The Cloudera Manager Web console is the control center to manage the entire cluster. Once you are logged in to Cloudera Manager, the landing page displays a wealth of information. The different screens can be visited using the Cloudera Manager toolbar as shown in the following screenshot:
The Home screen is divided into four different tabs, which are as follows:
- This Status tab displays the overall status of the cluster with a list of all the components running as shown in the following screenshot. Each service displayed can be started and stopped from this interface.
The cluster information is divided into two columns. The first column displays the name of the Hadoop components and the second column displays the important status messages. The circular icon to the left of the component name is the health indicator of the component. The health can be checked by hovering the mouse over the indicator as shown in the following screenshot:
The preceding screenshot indicates that the ZooKeeper component has a health concern. The second column gives a few more details indicating that the ZooKeeper component has one warning configuration issue. To see the details of these, you can click these indicators, which will pop up the details of the indicator, as shown in the following screenshot. You can further click on the component name to see more details.
The Status tab also contains a section that contains charts that display status information of cluster resources. By default, the Cluster CPU, Cluster Disk IO, Cluster Network IO, and HDFS IO resources are present on the dashboard, as shown in the following screenshot:
- The All Health Issues tab displays the list of components that have health issues as shown in the following screenshot. The screenshot shows that there are two health issues, one for the hivemetastore component and one for jobhistory. You can see more details by clicking on the individual components listed on the screen as shown in the following screenshot:
- The All Configuration Issues tab displays the list of components that have configuration issues as shown in the following screenshot. The screenshot shows that there are three configuration issues on the cluster. Each issue is described in complete text so you can understand the nature of the issue along with a recommendation. Clicking on any issue will take you to the configuration page of the service and you can resolve the issue there.
- The All Recent Commands tab lists all the recent commands executed on the cluster. As you can see in the following screenshot, the recent commands give us information that the ZooKeeper service was recently started:
The Clusters menu on the Cloudera Manager toolbar displays the list of all services installed on the cluster. The following screenshot shows the menu items of the Services menu:
You can click on the services to bring up a detailed view of the selected service. Let us look at one of the services. Each detail window is divided into multiple tabs. For example, if you select the HDFS service, the following tabs are displayed:
- Status: This tab displays the HDFS summary information along with detailed health information. This page also contains several charts, for example, HDFS Capacity, Total Bytes Read Across DataNodes, and Total Bytes Written Across DataNodes.
- Instances: This tab displays the various nodes of the cluster that hosts the HDFS service. Any node that is running the namenode, secondary namenode, or datanode is displayed here along with status, role, and health information.
- Commands: This tab displays the list of all the running commands and recent commands executed in relation to the HDFS service.
- Configuration: This tab presents a drop-down menu, listing the options to view and edit configurations, role configurations, and an option to view the history of the HDFS configurations along with the configuration options for rollback.
- Audits: This tab lists all the actions taken for the HDFS service. This information helps the administrator understand the activities the service is performing. An option to download the audit log is also available.
- Charts Library: This tab lists all the charts related to the HDFS service. The page is divided into groups of charts. You will find charts that display information for the entire service along with the ones for the namespace and datanodes.
- File Browser: This tab displays the list of files and folders on HDFS.
- Cache Statistics: This tab provides the HDFS caching information.
- Replications: This tab provides options to configure schedules and sources for HDFS replication and Hive replication.
- NameNode Web UI: This tab links to the namenode web interface.
The following screenshot shows the details for the HDFS service.
The Hosts menu on the Cloudera Manager toolbar displays information of all the hosts that are part of the cluster. The screen is divided into four tabs: Status, Configuration, Templates, and Parcels. Let’s look into the details of the latter two tabs here:
- Templates: This tab provides the administrator with an option to predefine the properties for a specific service or node. For example, a template for the TaskTracker can be created with all the required configuration parameters and saved. Later on, when the administrator needs to add a new TaskTracker in the cluster, he can apply all the required configurations to the new TaskTracker using the template.
- Parcels: This tab lists all the parcels installed on the cluster along with the new parcels available for download. Parcels provide an easy way to install the packages on the cluster and it is the Cloudera-recommended method for software management.
The Diagnostics menu on the Cloudera Manager toolbar provides the following three menu items:
- Events: This screen displays the list of all the events that occur on the cluster. Three types of events are displayed here: IMPORTANT, INFORMATIONAL, and CRITICAL. As there can be several events that occur, a provision to filter events by the type of events is also available. The following screenshot displays an event with severity—INFORMATIONAL. The search can be filtered by other types too, for example, Content, Role, Hosts, Cluster, and many more.
