotas can be complex, as it's not immediately obvious which quotas may apply to a given user and/or client ID. Providing descriptive information about how quotas are matched is a the first goal of this KIP. Likewise, retrieving and modifying quota values can be done in a more expressive and robust way, which is the second goal of the KIP.

APIs

In order to clearly specify the APIs, let's first disambiguate some terminologyNote: Every client request that is processed is associated with a quota entity, which is a map of entity types to their corresponding entity names for the request. Using the current entity types in the previous examples, an entity may be is of the form {user=test-user, clientId client-id=test-client}. When , where user and client-id are the types, and test-user and test-client are the names. However, when specifying a quota configuration entry, only a subset of the entity types need to be provided, which is referred to as an entity match, for example, {user=<default>}.

...

For describing quotas, there's two modes of operation that are necessary for administration: config-centric, and entity-centric.

  1. The config-centric mode describes what is exactly specified for the configuration for the given entity match. However, it would also be useful to also be able to determine which matches have configuration values defined, so the presence of a filter is used for gathering information about the entity matches that the administrator is interested in. This is DescribeQuotas DescribeClientQuotas.
  2. The entity-centric mode describes what quotas are applied apply to an entity. Note that an entity may match to various configuration entries depending on how the quotas are specified, e.g. the producer byte rate may be specified for the user, but the consumer byte rate for the client ID. Since upon querying this information, it may not be clear how quotas were matched for an entity from the configuration, additional information should be returned to give provide more context. This is DescribeEffectiveQuotas ResolveClientQuotas.

Altering quotas only works on a config-centric manner, and therefore doesn't need distinguishing. For a given entity match, the administrator should be able to specify which quotas apply, or alternatively remove existing quotas so they don't no longer match. This is AlterQuotas AlterClientQuotas.

Units

This KIP introduces the concept of a quota unit to be applied to a quota value. Currently, only a single unit is used for quotas: bytes-per-second, however this has limitations to effective quota management. For example, since it's a global value, it doesn't scale well as brokers are added or removed, and so a broker-bytes-per-second unit could be added to better manage this behavior. As units are added, the possible quota configuration entries becomes the cross product of the quota types by the quota units, which means that it'd be possible to specify bytes-per-second both on a global and per-broker basis, and quota enforcement would occur at whichever limit was hit first. Additional considerations could be made for a fair-share system. Units of shares could be configured to entities, and when bandwidth is contested, the share count of the various entities could be used to determine their restricted throughput.

While it's beyond the scope of this KIP to implement such functionality in the broker, it must be noted for future extensibility of the APIs.

Types Rationale

While there's two defined entity types in AK, a server-side plugin mechanism allows for further expansion. Likewise, as use cases evolve, finer-grained control may be necessary. Therefore, entity types should not be statically bound to what's publicly defined, and instead the API should support flexible entity types by interpreting them as a String identifier. Any entity types that the broker doesn't understand should return an error back to the client.

The quota types (producer byte rate, etc.) and units should also be given the same consideration. The possible quota applications may expand in the future, and the API shouldn't lock in which quota types are accessible. Modification of quota types/units that are unknown should fail with error.

For forming entities, since a fixed set of entity types aren't defined, a Map<String, String> should be used to map entity type to entity name.

Public Interfaces

Admin client calls will be added to correspond to describeQuotas, describeEffectiveQuotas, and alterQuotas, with supporting types defined in the common.quotas package.

Common types in package org.apache.kafka.common.quota:

The quota values are of type Double, which presents a complication in that the RPC protocol doesn't support floating point values. To accommodate this, RPC protocol message type 'double' will be added, which will serialize doubles according to the IEEE 754 floating-point "double format" bit layout.

Types Rationale

While there's two defined entity types in AK, a server-side plugin mechanism allows for further expansion. Likewise, as use cases evolve, finer-grained quota control may be necessary. Therefore, entity types should not be statically bound to publicly defined constants, and instead the API should support flexible entity types by interpreting them as a String identifier. Any entity types that the broker doesn't understand should throw an IllegalArgumentException back to the client.

The quota types (producer byte rate, consumer byte rate, etc.) should also be given the same consideration. The possible quota applications may expand in the future, and the API shouldn't lock in which quota types are accessible. Modification of quota types that are unknown should also fail with error.

Since a fixed set of entity types aren't defined, an entity should be represented by a Map<String, String>, which maps an entity type to the entity name.

Public Interfaces

Admin client calls will be added to correspond to DescribeClientQuotas, ResolveClientQuotas, and AlterClientQuotas, with supporting types defined in the common.quotas package.

