Introduction

The CDAP 4.0 UI is designed to provide operational insights about both - CDAP services as well as other service providers such as YARN, HBase and HDFS. The CDAP platform will need to expose additional APIs to surface this information.

Goals

The operational APIs should surface information for the Management Screen

These designs translate into the following requirements:

CDAP Uptime
- P1: Should indicate the time (number of hours, days?) for which the CDAP Master process has been running.
- P2: In an HA environment, it would be nice to indicate the time of the last master failover.
CDAP System Services:
- P1: Should indicate the current number of instances.
- P1: Should have a way to scale services.
- P1: Should show service logs
- P2: Node name where container started
- P2: Container name
- P2: master.services YARN application name
Middle Drawer:
- CDAP:
  - P1* (Stretch goal - only possible if there's a straightforward approach): # of masters, routers, kafka-servers, auth-servers
  - P1: Router requests - # 200s, 404s, 500s
  - P1: # namespaces, artifacts, apps, programs, datasets, streams, views
  - P1: Transaction snapshot summary (invalid, in-progress, committing, committed)
  - P1: Logs/Metrics service lags
  - P2: Last GC pause time
- HDFS:
  - P1: Space metrics: total, free, used
  - P1: Nodes: total, healthy, decommissioned, decommissionInProgress
  - P1: Blocks: missing, corrupt, under-replicated
- YARN:
  - P1: Nodes: total, new, running, unhealthy, decommissioned, lost, rebooted
  - P1: Apps: total, submitted, accepted, running, failed, killed, new, new_saving
  - P1: Memory: total, used, free
  - P1: Virtual Cores: total, used, free
  - P1: Queues: total, stopped, running, max_capacity, current_capacity
- HBase
  - P1: Nodes: total_regionservers, live_regionservers, dead_regionservers, masters
  - P1: No. of namespaces, tables
  - P2: Last major compaction (time + info)
- Zookeeper: Most of these are from the output of echo mntr | nc localhost 2181
  - P2: Num of alive connections
  - P2: Num of znodes
  - P2: Num of watches
  - P2: Num of ephemeral nodes
  - P2: Data size
  - P2: Open file descriptor count
  - P2: Max file descriptor count
- Kafka
  - JMX Metrics that Kafka exposes: https://kafka.apache.org/documentation#monitoring
  - P2: # of topics
  - P2: Message in rate
  - P2: Request rate
  - P2: # of under replicated partitions
  - P2: Partition counts
- Sentry
  - P2: # of roles
  - P2: # of privileges
  - P2: memory: total, used, available
  - P2: requests per second
  - any more?
- KMS
  - TBD: Having a hard time hitting the JMX endpoint for KMS
Component Overview
- P1: YARN, HDFS, HBase
- P1: For each component: version, url, logs_url
- P2: Zoookeeper, Kafka, Hive
- P2: Sentry, KMS
- P2: Distribution info
- P2: Plus button - to store custom components and version, url, logs_url for each.

User Stories

As a CDAP admin, I would like a single place to perform health checks and monitoring for CDAP system services as well as service providers that CDAP depends upon.
As a CDAP admin, I would like to have insights into the health of all CDAP system services including master, log saver, explore container, metrics processor, metrics, streams, transaction server and dataset executor
As a CDAP admin, I would like to know information about my CDAP setup including the version of CDAP
As a CDAP admin, I would like to know the uptime of CDAP including optionally the time since the last failover in an HA scenario
As a CDAP admin, I would like to know the versions and (optionally) links to the web UI and logs if available of the underlying infrastructure components.
As a CDAP admin, I would like to have operational insights including stats such as request rate, node status, available compute as well as storage capacity for the underlying infrastructure components that CDAP relies upon. These insights should help me understand the health of these components as well as help in root cause analysis in case CDAP fails or performs poorly.

