This page shows how to use Helm to operate Hive on MR3 on Kubernetes with multiple nodes. By following the instruction, the user will learn:

  1. how to start Metastore
  2. how to run Hive on MR3

This scenario has the following prerequisites:

  1. A running Kubernetes cluster is available, and the user should be able to execute command helm to use Helm.
  2. A database server for Metastore is running.
  3. Either HDFS or S3 (or S3-compatible storage) is available for storing the warehouse. For using S3, access credentials are required.
  4. The user can either create a PersistentVolume or store transient data on HDFS or S3.
  5. Every worker node has an identical set of local directories for storing intermediate data (to be mapped to hostPath volumes). These directories should be writable to the user with UID 1000 because all containers run as non-root user with UID 1000.
  6. The user can run Beeline to connect to HiveServer2 running at a given address.

We use a pre-built Docker image mr3project/hive3:1.5 available at DockerHub, so the user does not have to build a new Docker image. In our example, we use a MySQL server for Metastore, but Postgres and MS SQL are also okay.

This scenario should take less than 30 minutes to complete, not including the time for downloading a pre-built Docker image. We use Helm 2.16.9.

This page has been tested with MR3 release 1.5 and Kubernetes 1.17.0.
For asking questions, please visit MR3 Google Group.

Installation

Download an MR3 release containing the executable scripts.

$ git clone https://github.com/mr3project/mr3-run-k8s.git
$ cd mr3-run-k8s/kubernetes/
# git reset --hard 9cf574369d8c9f21cc6ebf0fc06606f24f0a858e

Linking configuration files

We will reuse the configuration files in conf/ (and keys in key if Kerberos is used for authentication). Create symbolic links.

$ mkdir -p key
$ ln -s $(pwd)/conf/ helm/hive/conf
$ ln -s $(pwd)/key/ helm/hive/key

Now any change to the configuration files in conf/ is honored when running Hive on MR3.

For configuring Hive on MR3, we create a new file values-test.yaml which is a collection of values to override those in helm/hive/values.yaml.

Overview on Hive on MR3 and storage

Hive on MR3 uses the following components:

  • Metastore
  • HiveServer2
  • MR3 DAGAppMaster
  • MR3 ContainerWorkers

Hive on MR3 requires three types of storage:

  • Data source such as HDFS or S3
  • PersistentVolume (or HDFS/S3) for storing transient data
  • hostPath volumes for storing intermediate data in ContainerWorker Pods

hive.k8s.volume.setup.png

The hostPath volumes are created and mounted by MR3 at runtime for each ContainerWorker Pod. These hostPath volumes hold intermediate data to be shuffled (by shuffle handlers) between ContainerWorker Pods. In order to be able to create the same set of hostPath volumes for every ContainerWorker Pod, an identical set of local directories should be ready in all worker nodes (where ContainerWorker Pods are created).

Configuring Metastore

Open values-test.yaml and set the following fields for Metastore.

  • Set databaseHost to the IP address of the MySQL server for Metastore. In our example, the MySQL server is running at the IP address 192.168.10.1.
  • Set databaseName to the database name for Metastore in the MySQL server.
  • Set warehouseDir to the HDFS directory or the S3 bucket storing the warehouse (e.g., hdfs://hdfs.server:8020/hive/warehouse or s3a://hivemr3/hive/warehouse). Note that for using S3, we should use prefix s3a, not s3.
  • Set dbType to the database type for Metastore which is used as an argument to schematool (mysql for MYSQL, postgres for Postgres, mssql for MS SQL).
$ vi values-test.yaml

metastore:
  databaseHost: "192.168.10.1"
  databaseName: hive3mr3
  warehouseDir: s3a://hivemr3/warehouse
  dbType: mysql

Setting host aliases (optional)

To use host names (instead of IP addresses) when configuring Hive on MR3, the user should update:

  1. hostAliases field in values-test.yaml
  2. configuration key mr3.k8s.host.aliases in conf/mr3-site.xml

For example, if metastore/databaseHost or metastore/warehouseDir in values-test.yaml uses a host name called orange0 with IP address 192.168.10.101, update as follows:

$ vi values-test.yaml

hostAliases:
- ip: "192.168.10.101"
  hostnames:
  - "orange0"
$ vi conf/mr3-site.xml

<property>
  <name>mr3.k8s.host.aliases</name>
  <value>orange0=192.168.10.101</value>
</property>

Directory for storing transient data

The user can use either a PersistentVolume or HDFS/S3 to store transient data. For using a PersistentVoume, follow the instruction in 1. Creating and mounting PersistentVolume. For using HDFS/S3, follow the instruction in 2. Using HDFS/S3.

