What CLI command will directly pull Transit Gateway route tables so I can get the destinations and attachments?

Question

I was looking through the AWS CLI commands for Transit Gateway and I have settled on 'search-transit-gateway-routes' but I can't tell if that would actually get me the destination and attachments or just the ID of the transit gateway route table.

Do I need to use a filter with it like 'attachment.transit-gateway-attachment-id' or would 'attachment.resource-id' be more useful?

Maybe - aws ec2 search-transit-gateway-routes --transit-gateway-route-table-id tgw-rtb-valuegoeshere --filters "Name=state,Values=active"

I want to be able to create a query that I could use to pull the routes for several Transit Gateway so I could script it instead of manually reviewing things in the console. But I want to be able to actually see the entire route table for the transit gateway via the output.

Accepted Answer

Good answer from Riku_Kobayashi - I'd like to point out one other thing:

When you create a Transit Gateway there is a single route table. But Transit Gateways can have more than one route tables to enabled for attachment traffic separation (think, VRF-Lite in traditional routers).

So the way to see "entire route table for the transit gateway" is to look at all of them, understanding that a route table is associated with an attachment (which you could consider to be a router interface in the traditional sense - VPCs, Direct Connect, VPNs and SD-WAN appliances can all be attachments).

For more information: https://youtu.be/X_4ekgRc4C8?t=710

Answer

Hello.

> I was looking through the AWS CLI commands for Transit Gateway and I have settled on 'search-transit-gateway-routes' but I can't tell if that would actually get me the destination and attachments or just the ID of the transit gateway route table.

An example output is provided in the document below, and the attachment ID, destination CIDR, etc. are output.  
https://awscli.amazonaws.com/v2/documentation/api/latest/reference/ec2/search-transit-gateway-routes.html

In fact, if you run it using the "--filters "Name=state,Values=active"" you're expecting, you'll see output like the one below.  
You can use "--filters "Name=state,Values=active"" to get routes with status "active".  
```
{
    "Routes": [
        {
            "DestinationCidrBlock": "172.31.0.0/16",
            "TransitGatewayRouteTableAnnouncementId": "",
            "TransitGatewayAttachments": [
                {
                    "ResourceId": "vpc-d05042b7",
                    "TransitGatewayAttachmentId": "tgw-attach-1111111111",
                    "ResourceType": "vpc"
                }
            ],
            "Type": "propagated",
            "State": "active"
        }
    ],
    "AdditionalRoutesAvailable": false
}
```

Also, if you want to get a list of TransitGateway route table IDs, you can use "describe-transit-gateway-route-tables" as shown below.  
```
aws ec2 describe-transit-gateway-route-tables --query "TransitGatewayRouteTables"[]."TransitGatewayRouteTableId" | jq -r .[]
```

What CLI command will directly pull Transit Gateway route tables so I can get the destinations and attachments?

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