Adding a Host to the Cluster

Minimum Required Role: Full Administrator

You can add one or more hosts to your cluster using the Add Hosts wizard, which installs the Oracle JDK, CDH, and Cloudera Manager Agent software. After the software is installed and the Cloudera Manager Agent is started, the Agent connects to the Cloudera Manager Server and you can use the Cloudera Manager Admin Console to manage and monitor CDH on the new host.

The Add Hosts wizard does not create roles on the new host; once you have successfully added the host(s) you can either add roles, one service at a time, or apply a host template, which can define role configurations for multiple roles.

Using the Add Hosts Wizard to Add Hosts

You can use the Add Hosts wizard to install CDH, Impala, and the Cloudera Manager Agent on a host.

  1. Disable TLS Encryption or Authentication
  2. Using the Add Hosts Wizard
  3. Enable TLS Encryption or Authentication
  4. Enable TLS/SSL for CDH Components
  5. Enable Kerberos

Disable TLS Encryption or Authentication

If you have enabled TLS encryption or authentication for the Cloudera Manager Agents, you must disable both of them before starting the Add Hosts wizard. Otherwise, skip to the next step.
  1. From the Administration tab, select Settings.
  2. Select the Security category.
  3. Disable all levels of TLS that are currently enabled by deselecting the following options: Use TLS Encryption for Agents, and Use TLS Authentication of Agents to Server.
  4. Click Save Changes to save the settings.
  5. Restart the Cloudera Management Server to have these changes take effect.

Using the Add Hosts Wizard

  1. Click the Hosts tab.
  2. Click the Add New Hosts button.
  3. Follow the instructions in the wizard to install the Oracle JDK and Cloudera Manager Agent packages and start the Agent.
  4. In the Specify hosts for your CDH Cluster installation page, you can search for new hosts to add under the New Hosts tab. However, if you have hosts that are already known to Cloudera Manager but have no roles assigned, (for example, a host that was previously in your cluster but was then removed) these will appear under the Currently Managed Hosts tab.
  5. You will have an opportunity to add (and start) role instances to your newly-added hosts using a host template.
    1. You can select an existing host template, or create a new one.
    2. To create a new host template, click the + Create... button. This will open the Create New Host Template pop-up. See Host Templates for details on how you select the role groups that define the roles that should run on a host. When you have created the template, it will appear in the list of host templates from which you can choose.
    3. Select the host template you want to use.
    4. By default Cloudera Manager will automatically start the roles specified in the host template on your newly added hosts. To prevent this, uncheck the option to start the newly-created roles.
  6. When the wizard is finished, you can verify the Agent is connecting properly with the Cloudera Manager Server by clicking the Hosts tab and checking the health status for the new host. If the Health Status is Good and the value for the Last Heartbeat is recent, then the Agent is connecting properly with the Cloudera Manager Server.

If you did not specify a host template during the Add Hosts wizard, then no roles will be present on your new hosts until you add them. You can do this by adding individual roles under the Instances tab for a specific service, or by using a host template. See Role Instances for information about adding roles for a specific service. See Host Templates to create a host template that specifies a set of roles (from different services) that should run on a host.

Enable TLS Encryption or Authentication

If you previously enabled TLS security on your cluster, you must re-enable the TLS options on the Administration page and also configure TLS on each new host after using the Add Hosts wizard. Otherwise, you can ignore this step. For instructions, see Configuring TLS Security for Cloudera Manager.

Enable TLS/SSL for CDH Components

If you have previously enabled TLS/SSL on your cluster, and you plan to start these roles on this new host, make sure you install a new host certificate to be configured from the same path and naming convention as the rest of your hosts. Since the new host and the roles configured on it are inheriting their configuration from the previous host, ensure that the keystore or truststore passwords and locations are the same on the new host. For instructions on configuring TLS/SSL, see Configuring TLS/SSL Encryption for CDH Services.

Enable Kerberos

If you have previously enabled Kerberos on your cluster:
  • Install the packages required to kinit on the new host. For the list of packages required for each OS, see Kerberos Prerequisites.
  • If you have set up Cloudera Manager to manage krb5.conf, it will automatically deploy the file on the new host.
  • If Cloudera Manager does not manage krb5.conf, you must manually update the file at /etc/krb5.conf.

Adding a Host by Installing the Packages Using Your Own Method

If you used a different mechanism to install the Oracle JDK, CDH, Cloudera Manager Agent packages, you can use that same mechanism to install the Oracle JDK, CDH, Cloudera Manager Agent packages and then start the Cloudera Manager Agent.
  1. Install the Oracle JDK, CDH, and Cloudera Manager Agent packages using your own method. For instructions on installing these packages, see Installation Path B - Installation Using Cloudera Manager Parcels or Packages.
  2. After installation is complete, start the Cloudera Manager Agent. For instructions, see Starting, Stopping, and Restarting Cloudera Manager Agents.
  3. After the Agent is started, you can verify the Agent is connecting properly with the Cloudera Manager Server by clicking the Hosts tab and checking the health status for the new host. If the Health Status is Good and the value for the Last Heartbeat is recent, then the Agent is connecting properly with the Cloudera Manager Server.
  4. If you have enabled TLS security on your cluster, you must enable and configure TLS on each new host. Otherwise, ignore this step.
    1. Enable and configure TLS on each new host by specifying 1 for the use_tls property in the /etc/cloudera-scm-agent/config.ini configuration file.
    2. Configure the same level(s) of TLS security on the new hosts by following the instructions in Configuring TLS Security for Cloudera Manager.
  5. If you have previously enabled TLS/SSL on your cluster, and you plan to start these roles on this new host, make sure you install a new host certificate to be configured from the same path and naming convention as the rest of your hosts. Since the new host and the roles configured on it are inheriting their configuration from the previous host, ensure that the keystore or truststore passwords and locations are the same on the new host. For instructions on configuring TLS/SSL, see Configuring TLS/SSL Encryption for CDH Services.

  6. If you have previously enabled Kerberos on your cluster:
    • Install the packages required to kinit on the new host. For the list of packages required for each OS, see Kerberos Prerequisites.
    • If you have set up Cloudera Manager to manage krb5.conf, it will automatically deploy the file on the new host.
    • If Cloudera Manager does not manage krb5.conf, you must manually update the file at /etc/krb5.conf.