Common types in package org.apache.kafka.common.quota (2.6.0)

Code Block
languagejava
/**
 * Describes a client quota entity, which is a mapping of entity types to their names.
 */
public class ClientQuotaEntity {

Code Block
languagejava
/**
 * Describes a fully-qualified entity.
 */
public class QuotaEntity {
    /**
     * TypeThe type of an entity entry.
     */
    public enumstatic Typefinal {
String USER       USER,= "user";
    public static final String CLIENT_ID;
    }= "client-id";

    /**
     * RepresentsConstructs thea defaultquota nameentity for the an entity, i.e. the entity that's matchedgiven types and names. If a name is null,
     * when an exact match isn't found then it is mapped to the built-in default entity name.
     */
    public * final@param staticentries String QUOTA_ENTITY_NAME_DEFAULT = // implementation defined

maps entity type to its name
     */**
    public * `entries` describes the fully-qualified entity. The key is a {@code Type} string, however
     * there may also exist keys that are not enumerated by {@code Type} that still apply, e.g.
     * the server may internally associate another type. It's necessary to return all quota typesClientQuotaEntity(Map<String, String> entries);

    /**
     * @return map of entity type to its name
     */
    public Map<String, String> entries();
}

/**
 * Describes a component for applying a client quota filter.
 */
public class ClientQuotaFilterComponent {

    /**
     * Constructs becauseand quotareturns valuesa forfilter thesecomponent typesthat mayexactly influencematches the effective quota value. However,provided entity
     * alteringname afor quota,the anyentity typestype.
 that aren't specified should be*
 able to be inferred by* the
@param entityType the entity type *the server,filter otherwisecomponent an error is returned.applies to
     *
 @param entityName the entity *name For example, {("CLIENT_ID" -> "test-client"),
     *               ("USER" -> "test-user"),
     *        that's matched exactly
     */
    public static ClientQuotaFilterComponent ofEntity(String entityType, String entityName);

    /**
     * Constructs and returns a filter component that matches the built-in default entity name
     * for ("GROUP" -> "internal-group")}the entity type.
     */
    public QuotaEntity(Map<String, String> entries);
}

/**
 * Describes a quota key.
 */
public class QuotaKey { * @param entityType the entity type the filter component applies to
     */
    public static ClientQuotaFilterComponent ofDefaultEntity(String entityType);

    /**
     * TheConstructs quotaand types.
returns a filter component that */
matches any specified name public enum Type {for the
     *   CONSUMER_BYTE_RATE,entity type.
     *
   PRODUCER_BYTE_RATE,
  * @param entityType the entity type REQUEST_PERCENTAGE;
the filter component applies }to

     */**
    public *static TheClientQuotaFilterComponent units for a quota value. Note there may be multiple units for a given quotaofEntityType(String entityType);

    /**
     * @return the component's entity type
     */
   that influencespublic quota behavior.String entityType();

     /**/
    public enum* Units@return {
the optional match string, where:
    RATE_BPS;
 *   }

    /**
  if present, the name that's matched * @param typeexactly
     *         if empty, matches the quotadefault typename
     *       @param units theif unitsnull, formatches theany quotaspecified typename
     */
    public QuotaKey(Type type, Units unitsOptional<String> match();
}

/**
 * Describes a client quota entity filter.
 */
public class QuotaFilterClientQuotaFilter {

    public/**
  enum Rule {
 * A filter to be applied to EXACT,matching client quotas.
  // exact name match*
     * @param components PREFIX;the components to //filter matcheson
 all names with the given* prefix
@param strict whether the }

filter only includes specified /**components
     */
  A  filteringprivate rule to be applied.ClientQuotaFilter(Collection<ClientQuotaFilterComponent> components, boolean strict);

     /**
     * @param entityType the entity type the rule applies to Constructs and returns a quota filter that matches all provided components. Matching entities
     * @paramwith ruleentity thetypes rulethat toare apply
not specified by a component * @param match the non-null string that's applied by the rulewill also be included in the result.
     *
     * @param components the components for the filter
     */
    public QuotaFilter(QuotaEntity.Type entityType, Rule rule, String matchstatic ClientQuotaFilter contains(Collection<ClientQuotaFilterComponent> components);
}

DescribeQuotas:

Code Block
languagejava
public class DescribeQuotasOptions extends AbstractOptions<DescribeQuotasOptions> { /**
    // Empty.
}

/**
 *Constructs Theand resultreturns ofa thequota {@link Admin#describeQuotas(Collection<QuotaFilter>, DescribeQuotasOptions)} call.
 */
public class DescribeQuotasResult {

filter that matches all provided components. Matching entities
    /**
     * Mapswith anentity entitytypes tothat itsare configurednot quota value(s). Note if no value is defined for a quotaspecified by a component will *not* be included in the result.
     *
 type for that entity's config,* then@param itcomponents isthe notcomponents included infor the resulting value map.filter
     */
    public static ClientQuotaFilter containsOnly(Collection<ClientQuotaFilterComponent> components);

    /* @param entities the collection of entities that matched the filter*
     * Constructs and returns a quota filter that matches all configured entities.
     */
    public DescribeQuotasResult(KafkaFuture<Map<QuotaEntity, Map<QuotaKey, Long>>> entitiesstatic ClientQuotaFilter all();

    /**
     * Returns@return athe map from quota entity to a future which can be used to check the status of the operation.filter's components
     */
    public Collection<ClientQuotaFilterComponent> components();

    /**
     */
 @return whether the filter publicis KafkaFuture<Map<QuotaEntitystrict, Map<QuotaKey, Long>>> entities();
}

public interface Admin extends AutoCloseable {
    ...