For running Hive on MR3 in production, using PersistentVolume is recommended.

1. Creating and mounting PersistentVolume

The workDir fields in values-test.yaml specify how to create a PersistentVolume. In our example, we use an NFS volume by setting workDir.isNfs to true. The NFS server runs at 192.168.10.1, uses a directory /home/nfs/hivemr3, and allows up to 100GB of disk space. We also specify the size of the storage to be used by Hive on MR3 in workDir.volumeClaimSize.

$ vi values-test.yaml

workDir:
  create: true
  isNfs: true
  nfs:
    server: "192.168.10.1"
    path: "/home/nfs/hivemr3"
  volumeSize: 100Gi
  volumeClaimSize: 10Gi

In order to use different types of PersistentVolumes, the user should set the field workDir.isNfs to false and set the field workDir.volumeStr appropriately to a string to be used in helm/hive/templates/workdir-pv.yaml.

2. Using HDFS/S3

As we do not use a PersistentVolume, set the field workDir.create to false in values-test.yaml.

$ vi values-test.yaml

workDir:
  create: false

Set the configuration keys hive.exec.scratchdir and hive.query.results.cache.directory in conf/hive-site.xml to point to the directory on HDFS or S3 for storing transient data. Note that for using S3, we should use prefix s3a, not s3.

$ vi conf/hive-site.xml

<property>
  <name>hive.exec.scratchdir</name>
  <value>s3a://hivemr3/workdir</value>
</property>

<property>
  <name>hive.query.results.cache.directory</name>
  <value>s3a://hivemr3/workdir/_resultscache_</value>
</property>

Configuring S3 (optional)

For accessing S3-compatible storage, additional configuration keys should be set in conf/core-site.xml. Open conf/core-site.xml and set configuration keys for S3. The configuration key fs.s3a.endpoint should be set to point to the storage server.

$ vi conf/core-site.xml

<property>
  <name>fs.s3a.aws.credentials.provider</name>
  <value>com.amazonaws.auth.EnvironmentVariableCredentialsProvider</value>
</property>

<property>
  <name>fs.s3a.endpoint</name>
  <value>http://192.168.10.100:9000</value>
</property>

<property>
  <name>fs.s3a.path.style.access</name>
  <value>true</value>
</property>

The user may need to change the parameters for accessing S3 to avoid SdkClientException: Unable to execute HTTP request: Timeout waiting for connection from pool. For more details, see Troubleshooting.

When using the class EnvironmentVariableCredentialsProvider to read AWS credentials, add two environment variables AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY in helm/hive/env-secret.sh.

$ vi helm/hive/env-secret.sh

export AWS_ACCESS_KEY_ID=_your_aws_access_key_id_
export AWS_SECRET_ACCESS_KEY=_your_aws_secret_secret_key_

Note that AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY are already appended to the values of the configuration keys mr3.am.launch.env and mr3.container.launch.env in conf/mr3-site.xml. For the security purpose, the user should NOT write AWS access key ID and secret access key in conf/mr3-site.xml.

$ vi conf/mr3-site.xml

<property>
  <name>mr3.am.launch.env</name>
  <value>LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$HADOOP_HOME/lib/native/,AWS_ACCESS_KEY_ID,AWS_SECRET_ACCESS_KEY,AWS_REGION</value>
</property>

<property>
  <name>mr3.container.launch.env</name>
  <value>LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/opt/mr3-run/hadoop/apache-hadoop/lib/native,AWS_ACCESS_KEY_ID,AWS_SECRET_ACCESS_KEY,AWS_REGION</value>
</property>

Public IP address for HiveServer2

The field hive.externalIp in values-test.yaml specifies the IP address for exposing HiveServer2 to the outside of the Kubernetes cluster. The user should specify a public IP address for HiveServer2 so that clients can connect to it from the outside of the Kubernetes cluster. By default, HiveServer2 uses port 9852 for Thrift transport and port 10001 for HTTP transport. In our example, we expose HiveServer2 at IP address 192.168.10.1.

$ vi values-test.yaml

hive:
  port: 9852
  httpport: 10001
  externalIp: 192.168.10.1

For our scenario (where we do not use secure communication with Ranger), a valid host name for the IP address is unnecessary.

