Managing an Ark Cluster

To view statistical information and log entries for a cluster, select the cluster name in the PEM Browser tree control and navigate to the Dashboard tab.

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The Cluster nodes table displays each node of the cluster, and the current state of the node.

  • Use the refresh icon in the upper-left corner of the panel header to refresh the displayed content; the most-recent entries in the cluster log file are displayed nearest to the top of the panel.
  • Use the search box in the upper-right corner of the panel header to search the table content for key words or strings; separate string values with a pipe character (|) to include entries that match more than one search term.

Icons in the left most column indicate the role of the node within the cluster; a disc icon indicates that the node is a master node within the scenario, and a copy symbol indicates that a node is currently acting as a replica.

The following columns display connection information about each node:

  • The Address column displays the IP address of the node.
  • The AZ column displays the Availability Zone in which the node resides.
  • The Subnet column displays the subnet ID on which the node resides.
  • The LBPort column displays the port number to which a client application should connect to utilize load balancing.
  • The DBPort column displays the default listener port for the Advanced Server or PostgreSQL server.
  • The CXN column displays the current number of connections to the node.

The following columns display the health of the node:

  • The VM column displays the state of the virtual machine on which the cluster resides.
  • The HA column displays the state of the high-availability cluster.
  • The DB column displays the state of the database server.
  • The UP column displays the current status of the packages installed on the cluster. Periodically, the cluster manager performs a check to see if the packages are up to date.

Indicators display the health of the node:

  • A green checkmark indicates that an object is healthy.
  • A yellow alert symbol calls attention to an object that requires attention.
  • A red error symbol signifies that an object is not available.
  • An hourglass signals that the cluster is processing a request.
  • A question mark indicates that the state of the resource is unknown.

Graphs display usage information about the cluster:

  • The memory usage of the cluster.
  • The average number of connections made to the cluster.
  • The average CPU Load of the cluster.

The Events panel displays events that are logged for the current cluster.

  • Use the refresh icon in the upper-left corner of the panel header to refresh the displayed content; the most-recent entries in the cluster log file are displayed nearest to the top of the panel.
  • Use the search box in the upper-right corner of the panel header to search the log file content for key words or strings; please note that the search is not context-sensitive.

To view information about the cluster configuration, select the cluster name in the PEM Browser tree control and navigate to the Properties tab.

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Panels on the Properties tab display deployment details for the cluster.

  • The General panel displays deployment details such as owner information, creation date, and current cluster state.
  • The Storage panel displays information about the storage allocated for the cluster, the amount of storage used, and the amount of storage still available.
  • The Network panel displays information about the network addresses and ports in use by the cluster.
  • The Maintenance panel displays information about the monitoring and healing policies enforced on the cluster.
  • The Auto Scale panel displays information about the scaling policies currently in use by the cluster; if automatic scaling is enabled, the cluster will be scaled up when the thresholds specified in the % of storage size used or # of server connections fields are reached.
  • The Backup panel displays the backup schedule and retention policy enforced on the cluster.

You can use options on the cluster’s context menu to manage the cluster.

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To access the context menu, right-click on the cluster name in the PEM Browser tree control. Then, to manage the cluster, select from the menu options:

Option Action
Refresh Select Refresh to update the cluster information.
Delete/Drop Select Delete/Drop to delete the cluster. PEM will confirm that you wish to delete the cluster before removing it.
Download SSH Key Select Download SSH Key to download the SSH key for the cluster.
Backup… Select Backup… to take a backup of the cluster.
Scale Up Select Scale Up to add replicas or storage to the selected cluster.
Scale Down Select Scale Down to remove replicas from the selected cluster.
Scale Machine Type Select Scale Machine Type to change the size of the virtual machine on which the cluster resides.
Upgrade OS/Software Select Upgrade OS/Software to perform a yum update on each node of the cluster.
Properties… Select Properties… to review or modify cluster properties.