Design

Data Sources

Versions

CDAP - co.cask.cdap.common.utils.ProjectInfo
HBase - co.cask.cdap.data2.util.hbase.HBaseVersion
YARN - org.apache.hadoop.yarn.util.YarnVersionInfo
HDFS - org.apache.hadoop.util.VersionInfo
Zookeeper - No client API available. Will have to build a utility around echo stat | nc localhost 2181
Hive - org.apache.hive.common.util.HiveVersionInfo

URL

CDAP - $(dashboard.bind.address) + $(dashboard.bind.port)
YARN - $(yarn.resourcemanager.webapp.address)
HDFS - $(dfs.namenode.http-address)
HBase - hbaseAdmin.getClusterStatus().getMaster().toString()

HDFS

DistributedFileSystem - For HDFS stats

YARN

YarnClient - for YARN stats and info

HBase

HBaseAdmin - for HBase stats and info

Kafka

JMX

Reference: https://github.com/linkedin/kafka-monitor

Zookeeper

Option 1: Four letter commands - mntr. Drawbacks: mntr was introduced in 3.5.0 - users may be running older versions of Zookeeper

Option 2: Zookeeper also exposes JMX - https://zookeeper.apache.org/doc/trunk/zookeeperJMX.html

HiveServer2

TBD

Sentry

JMX

The following is available by enabling the sentry web service (ref: http://www.cloudera.com/documentation/enterprise/latest/topics/sg_sentry_metrics.html) and querying for metrics (API: http://[sentry-service-host]:51000/metrics?pretty=true).

