Friday Tip – AWS ECS container IP’s?

Have you ever had the problem where you quickly need to know what IP does a container use when running in the ECS?

Well, here’s one for that… 

• Upload to your cloudshell. 
• run chmod +x ecs2ip.sh
• then, execute such as ./ecs2ip.sh dev or ./ecs2ip.sh dev 'container-name'

#!/bin/bash

CLUSTER="$1"
SEARCH="$2"

if [ -z "$CLUSTER" ] 
then
    echo "Usage: $0  ['optional search phrase']"
    exit 1
fi

# Change to match your region, or add as an argument... 
REGION=eu-west-1

TASK_ARNS=$(aws ecs list-tasks \
  --cluster "$CLUSTER" \
  --desired-status RUNNING \
  --region "$REGION" \
  --query 'taskArns' \
  --output text)

[ -z "$TASK_ARNS" ] && echo "No running tasks found" && exit 0

printf '%s\n' $TASK_ARNS | xargs -n100 | while read -r CHUNK; do
  aws ecs describe-tasks \
    --cluster "$CLUSTER" \
    --region "$REGION" \
    --tasks $CHUNK \
    --output json \
  | jq -r '
      .tasks[] as $t
      | (
          $t.attachments[]
          | select(.type=="ElasticNetworkInterface")
          | .details[]
          | select(.name=="privateIPv4Address")
          | .value
        ) as $ip
      | $t.containers[].name as $c
      | "container=\($c) ip=\($ip) taskArn=\($t.taskArn)"
    '
done 2>&1 > /tmp/ecslist.txt 

if [ -z "$SEARCH" ]  
then
   cat /tmp/ecslist.txt 
else
   grep "$SEARCH" /tmp/ecslist.txt 
fi

rm /tmp/ecslist.txt

The output would look something like: 

[cloudshell-user@ip-*****~]$ ./ecs2ip.sh dev container-name
container=container-name ip=10.0.0.1 taskArn=arn:aws:ecs:eu-west-1:**************:task/dev/****…***
container=container-name ip=10.0.0.2 taskArn=arn:aws:ecs:eu-west-1:**************:task/dev/****…***

Njoy!