    i.e. only includes specified components
     */
    public boolean strict();
}

/**
 * Describes a configuration *alteration Describesto allbe entitiesmade matchingto alla providedclient filters (logical AND) that have at least onequota entity.
 */
public class ClientQuotaAlteration {

    public *static quotaclass valueOp defined.{

        /**
         * @param key filtersthe filteringquota rulestype to applyalter
  to matching entities
     * @param optionsvalue if set then the optionsexisting value tois useupdated,
      * @return result containing* all matching entities
     */
    DescribeQuotasResult describeQuotas(Collection<QuotaFilter> filters,otherwise DescribeQuotasOptions options);
}

DescribeEffectiveQuotas:

Code Block
languagejava
public class DescribeEffectiveQuotasOptions extends AbstractOptions<DescribeEffectiveQuotasOptions> {
if null, the existing value is cleared
    /**
     */
 Whether to exclude the list of overridden valuespublic for every quota type in the result.Op(String key, Double value);

     */
    public DescribeEffectiveQuotasOptions setOmitOverriddenValues(boolean omitOverriddenValues);
}

/**
 * The result of the {@link Admin#describeEffectiveQuotas(Collection<QuotaEntity>, DescribeEffectiveQuotasOptions)} call.
 */
public class@return DescribeEffectiveQuotasResultthe {
quota type to  /**alter
     * Information about a specific quota configuration entry.
  */
    */
    public class Entry {String key();

        /**
         * @param source@return if set then the entityexisting sourcevalue for the valueis updated,
         * @param value        otherwise if null, the non-nullexisting value is cleared
         */
        public Entry(QuotaEntity source, Long valueDouble value();
    }

    /**
private final ClientQuotaEntity entity;
  * Information aboutprivate thefinal value for a quota type.Collection<Op> ops;

     /**/
    public class* Value@param {
entity the entity whose config will be  /**modified
     * @param ops the *alteration @param entry the quota entryto perform
         */
 @param overriddenEntries all valuespublic that are overridden due to being lower inClientQuotaAlteration(ClientQuotaEntity entity, Collection<Op> ops);

    /**
     * @return the entity *whose config will be modified
     */
    public ClientQuotaEntity entity();

    /**
     * @return specificity,the oralteration null if not requested
   to perform
      */
    public Collection<Op>   public Value(Entry entry, List<Entry> overriddenEntries);ops();
}

DescribeClientQuotas (2.6.0)

Code Block
languagejava
public class DescribeClientQuotasOptions extends AbstractOptions<DescribeClientQuotasOptions> {
    // Empty.
}

    /**
     * MapsThe a collectionresult of entitiesthe to their effective quota values{@link Admin#describeClientQuotas(Collection, DescribeClientQuotasOptions)} call.
 */
public class DescribeClientQuotasResult  *{

     /**
 @param config the quota configuration* forMaps thean requestedentity entities
to its configured   */
    public DescribeEffectiveQuotasResult(Map<QuotaEntity, KafkaFuture<Map<QuotaKey, Value>>> config);

quota value(s). Note if no value is defined for a quota
     /**
     * Returns a map from quota entity to a future which can be used to check the status of the operation.* type for that entity's config, then it is not included in the resulting value map.
     *
     * @param entities future for the collection of entities that matched the filter
     */
    public Map<QuotaEntityDescribeClientQuotasResult(KafkaFuture<Map<ClientQuotaEntity, KafkaFuture<Map<QuotaKeyMap<String, Value>>>Double>>> config(entities);

    /**
     * Returns a future which succeeds only if all quota descriptions succeedmap from quota entity to a future which can be used to check the status of the operation.
     */
    public KafkaFuture<Void> allKafkaFuture<Map<ClientQuotaEntity, Map<String, Double>>> entities();
}

public interface Admin extends AutoCloseable {
    ...

    /**
     * Describes theall effectiveentities quotasmatching for the provided entities.
     * filter that have at least one client quota configuration
     * @paramvalue entitiesdefined.
 the entities to describe the effective quotas for* <p>
     * @paramThe optionsfollowing theexceptions optionscan tobe use
anticipated when calling {@code get()} *on @return the effectivefuture quotas forfrom the entities
     */
 returned {@link DescribeClientQuotasResult}:
 DescribeEffectiveQuotasResult  describeEffectiveQuotas(Collection<QuotaEntity> entities, DescribeEffectiveQuotasOptions* options);
}

AlterQuotas

Code Block
languagejava
titleAlterQuotas
public class AlterQuotasEntry {
<ul>
     * public class Op {<li>{@link org.apache.kafka.common.errors.ClusterAuthorizationException}
        /**
   If the authenticated user didn't have *describe @paramaccess keyto the quota type and units to alter
cluster.</li>
     *   <li>{@link org.apache.kafka.common.errors.InvalidRequestException}
     * @param value ifIf setthe thenrequest thedetails existingare value is updated,
      invalid. e.g., an invalid entity type was specified.</li>
   *  *   <li>{@link org.apache.kafka.common.errors.TimeoutException}
     *   otherwiseIf if null, the existingrequest valuetimed isout cleared
before the describe could finish.</li>
     * </ul>
     * <p>
  public Op(QuotaKey key, Long value);
    }

 * This operation is supported by brokers with version 2.6.0 or higher.
     /**
     * @param entityfilter the entityfilter whoseto configapply willto bematch modifiedentities
     * @param opsoptions the alterationoptions to performuse
 - if value is set,* then@return the existingDescribeClientQuotasResult valuecontaining isthe updated,result
     */
    DescribeClientQuotasResult describeClientQuotas(ClientQuotaFilter filter, DescribeClientQuotasOptions options);
}

