Termination Protection and Unhealthy YARN Nodes Amazon EMR periodically checks

Termination protection and unhealthy yarn nodes

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Termination Protection and Unhealthy YARN Nodes Amazon EMR periodically checks the Apache Hadoop YARN status of nodes running on core and task Amazon EC2 instances in a cluster. The health status is reported by the NodeManager Health Checker Service . If a node reports UNHEALTHY , the Amazon EMR instance controller blacklists the node and does 88
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Amazon EMR Management Guide Using Termination Protection not allocate YARN containers to it until it becomes healthy again. A common reason for unhealthy nodes is that disk utilization goes above 90%. For more information about identifying unhealthy nodes and recovering, see Resource Errors (p. 367) . If the node remains UNHEALTHY for more than 45 minutes, Amazon EMR takes the following action based on the status of termination protection. Termination Protection Result Enabled (Recommended) The Amazon EC2 instance remains in a blacklisted state and continues to count toward cluster capacity. You can connect to the Amazon EC2 instance for configuration and data recovery, and resize your cluster to add capacity. For more information, see Resource Errors (p. 367) . Disabled The Amazon EC2 instance is terminated. Amazon EMR provisions a new instance based on the specified number of instances in the instance group or the target capacity for instance fleets. If all core nodes are UNHEALTHY for more than 45 minutes, the cluster terminates, reporting a NO_SLAVES_LEFT status. Important HDFS data may be lost if a core instance terminates because of an unhealthy state. If the node stored blocks that were not replicated to other nodes, these blocks are lost, which might lead to data loss. We recommend that you use termination protection so that you can connect to instances and recover data as necessary. Termination Protection, Auto-Termination, and Step Execution The auto-terminate setting takes precedence over termination protection. If both are enabled, when steps finish executing, the cluster terminates instead of entering a waiting state. When you submit steps to a cluster, you can set the ActionOnFailure property to determine what happens if the step can't complete execution because of an error. The possible values for this setting are TERMINATE_CLUSTER ( TERMINATE_JOB_FLOW with earlier versions), CANCEL_AND_WAIT , and CONTINUE . For more information, see Work with Steps Using the AWS CLI and Console (p. 345) . If a step fails that is configured with ActionOnFailure set to CANCEL_AND_WAIT , if auto-termination is enabled, the cluster terminates without executing subsequent steps. If a step fails that is configured with ActionOnFailure set to TERMINATE_CLUSTER , use the table of settings below to determine the outcome. ActionOnFailure Auto-Termination Termination Protection Result Enabled Disabled Cluster terminates TERMINATE_CLUSTER Enabled Enabled Cluster terminates 89
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Amazon EMR Management Guide Using Termination Protection ActionOnFailure Auto-Termination Termination Protection Result Disabled Enabled Cluster continues Disabled Disabled Cluster terminates
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  • Spring '12
  • LauraParker
  • Amazon Web Services, Amazon Elastic Compute Cloud

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