For App Mesh to work each of your pods needs to have a sidecar. This sidecar handles the network routing and is the point in each of services that helps to enable functionality like the end-to-end observability.
We can manually add the sidecar to each of pods (via Deployments for example). However, this can become quite a maintenance burden and additionally this shouldn’t be a concern of application teams.
Luckily, we can automatically inject the App Mesh sidecar into the pods. Kubernetes has a feature called Dynamic Admission Controllers that allow you to mutate the resources as they are applied to Kubernetes and this can be used to inject the sidecar…..and for this purpose there is the App Mesh Injector.
The AWS App Mesh Injector is also available as a Helm package from the EKS Chart Repository. We will use the Helm Operator along with this chart to install the injector.
Create a new file called appmesh-injector.yaml in the appmesh-system folder. Add the following as contents to the file:
---
apiVersion: helm.fluxcd.io/v1
kind: HelmRelease
metadata:
name: appmesh-inject
namespace: appmesh-system
spec:
releaseName: appmesh-inject
chart:
repository: https://aws.github.io/eks-charts/
name: appmesh-inject
version: 0.9.0
values:
mesh:
create: true
name: apps
This HelmRelease is declaring that we want to create a Helm release for a chart called appmesh-injector with a version 0.9.0 that is available in the EKS chart repository https://aws.github.io/eks-charts/. The name of the release is appmesh-injector.
We are also setting some values within the helm chart. This is equivalent to using a values.yaml value, see the Helm documentation for details of values. By setting these values in our HelmRelease we are stating that we want to create a new mesh called apps.
You folder structure should look like this now:
.
├── appmesh-system
│ ├── appmesh-controller.yaml
│ ├── appmesh-inject.yaml
│ └── crds.yaml
├── namespaces
│ └── appmesh-system.yaml
└── README.md
Add and then commit the appmesh-inject.yaml file and push the the changes to your GitHub repo.
Flux will now see that the desired state of the appmesh-system namespace has changed in Git and will apply the CRDs to our cluster. This will take up to 1 minute to apply.
Check that the App Mesh Injector is up & running by running the following command:
kubectl get pods -n appmesh-system
You should see the injector pod in a Running state:
NAME READY STATUS RESTARTS AGE
appmesh-controller-54dd6bdfd8-n8zlq 1/1 Running 0 30m
appmesh-inject-55cdc99595-qm8pt 1/1 Running 0 17s