ResolveClientQuotas (pending future release)

Code Block
languagejava
public class ResolveClientQuotasOptions extends otherwiseAbstractOptions<ResolveClientQuotasOptions> if{
 null, the existing value is cleared// Empty.
}

/**
 * The result of */
the    public AlterQuotasEntry(QuotaEntity entity, Collection<Op> ops);
}
{@link Admin#resolveClientQuotas(Collection, ResolveClientQuotasOptions)} call.
 */
public class AlterQuotasOptions extends AbstractOptions<AlterQuotasOptions>ResolveClientQuotasResult {
    /**
     * SetsInformation whetherabout thea requestspecific shouldquota be validated without altering the configsconfiguration entry.
     */
    public AlterQuotasOptionsclass validateOnly(boolean validateOnly);
}

Entry {
        /**
 * The result of       * @param source the {@link Admin#alterQuotas(Collection<AlterQuotasEntry>, AlterQuotasOptions)} call.
 *
 * The API of this class is evolving, see {@link Admin} for details.
 */
public class AlterQuotasResult {
entity source for the value
         * @param value the non-null value
         */
        public AlterQuotasResultEntry(Map<QuotaEntityQuotaEntity source, KafkaFuture<Void>>Double futuresvalue);
    }

    /**
     * Returns a map fromInformation about the value for a quota entitytype.
 to a future which can*
 be used to check the* statusNOTE: ofWe themaintain operation.
a `Value` class because additional */
information may be  public Map<QuotaEntity, KafkaFuture<Void>> values();

added, e.g.,
      /**
     * Returns a futurelist whichof succeeds only if all quota alterations succeedoverridden entries.
     */
    public KafkaFuture<Void> all();
}

public interface Admin extends AutoCloseable class Value {
    ...

    /**
     * Alters the quotas as* specified@param forentry the entries.
 quota entry
         */
        public Value(Entry entry);
    }

    /**
     * @paramMaps a alterationscollection theof alterationsentities to perform their resolved quota values.
     *
     * @param @returnconfig the resultquota configuration offor the alterationsrequested entities
     */
    AlterQuotasResultpublic alterQuotasResolveClientQuotasResult(Collection<AlterQuotasEntry>Map<QuotaEntity, entriesKafkaFuture<Map<String, AlterQuotasOptionsValue>>> options);
}

kafka-quotas.sh/QuotasCommand:

A QuotasCommand would be constructed with an associated script for managing quotas via command line.

Common flags:
--bootstrap-server: The standard bootstrap server.
--command-config: Property file for the Admin client.

Operations (mutually exclusive):
--list: Lists the entities that match the given specification, and prints out their configuration values.
--describe: Describes the effective quota values for an entity.
--alter: Alters the configuration for the given specification.

Entity specification flags (common to all):
--names: Comma-separated list of type=name pairs, e.g. --names=user=some-user,client-id=some-client-id
--defaults: Comma-separated list of entity types with the default name, e.g. defaults=user,client-id (Note a separate flag is necessary since names are opaque.)

Exclusive to --list:
--match: Comma-separated prefix=name pairs, e.g. --match=prefix=user

Exclusive to --describe:
--include-overrides: Whether to include overridden config entries.

Exclusive to --alter:
--add: Adds or updates a configuration entry to the given value. The unit must be specified.
--delete: Removes a configuration entry.
--validate-only: If set, validates the alteration but doesn't perform it.

TODO: Specify output.

...

config);

    /**
     * Returns a map from quota entity to a future which can be used to check the status of the operation.
     */
    public Map<QuotaEntity, KafkaFuture<Map<String, Value>>> config();

    /**
     * Returns a future which succeeds only if all quota descriptions succeed.
     */
    public KafkaFuture<Void> all();
}

public interface Admin extends AutoCloseable {
    ...

    /**
     * Resolves the effective quota values for the provided entities.
     *
     * @param entities the entities to describe the resolved quotas for
     * @param options the options to use
     * @return the resolved quotas for the entities
     */
    ResolveClientQuotasResult resolveClientQuotas(Collection<QuotaEntity> entities, ResolveClientQuotasOptions options);
}

AlterClientQuotas (2.6.0)

Code Block
languagejava
titleAlterQuotas
/**
 * Options for {@link Admin#alterClientQuotas(Collection, AlterClientQuotasOptions)}.
 *
 * The API of this class is evolving, see {@link Admin} for details.
 */
public class AlterClientQuotasOptions extends AbstractOptions<AlterClientQuotasOptions> {

    /**
     * Returns whether the request should be validated without altering the configs.
     */
    public boolean validateOnly();

    /**
     * Sets whether the request should be validated without altering the configs.
     */
    public AlterClientQuotasOptions validateOnly(boolean validateOnly);
}

/**
 * The result of the {@link Admin#alterClientQuotas(Collection, AlterClientQuotasOptions)} call.
 *
 * The API of this class is evolving, see {@link Admin} for details.
 */
@InterfaceStability.Evolving
public class AlterClientQuotasResult {

    /**
     * Maps an entity to its alteration result.
     *
     * @param futures maps entity to its alteration result
     */
    public AlterClientQuotasResult(Map<ClientQuotaEntity, KafkaFuture<Void>> futures);

    /**
     * Returns a map from quota entity to a future which can be used to check the status of the operation.
     */
    public Map<ClientQuotaEntity, KafkaFuture<Void>> values();

    /**
     * Returns a future which succeeds only if all quota alterations succeed.
     */
    public KafkaFuture<Void> all();
}

public interface Admin extends AutoCloseable {
    ...