Connecting to a Cluster Instance

To download the cluster’s SSH key, select Download SSH Key from the console’s context menu. An informational popup will provide information about connecting to the cluster instance:

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Before using SSH to connect to an instance, an administrative user must modify the security group used by the cluster to allow SSH connections. For more information, please see the EDB Ark Administrative User’s Guide, available via the Ark server’s Dashboard tab.

Taking a Cluster Backup

To take a backup of the currently selected cluster, select Backup… from the console’s context menu or the PEM web interface’s Object menu. A popup will open, prompting you to provide a comment so you can identify the backup later should you need to use the backup to restore or clone the cluster:

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Provide a comment in the Notes for the backup field, and click Backup to start the backup. An informational popup will confirm that the backup process has started.

Managing a Backup

You can use options on the backup’s context menu to manage the backup. To access the context menu, right-click on the backup identifier in the PEM Browser tree control. Then, select from the menu options:

Option Action
Refresh Select Refresh to update the backup.
Delete/Drop Select Delete/Drop to delete the cluster. PEM will confirm that you wish to delete the backup before removing it.

Reviewing a List of Backups

To view a list of cluster backups, select the Backups node in the PEM Browser tree control and navigate to the Properties tab.

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The Properties tab displays detailed information about completed backups:

  • The ID column displays the backup identifier.
  • The Cluster column displays the name of the cluster that was backed up.
  • The Notes column displays the note provided when the backup was taken.
  • The Engine version column displays the engine version of the cluster.
  • The Capacity (in GB) column displays the names of the groups/roles/tenants that have access to the template.
  • The Backup type column displays Automatic if the backup is a scheduled backup, and Manual if the backup was started by a user.
  • The Start time column displays the time at which the backup was started.
  • The End time column displays time at which the backup completed.

Scaling a Cluster

You can use the Scale Up and Scale Down menu options to add replicas or storage to your cluster, or to delete unneeded replica nodes. Access the scaling options on either the cluster’s context menu or on the PEM web interface’s Object menu.

To add one or more replicas to a cluster, select Scale Up, then Replicas.

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When the Scale Up dialog opens, specify the number of replicas that you would like to add to the cluster. If applicable, select a subnet and an availability zone for each replica, and then click Ok. The server will confirm that you wish to add the specified number of replicas; click Yes to continue. An informational popup will confirm when the replica(s) are being added.

To remove one or more replicas from a cluster, select Scale Down.

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When the Scale Down dialog opens, click in the field and select a replica address from the list of replicas. To select more than one replica for removal, click in the field again, and select an additional address. When you’ve finished selecting replicas for removal, click Ok. The server will confirm that you wish to remove the replicas; click OK to continue. An informational popup will confirm when the replica(s) are being removed.

To add more storage space to a cluster, select Scale Up, then Storage.

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When the Scale Up dialog opens, specify the amount of storage (in Gigabytes) that you would like to add to the cluster, and click Ok. The server will confirm that you wish to add the specified storage; click Yes to continue. An informational popup will confirm when the storage is being added.

Scaling a Machine Type

To modify the instance type on which a cluster resides, select Scale Machine Type from the console’s context menu or from the PEM web interface’s Object menu.

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Use fields on the Scale machine type dialog to specify your scaling preferences:

  • The Cluster name field displays the name of the cluster; this field is not modifiable.
  • Move the Perform OS and software update slider to Yes to perform a software update with the cluster is provisioned; this option can be time consuming.
  • Use the Server class drop-down listbox to select the new server class for the cluster.

When you’ve specified your preferences, click Scale to continue. The server will ask you to confirm your changes; click Continue to start the scaling process. An informational popup confirms when the scaling begins.

Upgrading the OS/Software

You can use the Upgrade OS/Software option to invoke a yum update command on each node of your cluster, updating any installed packages to the most recent version available through your specified repositories. To perform an upgrade, select Upgrade OS/Software from the console’s context menu or from the PEM web interface’s Object menu.

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Before initiating an upgrade, PEM will prompt you to confirm that you wish to Continue. Please note that a software update can take some time to complete; we recommend scheduling software updates during a maintenance window. After performing a yum update, the cluster nodes will be rebooted (initiating any kernel updates required).