Sentry JMX output

{
  "version" : "3.0.0",
  "gauges" : {
    "buffers.direct.capacity" : {
      "value" : 57344
    },
    "buffers.direct.count" : {
      "value" : 5
    },
    "buffers.direct.used" : {
      "value" : 57344
    },
    "buffers.mapped.capacity" : {
      "value" : 0
    },
    "buffers.mapped.count" : {
      "value" : 0
    },
    "buffers.mapped.used" : {
      "value" : 0
    },
    "gc.PS-MarkSweep.count" : {
      "value" : 0
    },
    "gc.PS-MarkSweep.time" : {
      "value" : 0
    },
    "gc.PS-Scavenge.count" : {
      "value" : 2
    },
    "gc.PS-Scavenge.time" : {
      "value" : 26
    },
    "memory.heap.committed" : {
      "value" : 1029701632
    },
    "memory.heap.init" : {
      "value" : 1073741824
    },
    "memory.heap.max" : {
      "value" : 1029701632
    },
    "memory.heap.usage" : {
      "value" : 0.17999917863585554
    },
    "memory.heap.used" : {
      "value" : 185345448
    },
    "memory.non-heap.committed" : {
      "value" : 31391744
    },
    "memory.non-heap.init" : {
      "value" : 24576000
    },
    "memory.non-heap.max" : {
      "value" : 136314880
    },
    "memory.non-heap.usage" : {
      "value" : 0.2187954829289363
    },
    "memory.non-heap.used" : {
      "value" : 29825080
    },
    "memory.pools.Code-Cache.usage" : {
      "value" : 0.029324849446614582
    },
    "memory.pools.PS-Eden-Space.usage" : {
      "value" : 0.6523454156767787
    },
    "memory.pools.PS-Old-Gen.usage" : {
      "value" : 1.1440740671897877E-4
    },
    "memory.pools.PS-Perm-Gen.usage" : {
      "value" : 0.32970512204053926
    },
    "memory.pools.PS-Survivor-Space.usage" : {
      "value" : 0.22010480095358456
    },
    "memory.total.committed" : {
      "value" : 1061093376
    },
    "memory.total.init" : {
      "value" : 1098317824
    },
    "memory.total.max" : {
      "value" : 1166016512
    },
    "memory.total.used" : {
      "value" : 215170528
    },
    "org.apache.sentry.provider.db.service.persistent.SentryStore.group_count" : {
      "value" : 3
    },
    "org.apache.sentry.provider.db.service.persistent.SentryStore.privilege_count" : {
      "value" : 0
    },
    "org.apache.sentry.provider.db.service.persistent.SentryStore.role_count" : {
      "value" : 132
    },
    "threads.blocked.count" : {
      "value" : 1
    },
    "threads.count" : {
      "value" : 38
    },
    "threads.daemon.count" : {
      "value" : 27
    },
    "threads.deadlocks" : {
      "value" : [ ]
    },
    "threads.new.count" : {
      "value" : 0
    },
    "threads.runnable.count" : {
      "value" : 6
    },
    "threads.terminated.count" : {
      "value" : 0
    },
    "threads.timed_waiting.count" : {
      "value" : 8
    },
    "threads.waiting.count" : {
      "value" : 23
    }
  },
  "counters" : { },
  "histograms" : { },
  "meters" : { },
  "timers" : {
    "org.apache.sentry.provider.db.service.thrift.SentryPolicyStoreProcessor.create-role" : {
      "count" : 0,
      "max" : 0.0,
      "mean" : 0.0,
      "min" : 0.0,
      "p50" : 0.0,
      "p75" : 0.0,
      "p95" : 0.0,
      "p98" : 0.0,
      "p99" : 0.0,
      "p999" : 0.0,
      "stddev" : 0.0,
      "m15_rate" : 0.0,
      "m1_rate" : 0.0,
      "m5_rate" : 0.0,
      "mean_rate" : 0.0,
      "duration_units" : "seconds",
      "rate_units" : "calls/second"
    },
    "org.apache.sentry.provider.db.service.thrift.SentryPolicyStoreProcessor.drop-privilege" : {
      "count" : 0,
      "max" : 0.0,
      "mean" : 0.0,
      "min" : 0.0,
      "p50" : 0.0,
      "p75" : 0.0,
      "p95" : 0.0,
      "p98" : 0.0,
      "p99" : 0.0,
      "p999" : 0.0,
      "stddev" : 0.0,
      "m15_rate" : 0.0,
      "m1_rate" : 0.0,
      "m5_rate" : 0.0,
      "mean_rate" : 0.0,
      "duration_units" : "seconds",
      "rate_units" : "calls/second"
    },
    "org.apache.sentry.provider.db.service.thrift.SentryPolicyStoreProcessor.drop-role" : {
      "count" : 0,
      "max" : 0.0,
      "mean" : 0.0,
      "min" : 0.0,
      "p50" : 0.0,
      "p75" : 0.0,
      "p95" : 0.0,
      "p98" : 0.0,
      "p99" : 0.0,
      "p999" : 0.0,
      "stddev" : 0.0,
      "m15_rate" : 0.0,
      "m1_rate" : 0.0,
      "m5_rate" : 0.0,
      "mean_rate" : 0.0,
      "duration_units" : "seconds",
      "rate_units" : "calls/second"
    },