    /**
     * Alters client quota configurations with the specified alterations.
     * <p>
     * Alterations for a single entity are atomic, but across entities is not guaranteed. The resulting
     * per-entity error code should be evaluated to resolve the success or failure of all updates.
     * <p>
     * The following exceptions can be anticipated when calling {@code get()} on the futures obtained from
     * the returned {@link AlterClientQuotasResult}:
     * <ul>
     *   <li>{@link org.apache.kafka.common.errors.ClusterAuthorizationException}
     *   If the authenticated user didn't have alter access to the cluster.</li>
     *   <li>{@link org.apache.kafka.common.errors.InvalidRequestException}
     *   If the request details are invalid. e.g., a configuration key was specified more than once for an entity.</li>
     *   <li>{@link org.apache.kafka.common.errors.TimeoutException}
     *   If the request timed out before the alterations could finish. It cannot be guaranteed whether the update
     *   succeed or not.</li>
     * </ul>
     * <p>
     * This operation is supported by brokers with version 2.6.0 or higher.
     *
     * @param entries the alterations to perform
     * @return the AlterClientQuotasResult containing the result
     */
    AlterClientQuotasResult alterClientQuotas(Collection<ClientQuotaAlteration> entries, AlterClientQuotasOptions options);
}

kafka-configs.sh/ConfigCommand (2.6.0)

As a result of introducing the APIs, the ConfigCommand will be updated to support the users and clients entity types when using the --bootstrap-server option.  The modification to ConfigCommand was adopted in KIP-543, and usage will remain unchanged from the original --zookeeper functionality.

kafka-client-quotas.sh/ClientQuotasCommand (pending future release)

A ClientQuotasCommand would be constructed with an associated bin/kafka-client-quotas.sh script for managing quotas via command line, and would have three modes of operation, roughly correlating to each of the API calls:

  1. Describe: Describes the quota entities for the given entity specification and their corresponding quota values, as explicitly specified in the configuration. The user may provide explicit entity types+names, or a pattern to apply to an entity type find matching entity names. If an entity type is omitted from the input, it is treated as a wildcard.
  2. Resolve: Resolves the effective quotas for an entity, including contextual information about how those quotas were derived. This includes what configuration entries matched to the entity.
  3. Alter: Modifies a quota configuration entry in an incremental manner, i.e. specify which entries to add, update, and/or remove.
Flags

Various flags will be used to accomplish these operations.

Common flags:
--bootstrap-server: The standard bootstrap server.
--command-config: Property file for the Admin client.

Operations (mutually exclusive):
--describe: Describes the entities that match the given specification, and prints out their configuration values.
--resolve: Resolves the effective quota values for an entity.
--alter: Alters the configuration for the given specification.

Entity specification flags (common to all):
--names: Comma-separated list of type=name pairs, e.g. "user=some-user,client-id=some-client-id"
--defaults: Comma-separated list of entity types with the default name, e.g. "defaults=user,client-id" (Note a separate flag is necessary since names are opaque.)

Exclusive to --describe: None.

Exclusive to --resolve: None.

Exclusive to --alter:
--add: Comma-separated list of entries to add or update to the configuration, in format "name=value".
--delete: Comma-separated list of entries to remove from the configuration, in format "name".
--validate-only: If set, validates the alteration but doesn't perform it.

Input

When specifying configuration entries, the form: quota-name[=quota-value] is used.

Output

In general, the output of the entities will be of the form: {entity-type=entity-name, ...}, where entity-name is sanitized for output since it is an opaque string. When displaying configuration values, the form: quota-name=quota-value.

Describe:

Code Block
$./bin/kafka-client-quotas.sh --bootstrap-server localhost:9092 --describe \
                              --names=client-id=my-client

{user=user-one, client-id=my-client}
consumer_byte_rate=4000000
producer_byte_rate=1000000

{user=user-two, client-id=my-client}
producer_byte_rate=2000000

{user=<default>, client-id=my-client}
consumer_byte_rate=1000000
producer_byte_rate=500000

Resolve:

Code Block
$./bin/kafka-client-quotas.sh --bootstrap-server localhost:9092 --resolve \
                              --names=user=user-two,client-id=my-client

consumer_byte_rate=2000000 {user=user-two, client-id=my-client}
producer_byte_rate=500000 {user=<default>, client-id=my-client}

Alter:

Code Block
$./bin/kafka-client-quotas.sh --bootstrap-server localhost:9092 --alter   \
                              --names=client-id=my-client --defaults=user \
                              --add=consumer_byte_rate=2000000            \
                              --delete=producer_byte_rate

<no output on success>

$./bin/kafka-client-quotas.sh --bootstrap-server localhost:9092 --describe \
                              --names=client-id=my-client --defaults=user