Resources for Metastore and HiveServer2 Pods

To adjust resources for Metastore and HiveServer2 Pods, set the following fields in values-test.yaml: metastore.resources, metastore.heapSize, hive.resources, hive.heapSize. metastore.heapSize and hive.heapSize specify the Java heap size (in MB).

$ vi values-test.yaml

metastore:
  resources:
    requests:
      cpu: 2
      memory: 16Gi
    limits:
      cpu: 2
      memory: 16Gi
  heapSize: 16384

hive:
  resources:
    requests:
      cpu: 2
      memory: 16Gi
    limits:
      cpu: 2
      memory: 16Gi
  heapSize: 16384

Resources for DAGAppMaster Pod

By default, we allocate 16GB of memory and 4 CPUs to a DAGAppMaster Pod. To adjust resources, update conf/mr3-site.xml.

$ vi conf/mr3-site.xml

<property>
  <name>mr3.am.resource.memory.mb</name>
  <value>16384</value>
</property>

<property>
  <name>mr3.am.resource.cpu.cores</name>
  <value>4</value>
</property>

Resources for mappers, reducers, and ContainerWorker Pods

Change resources to be allocated to each mapper, reducer, and ContainerWorker by updating conf/hive-site.xml. In particular, the configuration keys hive.mr3.all-in-one.containergroup.memory.mb and hive.mr3.all-in-one.containergroup.vcores should be adjusted so that a ContainerWorker can fit in a worker node. In our example, we allocate 4GB of memory to each mapper/reducer, and 16GB of memory to each ContainerWorker Pod.

$ vi conf/hive-site.xml

<property>
  <name>hive.mr3.map.task.memory.mb</name>
  <value>4096</value>
</property>

<property>
  <name>hive.mr3.map.task.vcores</name>
  <value>1</value>
</property>

<property>
  <name>hive.mr3.reduce.task.memory.mb</name>
  <value>4096</value>
</property>

<property>
  <name>hive.mr3.reduce.task.vcores</name>
  <value>1</value>
</property>

<property>
  <name>hive.mr3.all-in-one.containergroup.memory.mb</name>
  <value>16384</value>
</property>
  
<property>
  <name>hive.mr3.all-in-one.containergroup.vcores</name>
  <value>4</value>
</property>

For more details, see Performance Tuning.

Mounting hostPath volumes

As a prerequisite, every worker node where ContainerWorker Pods may run should have an identical set of local directories for storing intermediate data. These directories are mapped to hostPath volumes in each ContainerWorker Pod. Set the configuration key mr3.k8s.pod.worker.hostpaths to the list of local directories in conf/mr3-site.xml.

$ vi conf/mr3-site.xml

<property>
  <name>mr3.k8s.pod.worker.hostpaths</name>
  <value>/data1/k8s,/data2/k8s,/data3/k8s</value>
</property>

Docker image

By default, we use a pre-built Docker image mr3project/hive3:1.5. If the user wants to use a different Docker image, set docker fields in values-test.yaml.

$ vi values-test.yaml

docker:
  image: mr3project/hive3:1.5
  containerWorkerImage: mr3project/hive3:1.5

Configuring Metastore

Open conf/hive-site.xml and update configurations for Metastore as necessary. Below we list some of configuration keys that the user should check. The two configuration keys javax.jdo.option.ConnectionUserName and javax.jdo.option.ConnectionPassword should match the user name and password of the MySQL server for Metastore. For simplicity, we disable security on the Metastore side.

$ vi conf/hive-site.xml

<property>
  <name>hive.metastore.db.type</name>
  <value>MYSQL</value>
</property>

<property>
  <name>javax.jdo.option.ConnectionDriverName</name>
  <value>com.mysql.cj.jdbc.Driver</value>
</property>

<property>
  <name>javax.jdo.option.ConnectionUserName</name>
  <value>root</value>
</property>

<property>
  <name>javax.jdo.option.ConnectionPassword</name>
  <value>passwd</value>
</property>

<property>
  <name>hive.metastore.pre.event.listeners</name>
  <value></value>
</property>
<property>
  <name>metastore.pre.event.listeners</name>
  <value></value>
</property>

<property>
  <name>hive.security.authorization.enabled</name>
  <value>false</value>
</property>

<property>
  <name>hive.security.authenticator.manager</name>
  <value>org.apache.hadoop.hive.ql.security.HadoopDefaultAuthenticator</value>
</property>

<property>
  <name>hive.security.authorization.manager</name>
  <value>org.apache.hadoop.hive.ql.security.authorization.plugin.sqlstd.SQLStdConfOnlyAuthorizerFactory</value>
</property>

For the purpose of testing, we do not need initiator and cleaner threads in Metastore.