    "org.apache.sentry.provider.db.service.thrift.SentryPolicyStoreProcessor.grant-privilege" : {
      "count" : 0,
      "max" : 0.0,
      "mean" : 0.0,
      "min" : 0.0,
      "p50" : 0.0,
      "p75" : 0.0,
      "p95" : 0.0,
      "p98" : 0.0,
      "p99" : 0.0,
      "p999" : 0.0,
      "stddev" : 0.0,
      "m15_rate" : 0.0,
      "m1_rate" : 0.0,
      "m5_rate" : 0.0,
      "mean_rate" : 0.0,
      "duration_units" : "seconds",
      "rate_units" : "calls/second"
    },
    "org.apache.sentry.provider.db.service.thrift.SentryPolicyStoreProcessor.grant-role" : {
      "count" : 0,
      "max" : 0.0,
      "mean" : 0.0,
      "min" : 0.0,
      "p50" : 0.0,
      "p75" : 0.0,
      "p95" : 0.0,
      "p98" : 0.0,
      "p99" : 0.0,
      "p999" : 0.0,
      "stddev" : 0.0,
      "m15_rate" : 0.0,
      "m1_rate" : 0.0,
      "m5_rate" : 0.0,
      "mean_rate" : 0.0,
      "duration_units" : "seconds",
      "rate_units" : "calls/second"
    },
    "org.apache.sentry.provider.db.service.thrift.SentryPolicyStoreProcessor.list-privileges-by-authorizable" : {
      "count" : 0,
      "max" : 0.0,
      "mean" : 0.0,
      "min" : 0.0,
      "p50" : 0.0,
      "p75" : 0.0,
      "p95" : 0.0,
      "p98" : 0.0,
      "p99" : 0.0,
      "p999" : 0.0,
      "stddev" : 0.0,
      "m15_rate" : 0.0,
      "m1_rate" : 0.0,
      "m5_rate" : 0.0,
      "mean_rate" : 0.0,
      "duration_units" : "seconds",
      "rate_units" : "calls/second"
    },
    "org.apache.sentry.provider.db.service.thrift.SentryPolicyStoreProcessor.list-privileges-by-role" : {
      "count" : 0,
      "max" : 0.0,
      "mean" : 0.0,
      "min" : 0.0,
      "p50" : 0.0,
      "p75" : 0.0,
      "p95" : 0.0,
      "p98" : 0.0,
      "p99" : 0.0,
      "p999" : 0.0,
      "stddev" : 0.0,
      "m15_rate" : 0.0,
      "m1_rate" : 0.0,
      "m5_rate" : 0.0,
      "mean_rate" : 0.0,
      "duration_units" : "seconds",
      "rate_units" : "calls/second"
    },
    "org.apache.sentry.provider.db.service.thrift.SentryPolicyStoreProcessor.list-privileges-for-provider" : {
      "count" : 0,
      "max" : 0.0,
      "mean" : 0.0,
      "min" : 0.0,
      "p50" : 0.0,
      "p75" : 0.0,
      "p95" : 0.0,
      "p98" : 0.0,
      "p99" : 0.0,
      "p999" : 0.0,
      "stddev" : 0.0,
      "m15_rate" : 0.0,
      "m1_rate" : 0.0,
      "m5_rate" : 0.0,
      "mean_rate" : 0.0,
      "duration_units" : "seconds",
      "rate_units" : "calls/second"
    },
    "org.apache.sentry.provider.db.service.thrift.SentryPolicyStoreProcessor.list-roles-by-group" : {
      "count" : 0,
      "max" : 0.0,
      "mean" : 0.0,
      "min" : 0.0,
      "p50" : 0.0,
      "p75" : 0.0,
      "p95" : 0.0,
      "p98" : 0.0,
      "p99" : 0.0,
      "p999" : 0.0,
      "stddev" : 0.0,
      "m15_rate" : 0.0,
      "m1_rate" : 0.0,
      "m5_rate" : 0.0,
      "mean_rate" : 0.0,
      "duration_units" : "seconds",
      "rate_units" : "calls/second"
    },
    "org.apache.sentry.provider.db.service.thrift.SentryPolicyStoreProcessor.rename-privilege" : {
      "count" : 0,
      "max" : 0.0,
      "mean" : 0.0,
      "min" : 0.0,
      "p50" : 0.0,
      "p75" : 0.0,
      "p95" : 0.0,
      "p98" : 0.0,
      "p99" : 0.0,
      "p999" : 0.0,
      "stddev" : 0.0,
      "m15_rate" : 0.0,
      "m1_rate" : 0.0,
      "m5_rate" : 0.0,
      "mean_rate" : 0.0,
      "duration_units" : "seconds",
      "rate_units" : "calls/second"
    },
    "org.apache.sentry.provider.db.service.thrift.SentryPolicyStoreProcessor.revoke-privilege" : {
      "count" : 0,
      "max" : 0.0,
      "mean" : 0.0,
      "min" : 0.0,
      "p50" : 0.0,
      "p75" : 0.0,
      "p95" : 0.0,
      "p98" : 0.0,
      "p99" : 0.0,
      "p999" : 0.0,
      "stddev" : 0.0,
      "m15_rate" : 0.0,
      "m1_rate" : 0.0,
      "m5_rate" : 0.0,
      "mean_rate" : 0.0,
      "duration_units" : "seconds",
      "rate_units" : "calls/second"
    },
    "org.apache.sentry.provider.db.service.thrift.SentryPolicyStoreProcessor.revoke-role" : {
      "count" : 0,
      "max" : 0.0,
      "mean" : 0.0,
      "min" : 0.0,
      "p50" : 0.0,
      "p75" : 0.0,
      "p95" : 0.0,
      "p98" : 0.0,
      "p99" : 0.0,
      "p999" : 0.0,
      "stddev" : 0.0,
      "m15_rate" : 0.0,
      "m1_rate" : 0.0,
      "m5_rate" : 0.0,
      "mean_rate" : 0.0,
      "duration_units" : "seconds",
      "rate_units" : "calls/second"
    }
  }
}

KMS

KMS also exposes JMX via the endpoint http://host:16000/kms/jmx.

Implementation

Operational Stats Extensions

The service provider stats fetchers will be implemented as extensions. Each such extension will be installed by CDAP in the master/ext/operations directory as jar files. Each jar file in this directory will be scanned for implementations of the OperationalStats interface defined below.

/**
 * Interface for all operational stats emitted using the operational stats extension framework.
 *
 * To emit stats using this framework, create JMX {@link MXBean} interfaces, then have the implementations of those
 * interfaces extend this class. At runtime, all sub-classes of this class will be registered with the
 * {@link MBeanServer} with the <i>name</i> property determined by {@link #getServiceName()} and the <i>type</i>
 * property determined by {@link #getStatType()}.
 */
public interface OperationalStats {
  /**
   * Returns the service name for which this operational stat is emitted. Service names are case-insensitive, and will
   * be converted to lower case.
   */
  String getServiceName();

  /**
   * Returns the type of the stat. Stat types are case-insensitive, and will be converted to lower case.
   */
  String getStatType();

  /**
   * Collects the stats that are reported by this object.
   */
  void collect() throws IOException;
}

There will be one implementation of this interface for every service provider and stat type.
For example, HDFSStorage can be an implementation that provides stats of type "storage" for the service provider HDFS.
A single jar file may contain multiple implementations of this interface.
These classes will be loaded in a separate classloader, but there will not be classloader isolation, so extensions will have classes from the CDAP classloader available.
CDAP will provide a core extension installed at master/ext/operations/core/cdap-operations-extensions-core.jar which will contain stats for some standard service providers. Additional services can be configured by implementing OperationalStats for the service, and placing the jar file under master/ext/operations/

Collecting and reporting stats

For collecting and reporting OperationalStats, the JMX API will be used. Hence, in addition to implementing the OperationalStats interface so it can be recognized as an operational extension, each implementation should also define and implement a Java MXBean interface.

After loading an operational stats extension, the MXBean it implements will be registered with the MBeanServer using the property name set to the value returned from getServiceName and type set to the value returned from getStatType. These properties can then be used to create an ObjectName to retrieve the stats from JMX.

TODO: CDAP Master Uptime?

Caching

The collect method of every operational stats extension will be called at a configurable time interval, and is expected to refresh its stats. A call to an accessor method in the MXBean will simply return the current value cached inside the class.

API changes

New REST APIs

The following REST APIs will be exposed from app fabric.