{user=<default>, client-id=my-client}
consumer_byte_rate=2000000

Proposed Changes

In addition to the API changes above, the following write protocol would be implemented:

DescribeClientQuotas (2.6.0)

Code Block
{
  "apiKey": 48,
  "type": "request",
  "name": "DescribeClientQuotasRequest",
  "validVersions": "0",
  "flexibleVersions": "none",
  "fields": [
    { "name": "Components", "type": "[]ComponentData", "versions": "0+",
      "about": "Filter components to apply to quota entities.", "fields": [
      { "name": "EntityType", "type": "string", "versions": "0+",
        "about": "The entity type that the filter component applies to." },
      { "name": "MatchType", "type": "int8", "versions": "0+",
        "about": "How to match the entity {0 = exact name, 1 = default name, 2 = any specified name}." },
      { "name": "Match", "type": "string", "versions": "0+", "nullableVersions": "0+",
        "about": "The string to match against, or null if unused for the match type." }
    ]},
    { "name": "Strict", "type": "bool", "versions": "0+",
      "about": "Whether the match is strict, i.e. should exclude entities with unspecified entity types." }
  ]
}

{
  "apiKey": 48,
  "type": "response",
  "name": "DescribeClientQuotasResponse",
  "validVersions": "0",
  "flexibleVersions": "none",
  "fields": [
    { "name": "ThrottleTimeMs", "type": "int32", "versions": "0+",
      "about": "The duration in milliseconds for which the request was throttled due to a quota violation, or zero if the request did not violate any quota." },
    { "name": "ErrorCode", "type": "int16", "versions": "0+",
      "about": "The error code, or `0` if the quota description succeeded." },
    { "name": "ErrorMessage", "type": "string", "versions": "0+", "nullableVersions": "0+",
      "about": "The error message, or `null` if the quota description succeeded." },
    { "name": "Entries", "type": "[]EntryData", "versions": "0+", "nullableVersions": "0+",
      "about": "A result entry.", "fields": [
      { "name": "Entity", "type": "[]EntityData", "versions": "0+",
        "about": "The quota entity description.", "fields": [
        { "name": "EntityType", "type": "string", "versions": "0+",
          "about": "The entity type." },
        { "name": "EntityName", "type": "string", "versions": "0+", "nullableVersions": "0+",
          "about": "The entity name, or null if the default." }
      ]},
      { "name": "Values", "type": "[]ValueData", "versions": "0+",
	"about": "The quota values for the entity.", "fields": [
        { "name": "Key", "type": "string", "versions": "0+",
          "about": "The quota configuration key." },
        { "name": "Value", "type": "float64", "versions": "0+",
          "about": "The quota configuration value." }
      ]}
    ]}
  ]
}

ResolveClientQuotas (pending future release)

In addition to the API changes above, the following write protocol would be implemented:

...

Code Block
{
  "apiKey": 4850,
  "type": "request",
  "name": "DescribeQuotasRequestResolveClientQuotasRequest",
  "validVersions": "0",
  "flexibleVersions": "none",
  "fields": [
    { "name": "FilterEntity", "type": "[]QuotaFilterDataQuotaEntityData", "versions": "0+",
      "about": "FiltersThe toquota apply to quota entitiesentity description.", "fields": [
      { "name": "EntityType", "type": "string", "versions": "0+",
        "about": "The entity type that the filter applies to." },
      { "name": "Rule", "type": "string", "versions": "0+",
        "about": "The rule the filter performs." },
      { "name": "MatchEntityName", "type": "string", "versions": "0+",
        "about": "The string to apply the rule againstentity name." }
    ]}
  ]
}

{
  "apiKey": 4850,
  "type": "response",
  "name": "DescribeQuotasResponseResolveClientQuotasResponse",
  "validVersions": "0",
  "flexibleVersions": "none",
  "fields": [
    { "name": "ThrottleTimeMs", "type": "int32", "versions": "0+",
      "about": "The duration in milliseconds for which the request was throttled due to a quota violation, or zero if the request did not violate any quota." },
    { "name": "Entry", "type": "[]EntryDataQuotaEntryData", "versions": "0+",
      "about": "AResolved resultquota entryentries.", "fields": [
      { "name": "ErrorCode", "type": "int16", "versions": "0+",
        "about": "The error code, or `0` if the resolved quota description succeeded." },
      { "name": "ErrorMessage", "type": "string", "versions": "0+", "nullableVersions": "0+",
        "about": "The error message, or `null` if the resolved quota description succeeded." },
      { "name": "EntityQuotaEntity", "type": "[]QuotaEntityDataQuotaEntity", "versions": "0+",
        "about": "TheResolved quota entity descriptionentries.", "fields": [
        { "name": "EntityType", "type": "string", "versions": "0+",
          "about": "The entity type." },
        { "name": "EntityName", "type": "string", "versions": "0+",
          "about": "The entity nametype." },
      ]},
      { "name": "TypeEntityName", "type": "string", "versions": "0+",
          "about": "The quotaentity typename." }
      ]},
      { "name": "UnitsQuotaValues", "type": "string[]QuotaValueData", "versions": "0+",
        "about": "TheQuota units for the value." },
configuration values.", "fields": [
        { "name": "ValueType", "type": "int64string", "versions": "0+",
          "about": "The quota valuetype." },
    ]}
  ]
}

