Apache ZooKeeper

The Apache ZooKeeper integration collects traffic metrics for nodes, such as latency, active requests, and active connections. The integration also collects ZooKeeper logs and parses them into a JSON payload. The result includes fields for node ID, source, level, and message.

For more information about ZooKeeper, see the Apache ZooKeeper documentation.

Prerequisites

To collect ZooKeeper telemetry, you must install the Ops Agent:

For metrics, install version 2.10.0 or higher.
For logs, install version 2.11.0 or higher.

This integration supports ZooKeeper versions 3.5, 3.6, and 3.7.

Configure the Ops Agent for ZooKeeper

Following the guide to Configure the Ops Agent, add the required elements to collect telemetry from ZooKeeper instances, and restart the agent.

Example configuration

The following commands create the configuration to collect and ingest telemetry for ZooKeeper:

# Configures Ops Agent to collect telemetry from the app. You must restart the agent for the configuration to take effect.

set -e

# Check if the file exists
if [ ! -f /etc/google-cloud-ops-agent/config.yaml ]; then
  # Create the file if it doesn't exist.
  sudo mkdir -p /etc/google-cloud-ops-agent
  sudo touch /etc/google-cloud-ops-agent/config.yaml
fi

# Create a back up of the existing file so existing configurations are not lost.
sudo cp /etc/google-cloud-ops-agent/config.yaml /etc/google-cloud-ops-agent/config.yaml.bak

# Configure the Ops Agent.
sudo tee /etc/google-cloud-ops-agent/config.yaml > /dev/null << EOF
metrics:
  receivers:
    zookeeper:
      type: zookeeper
  service:
    pipelines:
      zookeeper:
        receivers:
          - zookeeper

logging:
  receivers:
    zookeeper_general:
      type: zookeeper_general
  service:
    pipelines:
      zookeeper_general:
        receivers:
          - zookeeper_general

EOF

For these changes to take effect, you must restart the Ops Agent:

Linux

To restart the agent, run the following command on your instance:
```
sudo systemctl restart google-cloud-ops-agent
```
To confirm that the agent restarted, run the following command and verify that the components "Metrics Agent" and "Logging Agent" started:
```
sudo systemctl status "google-cloud-ops-agent*"
```

Windows

Connect to your instance using RDP or a similar tool and login to Windows.
Open a PowerShell terminal with administrator privileges by right-clicking the PowerShell icon and selecting Run as Administrator
To restart the agent, run the following PowerShell command:
```
Restart-Service google-cloud-ops-agent -Force
```
To confirm that the agent restarted, run the following command and verify that the components "Metrics Agent" and "Logging Agent" started:
```
Get-Service google-cloud-ops-agent*
```

Configure logs collection

To ingest logs from ZooKeeper, you must create a receiver for the logs that ZooKeeper produces and then create a pipeline for the new receiver.

To configure a receiver for your zookeeper_general logs, specify the following fields:

Field	Default	Description
`exclude_paths`		A list of filesystem path patterns to exclude from the set matched by `include_paths`.
`include_paths`	`[/opt/zookeeper/logs/zookeeper-*.out, /var/log/zookeeper/zookeeper.log]`	A list of filesystem paths to read by tailing each file. A wild card (``) can be used in the paths; for example, `/var/log/zookeeper/*.log`.
`record_log_file_path`	`false`	If set to `true`, then the path to the specific file from which the log record was obtained appears in the output log entry as the value of the `agent.googleapis.com/log_file_path` label. When using a wildcard, only the path of the file from which the record was obtained is recorded.
`type`		The value must be `zookeeper_general`.
`wildcard_refresh_interval`	`60s`	The interval at which wildcard file paths in `include_paths` are refreshed. Given as a time duration, for example `30s` or `2m`. This property might be useful under high logging throughputs where log files are rotated faster than the default interval.

What is logged

The logName is derived from the receiver IDs specified in the configuration. Detailed fields inside the LogEntry are as follows.

The zookeeper_general logs contain the following fields in the LogEntry:

Field	Type	Description
`jsonPayload.level`	string	Log entry level
`jsonPayload.line`	number	Line number from which the log was generated in source
`jsonPayload.message`	string	Log message, including detailed stacktrace where provided
`jsonPayload.myid`	number	Numeric ID of the Zookeeper instance
`jsonPayload.source`	string	Source of where the log originated
`jsonPayload.thread`	string	Thread from which the log originated
`severity`	string (`LogSeverity`)	Log entry level (translated).

Configure metrics collection

To ingest metrics from ZooKeeper, you must create a receiver for the metrics that ZooKeeper produces and then create a pipeline for the new receiver.

This receiver does not support the use of multiple instances in the configuration, for example, to monitor multiple endpoints. All such instances write to the same time series, and Cloud Monitoring has no way to distinguish among them.

To configure a receiver for your zookeeper metrics, specify the following fields:

Field	Default	Description
`collection_interval`	`60s`	A time duration value, such as `30s` or `5m`.
`endpoint`	`localhost:2181`	The URL exposed by ZooKeeper.
`type`		This value must be `zookeeper`.

What is monitored

The following table provides the list of metrics that the Ops Agent collects from the ZooKeeper instance.

