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Setting YAML files

Below we provide details about YAML files in the yaml directory.

These files should be updated to reflect the settings in env.sh and the specific configuration of the Kubernetes cluster. Since YAML files do not read environment variables, all necessary updates must be made manually.

Common to all Pods​

namespace.yaml​

This manifest defines a namespace for all Kubernetes objects. The name field should match the namespace specified in MR3_NAMESPACE in kubernetes/env.sh.

vi yaml/namespace.yaml

  name: hivemr3

Similarly the namespace field in the other YAML files should match the same namespace.

hive-service-account.yaml​

This manifest defines a ServiceAccount. The name of the ServiceAccount object (hive-service-account) is read in run-hive.sh, so there is no need to update this file.

cluster-role.yaml​

This manifest defines a ClusterRole. The name of the ClusterRole resource (node-reader) is read in run-hive.sh, so there is no need to update this file.

metastore-role.yaml​

This manifest defines a Role for a Metastore Pod. The name of the Role resource (metastore-role) is read in run-metastore.sh, so there is no need to update this file.

hive-role.yaml​

This manifest defines a Role for HiveServer2 Pods. The name of the Role resource (hive-role) is read in run-hive.sh, so there is no need to update this file.

workdir-pv.yaml​

This manifest defines a PersistentVolume for copying the result of running a query from ContainerWorkers to HiveServer2. The user should update it in order to use a desired type of PersistentVolume.

workdir-pvc.yaml​

This manifest defines a PersistentVolumeClaim which references the PersistentVolume created by workdir-pv.yaml. The user should specify the size of the storage.

vi yaml/workdir-pvc.yaml

      storage: 10Gi

Configuring Metastore​

metastore-service.yaml​

This manifest defines a governing Service required for the StatefulSet for Metastore. The user should use the same port number specified by the environment variable HIVE_METASTORE_PORT in env.sh.

vi yaml/metastore-service.yaml

  ports:
  - name: tcp
    port: 9850

metastore.yaml​

This manifest defines a Pod for running Metastore. The user should update several sections in this file according to Kubernetes cluster settings.

In the spec.template.spec.containers section:

  • The image field should match the Docker image specified by DOCKER_HIVE_IMG in env.sh.
  • The resources.requests and resources.limits specify the resources to to be allocated to a Metastore Pod.
  • The ports.containerPort field should match the port number specified in metastore-service.yaml.
vi yaml/metastore.yaml

spec:
  template:
    spec:
      containers:
      - image: mr3project/hive:4.0.0.mr3.2.0
        resources:
          requests:
            cpu: 2
            memory: 16Gi
          limits:
            cpu: 2
            memory: 16Gi
        ports:
        - containerPort: 9850
          protocol: TCP

In the spec.template.spec.volumes section:

  • The configMap.name field under conf-k8s-volume should match the name specified by CONF_DIR_CONFIGMAP in env.sh.
  • The secret.secretName field under key-k8s-volume should match the name specified by KEYTAB_SECRET in env.sh.
vi yaml/metastore.yaml

spec:
  template:
    spec:
      volumes:
      - name: conf-k8s-volume
        configMap:
          name: hivemr3-conf-configmap
      - name: key-k8s-volume
        secret:
          secretName: hivemr3-keytab-secret

In the spec.template.spec.hostAliases section:

  • HIVE_DATABASE_HOST in env.sh specifies the host where the database for Metastore is running. If it uses a host unknown to the default DNS, the user should add its alias. The following example adds host names red0 and indigo20 that are unknown to the default DNS.
vi yaml/metastore.yaml

spec:
  template:
    spec:
      hostAliases:
      - ip: "10.1.91.4"
        hostnames:
        - "red0"
      - ip: "10.1.91.41"
        hostnames:
        - "indigo20"

Configuring HiveServer2​

hiveserver2-service.yaml​

This manifest defines a Service for exposing HiveServer2 to the outside of the Kubernetes cluster. The user should specify a public IP address with a valid host name and a port number (with name thrift) for HiveServer2 so that clients can connect to it from the outside of the Kubernetes cluster. Another port number with name http should be specified if HTTP transport is enabled (by setting the configuration key hive.server2.transport.mode to all or http in conf/hive-site.xml). The host name is necessary in order for Ranger to securely communicate with HiveServer2.

vi yaml/hiveserver2-service.yaml

  ports:
  - protocol: TCP
    port: 9852
    targetPort: 9852
    name: thrift
  - protocol: TCP
    port: 10001
    targetPort: 10001
    name: http
  externalIPs:
  - 10.1.91.41

In our example, we use 10.1.91.41:9852 as the full address of HiveServer2. The user should make sure that the IP address exists with a valid host name and is not already taken.

hive.yaml​

This manifest defines a Pod for running HiveServer2 (by creating a Deployment). The user should update several sections in this file according to Kubernetes cluster settings.

In the spec.template.spec.containers section:

  • The image field should match the Docker image specified by DOCKER_HIVE_IMG in env.sh.
  • The args field specifies the DAGAppMaster mode: --localthread for LocalThread mode, --localprocess for LocalProcess mode, and --kubernetes for Kubernetes mode.
  • The resources.requests and resources.limits fields specify the resources to to be allocated to a HiveServer2 Pod.
  • The three fields ports.containerPort, readinessProbe.tcpSocket.port, and livenessProbe.tcpSocket.port should match the port number specified in hiveserver2-service.yaml.
$ vi yaml/hive.yaml

spec:
  template:
    spec:
      containers:
      - image: mr3project/hive:4.0.0.mr3.2.0
        args: ["start", "--kubernetes"]
        resources:
          requests:
            cpu: 4
            memory: 32Gi
          limits:
            cpu: 4
            memory: 32Gi
        ports:
        - containerPort: 9852
        readinessProbe: 
          tcpSocket: 
            port: 9852 
        livenessProbe: 
          tcpSocket: 
            port: 9852

In the spec.template.spec.volumes section:

  • The configMap.name field under conf-k8s-volume should match the name specified by CONF_DIR_CONFIGMAP in env.sh.
  • The secret.secretName field under key-k8s-volume should match the name specified by KEYTAB_SECRET in env.sh.
vi yaml/hive.yaml

spec:
  template:
    spec:
      volumes:
      - name: conf-k8s-volume
        configMap:
          name: hivemr3-conf-configmap
      - name: key-k8s-volume
        secret:
          secretName: hivemr3-keytab-secret

The spec.template.spec.hostAliases field can list aliases for hosts that may not be found in the default DNS. For example, the host running Metastore may be unknown to the default DNS, in which case the user can add an alias for it.