DescribeEffectiveQuotas:

Code Block
{
  "apiKey": 49,
  "type{ "name": "requestEntry",
  "nametype": "DescribeEffectiveQuotasRequest[]ValueEntryData",
  "validVersionsversions": "0+",
          "flexibleVersionsabout": "noneQuota value entries.",
  "fields": [
          { "name": "EntityQuotaEntity", "type": "[]QuotaEntityDataValueQuotaEntity", "versions": "0+",
            "about": "TheResolved quota entity descriptionentries.", "fields": [
            { "name": "EntityType", "type": "string", "versions": "0+",
              "about": "The entity type." },
            { "name": "EntityName", "type": "string", "versions": "0+",
              "about": "The entity name." }
          ]},
          { "name": "OmitOverriddenValuesValue", "type": "booldouble", "versions": "0+",
            "about": "The quota configuration "Whether to exclude the list of overridden values for every quota type." value." }
        ]}
      ]}
    ]}
  ]
}

AlterClientQuotas (2.6.0)

Code Block

{
  "apiKey": 49,
  "type": "responserequest",
  "name": "DescribeEffectiveQuotasResponseAlterClientQuotasRequest",
  "validVersions": "0",
  "flexibleVersions": "none",
  "fields": [
    { "name": "ThrottleTimeMsEntries", "type": "int32[]EntryData", "versions": "0+",
      "about": "The duration in milliseconds for which the request was throttled due to a quota violation, or zero if the request did not violate any quota." },
 quota configuration entries to alter.", "fields": [
      { "name": "Entity", "type": "[]EntityData", "versions": "0+",
        "about": "The quota entity to alter.", "fields": [
        { "name": "EntryEntityType", "type": "[]QuotaEntryDatastring", "versions": "0+",
          "about": "EffectiveThe quotaentity entriestype." },
 "fields": [
      { "name": "ErrorCodeEntityName", "type": "int16string", "versions": "0+", "nullableVersions": "0+",
          "about": "The error codename of the entity, or `0`null if the effective quota description succeeded." default." }
      ]},
      { "name": "ErrorMessageOps", "type": "string[]OpData", "versions": "0+", "nullableVersions": "0+",
        "about": "TheAn errorindividual message,quota orconfiguration `null`entry if the effective quota description succeeded." },
to alter.", "fields": [
        { "name": "QuotaEntityKey", "type": "[]QuotaEntitystring", "versions": "0+",
          "about": "EffectiveThe quota entriesconfiguration key.", "fields": [ },
        { "name": "EntityTypeValue", "type": "stringfloat64", "versions": "0+",
          "about": "The entity type value to set, otherwise ignored if the value is to be removed." },
        { "name": "EntityNameRemove", "type": "stringbool", "versions": "0+",
          "about": "The entity nameWhether the quota configuration value should be removed, otherwise set." }
      ]},
    ]},
    { "name": "QuotaValuesValidateOnly", "type": "[]QuotaValueDatabool", "versions": "0+",
        "about": "Quota configuration values.", "fields": [
        { "nameWhether the alteration should be validated, but not performed." }
  ]
}

{
  "apiKey": 49,
  "type": "Typeresponse",
  "typename": "stringAlterClientQuotasResponse",
  "versionsvalidVersions": "0+",
          "aboutflexibleVersions": "The quota type." }none",
  "fields": [
     { "name": "UnitsThrottleTimeMs", "type": "stringint32", "versions": "0+",
          "about": "The unitsduration in milliseconds for which the request was throttled due to a quota type violation, or zero if the request did not violate any quota." },
        { "name": "EntryEntries", "type": "[]ValueEntryDataEntryData", "versions": "0+",
          "about": "QuotaThe quota valueconfiguration entries to alter.", "fields": [
          { "name": "QuotaEntityErrorCode", "type": "[]ValueQuotaEntityint16", "versions": "0+",
            "about": "EffectiveThe quotaerror entries."code, "fields": [
      or `0` if the quota alteration succeeded." },
      { "name": "EntityTypeErrorMessage", "type": "string", "versions": "0+",
      "nullableVersions": "0+",
        "about": "The error entity type." },
      message, or `null` if the quota alteration succeeded." },
      { "name": "EntityNameEntity", "type": "string[]EntityData", "versions": "0+",
              "about": "The quota entity nameto alter." }
          ]},
 , "fields": [
         { "name": "ValueEntityType", "type": "int64string", "versions": "0+",
            "about": "The quotaentity configuration valuetype." },
        ]}
      ]}
    ]}
  ]
}

AlterQuotas:

Code Block
{
  "apiKeyname": 50"EntityName",
  "type": "requeststring",
  "nameversions": "AlterQuotasRequest0+",
  "validVersionsnullableVersions": "0+",
  "flexibleVersions        "about": "none",
  "fields": [
    { "name": "Entry", "type": "[]EntryData", "versions": "0+",The name of the entity, or null if the default." }
      ]}
      "about": "The quota configuration entries to alter.", "fields": [
      { "name": "QuotaEntity", "type": "[]QuotaEntity", "versions": "0+",]}
  ]
}

Kafka RPC 'double' support (2.6.0)

Note that, while the ByteBuffer natively supports serializing a Double, the format in which the value is serialized is not strongly specified, so the preference is to explicitly ensure a standard representation of double-precision 64-bit IEEE 754 format. This is achieved in Java using Double.doubleToRawLongBits() and Double.longBitsToDouble() and should be easily portable to other languages.

