Hi, I have the following aws vpc configuration:

export const vpc = new awsx.ec2.Vpc("vpc", {
   numberOfAvailabilityZones: 3,
});

I'm struggling to find a way to grab the private subnet so that I can use it to create an EC2 instance. This is what I came to thus far:

const privateSubnets = pulumi.output(vpc.privateSubnets).apply(
    subnets => subnets.filter(x => x.subnet.availabilityZone == pulumi.output("us-east-1a"))
);

export const server = new aws.ec2.Instance("server", {
    instanceType: aws.ec2.C5InstanceLarge,
    vpcSecurityGroupIds: [ vpc.sgInternal.id ],
    subnetId: privateSubnets.apply(x => x[0].id),
    ami: "ami-;02507631a9f7bc956",
});

I'm getting the following error:

$ pulumi up
Previewing update (xxx):

     Type                 Name                      Plan     Info
     pulumi:pulumi:Stack  xxx           1 error; 5 messages
 
Diagnostics:
  pulumi:pulumi:Stack (xxx):
    TypeError: Cannot read property 'id' of undefined
        at exports.server.aws.ec2.Instance.subnetId.privateSubnets.apply.x (ec2.ts:24:46)
        at OutputImpl.<anonymous> (node_modules/@pulumi/pulumi/output.js:104:47)
        at Generator.next (<anonymous>)
        at fulfilled (node_modules/@pulumi/pulumi/output.js:17:58)

This should work for you:

const server = new aws.ec2.Instance("web-server", {
    // ...
    subnetId: vpc.privateSubnetsIds[0], // reference the subnet created by awsx
});

Will index 0 always be

us-east-1a

?

I believe it will always be the first available zone found, but different accounts have different zones.

my issue here is that I have an EBS volume in AZ

us-east-1a

that I need to attach to the instance. that's why I used a filter on the subnet collection.