At runtime, each node is configured the standard environment variables that all AWS Batch jobs receive. In addition, the nodes are configured with the following environment variables that are specific to multi-node parallel jobs:
AWS_BATCH_JOB_MAIN_NODE_INDEX-
This variable is set to the index number of the job's main node. Your application code can compare the
AWS_BATCH_JOB_MAIN_NODE_INDEXto theAWS_BATCH_JOB_NODE_INDEXon an individual node to determine if it's the main node. AWS_BATCH_JOB_MAIN_NODE_PRIVATE_IPV4_ADDRESS-
This variable is only set in multi-node parallel job child nodes. This variable isn't present on the main node. This variable is set to the private IPv4 address of the job's main node. Your child node's application code can use this address to communicate with the main node.
AWS_BATCH_JOB_NODE_INDEX-
This variable is set to the node index number of the node. The node index begins at 0, and each node receives a unique index number. For example, a multi-node parallel job with 10 children has index values of 0-9.
AWS_BATCH_JOB_NUM_NODES-
This variable is set to the number of nodes that you have requested for your multi-node parallel job.