$ vi conf/hive-site.xml

<property>
  <name>hive.compactor.initiator.on</name>
  <value>false</value>
</property>

By default, Metastore does not initialize schema. In order to initialize schema when starting Metastore, set the field metastore.initSchema to true in values-test.yaml:

$ vi values-test.yaml

metastore:
  initSchema: true

Update helm/hive/templates/metastore.yaml to remove nodeAffinity as we do not use node affinity rules.

$ vi helm/hive/templates/metastore.yaml

      affinity:
      # nodeAffinity:
      #   requiredDuringSchedulingIgnoredDuringExecution:
      #     nodeSelectorTerms:
      #     - matchExpressions:
      #       - key: roles
      #         operator: In
      #         values:
      #         - "masters"

Running Metastore and HiveServer2

Before running Metastore and HiveServer2, the user should make sure that no ConfigMaps and Services exist in the namespace hivemr3. For example, the user may see ConfigMaps and Services left over from a previous run.

$ kubectl get configmaps -n hivemr3
NAME                       DATA   AGE
mr3conf-configmap-master   1      16m
mr3conf-configmap-worker   1      16m

$ kubectl get svc -n hivemr3
NAME                    TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE
service-master-1237-0   ClusterIP   10.105.238.21   <none>        80/TCP    11m
service-worker          ClusterIP   None            <none>        <none>    11m

In such a case, manually delete these ConfigMaps and Services.

$ kubectl delete configmap -n hivemr3 mr3conf-configmap-master mr3conf-configmap-worker
$ kubectl delete svc -n hivemr3 service-master-1237-0 service-worker

Install Helm chart for Hive on MR3 with values-test.yaml. We use hivemr3 for the namespace. Metastore automatically downloads a MySQL connector from https://cdn.mysql.com/Downloads/Connector-J/mysql-connector-java-8.0.28.tar.gz.

$ helm install --namespace hivemr3 helm/hive -f values-test.yaml
2022/07/31 00:21:51 found symbolic link in path: /home/gitlab-runner/mr3-run-k8s/kubernetes/helm/hive/conf resolves to /home/gitlab-runner/mr3-run-k8s/kubernetes/conf
2022/07/31 00:21:51 found symbolic link in path: /home/gitlab-runner/mr3-run-k8s/kubernetes/helm/hive/key resolves to /home/gitlab-runner/mr3-run-k8s/kubernetes/key
NAME:   jaundiced-fox
LAST DEPLOYED: Sun Jul 31 00:21:51 2022
NAMESPACE: hivemr3
STATUS: DEPLOYED
...

==> v1/ConfigMap
NAME                    DATA  AGE
client-am-config        4     1s
env-configmap           1     1s
hivemr3-conf-configmap  15    1s
...

Check if all ConfigMaps are non-empty. If the DATA column for hivemr3-conf-configmap is 0, try to remove unnecessary files in the directory conf or helm/hive/conf. This usually happens when a temporary file (e.g., .hive-site.xml.swp) is kept at the time of installing Helm chart.

Helm mounts the following files inside the Metastore and HiveServer2 Pods:

  • helm/hive/env.sh
  • conf/*

In this way, the user can completely specify the behavior of Metastore and HiveServer2 as well as DAGAppMaster and ContainerWorkers.

HiveServer2 creates a DAGAppMaster Pod. Note, however, that no ContainerWorkers Pods are created until queries are submitted. Depending on the configuration for readiness probe, HiveServer2 may restart once before running normally. In our example, HiveServer2 becomes ready in 109 seconds.

$ kubectl get pods -n hivemr3
NAME                                  READY   STATUS    RESTARTS   AGE
hivemr3-hiveserver2-c6bc4b6f4-kjc2k   1/1     Running   0          109s
hivemr3-metastore-0                   1/1     Running   0          109s
mr3master-1627-0-59564dfb95-97kwc     1/1     Running   0          87s

The user can check the log of the DAGAppMaster Pod to make sure that it has started properly.

