zmoog · zmoog · Mar 31, 2022
diff --git a/elastic/how-to-run-the-elastic-agent-with-access-to-ecs-task-metadata-endpoint.md b/elastic/how-to-run-the-elastic-agent-with-access-to-ecs-task-metadata-endpoint.md
@@ -0,0 +1,135 @@
+# How to run the Elastic Agent with access to ECS Task Metadata endpoint
+
+Thanks to [@mtojek](https://github.com/mtojek), I discovered a nice [blog post from AWS](https://aws.amazon.com/blogs/compute/a-guide-to-locally-testing-containers-with-amazon-ecs-local-endpoints-and-docker-compose/) about how to locally testing ECS Local Endpoints.
+
+## Solution A: Toss containers in
+
+Simple solution where we `stack up` the dev environment and toss a couple of carefully crafted containers using `docker run`.
+
+### Start you dev stack
+
+```shell
+$ elastic-package stack up -v -d
+...
+```
+
+### Find the network
+
+The first think is to locate the network used by the stack containers:
+
+```shell
+$ docker network ls
+NETWORK ID     NAME                            DRIVER    SCOPE
+38ee458eed0a   bridge                          bridge    local
+4f60e5ced33a   elastic-package-stack_default   bridge    local <——— 👀
+6e9d2aa908d4   host                            host      local
+32ea7f983e52   none                            null      local
+```
+
+Let's pick the `elastic-package-stack_default` network.
+
+### Add the ECS Task Metadata endpoint
+
+Next, we need to set up an ECS Metadata endpoint in the same way Fargate provides one. We are so lucky today because AWS build one for us, in the form of a Docker image.
+
+Run the `amazon-ecs-local-container-endpoints` image and attach it to the stack network:
+
+```shell
+docker run --rm \
+    --name amazon-ecs-local-container-endpoints \
+    --network elastic-package-stack_default \
+    --volume /var/run:/var/run \
+    -i amazon/amazon-ecs-local-container-endpoints
+```
+
+Let's take a look at this container's detail and take not of the IP address:
+
+```shell
+$ docker inspect amazon-ecs-local-container-endpoints | jq '.[].NetworkSettings.Networks'
+{
+  "elastic-package-stack_default": {
+    "IPAMConfig": null,
+    "Links": null,
+    "Aliases": [
+      "8c250f699e8a"
+    ],
+    "NetworkID": "4f60e5ced33a15babe89ff7620f93715a1c2128a593bac59b279e779371855d3",
+    "EndpointID": "b0e321c7129de8378ffb6c42ae7ec9c6773a51f54b3075eeeb79445842dc0f56",
+    "Gateway": "172.20.0.1",
+    "IPAddress": "172.20.0.4",
+    "IPPrefixLen": 16,
+    "IPv6Gateway": "",
+    "GlobalIPv6Address": "",
+    "GlobalIPv6PrefixLen": 0,
+    "MacAddress": "02:42:ac:14:00:04",
+    "DriverOpts": null
+  }
+}
+```
+
+Nice, the IP address is `172.20.0.4`, let's test if task metadata endpoint is working as expected:
+
+```shell
+$ docker exec -it amazon-ecs-local-container-endpoints /bin/bash
+bash-4.2# curl -i http://172.20.0.4/v3
+HTTP/1.1 200 OK
+Content-Type: application/json
+Date: Wed, 30 Mar 2022 13:27:22 GMT
+Content-Length: 663
+
+{
+  "DockerId": "8c250f699e8a8bc3d692f6c00d00402244859c0de14ef3036f418d3013fffa7f",
+  "Name": "amazon-ecs-local-container-endpoints",
+  "DockerName": "amazon-ecs-local-container-endpoints",
+  "Image": "amazon/amazon-ecs-local-container-endpoints",
+  "ImageID": "sha256:b005329f50b1ae4e79c04aee4f1044ccad484d0c5fa2d3c85e8679729e61e1c1",
+  "Ports": [
+    {
+      "ContainerPort": 80,
+      "Protocol": "tcp"
+    }
+  ],
+  "DesiredStatus": "RUNNING",
+  "KnownStatus": "RUNNING",
+  "Limits": {},
+  "CreatedAt": "2022-03-30T13:24:35Z",
+  "StartedAt": "2022-03-30T13:24:35Z",
+  "Type": "NORMAL",
+  "Networks": [
+    {
+      "NetworkMode": "elastic-package-stack_default",
+      "IPv4Addresses": [
+        "172.20.0.4"
+      ]
+    }
+  ],
+  "Volumes": [
+    {
+      "Source": "/var/run",
+      "Destination": "/var/run"
+    }
+  ]
+}
+```
+
+This is a good thing, the endpoint is able to get a response from the metadata endpoint.
+
+### Enrol an Elastic Agent
+
+Time to run and enrol an Elastic Agent attaching it to the same network the dev stack and the amazon-ecs-local-container-endpoints container are, so it can start collecting and sending data to the dev stack:
+
+```shell
+$ docker run \
+    --rm \
+    --network elastic-package-stack_default \
+    -e FLEET_URL=http://fleet-server:8220 \
+    -e FLEET_ENROLL=true \
+    -e FLEET_ENROLLMENT_TOKEN=YlgyazJuOEJzOVVRTHViRExpUlI6SzhQdDM5QXRSbGlrc0N3Nkg5bkE1Zw== \
+    -e FLEET_INSECURE=true \
+    -e ECS_CONTAINER_METADATA_URI_V4="http://172.20.0.4/v3" \
+    -i docker.elastic.co/beats/elastic-agent:8.1.0
+```
+
+## Solution B: Spin up a docker compose
+
+TBA