Metric type
Kind, Type Monitored resources	Labels
`workload.googleapis.com/zookeeper.connection.active`
`GAUGE`, `INT64` gce_instance
`workload.googleapis.com/zookeeper.data_tree.ephemeral_node.count`
`GAUGE`, `INT64` gce_instance
`workload.googleapis.com/zookeeper.data_tree.size`
`GAUGE`, `INT64` gce_instance
`workload.googleapis.com/zookeeper.file_descriptor.limit`
`GAUGE`, `INT64` gce_instance
`workload.googleapis.com/zookeeper.file_descriptor.open`
`GAUGE`, `INT64` gce_instance
`workload.googleapis.com/zookeeper.fsync.exceeded_threshold.count`
`CUMULATIVE`, `INT64` gce_instance
`workload.googleapis.com/zookeeper.latency.avg`
`GAUGE`, `INT64` gce_instance
`workload.googleapis.com/zookeeper.latency.max`
`GAUGE`, `INT64` gce_instance
`workload.googleapis.com/zookeeper.latency.min`
`GAUGE`, `INT64` gce_instance
`workload.googleapis.com/zookeeper.packet.count`
`CUMULATIVE`, `INT64` gce_instance	`direction`
`workload.googleapis.com/zookeeper.request.active`
`GAUGE`, `INT64` gce_instance
`workload.googleapis.com/zookeeper.watch.count`
`GAUGE`, `INT64` gce_instance
`workload.googleapis.com/zookeeper.znode.count`
`GAUGE`, `INT64` gce_instance

Verify the configuration

This section describes how to verify that you correctly configured the ZooKeeper receiver. It might take one or two minutes for the Ops Agent to begin collecting telemetry.

To verify that ZooKeeper logs are being sent to Cloud Logging, do the following:

In the Google Cloud console, go to the Logs Explorer page:
Go to Logs Explorer

If you use the search bar to find this page, then select the result whose subheading is Logging.
Enter the following query in the editor, and then click Run query:
```
resource.type="gce_instance"
log_id("zookeeper_general")
```

To verify that ZooKeeper metrics are being sent to Cloud Monitoring, do the following:

In the Google Cloud console, go to the Metrics explorer page:
Go to Metrics explorer

If you use the search bar to find this page, then select the result whose subheading is Monitoring.
In the toolbar of the query-builder pane, select the button whose name is either MQL or PromQL.
Verify that MQL is selected in the Language toggle. The language toggle is in the same toolbar that lets you format your query.

Enter the following query in the editor, and then click Run query:

fetch gce_instance
| metric 'workload.googleapis.com/zookeeper.file_descriptor.limit'
| every 1m

View dashboard

To view your ZooKeeper metrics, you must have a chart or dashboard configured. The ZooKeeper integration includes one or more dashboards for you. Any dashboards are automatically installed after you configure the integration and the Ops Agent has begun collecting metric data.

You can also view static previews of dashboards without installing the integration.

To view an installed dashboard, do the following:

In the Google Cloud console, go to the Dashboards page:
Go to Dashboards

If you use the search bar to find this page, then select the result whose subheading is Monitoring.
Select the Dashboard List tab, and then choose the Integrations category.
Click the name of the dashboard you want to view.

If you have configured an integration but the dashboard has not been installed, then check that the Ops Agent is running. When there is no metric data for a chart in the dashboard, installation of the dashboard fails. After the Ops Agent begins collecting metrics, the dashboard is installed for you.

To view a static preview of the dashboard, do the following:

In the Google Cloud console, go to the Integrations page:
Go to Integrations

If you use the search bar to find this page, then select the result whose subheading is Monitoring.
Click the Compute Engine deployment-platform filter.
Locate the entry for ZooKeeper and click View Details.
Select the Dashboards tab to see a static preview. If the dashboard is installed, then you can navigate to it by clicking View dashboard.

For more information about dashboards in Cloud Monitoring, see Dashboards and charts.

For more information about using the Integrations page, see Manage integrations.

Install alerting policies

Alerting policies instruct Cloud Monitoring to notify you when specified conditions occur. The ZooKeeper integration includes one or more alerting policies for you to use. You can view and install these alerting policies from the Integrations page in Monitoring.

To view the descriptions of available alerting policies and install them, do the following:

In the Google Cloud console, go to the Integrations page:
Go to Integrations

If you use the search bar to find this page, then select the result whose subheading is Monitoring.
Locate the entry for ZooKeeper and click View Details.
Select the Alerts tab. This tab provides descriptions of available alerting policies and provides an interface for installing them.
Install alerting policies. Alerting policies need to know where to send notifications that the alert has been triggered, so they require information from you for installation. To install alerting policies, do the following:
1. From the list of available alerting policies, select those that you want to install.
2. In the Configure notifications section, select one or more notification channels. You have the option to disable the use of notification channels, but if you do, then your alerting policies fire silently. You can check their status in Monitoring, but you receive no notifications.
  
  For more information about notification channels, see Manage notification channels.
3. Click Create Policies.

For more information about alerting policies in Cloud Monitoring, see Introduction to alerting.