Code Block
titleclients/src/main/java/org/apache/kafka/common/utils/ByteUtils.java
    /**
     * Read  "about": "The quota entity to alter.", "fields": [a double-precision 64-bit format IEEE 754 value.
     *
   { "name": "EntityType", "type": "string", "versions": "0+",
    * @param buffer The buffer to read from
     * @return "about": "The entitylong type." },value read
     */
   { "name": "EntityName", "type": "string", "versions": "0+",public static double readDouble(ByteBuffer buffer) {
        return  "about": "The name of the entity." }
Double.longBitsToDouble(buffer.getLong());
    }

    /**
     * Write ]},
the given double following the  { "name": "Op", "type": "[]OpData", "versions": "0+",
double-precision 64-bit format IEEE 754 value into the buffer.
     *
    "about": "An individual quota configuration entry to alter.", "fields": [
        { "name": "Type", "type": "string", "versions": "0+", * @param value The value to write
     * @param buffer The buffer to write to
     */
    public static void writeDouble(double value,  "about": "The quota type." },ByteBuffer buffer) {
        buffer.putLong(Double.doubleToRawLongBits(value));
    }

The protocol type definition:

Code Block
titleclients/src/main/java/org/apache/kafka/common/protocol/types/Type.java
    { "name": "Units", "type": "string", "versions": "0+",
  public static final DocumentedType DOUBLE = new DocumentedType() {
        "about": "The units for the quota type." },
        { "name": "Value", "type": "int64", "versions": "0+",
@Override
        public void write(ByteBuffer buffer, Object o) {
            ByteUtils.writeDouble((Double) o, buffer);
  "about": "The value to set, otherwise ignored}

 if the value is to be removed." },@Override
        { "name": "Remove", "type": "bool", "versions": "0+",public Object read(ByteBuffer buffer) {
          "about": "Whether the quota configuration value should be removed, otherwise set."return ByteUtils.readDouble(buffer);
        }

      ]}
  @Override
  ]},
    { "name": "ValidateOnly", "type": "bool", "versions": "0+", public int sizeOf(Object o) {
      "about": "Whether the alteration should be validated, but not performed." }return 8;
  ]
}

{
  "apiKey": 50,
  "type": "response", }

  "name": "AlterQuotasResponse",
  "validVersions": "0",
  "flexibleVersions": "none",
  "fields": [
    { "name": "ThrottleTimeMs", "type": "int32", "versions": "0+",
      @Override
        public String typeName() {
            return "about": "The duration in milliseconds for which the request was throttled due to a quota violation, or zero if the request did not violate any quota." },
    { "name": "Entry", "type": "[]EntryData", "versions": "0+",
DOUBLE";
        }

        @Override
        public Double validate(Object item) {
             "about": "The quota configuration entries to alter.", "fields": [
if (item instanceof Double)
            { "name": "ErrorCode", "type": "int16", "versions": "0+", return (Double) item;
        "about": "The error code, orelse
 `0` if the quota alteration succeeded." },
      { "name": "ErrorMessage", "type": "string", "versions": "0+", "nullableVersions": "0+", throw new SchemaException(item + " is not a Double.");
        "about": "The error message, or `null` if the quota alteration succeeded." },
      { "name": "QuotaEntity", "type": "[]QuotaEntity", "versions": "0+",
}

        @Override
        public String documentation() {
            return "Represents  "about": "The quota entity to alter.", "fields": [
a double-precision 64-bit format IEEE 754 value. " +
         { "name": "EntityType", "type": "string", "versions": "0+",
          "about": "The entity type." },           "The values are encoded using eight bytes in network byte order (big-endian).";
        { "name": "EntityName", "type": "string", "versions": "0+",
          "about": "The name of the entity." }
      ]}
    ]}
  ]
}

kafka-configs.sh/ConfigCommand:

The ConfigCommand would be modified to extend its current quotas functionality to support the --bootstrap-server flag.

}
    };


In generator/src/main/java/org/apache/kafka/message/MessageGenerator.java, the following operations will be used (code omitted for brevity):

Code Block
titlegenerator/src/main/java/org/apache/kafka/message/MessageGenerator.java
Hash code: Double.hashCode(value)

Empty value: (double) 0

Parsing a default value string: Double.parseDouble(defaultValue)

Compatibility, Deprecation, and Migration Plan

All changes would be are forward-compatible, and no migration plan is necessary. It's outside the scope of this KIP to deprecate any functionality.

Rejected Alternatives

  • Use existing describeConfigs/incrementalAlterConfigs for quota functionality. This falls short for a couple reasons. First, quotas entity names are more dynamic than brokers and tasks which makes them awkward to fit into generic tools which expect a single unique, distinct key, e.g. ConfigCommand. Second, there's no tool that expresses a way to get the effective quota resolved quota for an entity without some heavy engineering on the client side, which lacks extensibility and is more expensive to perform, especially over large collection of entities. Therefore, it makes sense to approach quotas as a standalone set of APIs that provide more targeted information and can properly support future extensibility.

...