Path

Method

Description

Response Code

Response

/v3/system/serviceproviders

GET

Lists all the available service providers and (optionally) minimal info about each (version, url and logs_url)

200 - On success

500 - Any internal errors

List Service Providers Response

{
  "hdfs": {
    "version": "2.7.0",
    "url": "http://localhost:50070",
    "url": "http://localhost:50070/logs/"
  },
  "yarn": {
    "version": "2.7.0",
    "url": "http://localhost:8088",
    "logs": "http://localhost:8088/logs/"
  },
  "hbase": {
    "version": "1.0.0",
    "url": "http://localhost:50070",
    "logs": "http://localhost:60010/logs/"
  },
  "hive": {
    "version": 1.2
  },
  "zookeeper": {
    "version": "3.4.2"
  },
  "kafka": {
    "version": "2.10"
  }
}

/v3/system/serviceproviders/{service-provider-name}/stats

GET

Returns stats for the specified service provider

200 OK - stats for the specified service provider were successfully fetched

503 Unavailable - Could not contact the service provider for status

404 Not found - Service provider not found (not in the list returned by the list service providers API)

500 - Any other internal errors

CDAP Stats Response

{
    "services": {
      "masters": 2,
      "kafka-servers": 2,
      "routers": 1,
      "auth-servers": 1
    },
    "entities": {
      "namespaces": 10,
      "apps": 46,
      "artifacts": 23,
      "datasets": 68,
      "streams": 34,
      "programs": 78
    }
}

HDFS Stats Response

{
    "storage": {
      "total": 3452759234,
      "used": 34525543,
      "available": 3443555345
    },
    "nodes": {
      "total": 40,
      "healthy": 36,
      "decommissioned": 3,
      "decommissionInProgress": 1
    },
    "blocks": {
      "missing": 33,
      "corrupt": 3,
      "underreplicated": 5
    }
}

YARN Stats Response

{
    "nodes": {
      "total": 35,
      "new": 0,
      "running": 30,
      "unhealthy": 1,
      "decommissioned": 2,
      "lost": 1,
      "rebooted": 1
    },
    "apps": {
      "total": 30,
      "submitted": 2,
      "accepted": 4,
      "running": 20,
      "failed": 1,
      "killed": 3,
      "new": 0,
      "new_saving": 0
    },
    "memory": {
      "total": 8192,
      "used": 7168,
      "available": 1024
    },
    "virtualCores": {
      "total": 36,
      "used": 12,
      "available": 24
    },
    "queues": {
      "total": 10,
      "stopped": 2,
      "running": 8,
      "maxCapacity": 32,
      "currentCapacity": 21
    }
}

HBase Stats Response

{
    "nodes": {
      "totalRegionServers": 37,
      "liveRegionServers": 34,
      "deadRegionServers": 3,
      "masters": 3
    },
    "entities": {
      "tables": 56,
      "namespaces": 43
    }
}

TODO: Add responses for Kafka, Zookeeper, Sentry, KMS

CLI Impact or Changes

New CLI commands will have to be added to front the two new APIs.

List Service Providers

list service providers

Get Service Provider Stats

get stats for service provider <service-provider>

UI Impact or Changes

The Management screen on the CDAP 4.0 UI will have to be implemented using the APIs exposed by this design in addition to existing APIs for getting System Service Status and Logs

Security Impact

Currently CDAP does not enforce authorization for the system services APIs -

Error rendering macro 'jira' : Unable to locate Jira server for this macro. It may be due to Application Link configuration.

. The APIs in this design should enforce the same authorization policies as will be implemented for the system services APIs. Ideally, only users that have ADMIN privileges on the CDAP instance should be able to execute these APIs successfully.

Impact on Infrastructure Outages

Test Scenarios

Test ID	Test Description	Expected Results
T1	Positive test for list API	Should return all the configured service providers
T2	Positive test for stats of each service provider	Should return the appropriate details for each service provider
T3	Stop a configured storage provider and hit the API to get its stats	Should return 503 with a proper error message
T4	Hit the API to get stats of a non-existent API	Should return 404 with a proper error message

Releases

Release 4.0.0

Ground work for collecting stats from infrastructure components.
Focus on HDFS, YARN, HBase

Release 4.1.0

More components such as Hive, Kafka, Zookeeper, Sentry, KMS (in that order).

Related Work

Monitor APIs

Future work

TBD