injecting "ECS_IMAGE_PULL_BEHAVIOR=prefer-cached" into /etc/ecs/ecs.config

Question

Hello,  
 I have a working managed ComputeEnvironment and I would like to add "ECS_IMAGE_PULL_BEHAVIOR=prefer-cached" into /etc/ecs/ecs.config in order to assure   
 that the container is not reloaded from ECR for each job submit.  
  
 I have tried with the following LaunchTemplate which is defined among other Resources  
 in my cloudFormation file:  
  
 "mwmLaunchTemplate": {  
     "Type" : "AWS::EC2::LaunchTemplate",  
     "Properties" : {  
       "LaunchTemplateData" : {  
       "UserData"       : { "Fn::Base64" : { "Fn::Join" : \["", \[  
         "Content-Type: multipart/mixed; boundary="==MYBOUNDARY=="\n",  
         "MIME-Version: 1.0\n",  
         "\n",  
         "--==MYBOUNDARY==\n",  
         "Content-Type: text/x-shellscript; charset="us-ascii"\n",  
         "MIME-Version: 1.0\n",  
         "Content-Transfer-Encoding: 7bit\n",  
         "\n",  
         "#!/bin/bash\n",  
         "echo "ECS_IMAGE_PULL_BEHAVIOR=prefer-cached" >> /etc/ecs/ecs.config\n",  
         "\n",  
         "--==MYBOUNDARY==--"  
        ]]}}  
        }  
      }  
}  
  
The stack creation fails (rolling back without any message) if I am using mwmLaunchTemplate inside of my ComputeEnvironment:  
  
"mwmComputeEnvironment": {  
    "Type": "AWS::Batch::ComputeEnvironment",  
    "Properties": {  
      "Type": "MANAGED",  
       ...  
       ...  
        "launchTemplate": {  
            "LaunchTemplateId" : {"Ref": "mwmLaunchTemplate"}  
        },  
      }  
      ....  
 }  
  
mwmComputeEnvironment works well without the three lines:  
        "launchTemplate": {  
            "LaunchTemplateId" : {"Ref": "mwmLaunchTemplate"}  
        },

Thanks for your attention  
Walter Steffe

Answer

Hello,  something changed in AWS batch since my previous post.  
  
Today I retried to create my stack with the LaunchTemplate inside of the AWS::Batch::ComputeEnvironment. This time I got an error message referring to the raw:  
"launchTemplate": {"LaunchTemplateId" : {"Ref": "mwmLaunchTemplate"}},  
  
So I understood that there was a case error: I should have written "LaunchTemplate": (with initial uppercase).  
  
In the meantime I have also corrected the LaunchTemplate definition which now is:  
    "mwmLaunchTemplate": {  
     "Type" : "AWS::EC2::LaunchTemplate",  
     "Properties" : {  
       "LaunchTemplateData" : {  
       "UserData"       : { "Fn::Base64" : { "Fn::Join" : \["", \[  
         "MIME-Version: 1.0\n",  
         "Content-Type: multipart/mixed; boundary="==MYBOUNDARY=="\n",  
         "\n",  
         "--==MYBOUNDARY==\n",  
         "Content-Type: text/x-shellscript; charset="us-ascii"\n",  
         "\n",  
         "#!/bin/bash\n",  
         "echo ECS_IMAGE_PULL_BEHAVIOR=prefer-cached >> /etc/ecs/ecs.config\n",  
         "\n",  
         "--==MYBOUNDARY==--"  
        ]]}}  
        }  
      }  
    },  
  
After that the creation of my Batch Environment went well without any error.  
  
Regars  
Walter Steffè

injecting "ECS_IMAGE_PULL_BEHAVIOR=prefer-cached" into /etc/ecs/ecs.config

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