$ kubectl logs -f -n hivemr3 mr3master-1627-0-59564dfb95-97kwc
...
2022-07-30T15:24:05,825  INFO [DAGAppMaster-1-13] HeartbeatHandler$: Timeout check in HeartbeatHandler:Container
2022-07-30T15:24:05,905  INFO [K8sContainerLauncher-3-1] K8sContainerLauncher: Resynchronizing Pod states for appattempt_83201627_0000_000000: 0

Running Beeline

The user may use any client program to connect to HiveServer2. In our example, we run Beeline inside the Hiveserver2 Pod.

$ kubectl exec -n hivemr3 -it hivemr3-hiveserver2-c6bc4b6f4-kjc2k -- /bin/bash
hive@hivemr3-hiveserver2-c6bc4b6f4-kjc2k:/opt/mr3-run/hive$ export USER=hive
hive@hivemr3-hiveserver2-c6bc4b6f4-kjc2k:/opt/mr3-run/hive$ /opt/mr3-run/hive/run-beeline.sh
...
Connecting to jdbc:hive2://hivemr3-hiveserver2-c6bc4b6f4-kjc2k:9852/;;;
Connected to: Apache Hive (version 3.1.3)
Driver: Hive JDBC (version 3.1.3)
Transaction isolation: TRANSACTION_REPEATABLE_READ
Beeline version 3.1.3 by Apache Hive
0: jdbc:hive2://hivemr3-hiveserver2-c6bc4b6f4> 

After running a few queries, ContainerWorker Pods are created.

$ kubectl get pods -n hivemr3
NAME                                  READY   STATUS    RESTARTS   AGE
hivemr3-hiveserver2-c6bc4b6f4-kjc2k   1/1     Running   0          10m
hivemr3-metastore-0                   1/1     Running   0          10m
mr3master-1627-0-59564dfb95-97kwc     1/1     Running   0          9m51s
mr3worker-ed71-1                      1/1     Running   0          88s
mr3worker-ed71-2                      1/1     Running   0          56s
mr3worker-ed71-3                      1/1     Running   0          48s
mr3worker-ed71-4                      1/1     Running   0          40s
mr3worker-ed71-5                      1/1     Running   0          40s
mr3worker-ed71-6                      1/1     Running   0          40s
mr3worker-ed71-7                      1/1     Running   0          40s
mr3worker-ed71-8                      1/1     Running   0          40s
mr3worker-ed71-9                      1/1     Running   0          26s

Stopping Hive on MR3

In order to terminate Hive on MR3, the user should first delete the DAGAppMaster Pod and then delete Helm chart, not the other way. This is because deleting Helm chart revokes the ServiceAccount object which DAGAppMaster uses to delete ContainerWorker Pods. Hence, if the user deletes Helm chart first, all remaining Pods should be deleted manually.

Delete Deployment for DAGAppMaster which in turn deletes all ContainerWorker Pods automatically.

$ kubectl get deployment -n hivemr3
NAME                  READY   UP-TO-DATE   AVAILABLE   AGE
hivemr3-hiveserver2   1/1     1            1           10m
mr3master-1627-0      1/1     1            1           10m

$ kubectl -n hivemr3 delete deployment mr3master-1627-0
deployment.apps "mr3master-1627-0" deleted

Delete Helm chart.

$ helm delete jaundiced-fox
release "jaundiced-fox" deleted

As the last step, the user will find that the following objects belonging to the namespace hivemr3 are still alive:

  • two ConfigMaps mr3conf-configmap-master and mr3conf-configmap-worker
  • Service for DAGAppMaster, e.g., service-master-1627-0
  • Service service-worker
$ kubectl get configmaps -n hivemr3
NAME                       DATA   AGE
mr3conf-configmap-master   1      5m41s
mr3conf-configmap-worker   1      5m36s

$ kubectl get svc -n hivemr3
NAME                    TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)           AGE
service-master-1627-0   ClusterIP   10.96.143.123   <none>        80/TCP,9890/TCP   11m
service-worker          ClusterIP   None            <none>        <none>            11m

These ConfigMaps and Services are not deleted by the command helm delete because they are created not by Helm but by HiveServer2 and DAGAppMaster. Hence the user should delete these ConfigMaps and Services manually.

$ kubectl delete configmap -n hivemr3 mr3conf-configmap-master mr3conf-configmap-worker
configmap "mr3conf-configmap-master" deleted
configmap "mr3conf-configmap-worker" deleted

$ kubectl delete svc -n hivemr3 service-master-1627-0 service-worker
service "service-master-1627-0" deleted
service "service-worker" deleted