Fargate with EFS CDK

I struggled WAY too long trying to sort out the permissions for EFS. Turns out, there are 2 layers. The IAM role, and the Posix permissions. Both throw a similar looking access denied. Finally!

Don’t judge me on the single AZ. I am running a single task in Fargate and only need one instance.

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const {vpc, az, region, account} = props;

const fileSystem = new FileSystem(this, 'Efs', {
vpc,
performanceMode: PerformanceMode.GENERAL_PURPOSE,
vpcSubnets: {
subnetType: ec2.SubnetType.PUBLIC,
onePerAz: true,
availabilityZones: [az]
}
});

const accessPoint = new AccessPoint(this, 'AccessPoint', {
fileSystem: fileSystem,
});

const task = new ecs.FargateTaskDefinition(this, 'Task', {
cpu: 256,
memoryLimitMiB: 512
});

const volumeName = 'efs-volume';

task.addVolume({
name: volumeName,
efsVolumeConfiguration: {
fileSystemId: fileSystem.fileSystemId,
transitEncryption: 'ENABLED',
authorizationConfig:{
accessPointId: accessPoint.accessPointId,
iam: 'ENABLED'
}
}
});

const container = task.addContainer('Container', {
image: ecs.ContainerImage.fromAsset('./container'),
portMappings: [{hostPort: 80, containerPort: 80}],
});

container.addMountPoints({
containerPath: '/mount/data',
sourceVolume: volumeName,
readOnly: false
});

task.addToTaskRolePolicy(
new iam.PolicyStatement({
actions: [
'elasticfilesystem:ClientRootAccess',
'elasticfilesystem:ClientWrite',
'elasticfilesystem:ClientMount',
'elasticfilesystem:DescribeMountTargets'
],
resources: [`arn:aws:elasticfilesystem:${region}:${account}:file-system/${fileSystem.fileSystemId}`]
})
);

task.addToTaskRolePolicy(
new iam.PolicyStatement({
actions: ['ec2:DescribeAvailabilityZones'],
resources: ['*']
})
);

I hope this save someone a headache!

Me with a stray cat in Greece 2017

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