- Logs: This screen provides a search interface to look into the different logs of services running on the cluster. As shown in the following screenshot, there are several options to search through the logs for specific services. The different services can be selected using the Select Sources option.
- Server Log: The screen displays the Cloudera Manager Server logs as shown in the following screenshot:
The Audits menu on the Cloudera Manager toolbar lists all the actions/events performed on the cluster in an easy-to-read format. The interface also provides an option to perform a search on the events using advanced search filters as shown in the following screenshot. The screenshot also shows the list of components available as part of the search filter.
The Charts menu on the Cloudera Manager toolbar provides an option to create new charts using the Chart Builder screen as shown in the following screenshot. You can write a query to select the parameters to create the chart. Once created, you can save the chart.
The Backup menu provides screens to configure replications for HDFS and Hive data. The menu also provides an option to configure schedules for HDFS and HBase snapshots. We will cover these in detail in Chapter 9, Configuring Backups.
The Administration menu on the Cloudera Manager toolbar contains all the tools required by an administrator to manage the Apache Hadoop cluster. The Administration menu has the following items:
- Settings: This screen provides an interface to view and edit all the configuration parameters for Cloudera Manager. The properties are divided into multiple groups. The following is a brief description of each of the groups:
- Performance: This group contains the configuration parameters for Cloudera Manager. By default, the only property defined here is the heartbeat interval setting for agents to respond to the server.
- Advanced: This group contains a few properties, such as agent heartbeat logging directory, command data storage directory, and so on. These properties are very rarely modified.
- Thresholds: This group contains properties with respect to the health status check for the agents.
- Security: This group contains all the properties related to the security of Cloudera Manager.
- Ports and Addresses: This group consists of properties related to the Cloudera Manager services. For example, the hostname, HTTP port for the administrator console, HTTPS port for the administrator console, and the agents port to connect to the server. The following screenshot shows the Ports and Addresses group from the Settings page:
- Other: This group consists of few basic properties to configure the look and feel of the Cloudera Manager client.
- Support: This group consists of properties related to diagnostic data collection of Cloudera Manager. These properties help configure the frequency and size of the diagnostic data, which can be sent to Cloudera for usage analysis.
- External Authentication: This group consists of all the properties related to Lightweight Directory Access Protocol (LDAP) and Security Assertion Markup Language (SAML) authentication and authorization.
- Parcels: This group contains properties related to parcel package management provided by Cloudera Manager, for example, the parcel local repository directory, remote parcel URLs, and parcel update frequency.
- Network: This group provides options to configure the proxy server properties for Cloudera Manager.
- Custom Service Descriptors: This group provides options to configure custom add-on services to Cloudera Manager.
- Alerts: This screen enables the administrator to configure e-mail alerts for the various services running on the cluster. We will see more of this screen in Chapter 8, Cluster Monitoring Using Events and Alerts.
- Users: This screen, as the name suggests is the user management console for Cloudera Manager. By default, the admin user is created for Cloudera Manager. Basic user administration activities, such as add/remove the user, manage privileges, and change user passwords is available on this screen.
- Kerberos: This screen provides the administrator with options to set up Kerberos, the system to authenticate and authorize users in Apache Hadoop. We will be using this screen to set up Kerberos in Chapter 6, Implementing Security Using Kerberos.
- License: This screen displays the current license for Cloudera Manager. The following screenshot shows the License screen of Cloudera Manager:
As you can see in the preceding screenshot, we are using the trial license for Cloudera Manager. You have the option to stop the trial version using the End Trial button or upload a valid enterprise license. The page also displays the current license key along with the license expiry date.
- Language: This screen allows you to set the language for Cloudera Manager. The language set here will be the language used for messages such as events and e-mails. The language of Cloudera Manager is derived from the browser’s language settings. The following is the screenshot of the Language screen in Cloudera Manager:
- Peers: This screen provides the administrator with an interface to add peer clusters that are managed by Cloudera Manager. The peer cluster will then become the source from which data, that is, files can be replicated to the currently logged on cluster. Using this feature, you can get files/data (HDFS or Hive data) from a different cluster (peer cluster) and replicate the data in your cluster. The following screenshot shows the Peers screen in Cloudera Manager:
Then, the Add Peer screen, shown in the following screenshot, allows you to specify the name of the peer, the peer URL, and the admin credentials of the peer to connect to the peer Cloudera Manager:
As shown in the following screenshot, once you are done adding the peer, the peer is tested for connectivity and on successful connection, the status is updated to Connected: